Fluoride contamination in groundwater resources of Alleppey southern India

Contamination of groundwater under cultivated fields in an arid environment,central Arava Valley,IsraelO.Oren a,*,Y.Yechieli a,1,J.K.Bo¨hlke b,2,A.Dody c,3aGeological Survey of Israel,30Malchei Yisrael Str.,Jerusalem 95501,IsraelbUSGS,431National Center,Reston,VA 20192,USA cNRCN,POB.9001,Beer Sheva 84190,IsraelReceived 7May 2003;revised 5December 2003;accepted 10December 2003AbstractThe purpose of this study is to obtain a better understanding of groundwater contamination processes in an arid environment (precipitation of 50mm/year)due to cultivation.Additional aims were to study the fate of N,K,and other ions along the whole hydrological system including the soil and vadose zone,and to compare groundwater in its natural state with contaminated groundwater (through the drilling of several wells).A combination of physical,chemical,and isotopic analyses was used to describe the hydrogeological system and the recharge trends of water and salts to the aquifers.The results indicate that intensive irrigation and fertilization substantially affected the quantity and quality of groundwater recharge.Low irrigation efficiency of about 50%contributes approximately 3.5–4million m 3/year to the hydrological system,which corresponds to 0.65m per year of recharge in the irrigated area,by far the most significant recharge mechanism.Two main contamination processes were identified,both linked to human activity:(1)salinization due to circulation of dissolved salts in the irrigation water itself,mainly chloride,sulfate,sodium and calcium,and (2)direct input of nitrate and potassium mainly from fertilizers.The nitrate concentrations in a local shallow groundwater lens range between 100and 300mg/l and in the upper sub-aquifer are over 50mg/l.A major source of nitrate is fertilizer N in the excess irrigation water.The isotopic compositions of d 15N–NO 3(range of 4.9–14.8‰)imply also possible contributions from nearby sewage ponds and/or manure.Other evidence of contamination of the local groundwater lens includes high concentrations of K (20–120mg/l)and total organic carbon (about 10mg/l).q 2004Elsevier B.V.All rights reserved.Keywords:Groundwater;Arid environment;Nitrate;N isotope;Contamination;Agriculture1.IntroductionGroundwater is a significant or sole source of waterin arid areas.Contamination of groundwater due to agricultural activities could therefore severely endan-ger survival in these harsh environments.This contamination is usually expressed in increasing salinity and nitrateconcentrations.*Corresponding author.Tel./fax:þ972-2-5380688.E-mail addresses:orly.oren@.il (O.Oren),yechieli@.il (Y.Yechieli),jkbohlke@ (J.K.Bo¨hlke),dodik@bgumail.bgu.ac.il (A.Dody).The quantities and qualities of the recharge water substantially influence the pumping potential from the aquifers in arid environments.The natural source is limited to infiltration duringfloods,which are characterized by low frequency and irregularity (Simmers,1997).The anthropogenic sources may be excess of irrigation water and leakage from sewage ponds.Agriculture has had profound effects on the rates and compositions of groundwater recharge (Albus and Knighton,1998;Rodvang and Simpkins, 2001;Bo¨hlke,2002).The effects of irrigation and fertilization in arid zones could be:(1)salinization of the soil and groundwater below thefields(Stigter et al.,1998) and(2)increase of nitrate concentrations in ground-water(Singh et al.,1995;Oenema et al.,1998; Allaire-Leung et al.,2001).Irrigation in arid zones causes an increase of the salt concentrations in the root zone due to high evapotranspiration.In order to minimize soil salinization,excess amounts of water are required,much beyond that needed by the crops (Rhoads and Loveday,1990).The excess water causes the leaching of the salts to the groundwater.Hence,the presence of agricultural activities introduces a long-term risk of groundwater pollution by excess fertili-zers,salts and pesticides leached downward(Hadas et al.,1999).The fertilization efficiency(the fraction of applied N that is taken up by plants)in the study area was estimated to be about50%(Bar-Yosef et al., 1982).The average annual amount of applied N in the study area is55g/m2.Converting half of this amount to nitrate yields a potential annual nitrate load in recharging groundwater of approximately120g/m2.Agricultural activities,especially cultivation and fertilization,are principal causes of nitrate contami-nation on a regional scale(Hudak,2000;Nolan, 2001).Nitrate is very mobile in groundwater and tends not to adsorb or precipitate on aquifer solids (Hem,1985).High concentrations of nitrate constitute a health hazard and the American standard for drinking water is45mg/l NO3(EPA,1996).Agricultural application of K and P as plant nutrients commonly has less of a signature in groundwater(Bo¨hlke,2002).The fate of K is determined in part by ion exchange and sorption by clays hence K enrichment in groundwater is sporadic. P is sorbed strongly onto solid phases,hence no high values occur in groundwater.The purpose of this study is to obtain a better understanding of contamination processes of ground-water related to agriculture activity in an extremely arid environment.The word‘contamination’as used by Freeze and Cherry(1979)implies that human activities have increased the concentration of a constituent,though not necessarily harmful.Additional aims were to study the fate of N,K,and other ions along the whole hydrological system including the soil and vadose zone,to compare groundwater in its natural state with contaminated groundwater(through the drilling of several wells),among others,and to demonstrate the use of the15N isotope in nitrate.A combination of physical,chemical and isotopic analyses was used to explain the hydrological system and the trends of water and salt recharge.2.Study areaThe central Arava Valley is located in the southern part of Israel(Fig.1).The valley is drained to the north by Wadi Arava,which drains wadis from the east(Edom Mountains)and the west(Negev moun-tains)toward the Dead Sea.The area is characterized by desert climate.The average yearly precipitation is50mm and the potential evaporation exceeds3000mm.The average yearly temperature is258C.In the area there are several rural settlements with cultivatedfields totaling18km2.Groundwater is the only source of water for the settlements.Since the 1960s agriculture developed above the formations of the upper aquifers,which contained in the past fresh water of good quality.Eighty percent of the irrigation and drinking water is drawn from the upper aquifers of the Hazeva and Arava formations and the other20%is drawn from deep aquifers,mainly from the Lower Cretaceous sandstones of the Kurnub Group(Yechieli et al.,1992;Naor and Granit,2000).The water from different wells mix before they reach thefields.Over the years,increases in the salt concentrations,and especially nitrate were observed in the groundwater (Naor and Granit,2000).The research focused on thefields around the En Yahav settlement as a representative case.This settlement was thefirst(founded in1967)and is the biggest,with a cultivated area of5.6km2.It was,O.Oren et al./Journal of Hydrology290(2004)312–328313O.Oren et al./Journal of Hydrology290(2004)312–328314Fig.1.Location map of the study area in the central Arava Valley.Coordinate in ITM grid.therefore,expected that contamination processes would be most notable there.3.The hydrologic systemThe upper aquifers include the Neogene Hazeva and the Plio-Pleistocene Arava formations.The Hazeva formation consists mainly of alternating clay and sand beds forming sub-aquifers of limited areal extension due to frequent lateral lithological changes.It is overlain by the Plio-Pleistocene Arava fill aquifer consists of coarse clastic alluvial zones (Yechieli et al.,1992).Fig.2shows the typical field relations inthe area.The general direction of groundwater flow is NNE,toward the Dead Sea.The aquifer in the study area is divided by clay layers into two main sub-aquifers (Fig.3).The lower one is confined whereas the upper is a semi-confined aquifer.The hydraulic head of the upper sub-aquifer is about 2–10m higher than that of the lower one.Near the surface,at a depth of 2–5m there is a shallow groundwater lens that forms a perched aquifer (Fig.3)extending over an area of at least 2.5km 2.The hydraulic head of the perched aquifer is at least 2m higher than that of the upper sub-aquifer.The groundwater level measurements indicate that the flow direction of all three aquifer units is to the NNE.4.Agricultural activityThe cultivation of the fields in the Arava Valley began in the late 1960s,and the area has evolved into an advanced technological center of agriculture.Agriculture is based on intensive irrigation and fertilization to improve the soils.In recent years most of the fields have been covered with green-houses.The crops include mainly seasonal crops such as vegetables and flowers but also palmplantationsFig.2.Generalized stratigraphic column with indication of the main investigatedaquifer.Fig.3.Schematic geohydrological cross-section in the study area.O.Oren et al./Journal of Hydrology 290(2004)312–328315and vineyards.The growing season extends generally 10months a year.The irrigation regime begins with washing the soils by sprinklers with50m3of water per1000m2of land, equivalent to50mm/year.After that,the irrigation is accomplished by dripping.The entire amount of irrigation water ranges between1000and1500m3per 1000m2/year(1000–1500mm/year)depending on the crop type.The total amount of irrigation water is 7.5–8million m3/year.The fertilizers comprise three major nutrients: nitrogen,phosphorus,and potassium.The amounts applied average around50–60g N,5–6g P and40g K per m2/year,respectively.Moreover,at the beginning of the season,the farmers fertilize the fields with cattle manure,which adds about20g N, 10g P and20g K per m2.5.Methodology5.1.Unsaturated zoneSoil profiles were sampled to a depth of2–3m in cultivatedfields,in theflood channel of Wadi Arava, and in undisturbed natural soils.The samples were collected at intervals of20cm.Salts were extracted from the soil samples by drying the soil at1058C,sifting it with a2mm sieve to remove the large fractions,dividing the sample randomly by splitter,dissolving the salts with distilled water by shaking for4h(approx,water/soil ratio¼10,by weight),andfiltering the solution before the chemical analysis.The concentrations represent both the dissolved salts in1kg soil and the salts in the soil water.Irrigation water(in text ‘irrigation’)and irrigation water to which fertilizer has been added(in text‘irrigationþfertilizer’)were sampled in the cultivatedfields and analyzed.Ceramic cups were used to sample the water in and below the root zone of cultivatedfields.The sampler is a cylindrical ceramic chamber,6cm long with an external diameter of2cm and inner diameter of1.7cm;it has a maximum pore size of2–3m m. The ceramic cup is attached to a PVC pipe and the opposite end is sealed with a one-hole stopper with tubing and clamp so that air can be evacuated from the sampler.The buried porous cup collects a sample of soil water when the vacuum in the sampler exceeds the adjacent soil moisture tension(Hansen and Harris,1975).Nine samplers were inserted in the soil in three different greenhouses,and in each one,at different soil depths—20,40–60,80–120cm.Samples were collected every few days during the agriculture season.5.2.Saturated zoneEighteen shallow boreholes(2.5–5m depth)were drilled to the local groundwater lens between June and August2001(Fig.1).Anotherfive deeper boreholes were drilled in June2002to the local lens and to the upper sub-aquifer,at the center of the lens and at an upgradient location south of thefields (Arava22well).Groundwater was also sampled from pumping wells located at three sites near thefields(Fig.1);at every site there were two wells,one extracting from the upper sub-aquifer and the other from the lower sub-aquifer.The‘unpolluted wells’are wells that extract water from the same regional aquifer,some kilometers from the agricultural area and have low salt concentrations,similar to the natural composition before the settlement was built.Throughout the year(June2001–August2002)all the observation and pumping wells in the study area were sampled several times,and temperature and electrical conductivity were measured.Water levels in the shallow observation boreholes were measured regularly every2–3weeks.5.3.Chemical and isotopic analysesThe chemical analyses and d18O analyses in water were conducted at the Geological Survey of Israel. Major cations were analyzed on a Perkin Elmer Optima3300ICP AES.Anion concentrations were measured using a Dionex Series4000I Gradient Ion Chromatography and HPLC.Only analyses with charge balance,3%were used in this study.Oxygen isotope analyses of water were done by the VG SIRA II IRMS mass spectrometer with an analytical error of0.1‰.Tritium concentrations were determined at the Weizmann Institute following enrichment usingO.Oren et al./Journal of Hydrology290(2004)312–328 316an electrolysis system,by a low-level counting system,LKB1220Quantulus scintillation counter (Bowman and Hughes,1981).Tritium concentrations are expressed in Tritium Units(TU)with an analytical error of^0.2TU.Isotopic analyses of nitrogen(d15N)in nitrate were done at the USGS laboratory in Reston,Virginia. Nitrate samples and standards were prepared by freeze-drying and off-line combustion techniques for mass spectrometry,and the data were normalized to values ofþ0.4‰for IAEA-N1andþ180‰for USGS-32(Bo¨hlke and Denver,1995;Bo¨hlke and Coplen,1995;Bo¨hlke et al.,2002),with average reproducibility of^0.1to0.2.Analyses of total organic carbon(TOC)were done at the laboratory of the Israeli Ministry of Health.The analysis is based on the combustion-infrared method (Eaton et al.,1995),performed by the TOC analyzer, 5000A,Shimadzu.The precision of the method limits is5–10%.6.ResultsThe chloride,sulfate,and nitrate content in the soil profiles of natural soil,cultivatedfields,and Wadi Arava(profiles A,C,D,respectively,Fig.1)are presented in Fig.4.The ionic concentrations are expressed in g/kg-dried soil.The ion concentrations in the natural soil are two orders of magnitude higher than the concentrations in the cultivatedfields and Wadi Arava.The chloride and sulfate concentrations in the natural soil are around10g/kg while in the other profiles the chloride concentrations are below0.1g/kg and the sulfate concentrations are around 0.1g/kg.The nitrate concentration in the natural soil is about1g/kg while in the cultivatedfields and Wadi Arava it is around0.01g/kg.Some of the excavations in the cultivatedfields had water of the shallow lens at a depth of2–3m and their profiles were quite wet.The water table depth of the shallow lens rises by about30–40cm during the irrigation season,from September to March(Fig.5)and then drops again till August.Chemical and isotopic analyses of selected samples of irrigation water,irrigationþfertilizer water,soil water in and below the root zone(ceramic cups),and groundwater from the three sub-aquifers are presented in Table1.When plotting concen-trations of several ions versus Cl,the groundwater samples show a mixing line between groundwater from the local lens,which is highly contaminated,and groundwater from the lower sub-aquifer,which is mainly uncontaminated(Fig.6).The upper sub-aquifer is less contaminated and has intermediate values.In the upper sub-aquifer the salt concen-trations in the upgradient wells are lower than those of the downgradient wells(Table1).The Cl,SO4and other ionic concentration values of the water from the ceramic cups are in the same range as the local lens values.The irrigationþfertilizer water have the same concentrations of Cl,SO4,Mg,Na,Ca as theirrigation Fig.4.Ions profiles(Cl,SO4and NO3)in the unsaturated zone of the study area:in undisturbed natural soil(A),a cultivatedfield(C)and in Wadi Arava(D)(locations in Fig.1).O.Oren et al./Journal of Hydrology290(2004)312–328317water but much higher concentrations of NO 3and K (Figs.6and 7,Table 1).The nitrate and chloride concentrations over a period of about 13years in three boreholes located at the southern side of the fields are presented in Fig.8.In the lower sub-aquifer (Marzeva 9),the nitrate and chloride concentrations are low and have been constant over the years.The nitrate concentrations are lower than 10mg/l and the chloride concentrations are about 250mg/l.In contrast,in Marzeva 10and 4,which extract water from the upper sub-aquifer,concentrations are higher and have increased for nitrate over the years,mainly since 1999.The chloride concentrations in Marzeva 4have also increased (corresponding with the nitrate increase)but in Marzeva 10,variations of the chloride concentrations were found.Fig.9presents the nitrate concentration ranges in the three aquifer units and in the ceramic cups.The nitrate values of the ceramic cups have the largest range,between 150and 700mg/l,depending on the fertilization efficiency and the variability in the soil.The nitrate concentrations in the local lens,between 100and 300mg/l,far exceed the standard for drinking water.The range in the lower sub-aquifer,between 5and 35mg/l,reveal the presence of nitrate at deeper groundwater levels.The potassium concentrations in the three aquifer units and in the ceramic cups are presented in Fig.10.There is a large variability of the potassium concentration in the ceramic cups and in the lens close to the surface.Another component with relatively high concen-trations in the local lens is the TOC.The TOC values in the groundwater in the local lens are around 10ppm while in the unpolluted wells they are about 0.4ppm (Table 1).Water in one of the boreholes to the local lens (Arava 16)has a value of about 200ppm,which probably represents a local source of organic matter.It also has exceptionally high concentrations of salts,TDS around 30,000mg/l,therefore it is not rep-resented as a sample of the local lens in Figs.6–7,9,and 10.The TOC value in the upper sub-aquifer is little higher than in the unpolluted wells;values of 0.6–0.8compared to 0.4ppm.The isotopic values of d 18O of the groundwater ranged between 24.3and 25.2‰(Table 1),similar to values found in former works,e.g.Gat and Galai (1982).The isotopic composition of nitrogen in nitrate was also measured in some of the samples (Table 1).The unpolluted wells,with low concentration of nitrate (below 10mg/l),have d 15N values of 6.7and 7.0‰.Nitrate leached from the virgin natural soilhasFig.5.Variation in water levels in selected boreholes of the shallow lens.Values of the water table are relative to the first measurement.O.Oren et al./Journal of Hydrology 290(2004)312–328318somewhat higher d 15N values of 9.5and 12.0‰.This overall range of values (,7–12‰)is considered most likely to represent natural nitrate derived fromsoil organic matter (Densmore and Bo¨hlke,2000).In contrast,the fertilizer nitrates have d 15N values close to zero (0.9and 2.7‰)and nitrate in the drainage water from the root zone (ceramic cups,20–40cm depth)has an isotopic composition similar to that of the fertilizers used above (Table 1).The polluted boreholes have a wide range of d 15N values,between 4.9and 14.8‰.The boreholes upgradient from the sewage ponds (Fig.1)have lower values (4.9–6.2‰)than the natural nitrate,while the downgradient boreholes have d 15N values in the range of 5.5–14.8‰,some of which are higher than the values in unpolluted wells.There is no clear relation between d 15N values and either nitrate or chloride concentrations (Fig.11).7.DiscussionThe results of this study indicate that intensive irrigation in an arid environment significantly affects the groundwater recharge.Low irrigation efficiency contributes large additions of water to the hydro-logical system.The recharge coefficient of the irrigation water was estimated from the salt concen-tration factor.This was calculated by dividing the ion concentration in the local groundwater lens by the ion concentration in the irrigation water.The calculation was made only for ions that are considered con-servative and not uptaken by plants.Almost the same factor,of about 2.2,was found for Cl,Na,Mg and Sr,indicating that 55%of the water is lost by evapo-transpiration and the rest 45%infiltrates towards the groundwater.This means that from the 7.5–8million m 3of irrigation water per year,about 3.6million m 3infiltrates every year.Within the irrigated area,this is equivalent to about 0.65m per unit area.The infiltrating water from the fields is expected to raise the water table level.Indeed,there is a rise in the water table of the local lens of about 30–40cm from September to March (Fig.5).Although,this rise is much smaller than the expected value, 1.3m in September–March (calculation was done by dividing the excess irrigation water by porosity),it can be explained by down flow of 70%of the rechargeT a b l e 1(c o n t i n u e d )N a m eD e s c r i p t i o nD a t eN a (m g /l )K (m g /l )C a (m g /l )M g (m g /l )C l (m g /l )S O 4(m g /l )H C O 3(m g /l )N O 3(m g /l )B r (m g /l )S r (m g /l )T D S (m g /l )T O C (m g /l )d 15N N O 3(‰)d 18O H 2O(‰)T r i t i u m (T U )N a /C l (e q ./e q .)K /C l (e q ./e q .)N O 3/C l (e q ./e q .)H a z e v a 15U n p o l l u t e d w e l l14/10/011679156702504352444,1.04.513407.01.030.030.01H a z e v a 13a 14/10/011649146702404402567,1.04.413366.71.050.030.02H a z e v a 1708/04/0224810192101422587245102.65.918230.4b0.910.020.01J -38s o i l ,A p r o fil e eN a t u r a l s o i l25/06/0170131211702,0.020.07619.50.01,0.010.07O -96s o i l ,B p r o fil e e18/07/01160702323010.037012.00.01,0.010.017-1-7F e r t i l i z e r s18/09/01172712.76-6-618/09/01203710.9aO -18s a m p l e d a t 6/12/01.bT O C s a m p l e d a t 8/4/02.cO -18s a m p l e d a t 10/9/01.4O -18a n d T r i t i u m s a m p l e d a t 18/6/01.eS a l t c o n c e n t r a t i o n s i n g r /k g d r y s o i l .O.Oren et al./Journal of Hydrology 290(2004)312–328320O.Oren et al./Journal of Hydrology290(2004)312–328321Fig.6.SO4,Mg,and NO3concentrations versus Cl concentrations for several water types(aquifers).Note that Cl,Mg,and SO4concentrationslens.fall on a mixing line between the lower sub aquifer,through the upper sub aquifer,and the local Array Fig.7.Ion equivalent ratios versus Cl concentrations for several water types(aquifers).amount towards the upper sub-aquifer.The water level drop from April to August can be explained by decrease of the irrigation amounts and increase of the evapotranspiration rate.The water level decrease means that the recharge rate is less than the downward flow rate from the local lens to the upper sub-aquifer.The dependence of the water table on irrigation activity indicates that this is the main recharge source to the local lens.The natural recharge from floods depends on the rainfall in the whole basin each year.However,it is difficult to estimate how much water reaches the water table from this source.The natural recharge seems negligible in comparison to the recharge from irrigation,at least in the period from September 2001to November 2002.In that period only two flash floods crossed the study area in Wadi Arava for about 24–36h,above and along-side the shallow boreholes.According to the small decrease in groundwater temperature and to the temporary water level rise below the stream in the second flow,it seems that waters from the floods reached the water table,but their contribution,relative to the recharge from irrigation,was insignificant.Recharge from excess irrigation water was also found to be most significant in Sacramento Valley,California (80%of the recent recharge,Criss and Davisson,1996).Fig.8.Nitrate and chloride concentrations in the years 1987–2002in three wells:Marzeva 10and 4,upper sub-aquifer;Marzeva 9,lowersub-aquifer.Fig.9.Nitrate concentration ranges and average (squares)of the three aquifer units,unpolluted wells and ceramic cups.O.Oren et al./Journal of Hydrology 290(2004)312–328322Fig.11.d 15N values against NO 3and Cl of selected samples.The ion concentrations of the soils cannot be expressed in mg/l so they are out of the scale.Line A represents a hypothetical mixture between natural groundwater and excess “irrigation þfertilizer”water,and line B represents a hypothetical mixture between natural groundwater and sewage or manure source.O.Oren et al./Journal of Hydrology 290(2004)312–328323The tritium concentrations also confirm that the main recharge comes from irrigation water,whose source is regional groundwater,and not from the floods.This is indicated by low tritium concentration in the shallow groundwater in the studied area(e.g.0.5–1.3TU in the local lens),which is similar to the values in the regional aquifers(Yechieli et al.,1997) but different from those in modernflood waters (4.1–6TU,Yechieli et al.,2001).Unlike the tritium,the stable isotopic composition of the water does not help to distinguish between the recharge sources.According to Yechieli et al.(2001) the d18O values of the rains in the Arava Valley ranges between22.8and27.5‰(average of 24.9‰)and those of thefloods,between25.1and 26.6‰.These values are close to the values of the irrigation and ceramic cups waters that were measured in this work(25.3to25.9‰).Therefore,the different sources cannot be distinguished by the d18O composition.The somewhat higher d18O values of the local lens (24.3to4.9‰)related to the recharge sources may indicate some evaporation during infiltration in the unsaturated zone.The correlation between d18O values and Cl,SO4and NO3concentrations(Oren, 2003)may indicate recharge of evaporative irrigation water,such as found in the Sacramento Valley by Davisson and Criss(1993).In the cultivatedfields and Wadi Arava there is a flushing process,indicated by the low salt concen-trations in the soil profiles,while in the undisturbed natural soil there is a salt accumulation process (Fig.4).Displacement of the salt below2–2.5m in the cultivatedfields proves that the water infiltrates below this level towards the water table.Under a significant part of thefields,the shallow water table of the local lens is located2–5m below the surface; hence the salts reach the groundwater rapidly.It is, therefore,reasonable to maintain that irrigation water recharges the groundwater.The presence of salts, including gypsum and halite near the surface in the undisturbed natural soil,is typical in arid regions, whereflushing by rain is negligible.The effect of salinization in the Arava Valley due to recharge by excess irrigation water was previously reported in several preliminary works(Naor and Granit,1991,2000).The results of the present study indicate that intensive irrigation and fertilization significantly affect the groundwater quality by two main contamination processes:(1)salinization due to circulation of salts dissolved in the irrigation water itself,mainly chloride,sulfate,sodium and calcium, and(2)direct input of nitrate and potassium from fertilizers and sewage ponds.The behavior of the main ions in the irrigation water(e.g.chloride,sulfate,magnesium,sodium and calcium)is conservative,while the fertilizer ions (nitrate and potassium)concentrations are reduced because they are uptaken by plants.Whereas the salt concentration factor due to evapotranspiration of the ‘irrigationþfertilizers’water is about 2.2,the nitrate and potassium concentration factors are less than1(0.7and0.5,respectively).This difference is consistent with selective uptake of nitrate and potassium by plants and also potassium sorption by clays.One of the most important problems related to irrigation in arid zones,where groundwater tends to be brackish or saline,is the recycling of salts.Salts in groundwater that is used for irrigation penetrate to the aquifer system again after evapotranspiration with higher concentration.The major salts are not taken up substantially by plants and therefore eventually reach the water table.It is possible to estimate the salt mass addition by multiplying the chloride concentration in the irrigation water(370mg/l)and the irrigation water volume(about1.4m3/m2),yielding about520g/m2of chloride per year.A similar calculation yields an addition of280g/m2sodium,740g/m2sulfate and 280g/m2calcium per year.The same process of salt circulation was found in a semi-arid area in Portugal, where the excess evaporative irrigation water caused chloride concentration increase,ion exchange and calcite precipitation(Stigter et al.,1998).These hydrochemical processes and possibly also dissol-ution might occur in the case herein too,but are not very significantThe inverse relation between the depth of the aquifer units and the ion concentrations indicates that the contamination comes from the surface.This conclusion can be shown from the linear mixing lines between the major ions in the sub-aquifers(Fig.6). The lower sub-aquifer is interpreted to represent mainly natural water fromfloods,whereas in the groundwater closer to surface,the contaminant component is higher.O.Oren et al./Journal of Hydrology290(2004)312–328 324。

Introduction付会杰11210381.W hat is water pollution?Water pollution is an undesirable change in the state of water, contaminated with harmful substances. Any change in the physical, chemical, and biological properties of water that has a harmful effect on living things is called water pollution.2.T he general seriousness.The earth is a beautiful planet whose surface is covered by 73% of water. According to a survey in 2010, everyday around the earth, there are about 500 billion ton of polluted water running into rivers or oceans without any solution. In the most recent national report on water quality in the United States, 45 percent of assessed stream miles, 47 percent of assessed lake acres, and 32 percent of assessed bays and estuarine square miles were classified as polluted. It has been suggested that water pollution is the leading worldwide cause of deaths and diseases and that it accounts for the deaths of more than 14,000 people daily. An estimated of 580 people in India die of water pollution related sickness every day. Some 90% of China's cities suffer from certain degree of water pollution, and nearly 500 million people lack access to safe drinking water. According to a survey by the World Health Organization, over 20% of people in the world have no access to suitable drinking water, nearly 50% of people are drinking water that contain chemical or physical elements, and 80% of diseases and 30% of death rate are related to water pollution.Basic Types of Water Pollution郭美燕1121036Water pollution can be divided into different types, in the following part, I will introduce you the 7 types of water pollution.1.S urface Water PollutionSurface water pollution is the most visible form of pollution and we can see it floating on our waters in lakes, streams, and oceans.Trash from human consumption, such as water bottles, plastics and other waste products, is most often evident on water surfaces.This type of pollution also comes from oil spills and gasoline waste, which float on the surface and affect the water and its inhabitants.2. Groundwater PollutionThis type of pollution is becoming more and more relevant because it affects our drinking water and the aquifers below the soil.Groundwater pollution is usually caused by highly toxic chemicals and pesticides from farming that leak through the ground to contaminate the wells and aquifers below the surface.3. Microbial PollutionMicrobiological pollution is the natural form of water pollution that is caused by microorganisms in uncured water. Most of these organisms are harmless but some bacteria, viruses, and protozoa can cause serious diseases such as cholera and typhoid.This is a significant problem for people in third world countries who have no clean drinking water and/or facilities to cure the water.4. Oxygen Depletion PollutionMicroorganisms that thrive in water feed on biodegradable substances.When there is an influx of biodegradable material from such things as waste or erosion from farming, the numbers of these microorganisms increase and utilize the obtainable oxygen.When these oxygen levels are depleted, harmless aerobic microorganisms die and anaerobic microorganisms thrive. Some of these organisms produce damaging toxins like sulfide and ammonia.5. Nutrient PollutionNutrients are usually found in wastewater and fertilizers. These can cause excess vegetation in the water such as algae and weeds, using up the oxygen in the water and hurting the surrounding marine life and other organisms in the water.6. Suspended Matter PollutionThis type of pollution occurs when pollutants enter the water and do not mix in with the water molecules.These suspended particles form fine silt on the waterbed, harming the marine life by taking away the nutrients and disturbing their habitat.7. Chemical PollutionDue to the nature of industry these days and the mass production in industrial plants and farms, we have a lot of chemical run-off that flows into the nearby rivers and water sources.Metals and solvents flow out of factories and into the water, polluting the water and harming the wildlife. Pesticides from farms are like poison to the wildlife in the water and kill and endanger the aquatic life.If birds or humans eat these infected fish, the toxins are transferred to us and we swallow these dangerous pesticides and toxins, affecting our health.Petroleum is a different type of chemical pollutant that dramatically affects the aquatic life. This oil kills the fish and marine life and sticks to the feathers of birds, causing them to lose their ability to fly.Consequences钟文静1121042water pollution is very harmful to water life, animals and humans. The effects can be catastrophic, depending on concentrations of the pollutants, the kind of chemicals and where there are polluted. Below, we will see a summary of the effects of water pollution.Effect on environmentThe main problem caused by water pollution is that it kills life that depends on these water bodies. Dead fish, birds, crabs and dolphins, sea gulls and many other animals often wind up on beaches, killed by pollutants in their habitat.One of the very important pollutants is oil. Oil spills in the water causes animalto die when they ingest it or encounter it. Oil does not dissolve in water so it causes suffocation in fish and birds. For example， in 2011，sixty-seven bottlenose dolphins washed up on Gulf beaches and more than half are babies. Scientists determined that there's a link between Gulf of Mexico oil spill and a spike in dolphin deaths along the Gulf Coast.From these problem we can see that ecosystems can be severely changed or destroyed by water pollution. Many areas are now being affected by careless human pollution, and this pollution is coming back to hurt humans in many ways.Effect on humansPollution can disrupts the natural food chain. Pollutants such as lead and cadmium are eaten by tiny animals. Later, these animals are consumed by fish and shellfish, and the food chain continues to be disrupted at all higher levels. At last, humans are affected by this process.According to Global Environment Outlook 4, Three million people die from water-borne diseases each year in developing countries, the majority of whom are children under the age of five. Pollutants of primary concern include microbial pathogens and excessive nutrient loads. Water contaminated by microbes remains the greatest single cause of human illness and death on a global scale.Fluoride contamination of groundwater has been a cause of concern for a long time. Excessive intake of groundwater with large amount of fluoride leads to dental fluorosis, fluorosis of bones, and metabolic alterations in the body tissues.Arsenic contamination causes vomiting, nausea, diarrhea, and in extreme cases, skin and lung cancer.Cadmium is a metal found in sludge-derived fertilizers. This can be absorbed by crops. When people ingest cadmium, it may cause diarrhea, liver, and kidney damage. Heavy metals, like mercury, arsenic, and lead are toxic, and can lead to a fall in the hemoglobin levels, along with headache, abdominal pain, and problems of theendocrine system.Case study - The Minamata DiseaseMinamata disease is a neurological syndrome caused by severe mercury poisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of vision, and damage to hearing and speech. In extreme cases, insanity, paralysis, coma, and death follow within weeks of the onset of symptoms. Minamata disease was first discovered in Minamata city in Kumamoto prefecture, Japan, in 1956. It was caused by the release of methylmercury in the industrial wastewater from the Chisso Corporation's chemical factory, which continued from 1932 to 1968.(The Chisso factory and its wastewater routes)Methyl mercury flew out with the waste water from Chisso plant, was taken through the surface of plankton or through the bill of fishes into their bodies. This phenomenon is called “Biological concentration”. Plankton with methyl mercury was eaten by a small fish, and then the small fish was eaten by a big fish, and the big fish was eaten by bigger one, and so on. This relation is what we just mentioned the“Food Chain” . And the bigger the fish was, the more methyl mercury was accumulated in the body of the fish. Look at the chart 1. There were extremely polluted fishes, which looked normal at first sight, in Minamata bay and the neighboring sea. People had kept on eating many fishes without knowing that the fishes had been polluted. And finally they had gotten Minamata disease.(chart 1)As of April 30, 1997, the number of people in Kumamoto and Kagoshima prefectures who had applied for certification as Minamata disease victims numbered more than 17,000. Of these 2,265 ( of which 1,484 have passed away by January 31, 2003 )were certified by the government. Moreover, there are 11,540 persons set as the object of the Minamata disease synthesis measure medical enterprise which carried out the last decision in 1997 also including the person who had already died. Therefore, the victim permitted the influence of mercury by administration for the moment can call it 13,805 persons. However, there are some people who died before the official discovery of Minamata disease, and others who died after the discovery without submitting an application form for official recognition and / or for medical assistance. Furthermore, some people did not apply for compensation for other various reasons, so it is impossible to know the exact number of victims. The disease did not occur only in the Minamata area. In 1965 Minamata disease broke out alongthe Agano River in Niigata prefecture, caused by mercury discharged by the Showa Denko corporation. Ill-health or damage to one’s health as a result of mercury poisoning caused by factories was also reported in China and Canada. In recent years rivers and lakes in the Amazon and Tanzania polluted by mercury have created serious health concerns.Causes刘坤11210401. Agricultural PollutionExcess fertilizers, pesticides, and insecticides used for agricultural procedures often get discharged in water bodies right from streams to lakes and seas. Ungoverned control of manure and slurries also leads to polluting thewater.2. Mining ActivitiesDuring mining, the rock strata is crushed with the help of heavy equipment on a large scale. These rocks are often composed of sulfides and heavy metals, which when combined with water form sulfuric acid and other harmfulpollutants.3. Sewage WaterThe leftover or excess water that is left after carrying out domestic and industrial activities is called sewage water. This water consists of a lot of chemicals, and if left untreated, it can cause diarrhea. People flushing medicines and other chemical substances down the toilet has been a cause of concern for the developed countries today.4. Burning of Fossil FuelsIt is a well-known fact that combustion of fossil fuels, such as coal, oil, and natural gas, emits large amount of greenhouse gases. The offshore drilling of these fossil fuels poses a serious threat to water quality and the aquatic life that depends on it.5. EutrophicationWhen a water body is filledwith excessive nutrients, oftendue to surface runoff, it results indense growth of algae which inturn depletes the oxygen level inthe water. This process is calledeutrophication. Coupled with anthropogenic activity, it causes premature aging and waste-filled water content of the water body.6. Algal BloomThe amount of organic wastes that can be degraded by the water bodies is measured in terms of Biological Oxygen Demand (BOD). BOD is nothing but the amount of oxygen needed by microorganisms to decompose the organic waste present in the sewage. The higher the amount of BOD, the more water is polluted with organic waste and vice versa. Many people are not aware of the fact that soaps and detergents enrich the water bodies with phosphates. Thesephosphates often lead to harmful algal bloom (HAB), which is a common problem in stagnant water bodies, such as ponds and lakes. It leads to the suffocation of fish and other organisms in a water body.7. LandfillThe areas where a city'sgarbage is buried are calledlandfills. An ideal landfill should bewell-protected at the base toprevent seepage. However, if thereexists even a slight crack in thebottom layer, the pollutants seepthrough it and mix with the groundwater present below. This makes the water unfit for consumption in any form.8. Oil SpillsThe causes of oil spills can be both, natural and anthropogenic. More often than not, they result from human activities, be it accidentally, or deliberately. Oil products stored in special containers often leak over a long period; the same can happen during handling of the containers or improper transport. Sometimes, oil and its products are intentionally discharged down the drain after their use, proving harmful in the long run.Solution孙簃昉1121041Generally, we divide the solutions into two parts——biochemical method and physical method.1.B iochemical methodUsually it takes the chemical additive as the main means of processing. Also, it takes the bacteria as auxiliary means (swallow organic matter in water) Usually it uses an instrument for oxygen for the microorganisms to achieve the purpose of purifying water quality.Generally it was used for sewage treatment systemCharacteristic:It has an obvious purifying effect. As long as the microbial quantity can keep stable, the treatment effect can be achievedBut the raw water has to stay 4-5 hours, so that the decomposition time is enough. However, the whole equipment covers an area of large space. And this kindof treatment cannot produce too much effect on deep water.2.Physical methodIt uses precipitation, filtering, magnetic field pulse as the main means of processing, sometimes supplemented by chemical way, in order to help the impurity in the water as soon as possible change into the precipitation and speed up the formation of large particles.Here are the simple introductions of the three main methods.a.Precipitation (gravity separation) method:By using the principle that the suspended matter and water are in different proportion, borrowing the floating action of gravity, making the matter lighter than water float, the heavier sink and then removing them. Precipitation devices commonly use sand pool, sedimentation tank etc. The residence time of waste water in precipitation device usually is: sand pool 2h35min,oil separation tank0.25h.b.Filtering method:By using filter media to intercept the suspended matter remained in water, such as colloid, flocculation, algae to make the water clear. The filter medium contains screen, sand, filter cloth etc. Filtration equipments contain grid, sand filter etc. The treatment effect is related with the porosity of the filter medium.c.M agnetic field pulse method:It is a way to absorb the small particles by the magnetic field. Once the surface is full, the magnetic field would be cut down. After cleaning, it can be used again. As it is easy to be automatic and takes up less area, this kind of method is widely used now. Though it is promising, its infrastructure and operation cost high and much energy.Characteristic:It is characterized by small occupation of area, and can achieve the great treatment effect even of the deep water. And it can make the extremely purified water.But the process is a little more complex.If the quality of raw water is poor, the treatment is required (dosing,precipitation or natural decomposition) the filter to be frequently backwashed. It would also cause the waste of water resources. Even some media need to be replaced frequently, so the cost is higher.3.P revention for individualDealing with water pollution is something that everyone (including governments and local councils) needs to get involved with. Here are a few things you can do to help. Learning about the issue (like you are doing) is the greatest and most important step to take. Here are a few more:Do not throw chemicals, oils, paints and medicines down the sink drain, or the toilet. In many cities, your local environment office can help with the disposal of medicines and chemicals. Check with your local authorities if there is a chemical disposal plan for local residents.Use water wisely. Do not keep the tap running when not in use. Also, you can reduce the amount of water you use in washing and bathing. If we all do this, we can significantly prevent water shortages and reduces the amount of dirty water that needs treatment.Never throw rubbish away anyhow. Always look for the correct waste bin. If there is none around, please take it home and put it in your trash can. This includes places like the beach, riverside and water bodies.Buy more environmentally safe cleaning liquids for the use at home and other public places. They are less dangerous to the environment.If you use chemicals and pesticides for your gardens and farms, be mindful not to overuse pesticides and fertilizers. This will reduce runoffs of the material into nearby water sources. Start looking at options of composting and using organic manure instead.If you live close to a water body, try to plants lots of trees and flowers around your home, so that when it rains, chemicals from your home does not easily drain into the water.ConclusionsClearly, the problems associated with water pollution have the capabilities to disrupt life on our planet to a great extent. Congress has passed laws to try to combat water pollution thus acknowledging the fact that water pollution is, indeed, a seriousissue. But the government alone cannot solve the entire problem. It is ultimately up to us, to be informed, responsible and involved when it comes to the problems we face with our water. We must become familiar with our local water resources and learn about ways for disposing harmful household wastes so they don’t end up in sewage treatment plants that can’t handle them or landfills not designed to receive hazardous materials. In our yards, we must determine whetheradditional nutrients are needed before fertilizers are applied, and look for alternatives where fertilizers might run off into surface waters. We have to preserve existing trees and plant new trees and shrubs to help prevent soil erosion and promote infiltration of water into the soil. Around our houses, we must keep litter, pet waste, leaves, and grass clippings out of gutters and storm drains. These are just a few of the many ways in which we, as humans, have the ability to combat water pollution. As we head into the 21st century, awareness and education will most assuredly continue to be the two most important ways to prevent water pollution. If these measures are not taken and water pollution continues, life on earth will suffer severely.Global environmental collapse is not inevitable. But the developed world must work with the developing world to ensure that new industrialized economies do not add to the world's environmental problems. Politicians must think of sustainable development rather than economic expansion. Conservation strategies have to become more widely accepted, and people must learn that energy use can be dramatically diminished without sacrificing comfort. In short, with the technology that currently exists, the years of global environmental mistreatment can begin to be reversed.。

Journal of Hazardous Materials 186 (2011) 1042–1049Contents lists available at ScienceDirectJournal of HazardousMaterialsj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /j h a z m atDefluoridation from aqueous solutions by nano-alumina:Characterization and sorption studiesEva Kumar b ,Amit Bhatnagar a ,b ,∗,Umesh Kumar c ,Mika SillanpäädaInstitute of Environmental Technology and Energy Economics,Technische Universität Hamburg-Harburg (TUHH),21073Hamburg-Harburg,Germanyb LSRE –Laboratory of Separation and Reaction Engineering,Departamento de Engenharia Química,Faculdade de Engenharia da Universidade do Porto (FEUP),Rua Dr.Roberto Frias,4200-465Porto,Portugal cDepartment of Chemistry,National Cheng Kung University,Tainan 701,Taiwan,ROC dFaculty of Technology,Lappeenranta University of Technology,Patteristonkatu 1,FI-50100Mikkeli,Finlanda r t i c l e i n f o Article history:Received 25June 2010Received in revised form 12November 2010Accepted 24November 2010Available online 3 December 2010Keywords:Fluoride removal Nano-aluminaAdsorption isotherms Sorption mechanism pHa b s t r a c tThe present study was conducted to evaluate the feasibility of nano-alumina (Al 2O 3)for fluoride adsorp-tion from aqueous solutions.The nature and morphology of pure and fluoride-sorbed nano-alumina were characterized by SEM with EDX,XRD,and FTIR analysis.Batch adsorption studies were performed as a function of contact time,initial fluoride concentration,temperature,pH and influence of competing anions.Fluoride sorption kinetics was well fitted by pseudo-second-order model.The maximum sorption capacity of nano-alumina for fluoride removal was found to be 14.0mg g −1at 25◦C.Maximum fluoride removal occurred at pH 6.15.The fluoride sorption has been well explained using Langmuir isotherm model.Fluoride sorption was mainly influenced by the presence of PO 43−,SO 42−and CO 32−ions.© 2010 Elsevier B.V. All rights reserved.1.IntroductionFluoride contamination in drinking water due to natural and anthropogenic activities has been recognized as one of the major problems worldwide [1].Besides the natural geological sources for fluoride enrichment in groundwater,the discharge of the wastewa-ters from various industries,e.g.,drugs,cosmetics,semiconductor manufacturing,coal power plants,glass and ceramic production,electroplating,rubber,fertilizer manufacturing,also contaminate the surface and groundwater with fluoride [2,3].Fluoride is classi-fied as one of the human consumption water contaminant by the World Health Organization (WHO),which cause large-scale health problems through drinking water exposure,in addition to arsenic and nitrate [4].Consuming excess fluoride through drinking water often leads to skeletal fluorosis,causing debilitating bone structure disease,as well as discoloration and mottling of teeth,cancer or adverse effects on the brain and kidney [5].It was estimated that globally more than 70million people are suffering from fluorosis.∗Corresponding author at:LSRE –Laboratory of Separation and Reaction Engi-neering,Departamento de Engenharia Química,Faculdade de Engenharia da Universidade do Porto (FEUP),Rua Dr.Roberto Frias,4200-465Porto,Portugal.E-mail addresses:dr.amit10@ ,amit b10@yahoo.co.in (A.Bhatnagar).WHO has set the safe limit of fluoride concentration in drinking water as 1.5mg L −1.Several methods have been applied to remove excessive fluo-ride from aqueous solution,such as adsorption [6,7],precipitation [8],ion-exchange [9],electrodialysis [10]and reverse osmosis [11].Among these methods,adsorption is still one of the most exten-sively used methods,because of its simplicity and the availability of a wide range of adsorbents.Various materials such as activated alumina [6],clay [12],soil [13],bone char [14],zeolites [15],granu-lar ferric hydroxide [16]and biosorbent [17]have been successfully tested for defluoridation of drinking water.It has been well reported in literature that metal oxides (espe-cially iron and aluminium)have been found to be excellent sorbents for anions removal from aqueous solutions as generally they carry positive surface charge and negatively charged anions are sorbed on the positively charged surface of metal oxides by electro-static attraction.In the natural environment,fluoride has been proven to be strongly adsorbed onto various aluminium-containing mineral surfaces [18].United States Environmental Protection Agency (US EPA)has also recommended the use of activated alumina as an adsorbent for defluoridation [19].Conventionally,aluminium based micron-sized adsorbents have been employed for the removal of fluoride,however,in recent years use of nano-sized materials has emerged as one of the appealing technology for water treatment.Nanomaterials have a number of key physico-0304-3894/$–see front matter © 2010 Elsevier B.V. All rights reserved.doi:10.1016/j.jhazmat.2010.11.102E.Kumar et al./Journal of Hazardous Materials186 (2011) 1042–10491043chemical properties(rger surface area than bulk particles, enhanced reactivity and self-assembly)that make them particu-larly attractive as separation media for water purification[20,21]. As the sorption or binding sites reside only on the surface,nanoscale metal oxide particles with a very high surface-to-volume ratio offer significantly enhanced sorption capacity and shorter diffusion route[22–24].However,only a few reports are available in liter-ature dealing with the applications of nano-scale metal oxides for the removal offluoride and other anions from water[21,24–27]. In this perspective,it was thought desirable to test the potential of nano-alumina forfluoride removal as alumina and aluminum containing compounds have high affinity towardfluoride but no detailed studies are reported on the defluoridation of water using nano-alumina.In this study we combined the properties of metal oxides at nano-scale to achieve the enhanced removal offluoride from water.In the present study,the sorption feasibility of nano-alumina has been assessed forfluoride removal from aqueous solution.The physical and chemical characterization of nano-alumina by scan-ning electron micrographs(SEM),X-ray diffraction(XRD),Fourier transform infra-red spectroscopy(FTIR),energy dispersive X-ray analysis(EDX),and Brunauer–Emmett–Teller(BET),were con-ducted and further the potential of the nano-alumina was evaluated forfluoride removal.Defluoridation studies were conducted under various experimental conditions,such as pH,contact time,initial fluoride concentrations,temperature,and the presence of com-peting anions.The data from the experiments werefitted with different models to identify the adsorption mechanism.The results have been thoroughly discussed which would help in the better understanding of defluoridation mechanism by nano-alumina.2.Materials and methods2.1.MaterialsNano-alumina was purchased from Sigma–Aldrich.Fluoride stock solution was prepared by dissolving NaF(Sigma–Aldrich)in deionized(DI)water.Standards andfluoride spiked samples at a required concentration range were prepared by appropriate dilu-tion of the stock solution with DI water.All reagents used were of analytical reagent grade.2.2.Characterization of the sorbentNitrogen adsorption/desorption isotherms were obtained using a BEL Japan Inc.Belsorp-Max surface area analyzer at77K.The morphology of the sorbent was determined by scanning electron microscopy(SEM)using Quanta200(FEI,Netherlands)field-emission gun(FEG)scanning electron microscope.The X-ray diffraction(XRD)pattern of the nano-alumina was obtained using a Bruker AXS D8Advance X-ray diffractometer.FTIR spectra of the sorbent was collected using Nicolet8700FTIR spectrometer (Thermo Instruments,USA).2.3.Determination of point of zero chargeSolid addition method[28]was used to determine the zero sur-face charge characteristics(pH pzc)of nano-alumina using0.1M KCl solution along with20mg L−1fluoride and a blank.Forty milliliters of KCl andfluoride solutions of desired strengths were transferred to a series of50mL capped glass tubes.The initial pH(pH initial)of the solutions was adjusted in the range of2.0–12.0by adding0.1M HCl and0.1M NaOH solutions.The total volume of the solution in each tube was adjusted exactly to50mL by adding KCl andfluoride solution of the same strength.Further,0.5g of sorbent was added to all tubes and the suspensions were then equilibrated for48h.After completion of the equilibration time,the solutions werefil-tered andfinal pH values(pHfinal)of thefiltrates were measured again.The difference between the initial andfinal pH(pH f)values ( pH=pH i−pH f)was plotted against the pH i.The point of inter-section of the resulting curve with abscissa,at which pH=0,gave the point of zero charge.2.4.Fluoride analysisThe concentration offluoride in the solutions was determined by ion chromatography(Dionex,ICS-90,Ion Chromatography system, USA).The mobile phase consisted of a mixture of7.0mM sodium carbonate(Na2CO3)and2.0mM sodium bicarbonate(NaHCO3) delivered at theflow rate of 1.0mL min−1.AS40autosampler (Dionex,USA)was assembled with a10-␮L injection loop.A sepa-ration column,IonPac®AS9-HC,4.0mm×250mm(Dionex,USA), a guard column,IonPac®AG9-HC,4.0mm×50mm(Dionex,USA), and membrane suppressor,AMMS III4-mm were used.The data acquisition was performed using a Chromeleon6.5(Dionex,USA).2.5.Fluoride sorption studiesThe sorption offluoride on nano-alumina was conducted at room temperature(25±2◦C)by batch experiments.Twenty-five millilitres offluoride solution of varying initial concentrations (1–100mg L−1)in50mL capped tubes were shaken with0.025g of sorbent after adjusting the pH to the desired value,for a spec-ified period of contact time in a temperature controlled shaking assembly.After equilibrium,samples werefiltered and thefiltrate was then analyzed for residualfluoride concentration by ion chro-matography.Reproducibility of the measurements was determined in triplicates and the average values are reported.Relative standard deviations were found to be within±3.0%.The amount offluoride sorbed(q e in mg g−1)was calculated as follows:q e=(C0−C e)Vm(1) where C0and C e are the initial andfinal concentrations offluoride in solution(mg L−1),V is the volume of solution(L)and m is mass of the sorbent(g).The effect of contact time(1min to24h)was examined with initialfluoride concentrations of10and20mg L−1.The effect of equilibrium pH was investigated by adjusting solution pH from3 to12using0.1M HCl and0.1M NaOH under an initialfluoride con-centration of20mg L−1.The effects of competing anions(chloride, nitrate,carbonate,sulphate and phosphate)onfluoride adsorption were investigated by performingfluoride sorption under afixed fluoride concentration(20mg L−1)and initial competing anion con-centrations of20and50mg L−1with sorbent dosage of1g L−1.3.Results and discussion3.1.Characterization of nano-aluminaThe SEM images of pure andfluoride-sorbed nano-alumina are shown in Fig.1(A)and(B).As can be seen from Fig.1(A),the sor-bent does not possess any well-defined porous structure(only few pores on the surface)and no significant changes were observed influoride-sorbed nano-alumina(Fig.1(B)).The BET surface area of nano-alumina was found to be151.7m2g−1,whereas the total pore volume was1.09cm3g−1.EDX analyses were performed to determine the elemental constituents of pure andfluoride-sorbed nano-alumina(Fig.2(A) and(B)).It shows that the presence offluoride in small content appears in the spectrum other than the principal elements Al and O.The wt%of O and Al was found to be40.79and59.21%in pure nano-alumina.Whereas,the EDX results of thefluoride-sorbed1044 E.Kumar et al./Journal of Hazardous Materials186 (2011) 1042–1049Fig.1.SEM images of (A)pure nano-alumina;(B)fluoride-sorbed nano-alumina.nano-alumina showed fluoride peak (1.01%in weight)apart from Al (57.7%)and O (41.29%)peaks.Thus,the EDX results suggest the interaction of fluoride with nano-alumina in the fluoride-sorbed nano-alumina sample.The XRD patterns of the nano-alumina before and after sorp-tion with fluoride were also recorded.Fig.3(A)and (B)presents the X-ray diffractograms of original and fluoride-sorbed nano-alumina sample.The peaks of the original sample correspond to those of ␥-alumina.The similarity between the diffractograms of the original and the fluoride-sorbed sample indicates that no significant bulk structural changes occurred at that fluorination level (measured fluoride incorporation was 1.01%in weight as obtained by EDX results)and the fluoride ions do not change the phase of ␥-alumina.The FTIR spectra of pure and fluoride-sorbed nano-alumina is shown in Fig.4(A)and (B).In FTIR spectra of pure nano-alumina (before adsorption)(Fig.4A),the peak at 3500cm −1is attributed to the atmospheric water vapor.An absorption band at ca.1620cm −1was also observed which is in accordance with the reported literature that alumina presents an absorption band at ca.1620cm −1[29].The peak at 1040cm −1corresponds to the Al–O stretching vibration [30].After adsorption of fluoride ions (Fig.4B),the peaks corresponding to hydroxyl remains unaf-fected.However,the peak intensity at 1040cm −1is decreased and a new broad peak appeared in the region of 500–800cm −1.The decrease in the intensity of 1040cm −1peak indicated the involvement of the Al–O bonds in the interaction with fluo-ride ions.The new broad peak in the region of 500–800cm −1is due to the Al–F stretching vibrations [31]which can be attributed to the complexation of fluoride ions with Al.Theseobservations suggest possible interaction between fluoride and nano-alumina.3.2.Effect of contact time and initial fluoride concentrationThe sorption of fluoride on nano-alumina was investigated as a function of contact time (1min to 24h)at two different initial fluoride concentrations (10and 20mg L −1).It was noticed that flu-oride removal increased with time (Fig.5).The adsorbent exhibited an initial rapid uptake of fluoride followed by a slower removal rate that gradually reached an equilibrium condition.More than 85%removal of fluoride was attained within first 120min of con-tact time and equilibrium was achieved in 24h.A similar trend of fast kinetics was also observed onto nano-scale aluminum oxide hydroxide during fluoride sorption [25].The kinetics of fluoride sorption by nano-alumina was also studied at two different initial fluoride concentrations (10and 20mg L −1)(Fig.5).It was observed that fluoride uptake by nano-alumina increased with increase in initial fluoride concentration from 10to 20mg L −1(Fig.5).With the increase in initial fluoride concentration (C 0)from 10to 20mg L −1,both fluoride equilibrium concentration (C e )and equilibrium adsorption capacity (q e )exhib-ited increasing trends.These phenomena occurred as the results of the increase in the driving force provided by the concentration gradient with the increase in the initial fluoride concentration (C 0).In contrast,the percentage of fluoride removal showed a decreas-ing trend.Most fluoride interacted with the binding sites at low initial fluoride concentration,leading to the high percentage of flu-oride removal,while only part of fluoride combined with thefiniteFig.2.EDX spectra of (A)pure nano-alumina;(B)fluoride-sorbed nano-alumina (K:the K shell,a:alpha X-ray line (i.e.the type of peak)).E.Kumar et al./Journal of Hazardous Materials186 (2011) 1042–10491045Fig.3.XRD pattern of(A)pure nano-alumina(reprinted from[27]with permission from Elsevier);(B)fluoride-sorbed nano-alumina.binding sites at high initialfluoride concentration,resulting in the relatively low percentage offluoride removal[32].These results are similar to those previously reported for the removal offluoride by different adsorbents[24,32,33].3.3.Kinetic modelingThe kinetics offluoride sorption on nano-alumina was ana-lyzed using pseudo-first-order[34]and pseudo-second-order[35] kinetic models to identify the dynamics of the solute adsorption process.The best-fit model,i.e.pseudo-second-order model(Fig.6)Table1Comparison of pseudo-first-order and pseudo-second-order models parameters, and calculated q e(cal)and experimental q e(exp)values for different initialfluoride concentrations.Pseudo-first-order model:log(q e−q t)=log q e−(k f/2.303)tC0(mg L−1)q e(exp)(mg g−1)k f(min−1)q e(cal)(mg g−1)R210 5.30 4.37×10−2 2.640.8714209.43 2.87×10−2 4.830.8672 Pseudo-second-order model:t/q t=(1/k s q2e)+(1/q e)tC0(mg L−1)q e(exp)(mg g−1)k s(g mg−1min−1)q e(cal)(mg g−1)R210 5.308.36×10−2 5.330.9995209.43 6.06×10−29.630.9985q e:amount offluoride adsorbed on nano-alumina(mg g−1)at equilibrium;q t: amount offluoride adsorbed on nano-alumina(mg g−1)at time t(min);k f:rate constant for the pseudo-first-order kinetics;k s:rate constant for the pseudo-second-orderkinetics.Fig.4.FTIR spectra of(A)pure nano-alumina(reprinted from[27]with permission from Elsevier);(B)fluoride-sorbed nano-alumina.was selected based on the match between experimental(q e(exp)) and theoretical(q e(cal))uptake values and linear correlation coeffi-cient(R2)values at two studied concentrations.The rate equations and the related values are given in Table1.The values obtained by pseudo-second-order model were found to be in good agreement with experimental data and can be used to favourably explain the fluoride sorption onnano-alumina.Fig.5.Effect of contact time and initialfluoride concentration onfluoride sorp-tion on nano-alumina(temperature=25◦C;sorbent dose=1g L−1;pH=6.15±0.21; agitation speed=220rpm).1046 E.Kumar et al./Journal of Hazardous Materials186 (2011) 1042–1049Fig.6.Pseudo-second-order kinetic plots offluoride sorption on nano-alumina. 3.4.Effect of pHThe pH is an important parameter influencing the sorption pro-cess at the water–sorbent interfaces.To determine the optimum pH for the maximum removal offluoride,the equilibrium sorption offluoride(with initialfluoride concentration of20mg L−1)was investigated over a pH range of3–12.It can be seen(Fig.7)that the sorption offluoride on nano-alumina is strongly pH dependent.The sorption offluoride increases with increased pH,reaching a max-imum at pH6.15,and then decreased with further increase in pH. Initially,as the pH increased from3to6.15,thefluoride sorption also increased due to the fact that for pH<pH pzc(7.2),the surface of nano-alumina becomes positively charged and attracts negative fluoride anions,and becomes maximum at pH6.15.The decrease in sorption capacity at pH greater than6.15can be attributed to the competition for the active sites by OH−ions and the elec-trostatic repulsion of anionicfluoride by the negatively charged Al2O3surface.The minimalfluoride removal capacity in acidic pH is presumably due to the formation of HF,which reduces the coulombic attraction betweenfluoride and the adsorbent surface[2].3.5.Sorption isothermsIn order to evaluate the sorption capacity of nano-alumina for fluoride,the equilibrium sorption offluoride was studied as a func-tion offluoride concentration and the sorption isotherms are shownin Fig.8.A sorption capacity of ca.14.0mg g−1was observedforFig.7.Effect of pH onfluoride sorption on nano-alumina(C0=20mg L−1;tempera-ture=25◦C;contact time=24h;sorbent dose=1g L−1;agitation speed=220rpm).Fig.8.Sorption isotherms offluoride sorption on nano-alumina(contact time=24h;sorbent dose=1g L−1;pH=6.15;agitation speed=220rpm).fluoride on nano-alumina at25◦C.It can be found(Fig.8)that the sorption capacity at equilibrium gradually increased with the increase in equilibriumfluoride concentrations.The gradual rise in the isotherm indicates the availability of readily accessible sites for sorption during the initial phase.However,site saturation occurs as thefluoride concentration increases and a plateau is reached indicating that no more sites remain available for sorption.The mechanism offluoride removal process has been shown to involve the replacement of OH−with F−[36].Fluoride ions and hydroxide ions form Al n F m(OH)3n−m complexes with Al(III)ions as given in Eq.(2)[36].n Al3+(aq)+3n−m OH−(aq)+m F−(aq)→Al n F m(OH)3n−m(s)(2) Zhang et al.[37]studied the interaction offluoride on␥-alumina surface by multinuclear MAS NMR spectroscopy to identify thefluorine species on thefluorinated␥-alumina.The spectro-scopic analysis indicated thatfluorine enters the surface of alumina by substituting hydroxyl groups without breaking the bridging Al–O–Al bonds.At higherfluoride loadings,bridging Al–O–Al bonds were found to be broken to sorb morefluoride under the strong electron-withdrawing effect offluorine.It is expected that similar processes occur on nano-alumina.Adsorption potential of nano-alumina in the present study was compared with other adsorbents reported in previous studies for fluoride removal and is compiled in Table2.It is seen that nano-alumina used in the present study shows comparable adsorption capacity forfluoride removal compared to some previously devel-oped adsorbents.However,in some cases,it shows lower sorption potential towardsfluoride and research is being focused now to enhance the adsorption potential of nano-alumina by chemical modifications.3.6.Effect of temperature onfluoride sorption by nano-aluminaIn order to investigate the effect of temperature onfluoride removal by nano-alumina,sorption experiments were also per-formed at10◦C.A comparison of sorption isotherms at10and25◦C indicates thatfluoride sorption by nano-alumina is not significantly affected by temperature variation(Fig.8).The sorption data was further analyzed using two well known isotherm models,ngmuir and Freundlich models,which can be expressed by Eqs.(3)and(4):1e=1m+1m e(3) log q e=log K F+1+log C e(4)E.Kumar et al./Journal of Hazardous Materials186 (2011) 1042–10491047Table2Comparison of efficiency of various adsorbents forfluoride removal from water.Adsorbent Amount adsorbed(mg g−1)Experimental conditions ReferenceKMnO4modified carbon15.9pH:2.0Concentration:5–20mg L−1Temperature:25◦C[7]Granular ferric hydroxide(GFH)7.0pH:6.0–7.0Concentration:1–100mg L−1Temperature:25◦C[16]Fe3O4@Al(OH)3magnetic nanoparticles88.48pH:6.5Concentration:0–160mg L−1Temperature:25◦C[24]Granular activated alumina(PURALOX) Copper oxide coated alumina 2.2327.220Concentration:10mg L−1Temperature:30±1◦C[43]Iron(III)–Tin(IV)mixed oxide10.47pH:6.4Concentration:10–50mg L−1Temperature:303K[44]Fe–Al–Ce nano-adsorbent 2.22pH:7.0Concentration:0.0001MTemperature:25◦C[45]Scandinavia spruce wood charcoal(AlFe650/C)13.64pH:7.0Temperature:28±2◦CConcentration:2–50mg L−1[46]Acid treated spent bleaching earth7.752pH:3.5Concentration:5–45mg dm−3[47]Chemical treated laterite37.9pH:5.0Concentration:3–50mg L−1Temperature:305K[48]Magnetic-chitosan22.49pH:7.0Concentration:5–140mg L−1[49] Hydrous-manganese-oxide-coated alumina7.09pH:5.2Concentration:10–70mg L−1Temperature:30◦C[50]Hydrotalcite/chitosan composite 1.255Temperature:30◦CConcentration:upto15mg L−1pH:acidic pH[51]Granular ceramic12.12Temperature:20◦CConcentration:5–50mg L−1pH:6.90[52]Nano-alumina14.0pH:6.15Concentration:1–100mg L−1Temperature:25◦CPresent workwhere q e is amount sorbed at equilibrium concentration C e,q m is the Langmuir constant representing maximum monolayer sorption capacity,b is the Langmuir constant related to energy of sorption, K F and1/n are Freundlich constants,associated with adsorption capacity and adsorption intensity,respectively.The experimental data did notfit well with the Freundlich model (see Table3)but wasfitted well with Langmuir model.The plots of1/q e as a function of1/C e for the sorption offluoride on nano-alumina are shown in Fig.9.The values of q m and b are given in Table3.The values of q m calculated by the Langmuir isotherm were all close to experimental values at given temperatures.These facts suggest thatfluoride is sorbed in the form of monolayer coverage on the surface of the sorbent.The influence of sorption isotherm shape has been discussed [38]to examine whether sorption is favorable in terms of‘R L’,a dimensionless constant referred to as separation factor or equilib-rium parameter.‘R L’is calculated using the following equation:R L=11+bC0(5)ngmuir isotherm offluoride sorption on nano-alumina.Table3Langmuir and Freundlich constants for the adsorption offluoride on nano-alumina at10and25◦C.Temperature(◦C)Langmuir constants Freundlich constantsq m(mg g−1)b(L mol−1)R L R21/n K F(mg g−1)(L mg−1)1/n R2 1014.10 2.36×1030.310.99800.940.810.9823 2515.43 3.24×1030.270.99120.98 1.010.96261048 E.Kumar et al./Journal of Hazardous Materials186 (2011) 1042–1049Fig.10.Effect of different concentrations of competitive anions onfluoride sorption on nano-alumina(temperature=25◦C;contact time=24h;sorbent dose=1g L−1; agitation speed=220rpm).The R L values obtained are compiled in Table3.Both the R L values lie between0and1confirming that the adsorption isotherm is favorable.3.7.Thermodynamic parametersThe nature and thermodynamic feasibility of the sorption pro-cess were determined by evaluating the thermodynamic constants, standard free energy( G◦),standard enthalpy( H◦)and standard entropy( S◦)using the following equations:G◦=−RT ln(K)(6)ln K2K1=H◦R1T1−1T2(7)G◦= H◦−T S◦(8)where R is the universal gas constant(8.314J mol−1K−1),T is the temperature in Kelvin and K is the equilibrium constant,related to the Langmuir constant‘b’via Eq.(9),where the value55.5corre-sponds to the molar concentration of the solvent(in this case water) with units of mol L−1[39,40].K=b×55.5(9)The sorption process is spontaneous in nature,as indicated by the negative value of G◦(−29.97kJ mol−1)at298K.The positive value of H◦forfluoride adsorption is14.81kJ mol−1,suggesting that the interaction offluoride and nano-alumina is endothermic in nature.Affinity of the sorbent forfluoride is represented by the positive value of S◦(150.3J mol−1K−1).3.8.Effect of competing anions onfluoride adsorption bynano-aluminaThe influence of various anions present in groundwater such as, chloride(Cl−),nitrate(NO3−),sulphate(SO42−),carbonate(CO32−) and phosphate(PO43−)onfluoride removal by nano-alumina was investigated at20mg L−1of initialfluoride concentration(Fig.10). The concentrations of competing anions were20and50mg L−1. It was found that anions present influoride solution are likely to limit thefluoride removal efficiency.Fluoride sorption was mainly influenced by the presence of phosphate followed by carbonate and sulphate.In the presence of phosphate,relative percent removal offluoride was∼26%and17%at20and50mg L−1,respectively, while in case of sulphate and carbonate,relative percent removal offluoride was∼35%and30%and27%and20%at20and50mg L−1, respectively.Thefluoride removal was decreased in presence of phosphate and sulphate which indicates that the inner-spherically sorbing anions,phosphate and sulphate[41,42]can significantly interfere the sorption offluoride where the sorption competition occurred for the limited amount of sorption sites on nano-alumina. The decrease influoride adsorption in presence of carbonate was presumably due to the significant increase in pH of the solution. It was also confirmed from our experiments on the effect of pH (Section3.4)that thefluoride removal decreases in highly alkaline pH.Furthermore,fluoride sorption was least influenced in presence of chloride and nitrate(outer-spherically sorbing anions).4.ConclusionsThe results from the present study exhibit the potential of nano-alumina forfluoride removal from aqueous solutions.The sorption offluoride on nano-alumina was found to be strongly pH dependent with maximumfluoride removal occurring at pH 6.15.Kinetic analyses indicate that the sorption process followed pseudo-second-order kinetics under the selected concentration range.The sorption capacity of nano-alumina forfluoride was found to be ca.14.0mg g−1at25◦C.The sorption isotherm wasfitted well with Langmuir model.The FTIR and EDX results provide an evidence of the interaction betweenfluoride and nano-alumina moieties resulting in the formation of aluminum-fluoro complexes. Fluoride sorption was influenced more by the presence of PO43−, SO42−and CO32−.AcknowledgmentsA part of this research work was partially conducted at Insti-tute of Environmental Technology and Energy Economics(IUE), TUHH,Hamburg-Harburg,Germany and authors express their sin-cere thanks to IUE staff for providing necessary help.One of the authors(AB)is also thankful to FCT(Fundac¸ão para a Ciência e a Technologia),Lisbon,Portugal,for the award of post-doctoral grant (FCT-DFRH-SFRH/BPD/62889/2009).References[1]D.P.Das,J.Das,K.Parida,Physicochemical characterization and adsorp-tion behavior of calcined Zn/Al hydrotalcite-like compound(HTlc)towards removal offluoride from aqueous solution,J.Colloid Interface Sci.261(2003) 213–220.[2]A.M.Raichur,M.J.Basu,Adsorption offluoride onto mixed rare earth oxides,Sep.Purif.Technol.24(2001)121–127.[3]F.Shen,X.Chen,P.Gao,G.Chen,Electrochemical removal offluoride ions fromindustrial wastewater,Chem.Eng.Sci.58(2003)987–993.[4]WHO(World Health Organization),Guidelines for Drinking-Water Quality[Electronic Resource]:Incorporating First Addendum(vol.I)Recommenda-tions,2006,pp.375–377.[5]P.T.C.Harrison,Fluoride in water:a UK perspective,J.Fluorine Chem.126(2005)1448–1456.[6]S.Ghorai,K.K.Pant,Investigations on the column performance offluorideadsorption by activated alumina in afixed-bed,Chem.Eng.J.98(2004) 165–173.[7]A.A.M.Daifullah,S.M.Yakout,S.A.Elreefy,Adsorption offluoride in aqueoussolutions using KMnO4-modified activated carbon derived from steam pyrol-ysis of rice straw,J.Hazard.Mater.147(2007)633–643.[8]S.Saha,Treatment of aqueous effluent forfluoride removal,Water Res.27(1993)1347–1350.[9]K.Vaaramaa,J.Lehto,Removal of metals and anions from drinking water byion exchange,Desalination155(2003)157–170.[10]Z.Amor,B.Bariou,N.Mameri,M.Taky,S.Nicolas,A.Elmidaoui,Fluorideremoval from brackish water by electrodialysis,Desalination133(2001) 215–223.[11]P.I.Ndiaye,P.Moulin,L.Dominguez,let,F.Charbit,Removal offluoridefrom electronic industrial effluent by RO membrane separation,Desalination 173(2005)25–32.[12]G.Moges,F.Zewge,M.Socher,Preliminary investigations on the defluoridationof water usingfired clay chips,J.Afr.Earth Sci.21(1996)479–482.[13]Y.Wang,E.J.Reardon,Activation and regeneration of a soil sorbent for defluo-ridation of drinking water,Appl.Geochem.16(2001)531–539.[14]D.S.Bhargava,D.J.Killedar,Fluoride adsorption onfishbone charcoal througha moving media adsorber,Water Res.26(1992)781–788.[15]M.S.Onyango,Y.Kojima,A.Kumar,D.Kuchar,M.Kubota,H.Matsuda,Uptakeoffluoride by Al3+-pretreated low-silica synthetic zeolites:adsorption equilib-rium and rate studies,Sep.Sci.Technol.41(2006)683–704.。

水文地球化学专业术语（中英文对照）水文地球化学1 水文地球化学基础1.1 水化学 hydrochemistry研究天然水化学成分的形成、分布和演变的学科。

1.2 地下水物理性质physical properties of groundwater地下水的比重、温度、透明度、颜色、味、嗅味、导电性、放射性等物理特性之总和。

1.3 地下水化学成分chemical constituents in groundwater地下水中各类化学物质之总称。

它包括离子、气体、有机物、微生物、胶体以及同位素成分等。

1.4 库尔洛夫式 kurllov formation以类似数学分式形式表示单个水样化学成分的含量和组成的方法。

1.5 水文地球化学作用hydrogeochemical process在一定地球化学环境下，影响地下水化学成分形成、迁移和变化的作用。

1.5.1 水解作用 hydrolytic dissociation地下水与岩石相互作用，成岩矿物的晶格中，发生阳离子被水中氢离子取代的过程。

1.5.2 溶滤作用 lixiviation地下水与岩石相互作用，使岩石中一部分可溶成分转入水中，而不破坏矿物结晶格架的作用。

1.5.3 蒸发浓缩作用evaporation—concentration process地下水遭受蒸发，引起水中成分的浓缩，使水中盐分浓度增大，矿化度增高。

1.5.4 混合作用mixing hydrochemical reaction in groundwater两种或两种以上不同成分水之间的混合，使原有水的化学成分发生改变的作用。

1.5.5 阳离子交替吸附作用cation exchange and adsorption地下水与岩石相互作用，岩石颗粒表面吸附的阳离子被水中阳离子置换，并使水化学成分发生改变的过程。

1.5.6 脱碳酸作用 decarbonation在温度升高，压力降低的情况下，CO2自水中逸出，而HCO-3含量则因形成碳酸盐沉淀减少的过程。

地质工程专业英语考研必备Hydrogeologic terminology3 水文地质学原理3.1 水文地质学科分类3。

1.1 水文地质学 hydrogeology研究地下水的形成和分布、物理及化学性质、运动规律、开发利用和保护的科学.3.1.2 水文地质学原理(普通水文地质学)principles of hydrogeology(general hydrogeology) 研究水文地质学的基础理论和基本概念的学科。

3.1.3 地下水动力学 groundwater dynamics研究地下水在岩土中运动规律的学科。

3.1.4 水文地球化学 hydrogeochemistry研究地下水化学成分的形成和变化规律以及地下水地球化学作用的学科。

3.1。

5 专门水文地质学 applied hydrogeology为各种应用而进行的地下水调查、勘探、评价及开发利用的学科。

3.1。

5.1 供水水文地质学 water supply hydrogeology为各种目的供水，研究地下水的形成条件、赋存规律、勘查方法、水质、水量评价以及合理开发利用和管理的学科。

3。

1.5。

2 矿床水文地质学 mine hydrogeology研究矿床水文地质学理论、勘探方法及开采中有关水文地质问题的学科。

3。

1.5。

3 土壤改良水文地质学 reclamation hydrogeology研究土壤盐渍化及沼泽化等水文地质问题的学科。

3.1。

5。

4 环境水文地质学 environmental hydrogeology研究自然环境中地下水与环境及人类活动的相互关系及其作用结果，并对地下水与环境进行保护、控制和改造的学科。

3。

1。

5.5 同位素水文地质学 isotopic hydrogeology应用同位素方法解决水文地质问题的学科。

3。

1。

6 区域水文地质学 regional hydrogeology研究地下水埋藏、分布、形成条件及含水层的区域性规律的学科.3。

专业术语中英文对照表傍河水源地 riverside source field包气带 aeration zone饱和度 degree of saturation饱和流 saturated flow饱水带 saturated zone边界井 boundary well边界条件 boundary condition边界元法 boundary element method标准曲线法（配线法） type-curve method补给区 recharge area补给疏干法 compensation-dewatering method部分排泄型泉 local drainage spring采区充水性图 geologic map of potential flooding in mining area 测压高度 piezometric head层流laminar flow常量元素 common element in groundwater （macroelement ）沉积水（埋藏水） connate water（buried water）成垢作用 boiler scaling成井工艺 well completion technology承压含水层 confined aquifer承压含水层厚度 thickness of confined aquifer承压水 confined water承压水盆地 confined water basin承压水位（头） confining water level持水度 water-holding capacity/ specific retension充水岩层 flooding layer抽水孔 pumping well抽水孔流量 discharge of a pump well抽水孔组 jumping well group抽水量历时曲线图 flow-duration curve抽水试验 pumping test初见（始）水位 initial water level初始条件 initial condition次生盐渍土 secondary salinized soil达西定律Darcy’s law大肠菌群指数 index of coliform organisms大口井 large-diameter wd1大气降水渗入补给量 precipitation infiltration rate单井出水量 yield of single well单孔抽水试验 single well pumping test弹性储存量 elastic storage淡水 fresh groundwater导水系数 transmissivity等降深线 equiodrawdown line等势线 equipotential line等水头面 equipotential surface低频电磁法 very low frequency electromagnetic method 地表疏干 surface draining地表水 surface water地表水补给 surface water recharge地方病 endemic disease地方性氟中毒 endemic fluorosis地面沉降 subsidence地面开裂 land crack地面塌陷 ground surface collapse地下肥水 nutritive groundwater地下集水建筑物 groundwater collecting structure地下径流 underground runoff地下径流模数法 modulus method of groundwater runoff 地下库容 capacity of groundwater reservoir地下卤水 underground brine地下热水 geothermal water地下疏干 underground draining地下水 groundwater地下水补给量 groundwater recharge地下水补给条件 condition of groundwater recharge地下水超采 overdevelopment of groundwater地下水成矿作用 ore-forming process in groundwater地下水储存量（地下水储存资源） groundwater storage地下水的pH值 pH Value of groundwater地下水的碱度 alkalinity of groundwater地下水的酸度 acidity of groundwater地下水的总硬度 total hardness of groundwater地下水等水头线图 map of isopiestic level of confined water地下水等水位线图 groundwater level contour map地下水动力学 groundwater dynamics地下水动态 groundwater regime地下水动态成因类型 genetic types of groundwater regime地下水动态曲线 curve of groundwater regime地下水动态要素 element of groundwater regime地下水分水岭 grot1udwater divide地下水赋存条件 groundwater occurrence地下水化学成分 chemical constituents of groundwater地下水化学类型 chemical type of groundwater地下水环境质量评价groundwater environmental quality assessment 地下水径流量（地下水动储量） groundwater runoff地下水径流流出量 groundwater outflow地下水径流流入量 groundwater inflow地下水均衡 groundwater balance地下水均衡场 experimental field of groundwater balance地下水均衡方程 equation of groundwater balance地下水开采量 groundwater withdrawal地下水开采资源 exploitable groundwater resources地下水可开采量（地下水允许开采量） allowable withdrawal of groundwater 2地下水库 groundwater reservoir地下水埋藏深度 buried depth of groundwater table地下水埋藏深度图 map of buried depth of groundwater地下水模型 groundwater model地下水年龄 age of groundwater地下水年龄测定 dating of groundwater地下水排泄 groundwater discharge地下水盆地 groundwater basin地下水侵蚀性 Corrosiveness of groundwater地下水人工补给 artificial recharge of groundwater地下水人工补给资源 artificial-recharged groundwater resources 地下水设计开采量 designed groundwater withdrawal地下水实际流速 actual velocity of groundwater flow地下水实际流速测定 groundwater actual velocity measurement 地下水数据库 groundwater database地下水数学模型 mathematical model of groundwater地下水水化学图 hydrogeochemical map of groundwater地下水水量模型 groundwater flow model地下水水量评价 evaluation of groundwater quantity地下水水位动态曲线图 hydrograph of groundwater level地下水水质 groundwater quality地下水水质类型 type of groundwater quality地下水水质模型 groundwater quality model地下水天然资源 natural resources of groundwater地下水同位素测定 isotope assaying of groundwater地下水位持续下降 continuously drawndown of groundwater level 地下水污染 groundwater pollution地下水污染评价 groundwater pollution assessment地下水污染物 groundwater pollutants地下水物理模型 physical model of groundwater地下水物理性质 physical properties of groundwater地下水系统 groundwater system地下水预报模型 groundwater prediction model地下水源地 groundwater source field地下水质评价 evaluation of groundwater quality地下水资源 groundwater resources.地下水资源保护 groundwater resources protection地下水资源分布图 map of groundwater resources地下水资源管理区 groundwater resources management地下水资源枯竭 groundwater resources depletion地下水资源评价方法 methods of groundwater resource evaluation地下水总矿化度 total mineralization degree of groundwater地下微咸水 weak mineralized groundwater地下咸水 middle mineralized groundwater地下盐水 salt groundwater地中渗透仪 lysimeter电导率 specific conductance电法测井 electric logging电法勘探 electrical prospecting顶板裂隙带 fissure zone of top wall顶板冒落带 caving zone of top wall定降深抽水试验 constant-drawdown pumping test定解条件 definite condition定流量边界 boundary of fixed flow /constant flow定流量抽水试验 constant-discharge pumping test定水头边界 boundary of fixed water level动水位 dynamic water level断层泉 fault spring断裂带水压导升高度（潜越高度） height of water pressure in fault zone 断面流量 cross-sectional flow对流弥散 convective dispersion多孔抽水试验 multipe wells pumping test多孔介质 porous medium二维流 two-dimensional flow放射性测井 radioactivity logging放射性水文地质图 radio hydrogeological map放射性找水法 radioactive method for groundwater search放水试验 dewatering test非饱和流 unsaturated flow非均匀介质 inhomogeneous medium非均匀流 non-uniform flow非完整井 partially penetrating well非稳定流 unsteady flow非稳定流抽水试验 unsteady-flow pumping test分层抽水试验 separate interval pumping test分层止水 interval plugging分子扩散 molecular diffusion .分子扩散系数 coefficient of molecular diffusion福希海默定律 Forchheimer law辐射井 radial well腐蚀作用 corroding process负均衡 negative balance负硬度 negative hardness富水系数 water content coefficient of mine富水性 water yield property干扰抽水试验 interference-well pumping test干扰井出水量 yield from Interference wells干扰系数（涌水量减少系数） interference coefficient隔水边界 confining boundary隔水层 aquifuge隔水底板 lower confining bed隔水顶板 upper confining bed各向同性介质 isotropic medium各向异性介质 anisotropic medium给水度 specific yield供水水文地质勘查 hydrogeological investigation for water supply 供水水文地质学 water supply hydrogeology拐点法 inflected point method观测孔 observation well管井 tube well灌溉回归系数 irrigation return flow rate灌溉机井 pumping-well for irrigation灌溉系数 irrigation coefficient过水断面 water-carrying section海水入侵 sea-water intrusion3含水层 aquifer含水层储能 energy storage of aquifer含水层弹性释放 elasticity release of aquifers含水层等高线图 contour map of aquifer含水层等厚线图 aquifer impact map含水层等埋深图 isobaths map of aquifer含水层调节能力 regulation capacity of aquifer含水层自净能力 self-purification capability of aquifer含水率 moisture content化学需氧量（COD） chemical oxygen demand环境水文地质勘查 environmental hydrogeological investigation 环境水文地质图 environmental hydyogeologic map环境水文地质学 environmental hydrogeology环境自净作用 environmental self-purification恢复水位 recovering water level回灌井 injection well回灌量 quantity of water recharge回灌水源 recharge water source混合抽水试验 mixed-layer pumping test混合模拟 mixing analog混合作用 mixing hydrochemical action in groundwater激发补给量 induced recharge of groundwater极硬水 hardest water集中供水水源地 well field for concentrated water supply间歇泉 geyser简易抽水试验 simple pumping test降落漏斗 cone of depression降落漏斗法 depression cone method降落曲线 depression curve降水补给 precipitation recharge降水入渗试验 test of precipitation infiltration降水入渗系数 infiltration coefficient of precipitation接触泉 contact spring结构水（化合水） constitutional water （chemical water）结合水 bound water结晶水 crystallization water解逆问题（反演计算） solving of inverse problem解析法 analytic method解正问题（正演计算） solving of direct problem井下供水孔 water supply borehole in mines井中电视（超声成相测井） borehole television（BHTV）径流区 runoff area静止水位（天然水位） static water level （Natural water level）均衡期 balance period均衡区 balance area均匀介质 homogeneous medium均匀流 uniform flow开采模数法 evaluation method of employing groundwater extraction modulus 开采强度法 mining intensity method开采试验法 exploitation pumping test method开采性抽水试验 trail-exploitation pumping test坎儿井 karez空隙 void孔洞 pore space孔隙 pore孔隙比 pore ratio孔隙度（孔隙率） porosity（pore rate）孔隙含水层 porous aquifer孔隙介质 pore medium孔隙水 pore water库尔洛夫式 Kurllov formation矿床充水 flooding of ore deposit矿床充水水源 water source of ore deposit boding矿床充水通道 flooding passage in ore deposit矿床疏干 mine draining矿床疏干深度（疏干水平） dewatering level of mines矿床水文地质 mine hydrogeology矿床水文地质图 mine hydrogeological map矿床水文地质学 mine hydrogeology矿井水文地质调查 survey of mine hydrogeology矿井突水 water bursting in mines矿井涌水 water discharge into mine矿坑水 mine water矿坑突泥 mud gushing in mines矿坑突水量 bursting water quantity of mines矿坑涌砂 sand gushing in mines矿坑涌水量 water yield of mine矿坑正常涌水量 normal water yield of mines矿坑最大涌水量 maximum water yield of mines矿区水文地质勘查 mine hydrogeological investigation 矿泉 mineral spring雷诺数 Reynolds number连通试验 connecting test裂隙 fissure裂隙含水层 fissured aquifer裂隙介质 fissure medium裂隙率 fissure ratio裂隙水 fissure water临界深度 critical depth流量测井 flowmeter logging流量计 flowmeter流网 flow net流线 streamline滤料（填料） gravel pack滤水管（过滤器） screen pipe裸井 barefoot well毛细带 capillary zone毛细管测压水头 capillary piezometric head毛细上升高度 height of capillary rise毛细水 capillary water毛细性 capillarity弥散 dispersion弥散试验 dispersion test钠吸附比（SAR） sodium adsorption ratio拟稳定流 quasi-steady flow凝结水 condensation water凝结水补给 condensation recharge排泄区 discharge area平均布井法 method of well uniform4configuration起泡作用 forming process气体成分分析 gas analysis潜水 phreatic water /unconfined water潜水含水层厚度 thickness of water-table aquifer潜水位 water table潜水溢出量 groundwater overflow onto surface潜水蒸发量 evaporation discharge of phreatic water浅层地震勘探 shallow seismic prospecting强结合水（吸着水） strongly bound water adsorptive water 侵蚀泉 erosional spring侵蚀性二氧化碳 corrosive carbon dioxide裘布依公式 Dupuit formula区域地下水位下降漏斗 regional groundwater depression cone 区域水文地质普查 regional hydrogeological survey区域水文地质学 regional hydrogeology全排泄型泉 complete drainage spring泉 spring泉华 sinter泉流量衰减方程法 method of spring flow attenuation泉水不稳定系数 instability ratio of Spring discharge泉水流量过程曲线 hydrograph of spring discharge泉域 spring area确定性模型 deterministic model扰动土样 disturbed soil sample容积储存量 volumetric storage容水度（饱和含水率） water capacity溶洞 cave cavern溶解他固体总量 total dissolved solids溶解氧（DO） dissolved oxygen溶滤水 lixiviation water溶滤作用 lixiviation软水 soft water弱含水层 aquitard弱结合水（薄膜水） weakly bound water （film water）弱透水边界 weakly-permeable boundary三维流 three-dimensional flow上层滞水 perched water上升泉 ascending spring设汁水位降深 designed drawdown渗流场 seepage field渗流场剖分（单元划分） dissection of seepage field渗流速度 seepage velocity渗入水 infiltration water渗水试验 pit permeability test渗透 seepage渗透率 specific permeability渗透水流（渗流） seepage flow渗透系数（水力传导系数） hydraulic conductivity/ permeability 生化需氧量（BOD） biochemical oxygen demand声波测井 acoustic logging声频大地电场法 audio-frequency telluric method湿地 wet land实井 real well试验抽水 trail pumping手压井 manual-operated pumping well疏干工程排水量 discharge of dewatering excavation疏干巷道 draining tunnel疏干因数 factor of drainage数学模型法 method of mathematical model数学模型检验 verification of mathematical model数学模型识别 calibration d mathematical model数值法 numerical method水文地质勘查报告 report of hydrogeologicai investigation 水动力弥散系数 coefficient of dispersion.水分散晕 water dispersion halo水化学 hydrochemistry水解作用 hydrolytic dissociation水井布局 wafer well arrangement水均衡法 water balance method水均衡方程 equation of water balance水均衡要素 element of water balance水均衡原理 principle of water balance水力坡度 hydraulic gradient水力削减法 hydraulic cut method水流迭加原理 principle of flow superpersitiom水流折射定律 law of seepage flow refraction水圈 hydrosphere水头场 water head field水头场的拟合 fitting of water-head field水头降深场 fieId6f water head drawdown水头降深场的拟合 fitting of water head drawdown field水头损失 water head loss水位计 wellhead water-level gauge水位降深值 drawdown水文地球化学 hydrogeochemistry水文地球化学分带 hydrogeodenml zonality水文地球化学环境 hydrogeochemical environment水文地球化学作用 hydrogeochemical process水文地质比拟法 hydrogeologic analogy method水文地质参数 Hydrogeological parameters水文地质测绘 hydrogeological mapping水文地质单元 hydrogeologic unit水文地质地球物理勘探 hydrogeophysical prospecting水文地质分区 hydrogeological division水文地质概念模型 conceptual hydrogeological model水文地质勘查 hydrogeological investigation水文地质勘查成果 result of hydrogeological investigation 水文地质勘查阶段 hydrogeological investigation stage水文地质勘探孔 hydrogeological exploration borehole水文地质剖面图 hydrogeological profile水文地质试验 hydrogeological test水文地质试验孔 hydrogeological test borehole水文地质条件 hydrogeological condition水文地质学 hydrogeology水文地质学原理 principles of hydrogeology5水文地质钻探 hydrogeological drilling水文水井钻机 hydrogeologic drilling rig水文物探测井 hydrogeological well logging水循环 water cycle水盐均衡 water-salt balance水样 water sample水跃值 hydraulic jump value水质标准 water quality standard水质分析 chemical analysis of water速度水头 velocity head随机模型 stochastic model泰斯公式 Theis formula探采结合孔 exploration-production well同位素水文地质学 isotopic hydrogeology透水边界 permeable boundary透水层 permeable bed透水性 permeability突水水源 source of water bursting突水系数 water bursting coefficient突水预测图 water bursting prediction map土（岩）样 soil （rock）sample土的颗粒分析 grading analysis of soil土壤改良 soil reclamation土壤水 soil water土壤盐渍化 soil salinization脱硫酸作用 desulphidation脱碳酸作用 decarbonation脱硝（氮）作用 denitration完整井 completely penetrating well微量元素 microelement温泉 thermal spring紊流 turbulent flow稳定流 steady flow稳定流抽水试验 steady-flow pumping test稳定水位 steady water level污染通道 pollution channel污染源 pollution source污水资源化 water resources from sewage renewal无压含水层 unconfined aquifer物理模型法 method of physical model细菌总数 bacterial amount下降泉 descending spring咸淡水界面 interface of salt-fresh water相关分析法（回归分析法）correlation analysis method（regression analysis method）硝化作用 nitrification斜井 inclined well虚井 real well悬浮物 suspended solids悬挂泉（季节泉） suspended spring压力传导系数 hydraulic diffusivity压力水头 pressure head雅可布公式 Jacob formula延迟给水（滞后给水） delayed drainage延迟指数 delayed index岩溶含水层 karst aquifer岩溶含水系统 karst water-bring system岩溶介质 karst medium岩溶水 karst water岩石圈 lithosphere岩石渗透性测定 permeability determination of rock盐碱土 saline allkaline soil盐渍土 salinized soil阳离子交替吸附作用cation exchange and adsorption氧化还原电位 oxidation-reduction potential样品采集 sampling遥感技术 remote sensing technology一维流 one-dimensional flow溢流泉 overflow spring影响半径 radius of influence映射法 image method硬水 hard water涌水量方程外推法（试验推断法） discharge equation extrapolation method 游离性二氧化碳 free carbon dioxide有限差分法 finite-difference method有限单元法 finite element method有效降水量 effective precipitation有效孔隙度 effective porosity元素迁移 element migration原生水（初生水） juvenile water（native water）原生盐渍土 primary salinized soil原状土样 undisturbed soil sample越流 leakage越流补给 leakage recharge越流系数 leaky coefficient越流系统 leaky system越流因数（阻越流系数） leaky factor允许水位降深 allowable drawdown蒸发浓缩作用 evaporation-concentration process正均衡 positive balance直线法 linear method重力疏干 gravity drainage重力水 gravity water注水孔 injecting well注水试验 injecting test贮存量变化量 variation of groundwater storage贮水系数（释水系数） storage coefficient专门水文地质学 applied hydrogeology专门性水文地质勘查applied hydrogeclogic investigation专门性水文地质图 special hydrogeological map自流水 artesian water综合水文地质图 synthetic hydrogeoiogical map总水头（渗流水头） total head钻孔流速测 borehole flow-velocity measurement最佳开采量 optimal yield最佳控制水位 optimal controlled water level最佳配水方案 optimal water distribution scheme7.3.2.13斜井 inclined well一般断面尺寸1.8m×2.0 m、倾角20°～40°的倾斜坑道集水工程，适用于开采坚硬岩石、埋深较大的裂隙岩溶水。

生活垃圾填埋场地下水污染物识别与质量评价韩智勇;许模;刘国;程诚【摘要】基于现场调研和 1991~2014 年的相关报道,通过累计污染负荷比法对我国生活垃圾填埋场地下水的主要污染物进行了识别;并通过内梅罗指数法和地下水质量评分法对其地下水质量进行了评价,以期为我国生活垃圾填埋场地下水污染的评价、修复和治理提供依据.结果表明:我国生活垃圾填埋场地下水中已报道检出污染物共计99种,同时还有视觉污染指标2种,其他综合性污染指标6种.其中普遍性污染物主要包括:氨氮、硝酸盐、亚硝酸盐、高锰酸盐指数、COD、总硬度、氯化物、铁、锰、总大肠菌群、挥发酚等;局部性污染物主要包括:总磷、溶解性总固体、氟化物、硫酸盐、细菌总数、铬(六价)等;点源性污染物主要包括:三氯苯、镉、铅、汞、碘化物等,局部性和点源性污染物地区差异明显.我国生活垃圾填埋场附近地下水质量综合评分F值为7.85,属于极差级别,已受到严重污染.%In order to give a basis for the assessment, the remediation and the treatment of groundwater contaminations, the groundwater pollutants from MSWLs were identified by cumulative pollution load ratio; the groundwater quality near the MSWLs were assessed integrally by Nemero index method and grading methods based on authors′ survey and related reports from 1991to 2014. The results showed that there were 99 kinds of groundwater pollutants, 2 kinds of visual pollutants and 6 kinds of aggregative pollutants which had been detected. The widespread groundwater pollutants include ammonia, nitrate, nitrite, permanganate index, chemical oxygen demand, total hardness, chloride, iron, manganese, total coliform and volatile phenol; the local groundwater pollutants include totalphosphorus, total dissolved solids, fluoride, sulfate, bacterial count and hexavalent chromium; the point groundwater pollutants include trichloro-benzene, cadmium, lead, mercury and iodide. Additionally, the local groundwater pollutants and the point groundwater pollutants are very different in different areas. The comprehensive score of groundwater quality was 7.76. It is indicated that the groundwater near MSWLs had been contaminated seriously in China.【期刊名称】《中国环境科学》【年(卷),期】2015(035)009【总页数】10页(P2843-2852)【关键词】生活垃圾填埋场;地下水;污染物;环境质量评价【作者】韩智勇;许模;刘国;程诚【作者单位】成都理工大学环境与土木工程学院,地质灾害防治与地质环境保护国家重点实验室,四川成都 610059;成都理工大学环境与土木工程学院,地质灾害防治与地质环境保护国家重点实验室,四川成都 610059;成都理工大学环境与土木工程学院,地质灾害防治与地质环境保护国家重点实验室,四川成都 610059;成都理工大学环境与土木工程学院,地质灾害防治与地质环境保护国家重点实验室,四川成都610059【正文语种】中文【中图分类】X523当前,我国地下水污染形势日益严峻,局部地区地下水污染问题十分突出,其中生活垃圾填埋场已成为我国公认的地下水重点污染源之一.根据2014年《中国统计年鉴》,全国已建城镇生活垃圾卫生填埋场580座,实际卫生填埋量10492.7万 t,占城市生活垃圾无害化处理量的68.2%,而且还有数以万计的简易生活垃圾填埋场和堆弃点.这些填埋场在几十甚至上百年的运行和稳定化过程中会产生大量的渗滤液.渗滤液水质复杂,含有高浓度的有机物、无机盐、金属和重金属离子,细菌等微生物,以及少量异性生物有机化合物,具有持久和较高的毒性［1-4］.填埋场渗滤液渗漏后,会造成不同程度的地下水污染［5-13］.但是,在我国均是不同学者以某一地区或某一填埋场为个例,开展填埋场对地下水的点状污染的研究［14-41］,缺乏对这些分散的研究结果进行归纳总结和综合分析.为此,笔者通过文献检索和现场调研,采用累计污染负荷比法对我国生活垃圾填埋场地下水的主要污染物进行识别；并通过标准指数法、内梅罗指数法、地下水质量评分法等评价方法,评价我国生活垃圾填埋场对地下水的污染现状和程度,分析其污染特点,以期为总体把握我国生活垃圾填埋场对地下水的污染现状,以及对填埋场地下水污染的评价、修复和治理提供依据.1.1 文献检索通过“中国知识资源总库”检索1991年至2014年期间生活垃圾填埋场对地下水污染研究的相关报道,共筛选出28篇文献；通过“Elsevier ScienceDirect全文期刊数据库”检索全部年限内关键词为“landfill”+“groundwater”的相关报道,共筛选出3篇文献,并结合对四川某生活垃圾卫生填埋场地下水的调研数据和其他收集数据,进行数据统计分析和评价.这些文献覆盖了我国一半以上的省和自治区,并包括了不同填埋年限、不同地域和下覆场地条件、不同类型的填埋场,具有较好的代表性.生活垃圾填埋场的基本情况见表1所示.1.2 评价方法1.2.1 标准指数法生活垃圾填埋场地下水现状评价采用标准指数法［42］.标准指数法采用《地下水质量标准》（GB/T14848-93）中的III类标准值［43］,未列入的指标参考《地表水环境质量标准》（GB 3838-2002）中的III类标准值［44］.1.2.2 内梅罗指数法内梅罗指数法计算如式（1）所示：式中：PI为i组分的内梅罗指数,无量纲；Piavg为i组分标准指数Pi的平均值,无量纲；Pimax为i组分标准指数Pi的最大值,无量纲.1.2.3 评分法地下水质量综合评价采用评分法［43］.首先根据《地下水质量标准》（GB/T14848-93）或《地表水环境质量标准》（GB 3838-2002）进行各单项组分评价,划分组分所属质量类别.其次对各类别按表 2规定分别确定单项组分评价分值Fi,当标准值无类别划分时,超标按V类取值,未超标按I类取值.然后按照式（2）计算综合评价分值FI：式中：FI为 i区（或组分）的综合评分值,无量纲；Fiavg为i区（或组分）评分值Fi的平均值,无量纲；Fimax为i区（或组分）评分值Fi的最大值,无量纲.最后根据F值,按表3规定划分地下水质量级别.1.2.4 累计污染负荷比法首先根据1.2.3的计算结果,按照式（3）对不同区域（或组分）分别计算各组分（或各区域）的综合评分值FI的负荷比.式中：Ji为i组分的综合评分值负荷比,无量纲.然后将n区域（或组分）中累计负荷比的m组分（或区域）定为评价区（或组分）的主要污染物（或污染区）.2.1 污染物统计根据文献统计,目前我国生活垃圾填埋场地下水中已报道检出相关污染物共计99种,其中有机污染物3种,无机盐12种,金属离子5种,重金属15种,细菌学污染物2种,异性生物有机化合物62种；同时还包括视觉污染指标2种,其他综合性污染指标6种.除表4中有检出浓度报道的污染物［10-40］外,还有重金属钴［46］；异性生物有机化合物二氢苊、苯并（b）荧蒽、六六六、DDT［33］、芴、苯并（a）蒽、1,2-二氯乙烷、顺-1,2-二氯乙稀［45］、菲、荧蒽、芘［33,45］、酚［47］、苯酚［46,48］、烷烃、丁酸丁酯、1,1-二甲基乙基-4-甲氧基酚、酞酸二异辛酯、十六酸、环八硫烷［49］等.2.2 主要污染物识别为满足数理统计要求,确保数据的可信度,选取表4中样本量大于20,且FI值评价在较差以上程度的 24个污染物作为主要污染物的备选指标.根据累计负荷比 JI,得到我国生活垃圾填埋场地下水主要污染物包括：总大肠菌群、细菌总数、总磷、总硬度、氨氮、总溶解性固体、化学需氧量、锰、亚硝酸盐、挥发酚、铁、汞、高锰酸盐指数、硫酸盐、镉、三氯苯等,其JI=0.721.结合表 4中各污染物的超标率和 PI 值,我国生活垃圾填埋场地下水主要污染物如表5所示.这些污染物与填埋场渗滤液的主要污染物［1-5］相符,可见填埋场地下水中的主要污染物来自于填埋场渗滤液的入渗.3.1 地下水质量评价由图1可知,我国生活垃圾填埋场附近地下水质量为极差,其中华中、华东、华北和华南地区填埋场地下水质量为极差,东北、西南和西北地区填埋场地下水质量为较差.由此可见,我国生活垃圾填埋场已对其周围地下水造成了严重的污染.填埋场地下水污染主要由渗滤液入渗导致,由于渗滤液的特性受垃圾组分、填埋时间、填埋工艺、填埋方式、填埋场运行管理方式、气象条件等因素的影响［2］,而且入渗的污染物衰减也受到包气带和含水层中的稀释、吸附、离子交换、沉淀、氧化还原以及微生物的降解等作用的影响［5］,因此,导致了不同地区填埋场地下水受污染的程度差异较大,其中华东、华北地区污染最为严重,西北地区相对较轻.3.2 污染特征分析3.2.1 污染物分布特性根据Ji值,对不同污染物的地区分布进行排序,如表6所示. 考虑部分指标（如细菌学类指标、溶解性总固体等）监测分布样本量的局限性,结合表4中污染物的超标率和表6的主要污染物分布,综合分析得出生活垃圾填埋场地下水污染物主要包括普遍性污染物、局部性污染物和点源性污染物.其中：（1）普遍性污染物主要包括：氨氮、硝酸盐、亚硝酸盐、高锰酸盐指数、化学需氧量、总硬度、氯化物、铁、锰、总大肠菌群、挥发酚等.（2）局部性污染物主要包括：总磷、溶解性总固体、氟化物、硫酸盐、细菌总数、铬（六价）等.（3）点源性污染物主要包括：三氯苯、镉、铅、汞、碘化物等.3.2.2 区域污染物类型根据Ji值,对不同区域污染物的类型进行分析,结果如表7所示.由表7可知,华北和东北地区生活垃圾填埋场地下水污染物种类较多,相对复杂；华东和华中地区除细菌类污染物未见报道外,地下水受到其余类污染物不同程度的污染；西南地区主要为无机盐、重金属和细菌类污染；西北地区主要为无机物和重金属污染物；华南地区主要为有机物和无机盐污染.其中重金属、细菌学和异性生物有机化合物的种类和浓度地区差异明显.各地区污染物类型的差异除了与填埋场基本情况和其下覆水文地质条件密切相关外,各地区检索的文献样本量差异也是其影响因素之一.4.1 生活垃圾填埋场地下水中已报道检出污染物共计99种,其中有机污染物指标3种,无机盐12种,金属离子5种,重金属15种,细菌学污染指标2种,异性生物有机化合物62种；同时还包括视觉污染指标2种,其他综合性污染指标6种.4.2 生活垃圾填埋场地下水普遍性污染物主要包括：氨氮、硝酸盐、亚硝酸盐、高锰酸盐指数、化学需氧量、总硬度、氯化物、铁、锰、总大肠菌群、挥发酚等；局部性污染物主要包括：总磷、溶解性总固体、氟化物、硫酸盐、细菌总数、铬（六价）等；点源性污染物主要包括：三氯苯、镉、铅、汞、碘化物等；且局部性和点源性污染物地区差异明显.4.3 我国生活垃圾填埋场附近地下水质量综合评分F值为7.85,属于极差级别,已受到填埋场的严重污染.China Environmental Science, 2015,35（9）：2843～2852【相关文献】［1］郑曼英,李丽桃,邢益和,等.垃圾渗滤液的污染特性及其控制［J］. 环境卫生工程, 1997,（2）：7-11.［2］张正安,杨云贵,贾玉娟,等.垃圾填埋渗滤液水质特性及影响因素分析［J］. 宜宾学院学报, 2009,9（6）：71-72.［3］方艺民,许玉东.垃圾渗滤液中微量有机物分类及其污染特性［J］. 能源与环境, 2013,（5）：103-104.［4］Regadío M, Ruiz AI, Soto IS, et al. 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生活饮用水标准检验方法英文Methods for the Inspection of Standards of Potable Drinking Water 1. Physical Inspection1.1 Color test: The color of the water is observed visually and compared to the standard color scale.1.2 Odor test: The odor of the water is assessed using the sense of smell.1.3 Turbidity test: Turbidity of the water is measured using a turbidity meter or by visual assessment against a turbidity standard.1.4 Temperature test: The temperature of the water is measured using a thermometer.2. Chemical Inspection2.1 pH test: The pH of the water is measured using a pH meter or pH test strips.2.2 Chlorine residual test: The concentration of chlorine present in the water is determined using appropriate chemical titration methods.2.3 Total dissolved solids (TDS) test: The TDS content in the water is measured using a TDS meter.2.4 Nitrate test: The nitrate concentration in the water is determined using appropriate chemical methods.2.5 Fluoride test: The fluoride concentration in the water is measured using specific ion-selective electrodes or colorimetric methods.2.6 Heavy metal test: The presence of heavy metals such as lead, arsenic, and mercury is determined using suitable instrumental methods like atomic absorption spectroscopy or inductively coupled plasma mass spectrometry.3. Microbiological Inspection3.1 Total coliforms test: The presence of total coliform bacteria is determined using the Most Probable Number (MPN) technique or membrane filtration method.3.2 Escherichia coli (E. coli) test: The presence of E. coli bacteria, an indicator of fecal contamination, is determined using appropriate biochemical tests or molecular methods.3.3 Heterotrophic plate count (HPC) test: The microbial load in the water is assessed by culturing on suitable solid media and counting the number of colonies.These are some commonly employed methods for inspecting the standards of potable drinking water. It is important to note that these methods may vary depending on the specific requirements and regulations imposed by different regulatory bodies.。