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1.
Laser-induced breakdown spectroscopy (LIBS) was applied for the detection of toxic metals in oil spill contaminated soil (OSCS). The OSCS samples were collected from Khursania Saudi Arabia along the coast of Persian Gulf exposed to oil spills in 1991 Gulf war. Environmentally important elements like Aluminum Magnesium, Calcium, Chromium, Titanium, Strontium, Iron, Barium, Sodium, potassium, Zirconium and Vanadium from the contaminated soil have been detected. Optimal experimental conditions for analysis were investigated. The LIBS system was calibrated using standard samples containing these trace elements. The results obtained using Laser-Induced Breakdown Spectroscopy (LIBS) were compared with the results obtained using Inductively Coupled Plasma Emission Spectroscopy (ICP). The concentrations of some elements (Ba and Cr) were found higher than permissible safe limits. Health risks associated with exposure to such toxic elements are also discussed.  相似文献   

2.
Rapid measurement of heavy metals in soil is an important factor in modeling the effect of industrial pollution on agricultural soil. Conventional methods of heavy metal analysis are relatively slow in terms of measurement/analysis time and sample preparation time with the requirement of skilled manpower. Our results highlight the quantitative analysis of toxic metal lead (Pb), for the first time, in an Indian agricultural soil, in the vicinity of brick-kiln area, Phaphamau, near Allahabad, India, by using a novel technique named as Laser-induced breakdown spectroscopy (LIBS). LIBS spectra of soil has been recorded in the wavelength range from ultraviolet (UV) to infrared region (200-1,100 nm). The suitability of Pb lines for drawing the calibration curve is checked and realized, for the first time, that 220.3 nm, which is observed in the UV region of LIBS spectra, is completely interference free and best suited for the quantification of trace amount of Pb in soil instead of any other Pb lines, because it has best linear regression coefficient and smallest standard deviation of the background signal. In the present work the detection limit for Pb in soil is found to be 45 ppm. Based on the present work the concentration of Pb in agricultural soil of brick-kiln area in Phaphamau is found to be congruent with 570 ppm, which is more than the regulatory standards imposed by US Environmental Protection Agency (400 ppm) for the presence of lead in soil, therefore, it is of great concern to us.  相似文献   

3.
Water quality monitoring is a critical part of environmental management and protection, and to be able to qualitatively and quantitatively determine contamination and impurity levels in water is especially important. Compared to the currently available water quality monitoring methods and techniques, laser-induced breakdown spectroscopy (LIBS) has several advantages, including no need for sample pre-preparation, fast and easy operation, and chemical free during the process. Therefore, it is of great importance to understand the fundamentals of aqueous LIBS analysis and effectively apply this technique to environmental monitoring. This article reviews the research conducted on LIBS analysis for liquid samples, and the article content includes LIBS theory, history and applications, quantitative analysis of metallic species in liquids, LIBS signal enhancement methods and data processing, characteristics of plasma generated by laser in water, and the factors affecting accuracy of analysis results. Although there have been many research works focusing on aqueous LIBS analysis, detection limit and stability of this technique still need to be improved to satisfy the requirements of environmental monitoring standard. In addition, determination of nonmetallic species in liquid by LIBS is equally important and needs immediate attention from the community. This comprehensive review will assist the readers to better understand the aqueous LIBS technique and help to identify current research needs for environmental monitoring of water quality.  相似文献   

4.
Laser Induced Breakdown Spectroscopy (LIBS) is a fast and multi-elemental analytical technique particularly suitable for the qualitative and quantitative analysis of heavy metals in solid samples, including environmental ones. Although LIBS is often recognised in the literature as a well-established analytical technique, results about quantitative analysis of elements in chemically complex matrices such as soils are quite contrasting. In this work, soil samples of various origins have been analyzed by LIBS and data compared to those obtained by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The emission intensities of one selected line for each of the five analytes (i.e., Cr, Cu, Pb, V, and Zn) were normalized to the background signal, and plotted as a function of the concentration values previously determined by ICP-OES. Data showed a good linearity for all calibration lines drawn, and the correlation between ICP-OES and LIBS was confirmed by the satisfactory agreement obtained between the corresponding values. Consequently, LIBS method can be used at least for metal monitoring in soils. In this respect, a simple method for the estimation of the soil pollution degree by heavy metals, based on the determination of an anthropogenic index, was proposed and determined for Cr and Zn.  相似文献   

5.
The present study deals with the ground water quality assessment in Kahuta Industrial Triangle Islamabad, Pakistan. The objective of the study was to assess ground water quality against the drinking water standards for various toxic inorganic elements. Representative groundwater samples were collected and analyzed in the Water Quality Laboratory of Pakistan Council of Research in Water Resources (PCRWR) at Islamabad, Pakistan. The samples were run on ICP-MS (Inductively coupled plasma mass spectrometry), which has the capability to separate and quantify 70 elements at a time. One of the finding of study is that ICP-MS is a very good tool to analyze broad range of toxic inorganic elements to the level of parts per billion (ppb). World Health Organization drinking water standards shows that these toxic inorganic elements such as heavy metals even at this concentration level (ppb) are injurious to human health. This analysis indicated pollution of various toxic elements including Selenium. Vertical leachate through industrial waste septic tanks is identified as major cause of groundwater pollution in the Industrial Triangle. Monitoring of the septic tanks and groundwater quality in study area is suggested along with remedial measures.  相似文献   

6.
Laser-induced breakdown spectroscopy (LIBS) has been applied for the determination of nutrients in the green house soil samples. We determined appropriate spectral signatures of vital nutrients and calibrated the method to measure the nutrients in a naturally fertilized plot, cultivated with tomato and cucumber plants. From the calibration curves we predicted the concentrations of important nutrients such as Ca, K, P, Mg, Fe, S, Ni and Ba in the soil. Our measurements proved that the LIBS method rapidly and efficiently measures soil nutrients with excellent detection limits of 12, 9, 7, 9, 7, 10, 8 and 12~mg/kg for Ca, K, P, Mg, Fe, S, Ni and Ba respectively with a precision of 2%, The unique features of LIBS for rapid sample analysis demonstrated by this study suggests that this method offers promise for precision measurements of soil nutrients as compared to conventional methods in short span of time.  相似文献   

7.
Solid waste samples were collected from five small-scale industrial sites in the National Capital Territory (NCT) of Delhi. These industrial sites represent the regional spread of the industrial belt in the NCT of Delhi. Solid waste samples were digested using aqua-regia and HF in air tight teflon bombs for the quantitative analysis of heavy metals (Hg, Pb, Cd, Mn, Fe, Ni, Cu and Zn) by GBC model 902 atomic absorption spectrophotometer. Hg was analysed using hydrid generator attachment. Beside this sequential extraction was used to fractionate five heavy metals (Pb, Ni, Cd, Cu and Zn) into six operationally defined phases, viz. water soluble, exchangeable, carbonate-bound, Fe-Mn oxides, organic-bound and residual fractions to ascertain the relative mobility of these metals. The result obtained showed metal concentration to be in the range of Hg 0.42-2.3; Pb 23-530; Cd 014-224; Mn 494-19 964; Fe 35 684-233 119; Ni 192-1534; Cu 3065-10 144 and Zn 116-23 321 (all units in mg kg(-1)) in all the industrial areas studied. The fractionated toxic metals like Pb, Ni and Cd were observed to be in the range of 25-35, 15-50 and 40-50%, respectively, in mobile or bio-available fractions of solid waste. As this waste is often disposed-off by the roadsides, low lying areas, abandoned quarries or in landfill sites which are often not properly planned, thus posing potential risk to ground and surface water quality to millions of people living downstream.  相似文献   

8.
The genotoxicity of certain water bodies was evaluated employing the DNA repair defective mutants of Escherichia coli, induction of prophage lamda in the lysogen and the plasmid nicking assay. All the test DNA repair defective mutants invariably exhibited more sensitivity than their isogenic wild-type strains but distinctive patterns against the three water samples viz. industrial waste water and the groundwater samples obtained from industrial estate of Aligarh as well as river water of Yamuna at Agra. A significant level of phage induction was also recorded in the test system exhibiting maximum induction in case of industrial waste water followed by that in river and groundwater samples, respectively. The single- and double-strand breaks were also observed in the plasmid DNA treated with industrial waste water and the river water samples. These findings are suggestive of the DNA damage induced by the test samples with the probable role of SOS repair in E. coli.  相似文献   

9.
Pyrite oxidation and release of the oxidation products from a low-grade coal waste dump to stream, groundwater and soil was investigated by geochemical and hydrogeochemical techniques at Alborz Sharghi coal washing plant, Shahrood, northeast Iran. Hydrogeochemical analysis of water samples indicates that the metal concentrations in the stream waters were low. Moreover, the pH of the water showed no considerable change. The analysis of the stream water samples shows that except the physical changes, pyrite oxidation process within the coal washing waste dump has not affected the quality of the stream water. Water type was determined to be calcium sulphate. The results of the analysis of groundwater samples indicate that the pH varies from 7.41 to 7.51. The concentrations of the toxic metals were low. The concentration of SO4 is slightly above than its standard concentration in potable water. It seems that the groundwater less affected by the coal washing operation in the study area. Geochemical analysis of the sediment samples shows that Fe concentration decreases gradually downstream the waste dump with pH rising. SO(4) decreases rapidly downstream direction. Copper, Zn and Co concentrations decrease with distance from the waste dump due to a dilution effect by the mixing of uncontaminated sediments. These elements, in particular, Zn are considerably elevated in sediment sample collected at the nearest distance to the waste dump. There is no doubt that such investigations can help to develop an appropriate water remediation plan.  相似文献   

10.
Recently introduced microwave plasma-atomic emission spectroscopy (MP-AES) represents yet another and very important addition to the existing array of modern instrumental analytical techniques. In this study, an attempt is made to summarize the performance characteristics of MP-AES and its potential as an analytical tool for environmental studies with some practical examples from Patancheru and Uppal industrial sectors of Hyderabad city. A range of soil, sediment, water reference materials, particulate matter, and real-life samples were chosen to evaluate the performance of this new analytical technique. Analytical wavelengths were selected considering the interference effects of other concomitant elements present in different sample solutions. The detection limits for several elements were found to be in the range from 0.05 to 5 ng/g. The trace metals analyzed in both the sectors followed the topography with more pollution in the low-lying sites. The metal contents were found to be more in ground waters than surface waters. Since a decade, the pollutants are transfered from Patancheru industrial area to Musi River. After polluting Nakkavagu and turning huge tracts of agricultural lands barren besides making people residing along the rivulet impotent and sick, industrialists of Patancheru are shifting the effluents to downstream of Musi River through an 18-km pipeline from Patancheru. Since the effluent undergoes primary treatment at Common Effluent Treatment Plant (CETP) at Patanchru and travels through pipeline and mixes with sewage, the organic effluents will be diluted. But the inorganic pollutants such as heavy and toxic metals tend to accumulate in the environmental segments near and downstreams of Musi River. The data generated by MP-AES of toxic metals like Zn, Cu, and Cr in the ground and surface waters can only be attributed to pollution from Patancheru since no other sources are available to Musi River.  相似文献   

11.
Three atomic spectrometry techniques, namely sector field inductively coupled plasma mass spectroscopy, graphite furnace atomic absorption spectrometry and hydride generation atomic fluorescence spectroscopy (ICP-SMS, GF-AAS and HG-AFS, respectively), housed at separate independent laboratories, were used to analyse water and sediment samples collected from the Huon River Estuary, SE Tasmania (Australia) in the Austral spring 1998. A dithiocarbamate-chelation/back-extraction technique was used to separate and preconcentrate Co, Ni, Cu, Zn, Cd and Pb from eight collected water samples prior to analysis by ICP-SMS and GF-AAS. A number of other elements in the waters were analysed directly (Mn, Fe and Zn by GF-AAS; As by HG-AFS), or following sample dilution (1 + 19: V, Mn, Fe, As, Mo, Ba and U by ICP-SMS). Where possible, previously corroborated GF-AAS and HG-AFS techniques were used to verify obtained ICP-SMS results. From the analysis of four reference waters (SLEW-1 and -2, SLRS-3 and NASS-5), good agreement, to within +/- 10-20%, was typically found between certified (or information only values) and measured results (irrespective of analytical technique). Exceptions included Zn (and sometimes Fe) that could not be quantified by ICP-SMS due to elevated blank signals, and As which was found to lie below ICP-SMS detection limits. For Huon Estuary water samples, inter-method agreement was within +/- 10-20% (for those elements amenable to analysis by more than one technique). Nitric acid extracts of two certified reference materials (Buffalo River Sediment and BCSS-1) and six Huon Estuary sediments were analysed by ICP-SMS (for Al, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd and Pb) and HG-AFS (for As). Results from the certified reference materials indicated extraction efficiencies of 60 70% (for most elements). A close correlation between ICP-SMS and HG-AFS was obtained for leachable As in the sediments. In terms of potential inorganic contaminants, the Huon Estuary was found to be a relatively 'clean' water system. The elemental concentrations measured in water and sediment samples from this region were found to lie within current Australian guidelines for estuaries. In general, no one analytical technique was able to accurately determine all elements in all samples from this relatively pristine estuarine environment. A combination of all three analytical techniques was necessary for the successful analysis of the elements considered in this study.  相似文献   

12.
Metal Pollution in the Environment of Minas Gerais State – Brazil   总被引:3,自引:0,他引:3  
Intense mining activities in Minas Gerais State – Brazil brings out tons of waste to the environment. Considerable concentrations of toxic elements penetrate the soil, ground waters and rivers. This endangers the environment quality not only in the surrounding areas but also in ichthyofauna and in more distant areas of cattle raising and agricultural activities. After seasonal floods, veterinary clinic studies have shown that most animals raised in this region are affected by symptomatologic nervous diseases, still not clearly diagnosed, which suggests intoxication. These pathologies are mostly noted after floods. Instrumental Neutron Activation Analysis was applied to determine Al, As, Au, Ba, Br, Ca, Cl, Co, Cr, Cs, Cu, Fe, Hg, K, La, Mg, Mn, Na, Nd, Rb, Sb, Sc, Sm, Th and Zn in environmental samples. The obtained results show that the water and sediment contaminated with heavy metals and toxic elements from the Das Velhas River upstream basin, the mining region, carry contamination to the ichthyofauna and farming region within a distance of approximately 400 km.  相似文献   

13.
Diverse analytical techniques are available to determine the particle size distribution of potentially toxic elements in matrices of environmental interest such as soil, sediments, freshwater and groundwater. However, a single technique is often not exhaustive enough to determine both particle size distribution and element concentration. In the present work, the investigation of mercury in soil samples collected from a polluted industrial site was performed by using a new analytical approach which makes use of sedimentation field-flow fractionation (SdFFF) coupled to cold vapour generation electrothermal atomic absorption spectroscopy (CV-ETAAS). The Hg concentration in the SdFFF fractions revealed a broad distribution from about 0.1 to 1 μm, roughly following the particle size distributions, presenting a maximum at about 400-700 nm in diameter. A correlation between the concentration of Hg in the colloidal fraction and organic matter (O.M.) content in the soil samples was also found. However, this correlation is less likely to be related to Hg sorption to soil O.M. but rather to the presence of colloidal mercuric sulfide particles whose size is probably controlled by the occurrence of dissolved O.M. The presence of O.M. could have prevented the aggregation of smaller particles, leading to an accumulation of mercuric sulfides in the colloidal fraction. In this respect, particle size distribution of soil samples can help to understand the role played by colloidal particles in mobilising mercury (also as insoluble compounds) and provide a significant contribution in determining the environmental impact of this toxic element.  相似文献   

14.
采用翻转振荡方式以水为浸提剂浸提钢渣、尾矿渣、铬渣、铅渣、粉煤灰和电镀污泥试样,过滤后的浸提液经DDTC/CCl4体系萃取富集后,用ICP-AES法同时测定了Cu、Pb、Zn、Cd、Ni、Fe、Mn、Co和V等多种金属元素.方法具有较好的精密度和准确度,宜于推广应用。  相似文献   

15.
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.  相似文献   

16.
激光诱导击穿光谱技术在环境领域中的应用动态   总被引:1,自引:0,他引:1  
激光诱导击穿光谱技术是一种通过分析物质等离子体发射光谱而获取物质成分和含量的分析技术。近些年,该技术已经成为光谱学领域的研究热点且发展迅速,涌现出多种新的检测手段和仪器。从它的基本原理、发展历史及其在土壤、水和大气等生态环境保护领域的应用情况为基础,分析总结其优点以及所面临的问题和挑战。  相似文献   

17.
Industrial wastewater discharged into aquatic ecosystems either directly or because of inadequate treatment of process water can increase the concentrations of pollutants such as toxic metals and others, and subsequently deteriorate water quality, environmental ecology and human health in the Dhaka Export Processing Zone (DEPZ), the largest industrial belt of 6-EPZ in Bangladesh. Therefore, in order to monitor the contamination levels, this study collected water samples from composite effluent points inside DEPZ and the surrounding surface water body connected to effluent disposal sites and determined the environmental hazards by chemical analysis and statistical approach. The water samples were analysed by inductively coupled plasma mass spectrometry to determine 12 trace metals such as As, Ag, Cr, Co, Cu, Li, Ni, Pb, Se, Sr, V and Zn in order to assess the influence of multi-industrial activities on metal concentrations. The composite effluents and surface waters from lagoons were characterized by a strong colour and high concentrations of biochemical oxygen demand, chemical oxygen demand, electrical conductivity, pH, total alkalinity, total hardness, total organic carbon, Turb., Cl(-), total suspended solids and total dissolved solids, which were above the limit of Bangladesh industrial effluent standards, but dissolved oxygen concentration was lower than the standard value. The measurement of skewness and kurtosis values showed asymmetric and abnormal distribution of the elements in the respective phases. The mean trend of variation was found in a decreasing order: Zn > Cu > Sr > Pb > Ni > Cr > Li > Co > V > Se > As > Ag in composite industrial effluents and Zn > Cu > Sr > Pb > Ni > Cr > Li > V > As > Ag > Co > Se in surface waters near the DEPZ. The strong correlations between effluent and surface water metal contents indicate that industrial wastewaters discharged from DEPZ have a strong influence on the contamination of the surrounding water bodies by toxic metals. The average contamination factors were reported to be 0.70-96.57 and 2.85-1,462 for industrial effluents and surface waters, respectively. The results reveal that the surface water in the area is highly contaminated with very high concentrations of some heavy/toxic metals like Zn, Pb, Cu, Ni and Cr; their average contamination factors are 1,460, 860, 136, 74.71 and 4.9, respectively. The concentrations of the metals in effluent and surface water were much higher than the permissible limits for drinking water and the world average concentrations in surface water. Therefore, the discharged effluent and surface water may create health hazards especially for people working and living inside and in the surrounding area of DEPZ.  相似文献   

18.
Plant-based bioassays have recently gained remarkable popularity among the toxicological/eco-toxicological assessment procedures. The reasons for their wide use are comparative simplicity, sensitivity, and cost-effectiveness as well as a good correlation with other toxicity tests. The present study describes the use of two plant bioassays, Allium cepa test and seed germination test in the evaluation of the toxicity/genotoxicity of industrial waste water and river water and standardization with the commonly occurring pollutants in Indian waters namely heavy metals and phenolics. Both tests were standardized to suit the Indian conditions, and the local varieties were used. Both bioassays responded significantly with the test range of heavy metals and phenolics. The toxicity of heavy metals was in the order of Cu > Ni > Cd in both the tests whereas 2,4-dinitrophenol was the most toxic among the phenolic compounds. Cabbage, millet, and cucumber, respectively, were found to be the most sensitive in the seed germination test for the test heavy metals and phenols. Significant amounts of chromosomal abnormalities including bridges, stickiness, and fragmentations were recorded with both the industrial waste water and the XAD concentrated river water samples by A. cepa test.  相似文献   

19.
A sulfate-rich flue gas desulfurization scrubber sludge was used as a substitute backfill material in reclamation of an abandoned coal strip mine. The site was surrounded by monitor wells and the material was characterized for leaching behavior using open column experiments. A drain was placed directly beneath the 45 000 ton fill to enable sampling before dilution or attenuation. The column studies indicated that the scrubber sludge would adsorb manganese, iron, aluminium, cobalt, nickel, thallium and zinc contaminants from the water. Changes in pH appear inadequate to explain the removal by precipitation. The groundwater cleaning phenomenon has been confirmed on a field scale by the drain samples. Boron and molybdenum leach from the fly ash was used to fix the scrubber sludge and serve as marker elements enabling calibration of the dispersivity in computer models of the groundwater system at the site. The leachate front appears to be diluted by a factor of 8 : 1 within the first 15 meters. Since boron and molybdenum release are associated only with the first flush, environmental impacts will be minimal. Columns appear to create a time compression effect on the duration of leaching phenomenon. The effect for this site appears to be at least 5 : 1. The columns were effective in predicting which elements would leach or adsorb in the field and in predicting the actual source concentrations. Other shake tests such as the TCLP and the ASTM shake test were found to be less effective at predicting which elements would leach and were not helpful in predicting field concentrations.  相似文献   

20.
An attempt has been made in this study to evaluate the groundwater quality in two industrial blocks of Ghaziabad district. Groundwater samples were collected from shallow wells, deep wells and hand pumps of two heavily industrialized blocks, namely Bulandshahar road industrial area and Meerut road industrial area in Ghaziabad district for assessing their suitability for various uses. Samples were collected from 30 sites in each block before and after monsoon. They were analyzed for a total of 23 elements, namely, Ag, Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Se, U, V, and Zn. In addition to these elements, some other parameters were also studied viz: color, odor, turbidity, biological oxygen demand, chemical oxygen demand (COD), dissolved oxygen, total dissolved solids and total suspended solid. The water quality index was also calculated based on some of the parameters estimated. Out of the 23 elements, the mean values of 12 elements, namely, Al, As, Ca, Cd, Cr, Mg, Mn, Na, Ni, Pb, Se, and U, were higher than the prescribed standard limits. The concentrations (in milligram per liter) of highly toxic metals viz., Al, As, Cd, Cr, Ni, Pb, Se, and U, ranged from 1.33–6.30, 0.04–0.54, 0.005–0.013, 4.51–7.09, 0.14–0.27, 0.13–0.32, 0.16–2.11, and 0.10–1.21, respectively, in all groundwater samples, while the permissible limits of these elements as per WHO/BIS standards for drinking are 0.2, 0.01, 0.003, 0.05, 0.07, 0.01, 0.04, and 0.03 mg L?1, respectively. The EC, pH, and COD in all samples varied from 0.74–4.21, 6.05–7.72, and 4.5–20.0 while their permissible limits are 0.7 dS m?1, 6.5–8.5, and 10 mg L?1, respectively. On the basis of the above-mentioned parameters, the water quality index of all groundwater samples ranged from 101 to 491, and 871 to 2904 with mean value of 265 and 1,174 based on two criteria, i.e., physico-chemical and metal contaminations, respectively while the prescribed safe limit for drinking is below 50. The results revealed that the groundwater in the two blocks is unfit for drinking as per WHO/BIS guidelines. The presence of elements like As, Se, and U in toxic amounts is a matter of serious concern.  相似文献   

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