A Comparison of the Precipitation Chemistry Measurements Obtained by the CAPMoN and NADP/NTN Networks

Precipitation chemistry measurementsobtained by the Canadian Air and PrecipitationMonitoring Network (CAPMoN) and the U.S. NationalAtmospheric Deposition Program/National Trends Network(NADP/NTN) have been examined using more than 7 yrof collocated data from two sites, namely, Sutton,Quebec, Canada and State College, Pennsylvania, U.S.A.In the case of the CAPMoN data, weeklyprecipitation-weighted mean concentrations, totalsample depths and total standard gauge depths werecomputed from daily data and compared to thecorresponding weekly sampling data of the NADP/NTNnetwork. Seasonal and annual precipitation-weightedmean concentrations and deposition values were alsocomputed for both networks and compared. Statisticallysignificant between-network biases were found to existin the weekly results for most of the measuredvariables, particularly standard gauge depth, sampledepth, pH, H⁺, NO₃ ^-,NH₄ ⁺,Na⁺; the NADP/NTN values were consistently lowerthan those of CAPMoN with the exception of pH andNa⁺. The magnitude of the biases was less than35% of the median CAPMoN weekly value for the 7 yr. For most of the measured parameters, thevariability of the between-network differencesrepresented less than 20% of the median CAPMoN weeklyvalue. Both the between-network biases andvariabilities were functions of several physicalparameters, the most dominant being the sample depthand the ionic concentration. For seasonal and annualdeposition values, statistically significantbetween-network biases were found for H⁺,SO₄ ^2-, NO₃ ^-,Ca²⁺,NH₄ ⁺ for both periods; for Mg²⁺ andK⁺ for seasonal data; and Cl^- for yearlydata, with the NADP/NTN deposition values being lowerthan those of CAPMoN. The relative biases ranged from7 to 37%. Part of the between-network bias in thedeposition estimates was directly attributable to astrong bias in the standard gauge depths of the two networks.     

Comparison of precipitation chemistry measurements obtained by the Canadian Air and Precipitation Monitoring Network and National Atmospheric Deposition Program for the period 1995–2004

Precipitation chemistry and depth measurements obtained by the Canadian Air and Precipitation Monitoring Network (CAPMoN) and the US National Atmospheric Deposition Program/National Trends Network (NADP/NTN) were compared for the 10-year period 1995–2004. Colocated sets of CAPMoN and NADP instrumentation, consisting of precipitation collectors and rain gages, were operated simultaneously per standard protocols for each network at Sutton, Ontario and Frelighsburg, Ontario, Canada and at State College, PA, USA. CAPMoN samples were collected daily, and NADP samples were collected weekly, and samples were analyzed exclusively by each network’s laboratory for pH, H^?+?, Ca^2?+?, Mg^2?+?, Na^?+?, K^?+?, $\text{NH}_{4}^{+}$ , Cl^???, $\text{NO}_{3}^{-}$ , and $\text{SO}_{4}^{2-}$ . Weekly and annual precipitation-weighted mean concentrations for each network were compared. This study is a follow-up to an earlier internetwork comparison for the period 1986–1993, published by Alain Sirois, Robert Vet, and Dennis Lamb in 2000. Median weekly internetwork differences for 1995–2004 data were the same to slightly lower than for data for the previous study period (1986–1993) for all analytes except $\text{NO}_{3}^{-}$ , $\text{SO}_{4}^{2-}$ , and sample depth. A 1994 NADP sampling protocol change and a 1998 change in the types of filters used to process NADP samples reversed the previously identified negative bias in NADP data for hydrogen-ion and sodium concentrations. Statistically significant biases (α = 0.10) for sodium and hydrogen-ion concentrations observed in the 1986–1993 data were not significant for 1995–2004. Weekly CAPMoN measurements generally are higher than weekly NADP measurements due to differences in sample filtration and field instrumentation, not sample evaporation, contamination, or analytical laboratory differences.     

A Statistical Assessment of Changes in Precipitation Chemistry at CAPMoN Sites, Canada

The objective of this study is to decide if chemical concentrations measured during 1988-1997in precipitation by the Canadian Air and Precipitation Monitoring Network (CAPMoN) indicate changes in the annual patterns. The inference is based on SO₄, NO₃, Cl,NH₄, Na, Ca and K concentrations monitored daily with the rain water acidity pH. By pattern is understood the probability distribution of the annual sample at a particular location. Most of the annual data can be well described by means of a linear regression model with second order polynomial trend and autocorrelated noise. Statistical analysis based on the model shows luck of systematic significant year to year increases or declines of the concentrations.     

上海青浦地区大气降水的化学特征

利用上海青浦地区2003—2014年观测的大气降水监测资料,分析该区域12 a以来大气降水的酸化程度、化学组成特征,探讨降水中化学成分的不同来源及相对贡献。结果表明:降水pH年均值为4.43~6.33,酸雨频率为2.6%~86.8%,降水酸化程度大致经历了明显恶化和波动变化2个阶段。降水电导率年均值为1.77~4.01 m S/m,呈下降趋势。降水中各离子雨量加权平均当量浓度顺序为SO_4~(2-)NH_4~+Ca~(2+)NO_3~-Cl~-Na~+Mg~(2+)F-K~+,SO_4~(2-)、NH+4、Ca~(2+)和NO_3~-是降水中的主要离子,占离子总量的83.0%;降水类型由硫酸型向硫酸和硝酸混合型转变。降水离子中的二次组分SO_4~(2-)、NO_3~-和NH_4~+绝大部分来源于人为源,Ca~(2+)、Mg~(2+)和K+主要来自于土壤源和人为源的贡献,Cl~-主要来自海洋源,同时人为源的影响也不可忽视。     

A pragmatic approach to study the groundwater quality suitability for domestic and agricultural usage,Saq aquifer,northwest of Saudi Arabia

The present study deals with detailed hydrochemical assessment of groundwater within the Saq aquifer. The Saq aquifer which extends through the NW part of Saudi Arabia is one of the major sources of groundwater supply. Groundwater samples were collected from about 295 groundwater wells and analyzed for various physico-chemical parameters such as electrical conductivity (EC), pH, temperature, total dissolved solids (TDS), Na⁺, K⁺, Ca²⁺, Mg²⁺, CO₃ ^?, HCO₃ ^?, Cl^?, SO₄ ^2?, and NO₃ ^?. Groundwater in the area is slightly alkaline and hard in nature. Electrical conductivity (EC) varies between 284 and 9,902?μS/cm with an average value of 1,599.4 μS/cm. The groundwater is highly mineralized with approximately 30 % of the samples having major ion concentrations above the WHO permissible limits. The NO₃ ^? concentration varies between 0.4 and 318.2 mg/l. The depth distribution of NO₃ ^? concentration shows higher concentration at shallow depths with a gradual decrease at deeper depths. As far as drinking water quality criteria are concerned, study shows that about 33 % of samples are unfit for use. A detailed assessment of groundwater quality in relation to agriculture use reveals that 21 % samples are unsuitable for irrigation. Using Piper’s classification, groundwater was classified into five different groups. Majority of the samples show Mix-Cl-SO₄- and Na-Cl-types water. The abundances of Ca²⁺ and Mg²⁺ over alkalis infer mixed type of groundwater facies and reverse exchange reactions. The groundwater has acquired unique chemical characteristics through prolonged rock-water interactions, percolation of irrigation return water, and reactions at vadose zone.     

Chemical Characteristics of Rain Water at an Urban Site of South Western Turkey

In this study, chemical composition of the rain water in Mugla was investigated from February to April 2002. Rain water samples were obtained from Mugla, a small city in south western Turkey. The Yatagan Power Plant is located 30 km northwest of Mugla city. The values of pH and the concentrations of major ions (Ca²⁺, Na⁺, K⁺, SO₄ ²⁻, NO₃ ⁻, NH₄ ⁺) in the rainwater samples were analyzed. The pH varied from 4.5 to 7.7 with an average of 6.9 which was in alkaline range considering 5.6 as the neutral pH of cloud water with atmospheric CO₂ equilibrium. In the total 30 rain events, only two events were observed in acidic range (< 5.6) which occurred after continuous rains. The equivalent concentration of components followed the order: Ca²⁺ > SO₄ ²⁻ > NH₄ ⁺ > NO₃ ⁻ > Na⁺ > K⁺ > H⁺. The volume-weighted mean (VWM) of the measured ionic sum is 371.62 μeq/l. The ratio of between sum cations and sum anions (∑cations /∑ anions) is 1.52 μeq/l. The alkaline components (Ca²⁺, Na⁺, K⁺) contribute 52%, NH₄ ⁺ 8%, whereas, the contribution from the acidic components is relatively small (40%). The low concentrations of H⁺ found in rainwater samples from Mugla suggest that an important portion of H₂SO₄ and HNO₃ have been neutralized by alkaline particles in the atmosphere. The dust-rich local and surrounding limestone environment might have caused the high concentration of Ca²⁺ in Mugla area. The relatively high concentration of NH₄ ⁺ observed at Mugla is suspected to be due to surrounding agricultural. The results obtained in this study are compared with those other studies conducted at various places in the world.     

Groundwater Quality Monitoring in Shallow and Deep Aquifers in Saidabad Tahsil Area, Mathura District, India

Water availability in arid regions is both sporadic and highly variable in quantity. If the water quality shows large variations of salinity and concentration of other chemical constituents with depth and time span, it has considerable effect on the entire hydrological set up of the area. In the Saidabad tahsil area, the deep aquifers that supply water to borewells in the alluvial plain of the Mathura region, Uttar Pradesh, have higher salinity than those of the dugwells from the shallow aquifers. The excessive drilling of tubewells and high yield tubewells are resulting in deterioration of water quality of the shallow aquifers. On the contrary, the chemical constituents such as, Na⁺, K ⁺, Cl ^-, andHCO ₃ ^- show higher concentration in shallow aquifers than deep aquifers. A study carried out to monitor water quality in this region reveals that the groundwater quality varies with depth and time span in shallow and deep aquifers. Factors controlling variations in salinity and concentration of chemical constituents of the water in the two types of aquifers are discussed. The relative merits of the shallow water for potability are pointed out with respect to salinity concentrations and public health.     

Influence of Meteorological Parameters on Particulates and Atmospheric Pollutants at Taichung Harbor Sampling Site

Atmospheric aerosol particles and metallic concentrations, ionic species were monitored at the Experimental harbor of Taichung sampling site in this study. This work attempted to characterize metallic elements and ionic species associated with meteorological conditions variation on atmospheric particulate matter in TSP, PM_2.5, PM_2.5–10. The concentration distribution trend between TSP, PM_2.5, PM_2.5–10 particle concentration at the TH (Taichung harbor) sampling site were also displayed in this study. Besides, the meteorological conditions variation of metallic elements (Fe, Mg, Cr, Cu, Zn, Mn and Pb) and ions species (Cl⁻, NO₃ ⁻, SO₄ ²⁻, NH₄ ⁺, Mg²⁺, Ca²⁺ and Na⁺) concentrations attached with those particulate were also analyzed in this study. On non-parametric (Spearman) correlation analysis, the results indicated that the meteorological conditions have high correlation at largest particulate concentrations for TSP at TH sampling site in this study. In addition, the temperature and relative humidity of meteorological conditions that played a key role to affect particulate matter (PM) and have higher correlations then other meteorological conditions such as wind speed and atmospheric pressure. The parameter temperature and relative humidity also have high correlations with atmospheric pollutants compared with those of the other meteorological variables (wind speed, atmospheric pressure and prevalent wind direction). In addition, relative statistical equations between pollutants and meteorological variables were also characterized in this study.     

A Comparison of Precipitation Sensors Used on the Wet-Only Collectors

The variability in performance of three precipitation sensor types, mounted on three identical wet-only collectors, has been compared for eight months at a single site. The catch efficiencies, determined from the sample volumes, are relatively high for these three apparatuses, since they exceed 89% on average. The recorded data of openings and closings of collector lids reveal that the highest losses of collection efficiency, observed for rainfalls of low intensity and low amount, are largely imputable to design and running characteristics of each sensor. Ionic compositions between the samples of these three collectors are relatively close, although significant differences are especially found for H⁺, Ca²⁺, Mg²⁺ and K⁺, suggesting that these apparatuses are differently exposed to the dry deposition of soil particles. The RS 85 sensor seems to be the most suitable one of the three, since it ensures a high catch efficiency for all rain types and tends to limit the exposures of funnel to the dry deposition.     

重庆市黔江区降水地球化学特征

为了解生态旅游城市重庆市黔江区大气污染状况,2015年采集了91个降水样品,分析了降水中离子组分分布特征,运用富集因子法、海盐示踪法、相关性分析、主成分分析、聚类分析和HYSPLIT模型分析了降水化学组分来源。研究结果表明:黔江区域降水p H为5.66~6.96,加权平均值为6.34,降水离子组分浓度大小次序为SO_4~(2-)Ca~(2+)NH_4~+Mg~(2+)NO_3~-Cl~-Na~+K~+F~-,SO_4~(2-)、Ca~(2+)之和占总离子的63.95%;除Mg~(2+)和K+外,其余组分离子浓度与总离子浓度随季节变化(冬季春季秋季夏季)呈同样的变化特征。Ca~(2+)、Mg~(2+)和K+大部分均来源于陆源贡献,Na~+可能受到了海洋源的影响,SO_4~(2-)和NO_3~-主要来源于人为输入源的贡献,Cl~-是受土壤物质和海洋的双重影响。轨迹水汽运输结果表明:黔江区域的降水主要受到西北气团、西南季风、西风环流和极地气候共同作用输入。降水中各个离子组分均表现出显著性或极显著性关系,主成分分析结果表明,第一主成分上研究的降水离子组分中都具有相对较大正载荷,第二组分pH、降水量和气温为一类。     

Estimated Variability of National Atmospheric Deposition Program/Mercury Deposition Network Measurements Using Collocated Samplers

The National Atmospheric Deposition Program/Mercury Deposition Network (MDN) provides long-term, quality-assured records of mercury in wet deposition in the USA and Canada. Interpretation of spatial and temporal trends in the MDN data requires quantification of the variability of the MDN measurements. Variability is quantified for MDN data from collocated samplers at MDN sites in two states, one in Illinois and one in Washington. Median absolute differences in the collocated sampler data for total mercury concentration are approximately 11% of the median mercury concentration for all valid 1999–2004 MDN data. Median absolute differences are between 3.0% and 14% of the median MDN value for collector catch (sample volume) and between 6.0% and 15% of the median MDN value for mercury wet deposition. The overall measurement errors are sufficiently low to resolve between NADP/MDN measurements by ±2 ng·l⁻¹ and ±2 μg·m⁻²·year⁻¹, which are the contour intervals used to display the data on NADP isopleths maps for concentration and deposition, respectively.     

Analysis of Wet Precipitation of Air Pollutants in Mumbai (India)

Bulk precipitation samples at Mumbai (India) were collectedduring the monsoon seasons of 1991 to 1996 and analysed forionic concentrations using an Ion Chromatograph DIONEX model100. The variability of sulphate to nitrate ratio in rainwaterfluctuates in a wide range from 1.5 to 20 and governed by thesulphate concentrations in the sample. The regression analysisof the data reveals that in the bulk precipitation at Mumbai, SO₄ ^2- is becoming increasingly important relative toNO₃ ^-. The role of meteorological influences onscavenging of air pollutants by rain water has been tried toexplain the phenomena. The computed wet deposition rates for Sand N during 1991–1996 show that the S deposition is higherthan N in all the years. There is a wide fluctuation indeposition rates of S ranging from 2 to 55 kg km² per annum.     

沿海城市PM10和PM2.5自动监测过程中质量浓度“倒挂”现象分析与成因探讨

2020年2—3月,位于福建沿海地区中部的莆田市在环境空气质量自动监测过程中出现了严重的PM_(10)和PM_(2.5)质量浓度"倒挂"现象,小时值"倒挂"率为19.86%,日均值"倒挂"率为16.67%。在高相对湿度和低风速气象条件下,颗粒物会出现严重的"倒挂"现象,"倒挂"过程中常伴随着颗粒物和气态污染物(SO_2、NO_2和CO)质量浓度的增加。因此,于2020年2月16日—3月26日开展了颗粒物自动监测和手工监测比对,并结合气象参数、气态污染物质量浓度,以及PM_(10)和PM_(2.5)中水溶性离子和液态水的含量特征,进一步探讨了莆田市颗粒物质量浓度"倒挂"的主要成因。研究表明,PM_(10)和PM_(2.5)自动监测仪器检测原理的差异是导致颗粒物质量浓度"倒挂"的重要原因之一,而气象条件(相对湿度、气温和风速等)、颗粒物质量浓度、颗粒物中主要吸湿组分(NO_3~-、SO_4~(2-)和NH_4~+)和液态水的含量也是颗粒物质量浓度"倒挂"的主要影响因素。莆田市2020年2—3月出现高频率"倒挂"现象是多重因素共同作用的结果,解决该问题需要同时考虑监测仪器检测原理、气象参数、颗粒物质量浓度和吸湿组分等的影响。     

北京夏季大气主要含氮无机化合物的变化规律与相互作用

利用SJAC-MOBIC/FIA在2006年8月16日—9月9日在线测量了北京城市大气细颗粒物中主要水溶性含氮离子组分(NO₃^-和 NH₄⁺),与重要含氮气态污染物(HNO₃、HNO₂和 NH₃),以追踪细颗粒物中含氮二次无机组分和含氮气态污染物的变化规律及其相互作用。观测期间,NO₃^- 和 NH₄⁺的平均浓度分别为13.08和11.93 μg/m³,它们与SO₄^2-浓度之和在细颗粒物(PM_2.5)中的平均比例为55%,明显高于其他季节;污染过程中,积聚模态颗粒物体积浓度及其与爱根核模态颗粒物体积浓度比值逐渐增加,说明二次转化是北京夏季细颗粒物的重要来源。白天HONO迅速光解产生OH自由基,而OH自由基是生成HNO₃的重要物种,因此HONO和HNO₃具有相反的日变化规律。在温度较高的白天,大气环境不利于NH₄NO₃的生成与存在;夜间低温高湿的条件下硝酸铵理论平衡系数Ke与气态氨和硝酸的乘积Km相当或低于后者,较有利于NH₄NO₃的生成。北京夏季大气具有足量气态NH₃以中和硫酸盐;但在NO₃^-与阳离子的电荷平衡中,金属阳离子也非常重要。     

Field Comparison of two NO2 Passive Samplers to Assess Spatial Variation

Two-week average NO₂ concentrations were measured in Amsterdam (NL), Huddersfield (UK) and Prague (CZ) at 80 sites in each study area, to assess small area spatial variation, using a tube type and a badge type passive sampler. The badges appeared to be less robust than the tubes. The lower detection limit for tubes and badges was 3.7 and 0.91 µg/m³, respectively for fortnightly measurements. Accuracy of the samplers was determined with reference methods (chemiluminescence). The mean ratio of the concentration measured by diffusion tube over that by the reference method was 1.16, 1.03 and 0.77 in Amsterdam, Huddersfield and Prague, respectively. Standardizing the badges for the results obtained in Amsterdam, the relative mean ratio of the concentration measured by the badges over that by the reference method was 0.95 and 0.58 in Huddersfield and Prague, respectively. NO₂ concentrations measured by the two designs did not differ significantly. Mean NO₂ concentrations were 36, 26 and 22 µg/m³ in Amsterdam, Huddersfield and Prague, respectively. The precision of duplicate tubes and badges was 8% and 11%, respectively. Both samplers are suitable for determining real variation in small area NO₂ concentrations in the ranges which occurred. It is concluded that low-cost, simple NO₂ passive samplers can provide reliable information about variation in NO₂ concentrations within urban or rural areas on a small spatial scale. Based on its robustness and its precision, tubes were preferred over badges.     

Occurrence of Acid Rain over Delhi

Precipitation samples were collected as wet-fall only andprimarily on event basis in Delhi during the monsoon period of1995. Concentrations of major anions (SO₄ ^2-,NO₃ ^- and Cl^-) andcations (Ca²⁺, Mg²⁺,Na⁺ and K⁺) were determined. The pH of the rain waterwas found to be more than 5.6, showing alkalinity during theearly phase of monsoon, but during the late phase of monsoon pHtendency was towards acidity due to lack of proper neutralizationof acidic ions. Neutralization is not only due to the localprocess but also due to the pre-monsoon Andhi which bringsSuspended Particulate Matter (SPM) containing Ca²⁺,Mg²⁺, Na⁺ and K⁺ as well as the local emission ofNH₃. In the late monsoon the concentration of cations getsreduced because of heavy rainfall and relatively unfavourablecondition for their transport from the adjoining areas, whereasthe anion concentrations remain unchanged owing to theircontinuous emission.     

The Influence of a Coal-Fired Power Plant in Turkey on the Chemical Composition of Rain Water in a Certain Region

In this study, the chemical composition of the rainwater in Yatağan, which is a region surrounding a coal power plant was investigated from February to April 2002. Rainwater samples were obtained from Yatağan, located northwest of Muğla City in Turkey. pH values and concentrations of major ions (Ca²⁺, Na⁺, K⁺, , , ) in the rainwater samples were analyzed. The pH varied from 5.1 to 7.9 with an average of 6.7 which was in alkaline range considering 5.6 as the neutral pH of cloud water in equilibrium with atmospheric CO₂. In the total of 30 rain events, only three events were observed with water in the acidic range (<5.6), which occurred after continuous rains. The equivalent concentration of components followed the order: Ca²⁺ > > Na⁺ > > > K⁺ > H⁺. The anion and cation concentrations in the rainwater samples showed a high sulphate concentration (131 μEq/l), as well as high sodium (40 μEq/l) and calcium (298 μEq/l) concentrations. These values indicate that one probable source of the high sodium concentration is fly ash, after the coal burning process and the power plant can be effective on level concentrations in rainwater. In addition, the dust-rich local and surrounding limestone environment might have caused the high concentration of Ca²⁺ in rainwater of the Yatağan Basin. Due to a large contribution of these cations to the sulphate neutralization action, the rainwater of this region displays only a moderate acidity, which does not cause significant environmental impact.     

2010—2019年台州市市区降水化学组成特征及变化趋势

为了解台州市市区大气降水化学成分组成特征及变化规律,对2010—2019年台州市市区降水监测数据进行了统计分析。结果表明:2010—2019年降水样品pH为4.20～4.84夏高冬低,强酸性降水频率下降显著,电导率平均值为3.16 mS/cm。SO_4~(2-)和NO_3~-是降水中最主要的阴离子,NH_4~+和Ca~(2+)是降水中最主要的阳离子。Ca~(2+)浓度在2018年开始有所抬升,SO_4~(2-)和NO_3~-浓度整体呈波动下降趋势。SO_4~(2-)与NO_3~-浓度比均值为1.50,呈下降趋势,同大气中SO_2与NO_2的质量浓度比变化趋势基本一致。SO_4~(2-)和NO_3~-相关性显著,Cl~-、Na~+及Mg~(2+)三者之间具有较好相关性。降水与气态污染物相关性不大,对颗粒物有明显冲刷去除作用。SO_2和NO_x的排放量显著下降,酸雨污染呈现改善过程。     

Deposition in boreal forests in relation to type, size, number and placement of collectors

Open precipitation and throughfall was collected at a Norway spruce stand in Finland using funnel-type collectors and at a black spruce stand in Canada using trough-type collectors. The presence or absence of a rim on the funnel, funnel diameter (9, 14 and 20 cm) and length of sampling period (1, 2 and 4 weeks) on monthly values were evaluated at the Norway spruce stand, and the number of collectors required for defined levels of accuracy and precision of throughfall loads to be reached and the influence of the spatial arrangement of collectors on solute concentrations was studied at both stands. The presence of a rim had no significant effect on open precipitation and throughfall amounts, but did on throughfall DOC, Ca²⁺, Mg²⁺, K⁺, Na⁺ and Cl⁻ ion loads. Deposition loads increased with decreasing funnel diameter; for open precipitation, this was due to increased catch efficiency while for throughfall the increase was attributed to canopy interaction and leaching of litter trapped in the collectors. Calculated monthly H⁺ loads decreased and those for all other constituents increased with collection period length. Using 15 collectors at the Norway spruce stand would allow throughfall loads to be determined to within 20% of the true mean weekly value with a confidence level of 95% for most solute, but not for NH₄ ⁺–N, NO₃ ⁻–N, Mg²⁺ and SO₄ ²⁻-S. Using 15 trough collectors, the same confidence level at the more heterogeneous black spruce stand would only be achieved for H⁺, Cl⁻, DOC and SO₄ ²⁻-S loads. In both stands, using either random or systematic placements of throughfall collectors gave similar results.     

Leachate Characterization and Assessment of Groundwater Pollution Near Municipal Solid Waste Landfill Site

Leachate and groundwater samples were collected from Gazipur landfill-site and its adjacent area to study the possible impact of leachate percolation on groundwater quality. Concentration of various physico-chemical parameters including heavy metal (Cd, Cr, Cu, Fe, Ni, Pb and Zn) and microbiological parameters (total coliform (TC) and faecal coliform (FC)) were determined in groundwater and leachate samples. The moderately high concentrations of Cl⁻, NO⁻ ₃, SO²⁻ ₄, NH⁺ ₄, Phenol, Fe, Zn and COD in groundwater, likely indicate that groundwater quality is being significantly affected by leachate percolation. Further they proved to be as tracers for groundwater contamination. The effect of depth and distance of the well from the pollution source was also investigated. The presence of TC and FC in groundwater warns for the groundwater quality and thus renders the associated aquifer unreliable for domestic water supply and other uses. Although some remedial measures are suggested to reduce further groundwater contamination via leachate percolation, the present study demand for the proper management of waste in Delhi.