Influence of arsenic-bearing gold deposits on water quality in Zloty Stok mining area (SW Poland)

 The Sudety Mountains contain polymetallic deposits which have been exploited since the Middle Ages. Distinct concentrations of As, Hg, F, Cr in surface water near Zloty Stok suggested that groundwater in the area could also contain elevated metal concentrations. Water samples from 15 locations including Zloty Stream, mine adit discharges, and selected springs generally show low levels of dissolved components and near-neutral pH. However, arsenic concentrations range from 0.99 mg/l to 26.16 mg/l at all 15 sample locations. Mercury concentrations were locally as high as 0.011 mg/l. These high arsenic and mercury concentrations significantly exceed water quality standards and raise concerns for using Zloty Stream for potable water. Recieved: 21 December 1998 · Accepted: 8 June 1999     

Assessment of arsenic health risk and source apportionment of groundwater pollutants using multivariate statistical techniques in Chapai-Nawabganj district,Bangladesh

This study assessed arsenic health risk to the local residents through oral and dermal exposure pathways of drinking water and to investigate source apportionment of groundwater pollutants using multivariate statistical techniques in the Chapai-Nawabganj district, Bangladesh. Groundwater samples collected from shallow tube well and dug well at the depth ranges (15-60 m) were analyzed for physio-chemical parameters and trace elements. Most of the studied physio-chemical parameters were found within their respective permissible limits. However, total As, Fe and Mn concentrations exceeded Bangladesh and WHO guideline values. The assessment of arsenic health risk reveals that children as compared to adults are found at a higher risk as the values of hazard quotients (HQ) >1 in the most of the groundwater samples. This level of arsenic contamination should have medium to high chronic risk and medium carcinogenic risk when compared with US EPA guidelines which can cause serious health hazard. The results of principal component analysis (PCA) and factor analysis (CA) indicate that geogenic (interaction of water and basement rock) and anthropogenic (agrochemicals, agricultural fertilizer and domestic sewage) sources are responsible for variation in arsenic and other physio-chemical parameters in the groundwater aquifer of the study area. Furthermore,the inter-correlation of arsenic with metals and ions were also calculated by correlation matrix and linear regression analysis. The outcomes of this study will help to meet the challenge of sustainable groundwater quality management in Bangladesh and enhancing better vision of potential health risk of local inhabitants in the study area.     

Anthropogenic arsenic menace in Delhi Yamuna Flood Plains

Arsenic, one of the most poisonous chemical elements, was analyzed in the waters of the host of the 2010 Commonwealth Games, i.e., New Delhi. The study revealed shocking outcomes with arsenic concentrations well beyond the safe limits set by WHO, and a maximum concentration up to 180 ppb was found in the groundwater. Analysis of around 120 water samples collected extensively along the Yamuna Flood Plain showed that more than 55% had arsenic contamination beyond the WHO limit of 10 ppb. The maximum value of arsenic in coal and fly ash from Rajghat coal-based thermal power plant contained 200 and 3,200 ppb, respectively. Moreover, the ore petrography of coal samples shows the presence of arsenopyrite mineral. Maximum concentration of arsenic contamination is found within a 5-km radius from power plants. In the perspective of Delhi, arsenic contamination is purely anthropogenic due to coal-based thermal power plants, which had already shown toxic arsenic, fluorine and China-type coal effects. The presence of such power plants in coal field locations, e.g., West Bengal and Bangladesh, could release the arsenic due to combustion in superthermal power plants, thus accentuating the arsenic concentration besides the natural arsenic coming from the foreland basins of the Himalaya in Indian sub-continent.     

Arsenic enrichment in unconfined sections of the southern Gulf Coast aquifer system, Texas

Groundwater arsenic concentrations exceeding the federal drinking water standard are common in the southern Gulf Coast aquifer system in Texas, including in aerobic, unconfined groundwater which provides much of the municipal and domestic water supplies for the region. The objective of this study was to determine geochemical factors affecting the occurrence and distribution of groundwater As in unconfined portions of the southern Gulf Coast aquifer system through a comparative transect study of groundwater across three major hydrostratigraphic units (the Catahoula Formation, Jasper aquifer and Evangeline aquifer) and analysis of regional water quality data. Results show that As concentrations decrease with increasing distance from the Catahoula Formation, which is consistent with Miocene volcanic ash as the main source of As to groundwater in the region. Arsenic concentrations correlate with V, SiO₂ and K, all of which were released during weathering of volcanic sediments and their degradation products. In all three units, carbonate weathering and active recharge in the unconfined zones result in circum-neutral pH and oxidizing groundwater, which are typically amenable to As immobilization by adsorption of arsenate onto mineral oxides and clays. However, As concentrations exceed 10 μg/L in approximately 30% of wells. Silica that was co-released with As may compete for sorption sites and reduce the capacity for arsenate adsorption.     

Hydrogeochemistry and arsenic contamination of groundwater in the Rayen area, southeastern Iran

High As contents in groundwater were found in Rayen area and chosen for a detailed hydrogeochemical study. A total of 121 groundwater samples were collected from existing tube wells in the study areas in January 2012 and analyzed. Hydrogeochemical data of samples suggested that the groundwater is mostly Na–Cl type; also nearly 25.62 % of samples have arsenic concentrations above WHO permissible value (10 μg/l) for drinking waters with maximum concentration of aqueous arsenic up to 25,000 μg/l. The reducing conditions prevailing in the area and high arsenic concentration correlated with high bicarbonate and pH. Results show that arsenic is released into groundwater by two major phenomena: (1) through reduction of arsenic-bearing iron oxides/oxyhydroxides and Fe may be precipitated as iron sulfide when anoxic conditions prevail in the aquifer sediments and (2) transferring of As into the water system during water–acidic volcanic rock interactions.     

Sources and behavior of arsenic and trace elements in groundwater and surface water in the Poopó Lake Basin,Bolivian Altiplano

Water management in semiarid and arid catchments such as the Poopó Lake Basin requires improved understanding of the complex behavior of the various contaminants, which affect the drinking water quality and considered as crucial for sustainable development of the region. Mechanisms of arsenic (As) release in the surface and groundwater were studied. Hydrochemical data for surface water (4 samples) and groundwater (28 samples) were collected in a small watershed in the Poopó catchment at the highland of the Bolivian Andes (Altiplano). All of them show high electrical conductivity values and moderately oxidizing conditions. The surface water contains high concentration of sulfate and the trace elements As, Zn and Pb in the zone affected by acid mine drainage. There is a large variability of the concentration of As and of the trace elements in the groundwater in the five different regions within the Poopó catchment. The metal concentrations sensitive to changes of redox state and results of speciation modeling suggest that As (V) is a predominant aqueous species, which conforms to the prevailing oxidizing conditions in the shallow groundwater environment. Two generalized trends for As distribution were identified in groundwater: (a) high concentrations are found in the arid zone (100–250 μg/L) in the southern (region III) and in the northwestern (region V) regions, and (b) low concentrations (<50 μg/L) are found in the remaining part of the basin (region I, II and IV). However, the spatial distribution within these regions needs to be investigated further. A conclusion from the present study is that there are multiple sources of As as well as other trace elements (such as Cd, Mn and Zn) in the Poopó Lake Basin. Among the sources and the processes which led to the mobility of As and other trace metals in the region are: (a) weathering of sulfide minerals, (b) oxidation of pyrite and/or arsenopyrite in mineralized areas and (c) desorption from hydrous ferric oxide (HFO) surfaces. In non-mining areas, volcanic ash is suggested to be a significant source of As.     

Geostatistical analysis of arsenic concentration in groundwater in Bangladesh using disjunctive kriging

The National Hydrochemical Survey of Bangladesh sampled the water from 3,534 tube wells for arsenic throughout most of Bangladesh. It showed that 27% of the shallow tube wells (less than 150 m deep) and 1% of the deep tube wells (more than 150 m deep) exceeded the Bangladesh standard for arsenic in drinking water (50 µg L^–1). Statistical analyses revealed the main characteristics of the arsenic distribution. Concentrations ranged from less than the detection limit (0.5 µg L^–1), to as much as 1,600 µg L^–1, though with a very skewed distribution, and with spatial dependence extending to some 180 km. Disjunctive kriging was used to estimate concentrations of arsenic in the shallow ground water and to map the probability that the national limit for arsenic in drinking water was exceeded for most of the country (the Chittagong Hill Tracts and the southern coastal region were excluded). A clear regional pattern was identified, with large probabilities in the south of the country and small probabilities in much of the north including the Pleistocene Tracts. Using these probabilities, it was estimated that approximately 35 million people are exposed to arsenic concentrations in groundwater exceeding 50 µg L^–1 and 57 million people are exposed to concentrations exceeding 10 µg L^–1 (the WHO guideline value).     

Fluoride and arsenic hydrogeochemistry of groundwater at Yuncheng basin,Northern China

High fluoride and arsenic concentrations in groundwater have led to serious health problems to local inhabitants at Yuncheng basin, Northern China. In this study, groundwater with high fluoride and arsenic concentration at Yuncheng basin was investigated. A majority of the samples (over 60%) belong to HCO₃ type water. The predominant water type for the shallow groundwater collected from southern and eastern mountain areas was Ca/Mg-Ca-HCO₃ types. For the shallow groundwater from flow through and discharge area it is Na-HCO₃/SO₄-Cl/SO₄/Cl type. The predominant water type for the intermediate and deep groundwater is of Na/Ca/Mg-Ca-HCO₃ type. According to our field investigation, fluoride concentration in groundwater ranges between 0.31 and 14.2 mg/L, and arsenic concentration ranges between 0.243 and 153.7 μg/L. Out of seventy collected groundwater samples, there are 31 samples that exceed the World Health Organization (WHO) standard of 1.5 mg/L for fluoride, and 15 samples exceeds the WHO standard of 10 μg/L for arsenic. Over 40% of high fluoride and arsenic groundwater are related to the Na-HCO₃ type water, and the other fifty percent associated with Na-SO₄-Cl/HCO₃-SO₄-Cl type water; little relation was found in calcium bicarbonate type water. A moderate positive correlation between fluoride and arsenic with pH were found in this study. It is due to the pH-dependent adsorption characteristics of F and As onto the oxide surfaces in the sediments. The observed negative correlation between fluoride and calcium could stem from the dissolution equilibrium of fluorite. The high concentration of bicarbonate in groundwater can serve as a powerful competitor and lead to the enrichment of fluoride and arsenic in groundwater. Most of the groundwater with high fluoride or arsenic content has nitrate content about or over 10 mg/L which, together with the observed positive correlations between nitrate and fluoride/arsenic, are indicative of common source of manmade pollution and of prevailing condition of leaching in the study area.     

Slow arsenic poisoning of the contaminated groundwater users

This paper gives impact of Arsenic contaminated water on human health as well as overview of the extent and severity of groundwater arsenic contamination in Bangladesh. Scalp hair is the most important part of the human body to monitor the accumulation of this type of poison. Therefore, an experiment has been carried out by Neutron Activation Analysis (NAA) at Atomic Energy Research Establishment (AERE), Savar, Dhaka, Bangladesh on human hair of corresponding tube well water users of these areas to determine the total accumulation of arsenic to their body. Hair samples collected from the region where the groundwater was found highly contaminated with arsenic. The obtained results of arsenic concentration in the lower age (Hb) categories of users (below 12 years of age users) is in the range of 0.33 to 3.29 /gmg/g (ppm) and that in the Hu categories (upper 12 years of age users) is 0.47 to 6.64 μg/g (ppm). Where as maximum permissible range is 1 ppm certified from WHO. Results show that the peoples are highly affected where the groundwater is highly contaminated with arsenic and acts as the primary source of arsenic poisoning among the peoples of those areas. The results indicate that human population is affected with arsenic locally using the contaminated water for a long time.     

Environmental distribution and health impacts of As and Pb in crops and soils near Vinto smelter,Oruro, Bolivia

The Vinto Sb–Sn smelter (Oruro, Bolivia) has been linked to arsenic and heavy metal pollution in air, soils, residual waters of the smelter, and hair and urine of workers, but crop concentrations had not been assessed previously. In this article, alfalfa, onions, and carrots, separated into roots and shoots, were analyzed for As and Pb, together with corresponding soil samples. The aim was to assess the environmental distribution and potential health impacts of these toxic elements and to compare them to levels observed at other sites around the world. As and Pb concentrations in all analyzed crop samples exceed the FAO/WHO, UK or Chilean limits by 1.5–2 orders of magnitude and As health risk indices were 286 (carrot) and 651 (onion), showing that the potential health risk due to consumption of these products is extremely high. As and Pb soil–plant transfer factors are similar to other contaminated sites around the world, but daily intake and health risk index for As are much higher in Vinto area due to very high concentrations in soils. Arsenic and lead soil and crop concentrations suggest increasing trends toward VMC. Correlations are significant for Pb in some crop fractions, but not for As, possibly due to considerable geogenic contributions to soil As in the area. In future surveys, larger numbers of soil and crop samples should be analyzed, and additional analyses should be carried out to distinguish anthropogenic and geogenic sources of As and Pb in soils and crops in the area.     

Investigating water quality and arsenic contamination in drinking water resources in the Tavşanlı District (Kütahya,Western Turkey)

Arsenic is a natural component of the earth’s crust, and it is transported into surface water and groundwater through the dissolution of rocks, minerals and ores. In addition, arsenic leaching processes contaminate water sources and this geogenic arsenic contamination causes significant water quality problems in many parts of the world. In this study, water quality, arsenic contamination and human health risks of drinking water resources in the Tav?anl? District were determined and the origins were discussed. For this purpose, geological and hydrogeological properties were investigated. In situ measurements and chemical analyses were carried out on water samples taken from drinking water sources such as wells, springs and surface waters for hydrogeochemical studies. According to the obtained results, water resources are Ca–Mg–HCO₃, Mg–HCO₃ and Na–HCO₃ type. Total As (As_T) concentration of the water samples sometimes exceeds the permissible limit given by the TSI-266 (Standards for drinking waters, Turkish Standards Institution, Ankara, 2005) and WHO (Guidelines for drinking-water quality, World Health Organization, Geneva, 2008) for drinking water. H₃AsO ₃ ⁰ and HAsO₄ ^2? are dominant arsenic species in groundwater and surface water, respectively. Typically high total arsenic concentrations can be found in regions characterized by magmatic rocks. In addition, As concentrations in surface waters were found to be higher than in groundwater in the region, due to the anthropogenic influence of mining activities in the region.     

Major and trace elements in German bottled water,their regional distribution,and accordance with national and international standards

The market for mineral water has been growing steadily over the last few years. Germany is the country with the highest number of bottled mineral water brands (908 bottled water samples from 502 wells/brands were analyzed). The per capita consumption of mineral water in Germany in 2003 was 129 L. A wide range of values of one to seven orders of magnitude was determined for 71 elements in the bottled water samples analyzed by ICP-QMS, ICP-AES, IC, titration, photometric, conductometric and potentiometric methods. A comparison of the element concentrations and the legal limits for both bottled and tap water (EU, Germany, US EPA, WHO) shows that only 70% of the 908 mineral water samples fulfill the German and EU drinking water (i.e., tap water) regulations for all parameters (not including pH) for which action levels are defined. Nearly 5% of the bottled water samples not fulfill the German and EU regulations for mineral and table water. Comparison of our results with the current German and European action levels for mineral and table water shows that only 42 of the bottled water samples exceed the limits for one or more of the following elements: arsenic, nitrate, nitrite, manganese, nickel and barium concentrations. Ten of the bottled water samples contain uranium concentrations above the 10 μg/L recommended limit.     

Natural arsenic in Triassic rocks: A source of drinking-water contamination in Bavaria, Germany

 The aquifer system of the Upper Triassic Keuper Sandstone, an important source of drinking water in northern Bavaria, is affected by elevated arsenic concentrations. Within the study area of 8000 km², no evidence exists for any artificial source of arsenic. Data from about 500 deep water wells show that in approximately 160 wells arsenic concentrations are 10–150 μg/L. The regional distribution of arsenic in the groundwater shows that elevated arsenic concentrations are probably related to specific lithofacies of the aquifers that contain more sediments of terrestrial origin. Geochemical measurements on samples from four selected well cores show that arsenic has accumulated in the rocks. This indigenous arsenic is the source of arsenic in the groundwater of certain facies of the middle unit of the Keuper Sandstone. Received, June 1998 / Revised, January 1999, May 1999 / Accepted, June 1999     

Mobilization of natural arsenic in groundwater: targeting low arsenic aquifers in high arsenic occurrence areas

研究表明饮用水中微小数量的砷会对人类健康产生不利影响.世界上居住在贫穷地区的人数超过了100万,目前他们正直接饮用来自含水层中砷离子含量(>10μg/L)非安全标准的地下水.砷有时称为毒中之王,在水环境中常常以五价氧化物形式出现.自2000年以来,许多国家开始执行更为严格的10μg/L(WHO认可的居民安全饮水标准)饮用水标准,可以确定地说,在世界范围内的饮用水中检测到砷的情况越来越多.亚洲地区砷中毒的人数比世界其他地区总和还多.最受影响的地区位于南亚和东南亚富砷带,环绕恒河一雅鲁藏布江-梅克纳河三角洲及恒河平原上游的冲洪积扇含水层、红河三角洲、湄公河和伊洛瓦底江;在中国境内包括内蒙黄河冲积盆地,山西大同盆地、新疆准噶尔盆地,其中的地下水富含砷和氟化物而引发砷中毒和氟中毒.尽管还未完全掌握其中的水文地质及生物地球化学作用的详细过程,但对大多数沉积介质含水层,在还原条件下砷离子容易从沉积介质转移到地下水中.孟加拉研究实例表明地质时期尺度的冲刷降低了沉积介质中的As和有机物含量从而形成低砷地下水.这一认识为孟加拉国的降砷策略提供了科学指导,是未来水文学,矿物学,地质学和生物地球化学方面很有意义的研究方向,并有利于地砷病区低砷地下水的可持续利用.     

Fluoride contamination of groundwater and its seasonal variability in parts of Purulia district,West Bengal,India

The contamination of aquifers by fluoride and arsenic is a major cause of concern in several parts of India. A study has thus been conducted to evaluate the extent and severity of fluoride contamination and also its seasonal variability. Two blocks (Purulia-1 and Purulia-2) were considered for this purpose. Twenty groundwater samples (in each season) were collected from tube wells during the pre-monsoon and post-monsoon seasons. In addition to fluoride, groundwater samples were also analyzed for major cations, anions, and other trace elements. The concentration of fluoride shows significant seasonal variation and ranges between 0.94–2.52 and 0.25–1.43 mg/l during the pre-monsoon and post-monsoon seasons, respectively. In pre-monsoon season, more than 40% of the water samples show fluoride concentrations higher than the WHO limit. However, during the post-monsoon season, none of the groundwater sample shows fluoride concentrations higher than the WHO limit. Lesser concentration during the post-monsoon season is attributed to the dilution effect by the percolating rainwater, which has also been reflected in the form of a decrease in concentrations of other elements. The petrographic studies of the rock samples collected from the study area show that the rocks are mainly composed of plagioclase, orthoclase, and quartz with abundant biotite. The weathering and dissolution of biotite plays an important role in controlling the fluoride concentrations in the groundwater of the study area.     

Geochemical characteristics of ores and surface waters for environmental risk assessment in the Pinpet iron deposit,southern Shan State,Myanmar

Mining operations in the Pinpet Fe deposit, which is the second‐largest Fe deposit in Myanmar, are currently suspended, in part because of possible contamination of heavy metals and hazardous elements (e.g., Fe, As, Cu, Zn, and U) into the surrounding aquatic environment and associated public concern. However, a scientific investigation of the source and degree of contamination in streams near the deposit has not yet been conducted. Therefore, we quantified heavy‐metal and hazardous‐element concentrations of stream waters and sediments in stream beds, and measured the speciation and concentration of these metals in deposit Fe ores using the sequential extraction method, to better understand the influence of mining activities on the surrounding environment. Geochemical results for Nan‐tank‐pauk stream and its tributaries indicate that the chemical compositions of their waters are controlled by carbonate bedrock and that no detectable contamination has occurred as a result of mining activity or hematite and limonite ore beneficiation processes in either the wet or dry seasons. All measured heavy‐metal and hazardous‐element concentrations were below the World Health Organization standards for drinking water and the proposed national drinking water quality standards in Myanmar. Bulk chemical compositions of stream‐bed and tailings dam sediments show that As, Zn, and Cu concentrations are similar to those in uncontaminated sediments. Results of bulk mineralogical and chemical analyses of ore samples reveal that some limonite ore samples contain substantial amounts of As (up to 2 wt%). However, sequential extraction results indicate that most (>90%) of the As in these As‐rich ores is hosted in insoluble fractions (e.g., crystalline Fe hydroxides and clays). Therefore, arsenic is unlikely to be released into the aquatic environment by interacting with water during ore beneficiation processes should the mine resume operations.     

Arsenic enrichment in lakes near the smelters at Sudbury,Ontario

Roughly 200 tonnes of arsenic are produced annually with the base metal ores at Sudbury about 125 tonnes of which are released to the ambient environment via the atmosphere. The dispersion of this highly toxic element in lakes around the smelters is described. The total As concentrations in unfiltered lake waters vary from 0.2 to 0.6 ug 1^?1. The suspended particulates in the water column (with As contents of 2–6 ug g^?1) play a major role in the flux of arsenic to the lake sediments. The present-day rates of As accumulation in the sediments are found to be 1.5–6.4 mg m^?2 yr^?1; these rates exceed those of precolonial times by factors of 5–47. The changes in the rates of As flux to the sediments are shown to parallel the history of Cu and Ni production in the district.     

Comparison of metal(loid) concentrations in water, sediments and fish from two large shallow lakes

Hulun Lake and Taihu Lake are both large shallow lakes in China. In summer and winter of 2009, water, sediments and fish samples were collected from the two lakes and the concentrations of metal(loids) were analyzed. The results demonstrated that aqueous concentrations of arsenic (As), chromium (Cr), cadmium (Cd), nickel (Ni) and copper (Cu) in Hulun Lake were significantly higher than those in Taihu Lake. Especially, the As concentrations (about 130 μg/L) in Hulun Lake dramatically exceeded the permissible level of drinking water. Compared with Taihu Lake, metal(loid) concentrations in the sediments of Hulun Lake were significantly lower, which might have less impacts on the metal exchanges between water and sediments. In contrast, concentrations of the measured metal(loids) (including As) in fish from Hulun Lake and Taihu Lake were comparable, suggesting that the dramatic difference in aqueous and sediment metal(loid) concentrations had less influence on the metal(loid) bioavailability. The higher concentrations of dissolved organic carbon (DOC) and cations (e.g., Na⁺, K⁺ and Mg²⁺) in lake water might contribute to the reduced metal(loid) bioavailability to fish in Hulun Lake.     

Temporal variations in arsenic concentration in the groundwater of Murshidabad District,West Bengal,India

Systematic investigations on seasonal variations in arsenic (As) concentrations in groundwater in both space and time are scarce for most parts of West Bengal (India). Hence, this study has been undertaken to investigate the extent of As pollution and its temporal variability in parts of Murshidabad district (West Bengal, India). Water samples from 35 wells were collected during pre-monsoon, monsoon and post-monsoon seasons and analyzed for various elements. Based on the Indian permissible limit for As (50 μg/L) in the drinking water, water samples were classified into contaminated and uncontaminated category. 18 wells were reported as uncontaminated (on average 12 μg/L As) and 12 wells were found contaminated (129 μg/L As) throughout the year, while 5 wells could be classified as either contaminated or uncontaminated depending on when they were sampled. Although the number of wells that alternate between the contaminated and uncontaminated classification is relatively small (14%), distinct seasonal variation in As concentrations occur in all wells. This suggests that investigations conducted within the study area for the purpose of assessing the health risk posed by As in groundwater should not rely on a single round of water samples. In comparison to other areas, As is mainly released to the groundwater due to reductive dissolution of Fe-oxyhydroxides, a process, which is probably enhanced by anthropogenic input of organic carbon. The seasonal variation in As concentrations appear to be caused mainly by dilution effects during monsoon and post-monsoon. The relatively high concentrations of Mn (mean 0.9 mg/L), well above the WHO limit (0.4 mg/L), also cause great concern and necessitate further investigations.