Assessment on Seasonal Variation of Groundwater Quality of Phreatic Aquifers – a River Basin System

Spatial distribution of pH, electrical conductivity (EC), total dissolved solids (TDS), fluoride and total iron content of ground water samples collected from the muvattupuzha river basin, Kerala, India, has been studied for pre monsoon and post monsoon periods of year 2001. Results showed the groundwater of the basin is acidic for which the pH values ranged between 5.5 and 8.0. Average EC was found to be less than 100 μS/cm, for most of the study region. The pre monsoon minimum and maximum TDS were found as 25.6 and 227.84 mg/L respectively, where as post monsoon values ranged between 16 and 162.56 mg/L. The relatively low EC and TDS values found both during the seasons in the lateritic terrain of the river basin signifies the lower residence time of ground water with the country rock. This makes the groundwater quality of this river basin as good. Pre monsoon season samples showed high total iron content than that during the post monsoon period. During the study period values of the fluoride contents were found to be within the permissible limits.     

Assessment of ground water quality for drinking purpose, District Nainital, Uttarakhand, India

The ground water quality of District Nainital (Uttarakhand, India) has been assessed to see the suitability of ground water for drinking and irrigation applications. This is a two-part series paper and this paper examines the suitability of ground water including spring water for drinking purposes. Forty ground water samples (including 28 spring samples) were collected during pre- and post-monsoon seasons and analyzed for various water quality constituents. The hydrochemical and bacteriological data was analyzed with reference to BIS and WHO standards and their hydrochemical facies were determined. The concentration of total dissolved solids exceeds the desirable limit of 500 mg/L in about 10% of the samples, alkalinity values exceed the desirable limit of 200 mg/L in about 30% of the samples, and total hardness values exceed the desirable limit of 300 mg/L in 15% of the samples. However, no sample crosses the maximum permissible limit for TDS, alkalinity, hardness, calcium, magnesium, chloride, sulfate, nitrate, and fluoride. The concentration of chloride, sulfate, nitrate, and fluoride are well within the desirable limit at all the locations. The bacteriological analysis of the samples does not show any sign of bacterial contamination in hand pump and tube-well water samples. However, in the case of spring water samples, six samples exceed the permissible limit of ten coliforms per 100 ml of sample. It is recommended that water drawn from such sources should be properly disinfected before being used for drinking and other domestic applications. Among the metal ions, the concentration of iron and lead exceeds the permissible limit at one location whereas the concentration of nickel exceeds the permissible limit in 60 and 32.5% of the samples during pre- and post-monsoon seasons, respectively. The grouping of samples according to their hydrochemical facies indicates that majority of the samples fall in Ca–Mg–HCO₃ hydrochemical facies.     

Survey of the occurrence of residues of methyl tertiary butyl ether (MTBE) in Dutch drinking water sources and drinking water

An indicative survey has been carried out in The Netherlands investigating the presence of methyl tertiary butyl ether (MTBE) in drinking water and the corresponding sources. In total, 71 different sites used for the preparation of drinking water in The Netherlands were sampled in two successive seasons in 2001 involving the analysis of 156 samples. (ground water (n = 88), surface water (n = 17), bank filtrate water (n = 6) and drinking water (n = 45)). To combine high sample throughput with high selectivity and sensitivity, off-line purge and trap for sampling and gas chromatography mass spectrometry equipped with an automated thermal desorption sampler (TDS-GC-MS) was selected as the preferred analytical methodology. The developed procedure enabled the analysis of at least 40 samples per day and provided a limit of quantification of 2 ng l(-1). In the first period 63 samples of raw water were analyzed. Concentrations ranged between < 10 ng l(-1) and 420 ng l(-1) with a median concentration below 10 ng l(-1). The second period was focused at the re-sampling of positive locations (MTBE > 10 ng l(-1)) and a few additional drinking water utilities of which both the raw and drinking water of the utilities were analyzed. The median concentration of MTBE in the selected set of drinking water samples was 20 ng l(-1) (n = 45). At one location MTBE was found at a level of 2900 ng l(-1) caused by point source contamination of the ground water (11 900 ng l(-1)). Special attention has been paid to the quality of the results by analyzing all samples in duplicate and the analysis of control samples during each series of analyses.     

Influence of drought and municipal sewage effluents on the baseflow water chemistry of an upper piedmont river

The Reedy River in South Carolina is affected by the urban area of Greenville, the third most populous city in the state, and by the effluents from two large-scale municipal wastewater treatment plants (WWTPs) located on the river. Riverine water chemistry was characterized using grab samples collected annually under spring season baseflow conditions. During the 4-year time period associated with this study, climatic variations included two severe drought spring seasons (2001 and 2002), one above-normal precipitation spring season (2003), and one below-normal precipitation spring season (2004). The influence of drought and human activities on the baseflow chemistry of the river was evaluated by comparing concentrations of dissolved anions, total metals, and other important water chemistry parameters for these different years. Concentrations of copper and zinc, common non-point source contaminants related to urban activities, were not substantially elevated in the river within the urban area under baseflow conditions when compared with headwater and tributary samples. In contrast, nitrate concentrations increased from 1.2–1.6 mg/l up to 2.6–2.9 mg/l through the urban stream reach. Concentrations of other major anions (e.g., sulfate, nitrate) also increased along the reach, suggesting that the river receives continuous inputs of these species from within the urban area. The highest concentrations of major cations and anions typically were observed immediately downstream from the two WWTP effluent discharge locations. Attenuation of nitrate downstream from the WWTPs did not always track chloride changes, suggesting that nitrate concentrations were being controlled by biochemical processes in addition to physical processes. The relative trends in decreasing nitrate concentrations with downstream distance appeared to depend on drought versus non-drought conditions, with biological processes presumably serving as a more important control during non-drought spring seasons.     

Water quality assessment of Ogun river, South West Nigeria

The quality of Ogun river in South-West, Nigeria was studied by a field survey for a period of 1 year (covering dry season and rainy season). Water samples were collected from thirteen sites and analysed for physico-chemical and bacteriological parameters as well as heavy metals using standard methods. Generally, the values obtained for turbidity, phosphate, oil and grease, iron and faecal coliform from all the sites in both seasons were above the maximum acceptable limit set by the World Health Organization (WHO) for drinking water. Also, the manganese content from all the sites in the dry season, lead concentrations from three sites in the dry season and cadmium concentrations from some sites in both seasons were above the WHO limit. The values obtained for total dissolved solids, dissolved oxygen and chloride at site M in the dry season and nitrate at site J in the rainy season were also above the WHO limit. Pollution of Ogun river water along its course is evidenced by the high concentrations of pollution indicators, nutrients and trace metals above the acceptable limit. This poses a health risk to several rural communities who rely on the river primarily as their source of domestic water. The study showed a need for continuous pollution monitoring programme of surface waters in Nigeria.     

Rating curve based assessment of seasonal variability of sulfate in streamflow

Though constituent concentrations and loads in rivers exhibit apparent seasonal fluctuations, they are characterized by event-driven nature of the fluctuations in respond to natural processes and seasonal anthropogenic activities. This study aimed at establishing relationship between streamflow and sulfate load in Gin River, the major water source in southern Sri Lanka and assessing seasonal sulfate levels in the streamflow following monsoon pattern and cultivation seasons. Rating curve, a load-streamflow regression model, was developed using adjusted maximum likelihood estimation. Following the assumptions of model fit, the regression model showed low correlation among explanatory variables and good empirical agreement with the measured data exhibiting its applicability to deduce sulfate loads from streamflow data, during non-sampling periods. Sulfate loads, highly dependent on streamflow, peaked annually in April–June (south-west monsoon contributing to Yala cultivation season) and October–December (north-east monsoon contributing to Maha cultivation season), following the bimodal monsoon pattern in the catchment. Median sulfate load exhibited fourfold increase from the lowest value 8,888 kg/day in August (non-cultivation season) to the highest value 38,185 kg/day in November (Maha cultivation season), despite the twofold increase of median streamflow between the two months. Flow-weighted sulfate concentrations showed varying flow dependence attributed to the seasonality. At low streamflows (above 70th percentile), sulfate concentration and streamflow were inversely related and at high streamflows (below 30th percentile), and sulfate concentration and streamflow were directly related. Elevated sulfate concentrations attributed to less soluble sulfate irons were clearly evident during the two cultivation seasons which coincided with the monsoon periods.     

Fluoride, boron and nitrate toxicity in ground water of northwest Rajasthan, India

The study was carried out to access the fluoride, boron, and nitrate concentrations in ground water samples of different villages in Indira Gandhi, Bhakra, and Gang canal catchment area of northwest Rajasthan, India. Rural population, in the study site, is using groundwater for drinking and irrigation purposes, without any quality test of water. All water samples (including canal water) were contaminated with fluoride. Fluoride, boron, and nitrate were observed in the ranges of 0.50–8.50, 0.0–7.73, and 0.0–278.68 mg/l, respectively. Most of the water samples were in the categories of fluoride 1.50 mg/l, of boron 2.0–4.0 mg/l, and of nitrate <?45 mg/l. There was no industrial pollution in the study site; hence, availability of these compounds in groundwater was due to natural reasons and by the use of chemical fertilizers.     

Spatio-temporal variation in physicochemical properties of coastal waters off Kalpakkam, southeast coast of India, during summer, pre-monsoon and post-monsoon period

Seasonal observations on water-quality parameters and chlorophyll-a in the coastal waters off Kalpakkam, southeast coast of India, was carried out covering an area of about 30 km(2) to find out the variations in physicochemical properties during a monsoonal cycle of the year. Most of the parameters exhibited a significant spatial and seasonal variation. It revealed that the coastal water was significantly influenced by freshwater input from the nearby backwaters during North-east monsoon and post-monsoon periods. A marginal increase in pH from coast towards offshore was noticed during the observation. Relatively low salinity values were observed during pre and post monsoon when compared to summer. Bottom water was found to be highly turbid during summer and pre-monsoon conditions when compared to surface. This could be attributed to the strong northerly wind and northward current prior to the onset of southwest monsoon. N, P and Si based nutrients are relatively high in their concentration in the bottom water. Nitrate was significantly high during post-monsoon and contributed greatly towards total nitrogen as evident from the statistical correlation. Ammonia concentration was relatively high in the bottom samples during all the seasons except on a few occasions during post-monsoon. In general, phosphate and total phosphorous values remained low and particularly so in the surface water. Higher silicate concentration was observed in the bottom water, and there was a reducing trend towards offshore. High chlorophyll-a values were observed during summer and surface water was found to have higher pigment concentrations as compared to the bottom. Results show that phosphate acts as the limiting factor for phytoplankton production particularly during post-monsoon period whereas; none of the nutrients were found to be limiting the phytoplankton growth during other seasons.     

Seasonal variation in heavy metal contamination in water and sediments of river Sabarmati and Kharicut canal at Ahmedabad, Gujarat

The objective of the study is to reveal the seasonal variations in the river water and sediment quality with respect to heavy metal contamination. To get the extent of trace metals contamination, water and sediment samples were collected from five different sites along the course of Sabarmati River and its tributary Kharicut canal in pre-monsoon, monsoon and post-monsoon seasons. The concentration of trace metals such as chromium, copper, lead, nickel and zinc was determined using inductively coupled plasma spectroscopy. The concentrations of heavy metals were found to be higher in the pre-monsoon season than in the monsoon and post-monsoon seasons in water samples. The pollution load index, contamination factor and degree of contamination (C _d) in sediments were calculated to know the extent of anthropogenic pressures. The values of C _d clearly indicated very high degree of contamination at Kharicut canal (S-4: 32.25 and S-5: 54.52) and considerable degree of contamination at three sites of Sabarmati river viz; S-1, S-2 and S-3 with values 14.30, 14.42 and 17.21, respectively. Lead and nickel could not be traced in any of the river water samples.     

A comprehensive study on water balance, sedimentation and physico-chemical characteristics of Sagar Lake in India

In this study, an attempt has been made to work out water balance, determine rate of sedimentation and physico-chemical analysis of the lake water. The water balance is carried out using the mass balance equation to account for various input and output components. Sedimentation rates and pattern are estimated using (137)Cs and (210)Pb radiometric dating techniques. The physico-chemical analysis of the lake water is done by collecting samples from twelve locations of the lake at three different depths. The major inflow to the lake is catchment runoff, which accounts for nearly 56% of the total annual inflow and about 98% inflow takes place during monsoon period. The major outflow from the lake is weir overflow, which occurs in monsoon season only and accounts for about 85% of the total annual outflow. The estimated mean sedimentation rate in the lake is 0.58 +/- 0.028 cm/year. The estimated useful life of the lake based on post-1964 (appearance of the major peak of (137)Cs due to weapon fallout record pattern) average sedimentation rate is around 467 +/- 23 years. The lake has attained the hyper-eutrophic state due to high nitrogen and phosphorous contents in the lake water. Based on the trophic state index (TSI), the lake has become unsuitable for drinking, bathing and even for fish culture.     

Contamination of nitrate and fluoride in ground water along the Ganges Alluvial Plain of Kanpur district, Uttar Pradesh, India

Nitrate-N and Fluoride concentrations were analyzed in shallow and unconfined ground water aquifers of Kanpur district along the Ganges Alluvial Plain of Northern India. Kanpur district was divided into three zones namely, Bithore, Kanpur City and Beyond Jajmau and sampling was carried out three seasons (summer, monsoon and winter). The data set consisted of the results of water samples from around 99 India Mark II hand Pumps, which were analyzed for summer monsoon and winter seasons. In Bithore zone, 19% of the samples exceeded the BIS (Bureau of India Standards) limit 10.2 mg/l as nitrate-N and as high as 166 mg/l as nitrate-N was observed. 10% and 7% samples in Kanpur city and beyond Jajmau zone respectively, exceeded the BIS limit. The Frequency distribution histogram of nitrate-N revealed a skewed (non-normal) distribution. Both point and non-point sources contribute to the ground water contamination. Especially in Bithore zone, the point sources could be attributed to the animal wastes derived from cows and buffaloes and non point sources could be due to the extensive agricultural activity prevalent in that area. Fluoride concentration in most samples was within the BIS maximum permissible level of 1.5 mg/l. No significant seasonal variation in water quality parameters was observed.     

Karst aquifers on small islands—the island of Olib, Croatia

Water supply is a major problem in the Adriatic islands, especially during the summer tourism season, and represents a limiting factor to the islands' further economic development. Much attention has been given to water supply solutions, primarily in terms of attempting to use the existing island water. Unfortunately, few islands have favourable hydrological conditions to accumulate significant quantities of surface water or groundwater. In the period from 2001 to 2004, investigations were conducted on many islands to define their own freshwater or partially brackish water resources since desalinisation technology could resolve a significant part of the water supply demand on small and distant islands. Due to the specificity and complexity of research in karst areas, the study was conducted in phases and included the geological and hydrogeological reconnaissance of the island, aimed at locating possible areas on the island where the necessary quantities of groundwater of adequate quality could be captured; a detailed hydrogeological mapping of the specified areas, geophysical investigation and test drilling; and, over several days, test pumping of the most promising borehole. One of the islands investigated was the island of Olib. The conducted surveys indicated that it is possible to pump about 3.5 L/s of groundwater from the karst aquifer of the island of Olib, which fully complies with the sanitary quality of drinking water.     

Evaluation of groundwater quality and its suitability for drinking and agricultural use in Thanjavur city, Tamil Nadu, India

As groundwater is a vital source of water for domestic and agricultural activities in Thanjavur city due to lack of surface water resources, groundwater quality and its suitability for drinking and agricultural usage were evaluated. In this study, 102 groundwater samples were collected from dug wells and bore wells during March 2008 and analyzed for pH, electrical conductivity, temperature, major ions, and nitrate. Results suggest that, in 90% of groundwater samples, sodium and chloride are predominant cation and anion, respectively, and NaCl and CaMgCl are major water types in the study area. The groundwater quality in the study site is impaired by surface contamination sources, mineral dissolution, ion exchange, and evaporation. Nitrate, chloride, and sulfate concentrations strongly express the impact of surface contamination sources such as agricultural and domestic activities, on groundwater quality, and 13% of samples have elevated nitrate content (>45 mg/l as NO₃). PHREEQC code and Gibbs plots were employed to evaluate the contribution of mineral dissolution and suggest that mineral dissolution, especially carbonate minerals, regulates water chemistry. Groundwater suitability for drinking usage was evaluated by the World Health Organization and Indian standards and suggests that 34% of samples are not suitable for drinking. Integrated groundwater suitability map for drinking purposes was created using drinking water standards based on a concept that if the groundwater sample exceeds any one of the standards, it is not suitable for drinking. This map illustrates that wells in zones 1, 2, 3, and 4 are not fit for drinking purpose. Likewise, irrigational suitability of groundwater in the study region was evaluated, and results suggest that 20% samples are not fit for irrigation. Groundwater suitability map for irrigation was also produced based on salinity and sodium hazards and denotes that wells mostly situated in zones 2 and 3 are not suitable for irrigation. Both integrated suitability maps for drinking and irrigation usage provide overall scenario about the groundwater quality in the study area. Finally, the study concluded that groundwater quality is impaired by man-made activities, and proper management plan is necessary to protect valuable groundwater resources in Thanjavur city.     

Probability-based nitrate contamination map of groundwater in Kinmen

Groundwater supplies over 50 % of drinking water in Kinmen. Approximately 16.8 % of groundwater samples in Kinmen exceed the drinking water quality standard (DWQS) of NO₃ ^?-N (10 mg/L). The residents drinking high nitrate-polluted groundwater pose a potential risk to health. To formulate effective water quality management plan and assure a safe drinking water in Kinmen, the detailed spatial distribution of nitrate–N in groundwater is a prerequisite. The aim of this study is to develop an efficient scheme for evaluating spatial distribution of nitrate–N in residential well water using logistic regression (LR) model. A probability-based nitrate–N contamination map in Kinmen is constructed. The LR model predicted the binary occurrence probability of groundwater nitrate–N concentrations exceeding DWQS by simple measurement variables as independent variables, including sampling season, soil type, water table depth, pH, EC, DO, and Eh. The analyzed results reveal that three statistically significant explanatory variables, soil type, pH, and EC, are selected for the forward stepwise LR analysis. The total ratio of correct classification reaches 92.7 %. The highest probability of nitrate–N contamination map presents in the central zone, indicating that groundwater in the central zone should not be used for drinking purposes. Furthermore, a handy EC–pH-probability curve of nitrate–N exceeding the threshold of DWQS was developed. This curve can be used for preliminary screening of nitrate–N contamination in Kinmen groundwater. This study recommended that the local agency should implement the best management practice strategies to control nonpoint nitrogen sources and carry out a systematic monitoring of groundwater quality in residential wells of the high nitrate–N contamination zones.     

A hydrochemical profile for assessing the groundwater quality of Jaipur City

A study was conducted to evaluate the water quality of Jaipur City. Groundwater samples from hand pumps and tube wells of eleven sampling stations were analyzed during monsoon session with the help of standard methods of APHA. The analytical results shows higher concentration of total dissolved solids, electrical conductivity, total hardness and nitrate, which indicate signs of deterioration but values of pH, calcium, magnesium, sulphate and fluoride are within permissible limit as per WHO standards. From the Hill-Piper trilinear diagram, it is observed that the majority of ground water from sampling stations are calcium-magnesium-chloride-sulphate type water. The values of sodium absorption ratio and electrical conductivity of the ground water were plotted in the US salinity laboratory diagram for irrigation water. Most of the samples fall in C3S1 quality with high salinity hazard and low sodium hazard. Chemical analysis of groundwater shows that mean concentration of cation (in meq/l) is in order magnesium > sodium > calcium > potassium while for the anion (in meq/l) it is chloride > bicarbonate > sulphate > nitrate > carbonate > fluoride.     

Geo-spatial analysis of land–water resource degradation in two economically contrasting agricultural regions adjoining national capital territory (Delhi)

The present study was aimed at characterizing the soil-water resource degradation in the rural areas of Gurgaon and Mewat districts, the two economically contrasting areas in policy zones-II and III of the National Capital Region (NCR), and assessing the impact of the study area's local conditions on the type and extent of resource degradation. This involved generation of detailed spatial information on the land use, cropping pattern, farming practices, soils and surface/ground waters of Gurgaon and Mewat districts through actual resource surveys, standard laboratory methods and GIS/remote sensing techniques. The study showed that in contrast to just 2.54% (in rabi season) to 4.87% (in kharif season) of agricultural lands in Gurgaon district, about 11.77% (in rabi season) to 24.23% (in kharif season) of agricultural lands in Mewat district were irrigated with saline to marginally saline canal water. Further, about 10.69% of agricultural lands in the Gurgaon district and 42.15% of agricultural lands in the Mewat district were drain water irrigated. A large part of this surface water irrigated area, particularly in Nuh (48.7%), Nagina (33.5%), and Punhana (24.1%) blocks of Mewat district, was either waterlogged (7.4% area with 0.05 ppm). In fact, sub-surface drinking waters of some areas around battery and automobile manufacturing units in Gurgaon and Pataudi blocks were associated with exceptionally high (>0.1 ppm) Ni concentrations. In general, the ground waters of waterlogged or potentially waterlogged areas in the rural areas of Mewat were more contaminated than the ground waters in the rural areas of Gurgaon district with deeper (>5 m) water depths.Though Cr concentrations in the surface and sub-surface irrigation waters of both Gurgaon and Mewat districts were far above the maximum permissible limit of 1 ppm, their bio-available soil-Cr concentrations were well within permissible limit. Even bio-available Ni concentrations in agricultural lands of Gurgaon district associated with Ni contaminated sub-surface irrigations were well within desirable limit of 0.20 ppm. This was primarily attributed to the calcareous nature of the soils of the study area. About 35% of Gurgaon district and 59% of Mewat district irrigated with poor quality waters were salt-affected. These waterlogged/potentially waterlogged calcareous-salt affected soils of Mewat district were having acute zinc (Zn) deficiency (<0.6 ppm). Some areas with extremely high iron (Fe: 20-25 ppm) and Mn (10-25 ppm) concentrations were also noticed in the Gurgaon, Nuh and Punhana blocks. Generation of reduced conditions owing to paddy cultivation in areas with 3-3.5 m water depths appeared to be the main cause of such point contaminations. Extensive cadmium (Cd) contamination was also noticed in the waterlogged sodic agricultural lands of Nagina village in Mewat district associated with a large scale scrap automobile and battery business. The study could document the processes and provide spatially accurate information to the managers (e.g., National Capital Region Planning Board) and the concerned citizen groups. It could, in fact, clearly point out that dumping of industrial and domestic wastewaters especially from NCT-Delhi into river Yamuna and, to some extent, from NCT-Delhi re-located hazardous industrial units into Najafgarh drain tributaries at Delhi-Gurgaon boundary, and poor "off-farm" water management practices were the main reasons for extensive (point/non-point source) land-water degradation in Gurgaon and Mewat districts of NCR.     

Seasonal and spatial variation of reservoir water quality in the southwest of Ethiopia

This research investigated the spatiotemporal variation of water quality in the Gilgel Gibe reservoir, Ethiopia, using physicochemical water quality parameters. Nonparametric tests and multivariate statistical techniques were used to evaluate data sets measured during dry and rainy seasons. Electrical conductivity (EC), pH, biochemical oxygen demand (BOD₅), total phosphorus (TP), total nitrogen (TN), nitrate (NO₃^?), total dissolved solids (TDSs), and total suspended solids (TSSs) were all significantly different among seasons (Mann-Whitney U test, p?<?0.01). In addition, principal component analysis distinguished dry season samples from wet season samples. The dry season was positively associated with EC, pH, TP, TN, NO₃^?, TDS, and TSS and negatively associated with BOD₅. The wet season was in contrast associated with high values of turbidity, soluble reactive phosphorus (SRP), water temperature, and dissolved oxygen (DO). Within the reservoir, spatial variation was observed for some of the water quality parameters, with significant difference at p?=?<?0.05. Overall, high nutrient concentrations suggest eutrophic conditions, likely due to high nutrient loading from the watershed. Levels of TSS, attributed to inputs from tributaries, have been excessive enough to inhibit light penetration and thus have a considerable impact on the aquatic food web. Our findings indicate that the reservoir is at high risk of eutrophication and siltation, and hence, urgent action should target the planning and implementation of integrated watershed management for this and similar reservoirs in the region.     

Ground water contamination by organochlorine insecticide residues in a rural area in the indo-gangetic plain

Residues of several organochlorine insecticides were monitored in the ground water from a rural area near Farrukhabad in the vicinity of the Ganga River in northern India for one year (1991–1992). Almost all the samples were found to be contaminated with residues of Hexachlorocyclohexane (HCH) and Dichloro-diphenyl-trichloroethane (DDT). Residues of Aldrin, endosulfan and heptachlor were also detected in a large number of samples. The concentrations of aldrin residues greatly exceeded the WHO guideline value for drinking water, concentrations of heptachlor and DDT residues also occasionally exceeded the specified limits. Migration of pollutants through ground water recharge with polluted Ganga River water and monsoon rains carrying undergraded residues downwards from the soil surface are throught to be important sources of insecticide contamination of ground water in the region.     

Multivariate analysis of drinking water quality parameters in Bhopal, India

Pollution of water bodies is one of the areas of major concern to environmentalists. Water quality is an index of health and well being of a society. Industrialization, urbanization and modern agriculture practices have direct impact on the water resources. These factors influence the water resources quantitatively and qualitatively. The study area selected were the Upper lake and Kolar reservoir of Bhopal, the state capital of Madhya Pradesh, India. The Upper lake and Kolar reservoir both are the important sources of potable water supply for the Bhopal city. The physico–chemical parameters like temperature, pH, turbidity, total hardness, alkalinity, BOD, COD, Chloride, nitrate and phosphate were studied to ascertain the drinking water quality.     

Statistical analysis of arsenic contamination in drinking water in a city of Iran and its modeling using GIS

In this research, probable arsenic contamination in drinking water in the city of Ardabil was studied in 163 samples during four seasons. In each season, sampling was carried out randomly in the study area. Results were analyzed statistically applying SPSS 19 software, and the data was also modeled by Arc GIS 10.1 software. The maximum permissible arsenic concentration in drinking water defined by the World Health Organization and Iranian national standard is 10 μg/L. Statistical analysis showed 75, 88, 47, and 69% of samples in autumn, winter, spring, and summer, respectively, had concentrations higher than the national standard. The mean concentrations of arsenic in autumn, winter, spring, and summer were 19.89, 15.9, 10.87, and 14.6 μg/L, respectively, and the overall average in all samples through the year was 15.32 μg/L. Although GIS outputs indicated that the concentration distribution profiles changed in four consecutive seasons, variance analysis of the results showed that statistically there is no significant difference in arsenic levels in four seasons.