Spatial variability of depth and salinity of groundwater under irrigated ustifluvents in the Middle Black Sea Region of Turkey

Information on the potential risk for soil salinity buildup can be very helpful for soil salinity management in irrigated areas. We evaluated the spatial and temporal variability of groundwater salinity (GWS) and groundwater depth (GWD), which are two of the most important indicators of soil salinity, by indicator kriging technique in a large irrigated area in northern Turkey. GWS and GWD were measured on a monthly basis from irrigation season (August 2003) to rainy season (April 2004) at 60 observation wells in the 8,187-ha irrigated area. Five indicator thresholds were used for GWS and GWD. The semivariogram for each of the thresholds for both variables was analyzed then used together with experimental data to interpolate and map the corresponding conditional cumulative distribution functions (CCDF). Risk for soil salinity buildup was greater in the irrigation season compared to that in the rainy season. The greatest risk for soil salinity buildup occurred in the eastern part of the study area, suffering from poor drainage problem due to malfunctioning drainage infrastructure, as indicated by the CCDF of GWS and GWD obtained in both seasons. It was concluded that a combination of mechanical and cultural measures should be taken in high-risk locations to avoid further salinity problems.     

Incidence of metal and antibiotic resistance in Pseudomonas spp. from the river water, agricultural soil irrigated with wastewater and groundwater

A total of 144 isolates of Pseudomonas spp. (48 each from the Yamuna River water, wastewater irrigated soil and groundwater irrigated soil) were tested for their resistance against certain heavy metals and antibiotics. Minimum inhibitory concentrations (MICs) of Hg^2?+?, Cd^2?+?, Cu^2?+?, Zn^2?+?, Ni^2?+?, Pb^2?+?, Cr^3?+? and Cr^6?+? for each isolate were also determined. A maximum MIC of 200 ??g/ml for mercury and 3,200 ??g/ml for other metals were observed. The incidences of metal resistance and MICs of metals for Pseudomonas isolates from the Yamuna water and wastewater irrigated soil were significantly different to those of groundwater irrigated soil. A high level of resistance against tetracycline and polymyxin B (81.2%) was observed in river water isolates. However, 87.5% of Pseudomonas isolates from soil irrigated with wastewater showed resistance to sulphadiazine, whereas 79.1% were resistant to both ampicillin and erythromycin. Isolates from soil irrigated with groundwater exhibited less resistance towards heavy metals and antibiotics as compared to those of river water and wastewater irrigated soil. Majority of the Pseudomonas isolates from water and soil exhibited resistance to multiple metals and antibiotics. Resistance was transferable to recipient Escherichia coli AB2200 strains by conjugation. Plasmids were cured with the curing agent ethidium bromide and acridine orange at sub-MIC concentration.     

Geochemical evidence for the origin of vanadium in an urban environment

The city of Salamanca in central Mexico is surrounded by heavy industry, i.e., a refinery, a thermoelectric plant and chemical industries. Variable concentrations of vanadium (V) have been reported in the groundwater, and their presence has been related to particulates so this hypothesis was tested by sampling soil in the urban area and the surrounding uncontaminated country site. The 0-10-cm soil layer in the industrial and rural area was analyzed for V and other metal trace elements found in hydrocarbons, i.e., chromium (Cr), lead (Pb), zinc (Zn), and nickel (Ni). The concentrations of V were higher in the urban rather than in the rural soil, reaching values of >600 mg kg(-1) in the urban soils. In the rural area, V in the soil was related to regional geology, i.e., volcanic rocks such as basalts and rhyolites but not in the urban area where it was related to particulate distribution mostly emitted from the industries burning fuel oil number 6.     

Impacts of seawater intrusion on soil salinity and alkalinity in Bafra Plain, Turkey

This study was carried out to investigate possible seawater intrusion into groundwater along the coastal lines of the Bafra Plain and salinity–alkalinity problems over land areas irrigated with water exposed to seawater intrusion were evaluated. For this purpose, 32 groundwater wells were selected over the plain, water samples were taken from these wells between October 2007 and September 2008, and chemical analyses were performed over these samples. Soil samples were taken from the fields irrigated with this water at 32 different locations at the end of the irrigation season in September 2008 from 0–30, 30–60, 60–90, and 90–120 cm soil depths and textures. EC, pH, Na, Ca, Mg, and K analyses were performed over these samples. Excessive seawater intrusion was observed in some parts of the plain and impacts of seawater intrusion decreased with the distance from the coastal line. It was determined that groundwater quality was significantly affected from seawater intrusion. Salinity and especially alkalinity problems were observed in land areas irrigated with this water and alkalinity increased with the rate of intrusion.     

Natural and anthropogenic factors affecting the shallow groundwater quality in a typical irrigation area with reclaimed water,North China Plain

In this study, the hydrochemical characteristics of shallow groundwater were analyzed to get insight into the factors affecting groundwater quality in a typical agricultural dominated area of the North China Plain. Forty-four shallow groundwater samples were collected for chemical analysis. The water type changes from Ca·Na-HCO₃ type in grass land to Ca·Na-Cl (+NO₃) type and Na (Ca)-Cl (+NO₃+SO₄) type in construction and facility agricultural land, indicating the influence of human activities. The factor analysis and geostatistical analysis revealed that the two major factors contributing to the groundwater hydrochemical compositions were the water-rock interaction and contamination from sewage discharge and agricultural fertilizers. The major ions (F, HCO₃) and trace element (As) in the shallow groundwater represented the natural origin, while the nitrate and sulfate concentrations were related to the application of fertilizer and sewage discharge in the facility agricultural area, which was mainly affected by the human activities. The values of pH, total dissolved solids, electric conductivity, and conventional component (K, Ca, Na, Mg, Cl) in shallow groundwater increased from grass land and cultivated land, to construction land and to facility agriculture which were originated from the combination sources of natural processes (e.g., water-rock interaction) and human activities (e.g., domestic effluents). The study indicated that both natural processes and human activities had influences on the groundwater hydrochemical compositions in shallow groundwater, while anthropogenic processes had more contribution, especially in the reclaimed water irrigation area.     

A proposed methodology to determine accuracy of location and extent of geographically isolated wetlands

The disposal of industrial and sewage water is a problem of increasing importance throughout the world. In India, and most of the developing countries untreated sewage and industrial wastes are discharged on land or into the running water streams which is used for irrigating crops. These wastes often contain high amount of trace elements which may accumulate in soils in excessive quantities on long term use and enter the food chain through absorption by the plants. Among the trace metals, Cd has received the greater attention because of its easy absorption and accumulation in plants and animals to levels toxic for their health. The objective of this study conducted in three industrially different cities viz., Ludhiana, Jalandhar and Malerkotla was to monitor the extent of Cd accumulation in soils and plants receiving untreated sewage water. Plant and soil samples were collected from sewage and tubewell irrigated areas. Soil samples were analysed for texture, pH, EC, organic carbon (OC), CaCO(3), bioavailable DTPA-Cd and plant samples were analysed for total Cd. In sewage irrigated soils, the mean values of pH were lower but organic carbon and electrical conductivity were generally higher both in surface and sub-surface layers of all the three cities as compared to tubewell irrigated soils. The mean DTPA- extractable Cd in sewage irrigated soil was 6.3- and 4.36-fold in Ludhiana, 3.38- and 1.71-fold in Jalandhar and 3.35- and 6.67-fold in Malerkotla in 0-15 and 15-30 cm soil depth, respectively, compared with the values in tubewell irrigated soils. The accumulation of DTPA-Cd in sewage irrigated soils was restricted to 30 cm depth after which the values were generally close to values in tubewell irrigated soils. Soil pH, OC, CaCO(3), clay and silt collectively accounted for 37.1%, 65.1% and 53.9% DTPA-extractable bioavailable Cd in soils of Ludhiana, Jalandhar and Malerkotla, respectively. Lower R(2) values in Ludhiana suggest that factors other than the ones mentioned may be affecting Cd availability. At all sites plants receiving sewage irrigation had elevated levels of Cd as compared to the plants receiving tubewell irrigation. The mean Cd content of sewage irrigated plants irrespective of the city was 5.96 microg g(-1) dry matter as compared to 0.98 microg g(-1) dry matter in tubewell irrigated plants. The results suggest that the intake of Cd obtained from consumption of crops grown on sewage irrigated soils would be much higher than the tolerable limits set by WHO and may, therefore, prove potentially toxic leading to various health ailments to humans and animals.     

Total petroleum hydrocarbon distribution in soils and groundwater in Songyuan oilfield, Northeast China

In order to investigate the distribution of the total petroleum hydrocarbons (TPH) in groundwater and soil, a total of 71 groundwater samples (26 unconfined groundwater samples, 37 confined groundwater samples, and 8 deeper confined groundwater samples) and 80 soil samples were collected in the Songyuan oilfield, Northeast China, and the vertical variation and spatial variability of TPH in groundwater and soil were assessed. For the groundwater from the unconfined aquifer, petroleum hydrocarbons were not detected in three samples, and for the other 23 samples, concentrations were in the range 0.01–1.74 mg/l. In the groundwater from the confined aquifer, petroleum hydrocarbons were not detected in two samples, and in the other 35 samples, the concentrations were 0.04–0.82 mg/l. The TPH concentration in unconfined aquifer may be influenced by polluted surface water and polluted soil; for confined aquifer, the injection wells leakage and left open hole wells may be mainly responsible for the pollution. For soils, the concentrations of TPH varied with sampling depth and were 0–15 cm (average concentration, 0.63 mg/g), >40–55 cm (average concentration, 0.36 mg/g), >100–115 cm (average concentration, 0.29 mg/g), and >500–515 cm (average concentration, 0.26 mg/g). The results showed that oil spillage and losses were possibly the main sources of TPH in soil. The consequences concluded here suggested that counter measures such as remediation and long-term monitoring should be commenced in the near future, and effective measures should be taken to assure that the oilfields area would not be a threat to human health.     

Distribution of Iron, Manganese, Zinc and Atrazine in Groundwater in Parts of Palar and Cheyyar River Basins, South India

A study was carried out in a part of Palar and Cheyyar river basin to evaluate the current status of iron, manganese, zinc and atrazine concentrations, their origin and distribution in groundwater. Groundwater samples were collected during post-monsoon (March 1998 and February 1999) and pre-monsoon (June 1999) periods from 41 sampling wells distributed throughout the study area. The groundwater samples were analyzed for trace metals using AAS and atrazine using HPLC. The concentration of the trace elements in groundwater is predominant during pre-monsoon period. Distribution pattern indicates that the concentration of these elements increases from west to northeast and towards Palar river. Lower concentrations in the central part may be due to recharge of fresh water from the lakes located here. During most of the months, as there is no flow in Palar river, the concentrations of trace elements in groundwater are high. Drinking water standards indicate that Mn and Zn cross the permissible limit recommended by EPA during the pre-monsoon period. A comparison of groundwater data with trace element chemistry of rock samples shows the abundance of trace elements both in the rock and water in the order of Fe > Mn > Zn and Fe > Zn > Mn. This indicates that iron in groundwater is derived from lithogenic origin. Further, Fe, Mn and Zn have good correlation in rock samples, while it is reverse in the case of water samples, indicating the non-lithogenic origin of Mn and Zn. Atrazine (a herbicide) was not detected in any of the groundwater samples in the study area, perhaps due to low-application rate and adsorption in the soil materials.     

Iron content in groundwaters of Visakhapatnam environs, Andhra Pradesh, India

Trace elements are essential for human health. However, excess concentrations of these elements cause health disorders. A study has been carried out in Visakhapatnam environs, Andhra Pradesh, India to ascertain the causes for the origin and distribution of iron content in the groundwaters. Fifty groundwater samples are collected and analyzed for iron. The content of iron ranges from 400 to 780 μg/l. A comparison of groundwater data with rock and soil chemistry suggests that the concentration of iron (400–530 μg/l) in the groundwaters is derived from the rocks and soils due to geogenic processes. This concentration is taken as a natural occurrence of iron in the groundwaters of the study area for assessing the causes for its next higher content (>530 μg/l). Relatively higher concentration of iron (540–550 μg/l) is observed at some well waters, where the wells are located nearby municipal wastewaters, while the very high concentration of iron (610–780 μg/l) is observed in the industrially polluted groundwater zones, indicating the impact of anthropogenic activities on the groundwater system. These activities mask the concentration of iron caused by geogenic origin. Hence, both the geogenic and anthropogenic activities degrade the groundwater quality. Drinking water standards indicate that the iron content in all the groundwater samples exceeds the permissible limit (300 μg/l) recommended for drinking purpose, causing the health disorders. Necessity of close monitoring of groundwater quality for assessing the impact of geogenic and anthropogenic sources with reference to land use/land cover activities is emphasized in the present study area to protect the groundwater resources from the pollution.     

The occurrence of heavy metals in irrigated and non-irrigated arable soils,NW Albania

The study analysed the content of heavy metals in surface soil and sediment samples from the Bregu i Matit Plain in NW Albania in relation to irrigation in order to evaluate the soil pollution and the potential risk to human health. Evaluation of soil pollution was performed using the enrichment factor and geo-accumulation index. Contents of cadmium, chromium and nickel of irrigated soils were significantly higher than those of non-irrigated soil, while contents of lead (in three of the irrigated locations), zinc and arsenic (in one of the irrigated locations) were significantly lower. Correlation analysis (CA) and principal component analysis (PCA) indicated that the primary source of the first three metals was irrigation, and the last three metals were originated from other anthropic sources, like the use of chemicals, etc. Enrichment factor (E _f) calculation showed that irrigated soils were most enriched in cadmium, chromium, copper and nickel. Index of geo-accumulation (I _geo) revealed that arable soils of Bregu i Matit are unpolluted to moderately polluted with cadmium, chromium, copper and zinc and moderately to strongly polluted with nickel and arsenic. The presence of heavy metals in the studied soils indicates a potential risk of transfer of these elements in the food chain. Therefore, further studies on the speciation of heavy metals in the studied soils in order to evaluate their mobility are needed.     

Application of neural-based modeling in an assessment of pollution with mercury in the middle part of the Warta River

The level of pollution with various mercury species (organomercury, water- and acid-soluble mercury, mercury bound to humic matter and to sulphides) of the floodplain soils and sediments from middle part of the Warta River has been assessed using self-organizing maps (SOM). Chemometric evaluation allowed identification of moderately (median 173-187 ng g(-1), range 54-375 ng g(-1) in soil and 130 ng g(-1), range 47-310 ng g(-1) in sediment) and heavily polluted samples (662 ng g(-1), range 426-884 ng g(-1)). Heavily polluted were located mainly below and in the area of the Poznań city. Statistical comparison of mercury species distribution in floodplain soils of the Warta River shows different patterns for moderately and heavily polluted samples. In heavily polluted soils the contribution of mobile mercury (sum of organomercury species, water- and acid soluble species) is lower (4.2%) than in moderately polluted soils (6.1%). Higher contribution of mobile mercury was observed in sediments of the Warta River (12%). In case of moderately polluted samples, statistical differences in the contribution of mercury species are relatively low and thus the environmental risk from mercury deposited in aquatic system of the Warta River is relatively low. However, higher water levels and heavy floods may incite remobilisation of some organomercuries (2.2-2.9 ng g(-1) in soil and 10 ng g(-1) in sediment) and acid-soluble species of mercury (2.6-2.9 ng g(-1) in soil and 0.5 ng g(-1) in sediment).     

Impact of long-term wastewater application on microbiological properties of vadose zone

Impact of wastewater irrigation on some biological properties was studied in an area where treated sewage water is being supplied to the farmers since 1979 in the western part of National Capital Territory of New Delhi under Keshopur Effluent Irrigation Scheme. Three fields were selected which had been receiving irrigation through wastewater for last 20, 10 and 5 years. Two additional fields were selected in which the source of irrigation water was tubewell. The soil bacterial and fungal population density was studied in soil layers of 0?C15, 15?C30, 30?C60 and 60?C120 cm depths. Groundwater samples were collected from the piezometers installed in the field irrigated with sewage water for last 20, 10 and 5 years. Results indicate that there was significant increase in bacterial and fungal count in sewage-irrigated soils as compared to their respective control. The population density of bacteria and fungi in waste water-irrigated soils increased with the duration of sewage water application and decreased with increasing depth. The bacterial and fungal count was also directly proportional to organic carbon, sand and silt content and negatively correlated to the clay content, electrical conductivity, pH and bulk density of the soil. Groundwater under sewage-irrigated fields had higher values of most probable number (MPN) index as compared to that of tubewell water-irrigated fields. All the shallow and deep groundwaters were found to be contaminated with faecal coliforms. The vadose zone had filtered the faecal coliform to the tune of 98?C99%, as the MPN index was reduced from ??18,000 per 100 ml of applied waste water to 310 per 100 ml of groundwater under 20 years sewage-irrigated field. The corresponding values of MPN were 250 and 130 per 100 ml of shallow groundwater under 10 and 05 years sewage-irrigated fields, respectively. Rapid detection of faecal contamination suggested that the Citrobacter freundii and Salmonella were dominant in shallow groundwater, while Escherichia coli was dominant in deep groundwater collected from sewage-irrigated field.     

A study on chemical properties of groundwater and soil in ophiolitic rocks in Firuzabad, east of Shahrood, Iran: with emphasis to heavy metal contamination

In order to assess the chemical properties of groundwater and soil in ophiolitic zone of Firuzabad, in east of Shahrood, Iran, 10 soil samples with regard to sensitive points (vicinity to mine, ophiolitic rocks, and villages) and 10 groundwater samples including nine samples from springs, and also one sample from a well in a village of the study area were taken. These samples were analyzed in laboratories using inductively coupled plasma method. The soil samples were also evaluated for grain size. The obtained results show that most of heavy and major elements were exceeding the permissible levels in soil and water samples in the study area. On the subject of soil quality, concentrations of elements Cr, Mn, Fe, Ca, Mg, Ca, Ni, and Zn are above permissible levels. Enrichment factor and index of geoaccumulation have been calculated for heavy and major elements of all soil samples. According to the obtained results, it may be argued that soil samples are contaminated in relation to the above-mentioned indices. Comparing the concentrations of elements with results of grain size analysis illustrates that the concentrations of Cr, Ni, Fe, Mg, and Co are positively correlated with sand fraction and the concentrations of Al, P, Mn, and Pb are directly proportional with clay fraction in soil samples. The study on water contamination suggests that concentrations of elements Cr, Ni, and Mg in groundwater samples of the study area are above the permissible levels. Some indices like metal index and heavy metal pollution index show that most of the water samples include heavy metal contamination.     

Assessment of the potential hazards of nitrate contamination in surface and groundwater in a heavily fertilized and intensively cultivated district of India

We made an inventory of nitrate (NO3-N) enrichment in surface and groundwater systems in the Hooghly district of India owing to intensive farming with high fertilizer doses as a function of quantity of fertilizers use, soil characteristics, types of crop grown, depth of groundwater sampling and also N-load in soil profiles. Water samples were collected from different sources at 412 odd sites spread over in 17 blocks of the district along with representative soil profiles. On average, the study area had high clay and NO3-N in soil profiles with an increasing and decreasing trends along depth, respectively. The NO3-N content both in surface and groundwater varied from 0.01 microg mL(-1) to 4.56 microg mL(-1), being well below the threshold limit of 10 microg mL(-1) fixed by WHO for drinking purpose. The content decreased with increasing depth of wells (r = -0.39**) and clay content of soil profiles (r = -0.31**). It, however, increased with increasing rate of fertilizer application (r = 0.72**), NO3-N load in soil profiles (r = 0.85**) and was higher in areas where shallow--rather than deep-rooted crops are grown. Results indicated even under fairly high quantity of fertilizer use, groundwater of the study area is safe for drinking purpose.     

Lead (Pb) and arsenic (As) bioaccessibility in various soils from south China

Serious problems are faced in several parts of the world due to the presence of high concentration of fluoride in drinking water which causes dental and skeletal fluorosis to humans. Nalgonda district in Andhra Pradesh, India is one such region where high concentration of fluoride is present in groundwater. Since there are no major studies in the recent past, the present study was carried out to understand the present status of groundwater quality in Nalgonda and also to assess the possible causes for high concentration of fluoride in groundwater. Samples from 45 wells were collected once every 2 months and analyzed for fluoride concentration using an ion chromatograph. The fluoride concentration in groundwater of this region ranged from 0.1 to 8.8 mg/l with a mean of 1.3 mg/l. About 52% of the samples collected were suitable for human consumption. However, 18% of the samples were having less than the required limit of 0.6 mg/l, and 30% of the samples possessed high concentration of fluoride, i.e., above 1.5 mg/l. Weathering of rocks and evaporation of groundwater are responsible for high fluoride concentration in groundwater of this area apart from anthropogenic activities including irrigation which accelerates weathering of rocks.     

Contamination Levels and Preliminary Assessment of the Technical Feasibility of Employing Natural Attenuation in 5 Priority Areas of Presidente Bernardes Refinery in Cubatão, São Paulo, Brazil

Five priority areas of potential impact by contaminants (API) were investigated at the Presidente Bernardes Refinery in Cubatão, São Paulo, Brazil with the following aims: (i) to identify both organic and inorganic contaminants present in soil and groundwater; (ii) to define the environmental conditions relevant for microbial activity at the site and (iii) to evaluate the feasibility of employing natural attenuation for treatment of the hydrocarbon contamination. One area (API 1) was an uncontrolled landfill, where waste materials from the refinery were deposited between 1954 and 1986, and four areas (API 4, 5, 7 and 11) were located in the operational section of the refinery. Soil contamination by regulated BTEX compounds (benzene, toluene, total xylenes) was restricted to two samples from API 1. Nonregulated ethylbenzene was detected in one soil sample from API 4, one from API 5 and two from API 1. No soil contained regulated PAH above threshold levels. Several nonregulated PAHs were found in 6 soil samples from API 1, 3 soil samples from API 4 and 1 soil sample from API 5. Site soils contained very high aluminium concentrations, but metal contamination was restricted to one soil sample from API 1, which contained nickel above threshold limits. BTEX contamination of groundwater was due mostly to benzene. Of the 17 PAH molecules tested, only naphthalene and 2-methylnaphthalene occurred in groundwater. The sum of total BTEX and total PAH exceeded 200 μg/L in only a few monitoring wells in API 4, 5 and 11 and was always below 2.640 μg/L. Be, Cd, Cr, Cu, Hg, Ni, Se, Ag, Tl and Zn were not detected in groundwater, which was contaminated in a few locations by aluminium (mostly below 1 mg/L), lead (<0.066 mg/L) and arsenic (<0.056 mg/L). S, K, Ca, Mg and Fe were present in groundwater in excess of physiological requirements for microbial growth, but low concentrations of N and P could become growth limiting. However, BTEX were efficiently degraded in saturated and unsaturated zone microcosms and nutrient amendments did not stimulate biodegradation rates measurably. The inorganic carbon pool in groundwater was up to one order of magnitude larger than the organic carbon pool. Total inorganic carbon (TIC) in API groundwater exceeded TIC of clean groundwater by factors of 2 (API 4), 6 (API 5, 7 and 11) or 10 (API 1). Most of the inorganic carbon incorporated into groundwater beneath the refinery originated from biodegradation in the unsaturated soil, which contained a microbiota (10⁶ cells/g on average) capable of growth with most of the pure (benzene, toluene, ethylbenzene and xylene) and mixed hydrocarbons tested (diesel oil, gasoline, naphtha, condensate, aromatic residue and fuel oil). A viscous hydrocarbon paste uncovered in API 1 was insoluble in water but dissolved in dichloromethane. Many organic components of this paste were biodegradable as evidenced by weight reduction of the hydrocarbon paste and by the growth of suspended and attached biomass in saturated zone microcosms, where the paste was the only carbon source. This study indicates that monitored natural attenuation may be a technically feasible and efficient means for plume control in API 1, 4 and 5, provided the plumes in API 4 and 5 are not expanding. This technique is not suitable for contaminant reduction in API 11.     

Antibiotic-resistant E. coli in surface water and groundwater in dairy operations in Northern California

Generic Escherichia coli was isolated from surface water and groundwater samples from two dairies in Northern California and tested for susceptibility to antibiotics. Surface samples were collected from flush water, lagoon water, and manure solids, and groundwater samples were collected from monitoring wells. Although E. coli was ubiquitous in surface samples with concentrations ranging from several hundred thousand to over a million colony-forming units per 100 mL of surface water or per gram of surface solids, groundwater under the influence of these high surface microbial loadings had substantially fewer bacteria (3- to 7-log₁₀ reduction). Among 80 isolates of E. coli tested, 34 (42.5 %) were resistant to one or more antibiotics and 22 (27.5 %) were multi-antibiotic resistant (resistant to ≥3 antibiotics), with resistance to tetracycline, cefoxitin, amoxicillin/clavulanic acid, and ampicillin being the most common. E. coli isolates from the calf hutch area exhibited the highest levels of multi-antibiotic resistance, much higher than isolates in surface soil solids from heifer and cow pens, flush alleys, manure storage lagoons, and irrigated fields. Among E. coli isolates from four groundwater samples, only one sample exhibited resistance to ceftriaxone, chloramphenicol, and tetracycline, indicating the potential of groundwater contamination with antibiotic-resistant bacteria from dairy operations.     

Efficacy of electrical resistivity and induced polarization methods for revealing fluoride contaminated groundwater in granite terrain

The accumulation of fluoride (F) in groundwater is a common phenomenon in India and worldwide. Its location can be identified through a direct hydrochemical analysis, which was carried out in Kurmapalli watershed (located 60 km SE of Hyderabad city), Nalgonda district, Andhra Pradesh, India affected by F contamination. The results of the hydrochemical analysis showed that F varied from 0.71 to 19.01 mg/l and its concentration exceeded the permissible limit (i.e., 1.5 mg/l) in 78% of the total 32 samples analyzed. The highest F value (19.01 mg/l) was found near Madnapur village, which is located in the central part of the watershed. Resistivity and induced polarization (IP) surveys were also carried out to reveal the zones where elevated F-contaminated groundwater exists. The objective of this paper was to highlight the utility of resistivity and IP surveys, using hydrochemical constituents as constraint, for the successful delineation of such contaminated/polluted groundwater zones in the granite area.     

Pesticide occurrence in groundwater and the physical characteristics in association with these detections in Ireland

This study explores the associations of pesticide occurrence in groundwater to geological characteristics of the monitoring points (MPs) contributing area. Pesticide analyses were undertaken during a 2-year groundwater monitoring campaign which generated 845 samples. MCPA and mecoprop were the most frequently detected pesticides in groundwater. Each MP (n?=?158) had a specifically delineated zone of contribution (ZOC) and the dominant physical characteristics present from nine national datasets were recorded for each ZOC. Associations between detections in groundwater and the dominant physical characteristic in each MPs ZOC tested were then statistically analyzed using Fisher’s exact test, logistic regression, and multiple logistic regression. The original physical characteristic datasets used that were associated with detections in groundwater were the type of MP, aquifer type, and Quaternary deposit type. Logistic regression revealed that springs, regionally important aquifer types, aquifers with a karstic flow regime, and alkaline Quaternary deposits in existence above karst aquifers in a MP’s ZOC were more likely to have a pesticide detection in groundwater. Multiple regression from this exploratory work showed some mutual dependency between soil association, aquifer type, and the Geological Survey of Ireland groundwater vulnerability map. The combination of national monitoring data and physical attribute datasets can be used to explore key areas where groundwater is more vulnerable to pesticide contamination.     

Heavy metal concentrations in groundwaters and soils of Thane Region of Maharashtra, India

Thane district is one of the most industrialized districts in Maharashtra. The heavy industrialization and the increasing urbanization are responsible for the rapidly increasing stress on the water and soil environment of the area. Therefore, an attempt has been made through comprehensive study on the groundwater contamination and soil contamination due to heavy metals in Thane region of Maharashtra. The area undertaken for the study was Thane and its suburbans Kalwa, Divajunction, Dombivali, Kalyan, and Ulhasnagar. Industrialization and urbanization lead to generation of large volumes of wastewater from domestic, commercial, industrial, and other sources, which discharged in to natural water bodies like river and creek in this region. Groundwater samples and soil samples were collected from residential, commercial, agriculture, and industrial areas. Groundwater samples were analyzed for various water quality parameters. The analytical data shows very high concentration of total dissolved solids, total hardness, total alkalinity, chemical oxygen demand, chloride etc. Groundwater and soil samples were analyzed for ten heavy metals by inductively coupled plasma (ICPE-9000) atomic emission spectroscopy. The analytical data reveal that, very high concentration level of arsenic, cadmium, mercury, and nickel throughout the industrial area. The random dumping of hazardous waste in the industrial area could be the main cause of the groundwater and soil contamination spreading by rainwater and wind. In the residential areas the local dumping is expected to be the main source for heavy metals. A comparison of the results of groundwater with WHO guidelines show that most of the groundwater sampling station are heavily contaminated with organic matter and heavy metals. Groundwater samples are heavily contaminated by arsenic, cadmium, mercury, and nickel. Similarly, the results of heavy metals in soil compared with Swedish soil guideline values for polluted soil show that soil samples collected from residential, commercial and industrial areas are heavily contaminated by arsenic, cadmium, mercury, and nickel.