Year : 2019  |  Volume : 23  |  Issue : 3  |  Page : 126--132

Comparative quantification study of arsenic in the groundwater and biological samples of simri village of Buxar District, Bihar, India


Md Samiur Rahman1, Arun Kumar2, Ranjit Kumar2, Mohammad Ali2, Ashok Kumar Ghosh2, Sushil Kumar Singh1,  
1 Department of Biotechnology, Anugrah Narayan College, Patna, Bihar, India
2 Mahavir Cancer Institute and Research Centre, Patna, Bihar, India

Correspondence Address:
Dr. Arun Kumar
Mahavir Cancer Institute and Research Centre, Phulwarisharif, Patna - 801 505, Bihar
India

Abstract

Background: In the entire world, about 200 million populations are exposed to arsenic poisoning in groundwater. In Bihar, India about 50 million people are drinking arsenic contaminated water. This has caused various health related problems in the population like skin diseases, anemia, bronchitis, gastrointestinal problems, hormonal imbalance and cancer. Materials and Methods: In the present study, a total of 323 water samples were analyzed for the arsenic levels from the entire Simri village of Buxar district of Bihar and a total of 170 blood samples from the same household's subjects were collected for blood arsenic estimation through Graphite Furnace Atomic Absorption Spectrophotometer (Pinnacle 900T, Perkin Elmer, Singapore). Apart from this the correlation coefficient study between blood arsenic levels, age of the subjects, groundwater arsenic levels and depth of the handpumps were carried out. Statistical Analysis: Data were analyzed with statistical software (GraphPad Prism 5) and while scattered graphs were plotted through statistical software SPSS- 16.0. Results and Conclusion: The maximum arsenic concentration in the groundwater sample found during the study was 1929μg/L and in blood sample was 664.7μg/L. The study denotes high arsenic concentration in the drinking water of the village Simri with the highest concentration ever reported in this part of India. Furthermore, the blood samples have also been observed with high arsenic concentration in the village population which is also the highest reporting ever done in this area. The ill health of the village population also correlates our study.



How to cite this article:
Rahman MS, Kumar A, Kumar R, Ali M, Ghosh AK, Singh SK. Comparative quantification study of arsenic in the groundwater and biological samples of simri village of Buxar District, Bihar, India.Indian J Occup Environ Med 2019;23:126-132


How to cite this URL:
Rahman MS, Kumar A, Kumar R, Ali M, Ghosh AK, Singh SK. Comparative quantification study of arsenic in the groundwater and biological samples of simri village of Buxar District, Bihar, India. Indian J Occup Environ Med [serial online] 2019 [cited 2020 Jul 13 ];23:126-132
Available from: http://www.ijoem.com/text.asp?2019/23/3/126/273034


Full Text



 Introduction



Among Himalayan Rivers, Ganga river system is well known for its erosive activities throughout the evolution of Himalayas. It forms alluvial deposition around its course. The finding of elevated levels of arsenic in the Gangetic belt is supported by the river's erosive and alluvial forming nature. Arsenic naturally occurs in the sediments all over Asia, and is a particular problem in areas dominated by holocene and organic-rich sediments.[1],[2]

Arsenic is a very poisonous metalloid and it has three allotropic forms.[3],[4] The toxic inorganic arsenic converted and utilized metabolically into organic form. It is primarily disposed out from the human body through urine and also deposited in the hair, nails, and skin of the affected ones.[5] Arsenic, arsenic trioxide, arsenic pentoxide, arsenous acids, arsenic acid, and their salts (arsenites and arsenates) are carcinogenic substances (carcinogen category 1).[6],[7],[8],[9] In addition to their carcinogenic effects in man, arsenic and the above named arsenic compounds have toxic effects on the epidermal system, the nervous system, and the vascular system.[10]

Human exposure to elevated levels of inorganic arsenic occurs mainly through the consumption of arsenic contaminated groundwater, food prepared with this contaminated water, and food crops irrigated with high-arsenic water resources. According to the provisional guideline value of WHO, in the view of scientific uncertainties surrounding the risk assessment for arsenic carcinogenicity, arsenic in drinking water up to the level of 10 μg/L is decided as permissible limit.[11],[12],[13]

It is estimated that, in the entire world, about 300 million populations are exposed to arsenic poisoning in groundwater.[14] The largest number of people in the world affected by chronic arsenic toxicity is due to drinking of arsenic contaminated groundwater in Bangladesh, India, and China.[15] Inorganic arsenic is naturally present at high levels in the groundwater of a number of countries such as Argentina, Chile, Mexico, the United States of America, China, India, and particularly Bangladesh where approximately half of the total population are at the risk of drinking arsenic contaminated water from tube wells and groundwater hand pumps.[16] Approximately higher levels of arsenic contamination in the drinking water from several hundred ppb to over 1 ppm have been observed in several countries like Argentina, Bangladesh, Chile, India, Mexico, Thailand, and Taiwan.[10]

In India, arsenic contamination was first reported in Punjab, Haryana, Himachal Pradesh, and Uttar Pradesh.[17] Then after, in 1984, groundwater arsenic contamination was identified in the lower Ganga plain of West Bengal.[18] Furthermore, arsenic groundwater contamination was reported in Bangladesh,[19] the lower plain area (Terai) of Nepal [20] Bihar (middle Ganga plain), Uttar Pradesh (lying in middle and upper Ganga plain),[21],[22] Jharkhand,[23] and Assam.[24]

In Bihar, the high levels of arsenic in groundwater and associated health-related problems were first discovered in Semaria Ojhapatti village of Bhojpur district.[21] Currently, arsenic contamination in the groundwater of Bihar is reported from 18 districts, threatening more than 10 million people in the state.[25],[26] The arsenic poisoning has caused lots of health hazards in the population of Bihar.[27],[28] The present study is aimed to know the groundwater status in Buxar district along with health status of the population residing in the same area.

 Materials and Methods



Ethical approval

Ethical approval was obtained from the Institutional Ethics Committee (IEC) of Mahavir Cancer Sansthan and Research Centre with IEC No.MCS/Research/2015-16/2716 dated 08/01/2016.

Location

The study was conducted in India in Simri village of Buxar district of Bihar (25°38′17.6″N 84°06′49.4″E). The population of the Simri village was 17,670 in 2011 and there were 2,621 households.[29] The village is divided into seven strips: Bakulaha Patti, Bhan Bharauli, Khaira Patti, Ramo Patti, Halwa Patti, Doodhi Patti, and Gope Bharauli. The Simri village is situated approximately 1.65 km away from the banks of the river Ganga.

Water collection, analysis, and survey

The water sample bottles (500 ml polypropylene bottles) were well cleaned and pretreated with N/10 hydrochloric acid. Altogether, 323 water samples were randomly collected from the village in duplicates from hand pumps of each household situated at every 50 m of distance. The depth of the hand pumps was also recorded for the correlation of arsenic concentration. After the collection, all samples were digested using concentrated HNO3 on hot plate under fume hood and estimated as per the protocol [30] through Graphite Furnace Atomic Absorption Spectrophotometer (Pinnacle 900T, Perkin Elmer, Singapore). Simultaneously, health assessment of the population was also done through a health survey questionnaire performa. For determining the exact location of the hand pump, hand held global positioning system (GPS) receiver (Garmin etrex 10, of USA) with an estimated accuracy of approx. 10 m was utilized.

Blood collection and analysis

Blood samples (n = 170) 5ml were taken from the medial cubital vein in the arm using disposable syringes and transferred to heparinized vaccutainer as per the guidelines of IUPAC.[31] After the collection, all the blood samples were double digested using concentrated HNO3 on hot plate under fume hood and estimated as per the protocol [32] through Graphite Furnace Atomic Absorption Spectrophotometer (Pinnacle 900T, Perkin Elmer, Singapore).

GIS analysis

The data of arsenic concentration in water samples of hand pumps of the village along with the data of blood arsenic concentration of the subjects were undertaken as input in ArcGIS 10 software for spatial analysis, correlation, and synoptic observation. Concentration of arsenic in water, blood, and confirmed cancer cases were generated as three different GIS layers. Categorical classification of each layer was done for analysis. Water arsenic contamination was categorized into three classes: <10 μg/L, 10--50 μg/L, and >50 μg/L. Similarly, blood arsenic concentration data were categorized into two classes: <1 μg/L and >1 μg/L. Village map of Simri was overlayed over these layers. Background map was taken from Google Earth and geo-referenced accordingly. All the layers were overlayed and analyzed with an ArcGIS environment. Final output was generated as a thematic map.

Statistical analysis

Data were analyzed with statistical software (GraphPad Prism 5) and values were expressed as Mean ± SEM. Differences between the groups were statistically analyzed by one-way analysis of variance (ANOVA) using the Dunnett's test, while scattered graphs were plotted through another statistical software SPSS- 16.0 using linear regression analysis method.

 Results



GIS analysis

The synoptic view of high-arsenic concentration found in blood and water sample [Figure 1].{Figure 1}

Groundwater arsenic assessment

Total 323 water samples were analyzed from the entire village in which maximum arsenic concentration in groundwater sample reported was 1,929 μg/L [Figure 2]a and [Figure 2]b.{Figure 2}

Blood arsenic (BAs) assessment

Total 170 blood samples of Simri village people were analyzed and the maximum arsenic concentration in blood sample of the village people reported was 664.7 μg/L that is ultimately high level of arsenic in blood ever reported [Figure 3]a and [Figure 3]b.{Figure 3}

Correlation coefficient study

Correlation coefficient between blood arsenic levels and age of the subject

The study showed significant increase in blood arsenic levels with the increase of the age of the individual (r = 0.049, P < 0.05; [Figure 4]), especially in the age group of >40 years. It was also observed that one of the subject who was 64 years old had the highest arsenic concentration in her blood as 664.7 μg/L.{Figure 4}

Correlation coefficient between blood arsenic levels and groundwater arsenic levels

The study showed nonsignificant increase in the blood arsenic levels with increase in the arsenic concentrations in their drinking water samples (r = 0.003, P < 0.05; [Figure 5]). Furthermore, it is also observed that most of the individuals having highest blood arsenic levels belonged to the households bearing <500 μg/L groundwater arsenic level.{Figure 5}

Correlation coefficient between groundwater arsenic levels and age of the hand pumps

The study showed significant increase in the water arsenic levels with increase in the hand pump age (r = 0.442, P < 0.05; [Figure 6]).{Figure 6}

Correlation coefficient between groundwater arsenic levels and depth of the hand pumps

The study showed nonsignificant increase in the water arsenic levels with increase in the hand pump depth (r = 0.001, P < 0.05; [Figure 7]). Furthermore, it is also observed that in the village the majority of the hand pumps were present at the depth range of 50--120 feet and the highest ground water arsenic contamination were found in this depth range of hand pumps.{Figure 7}

Clinical health assessment

The village people exhibited typical symptoms of arsenicosis like hyperkeratosis in sole and palm, hyper-pigmentation in palm as they were drinking very high concentration of arsenic contaminated drinking water [Figure 8]a and [Figure 8]d. Many village people exhibited suspected cancerous nodes in the neck region (suspected lymphoma cancer) [Figure 8]b, while one subject exhibited severe cancerous growth over the neck region [Figure 8]c. On subject exhibited skin lesions in the head region [Figure 8]e. Most of the village people had health-related problems like gastritis and flatulence, constipation, anemia, loss of appetite, breathlessness, mental disability, etc., Moreover, there was reporting of cancer cases like breast cancer, liver cancer, gall bladder cancer, thyroid cancer, colorectal cancer cases, etc.{Figure 8}

 Discussion



Arsenic is abundantly distributed throughout earth's crust and can be released into the atmosphere and water by means of natural and human activities. Natural activities include volcanic activity, dissolution of minerals into groundwater, exudates from vegetation and wind-blown dust. Human activities include mining, metal smelting, combustion of fossil fuels, agricultural pesticide production and its use, timber treatment with preservatives, remobilization of historic sources such as mine drainage water and mobilization into drinking water from geological deposits by drilling of tube wells.[33],[34],[35],[36]

After ingestion, around 95% of inorganic arsenic compounds are absorbed through the gastrointestinal tract. In man, the ingested inorganic arsenic compounds, first of all, enter the blood and with a half-time of 2 h, inorganic arsenic is rapidly eliminated from the blood through the renal system. The metabolism of arsenic in man and in many species of the animal takes place in two steps: first of all pentavalent form of arsenic is usually reduced to trivalent form, which is then methylated to form monomethylated and dimethylated arsenic compounds. The trivalent arsenic compounds are three to four times more toxic than the corresponding pentavalent arsenic compounds.[37],[38]

Immediately, the acute arsenic poisoning results in vomiting, diarrhea, abdominal pain, then followed by the paresthesia of the extremities, muscle cramp, and death in the extreme rare cases. After long-term exposure to high levels of inorganic arsenic, the first changes are usually seen in the skin is the pigmentation changes and then skin lesions and hard patches on the palms of the hands and soles of the feet. Peripheral neuropathy, renal system effects, gastrointestinal symptoms, diabetes, high blood pressure, conjunctivitis, enlarged liver, bone marrow depression, destruction of erythrocytes, and cardiovascular disease are some other effects of long-term exposure to high levels of inorganic arsenic.[39],[40]

Arsenic can cause cancers of the skin, bladder, lungs, kidney, liver, and prostate.[41] The International Agency for Research on Cancer has classified arsenic and arsenic compounds as group 1 carcinogen to humans, which means that there is sufficient evidence for its carcinogenicity in humans.[9] Arsenic can pass through the placenta; therefore, pregnant women are chronically exposed to arsenic contaminated drinking water and are at increased risk for spontaneous abortion, stillbirth, and preterm birth. In uteri and early life, exposures to arsenic have been linked to the development of lung cancer and bronchiectasis later in life. The epidemiological data on human suggest an association between the arsenic exposure in drinking water and its adverse effect on reproductive system as well as outcomes.[42],[43]

In Simri village and Tilak Rai ka Hatta village, our previous study of groundwater arsenic level was based on SDDC method of arsenic estimation that showed the significant finding of arsenic contamination in the different strips of the following two villages. This study is the continuation of above described work.[27],[28]

Arsenic contamination in groundwater has caused severe health effects in the population of Simri village of Buxar district. The groundwater contamination in the Simri village is the highest concentration of arsenic in water ever reported in this area. The flood plain region of Ganges has peculiar geomorphic conditions but due to excessive harnessing of groundwater has led to the geomorphologic changes. Similar studies on water and geomorphologic changes have been well studied in the other districts of the state.[26] Furthermore, the arsenic contaminated groundwater has caused health-related issues in the village population like hyperkeratosis, severe skin diseases (eczema, fungal infection, etc.), anemia, bronchitis, apart from this the subjects also report diseases of lungs, liver, stomach (gastrointestinal problems), lower gut, hormonal imbalance, and cancer. In cancer, the most common was liver and gall bladder, lung cancer, skin melanoma, ovarian cancer, and breast cancer.[44] Similar studies have been documented by various studies conducted in West Bengal, India [18] and Bhojpur district of Bihar.[21]

In the present study, the blood arsenic levels have been reported with levels which are highest ever reported in India. The basic affinity of arsenic is with iron (Fe) and sulphur (S), as these two elements are in conjugation with each other in compound arseno-pyrite present in the sediments of these Gangetic flood plains.[45] Therefore, it has a great affinity to bind with the α-chain of the human hemoglobin of their red blood cells (RBCs). Therefore, it seems that the binding capacity of arsenic with blood remains till the life span of RBC (i.e., 120 days).[46] Furthermore, the present study also correlates the blood arsenic levels with the age of the subjects and the consumption of arsenic contaminated groundwater.[28],[47],[48],[49],[50] which shows the ill health of the village population.

 Conclusion



The present study deciphers the high arsenic concentration in the drinking water of the village Simri of the Buxar district with the highest concentration ever reported in this part of India. Furthermore, the blood arsenic levels have also been observed with high arsenic concentration in the village population blood samples which is also the highest reporting ever done in this area. The ill health of the village population also correlates our study. Therefore, at present a strategic policy has to be made to cater the problems of this population.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Acknowledgements

The authors extend their appreciation to the Department of Science and Technology, (SSTP Division) Ministry of Science and Technology, Government of India, New Delhi for the financial assistance of this work and to the Anugrah Narayan College, Patna and Mahavir Cancer Institute and Research Centre, Patna, Bihar, India for the entire infrastructural facilities.

Financial support and sponsorship

Department of Science and Technology (DST), TDT-SSTP Division, New Delhi, India (Government of India). Research Project No. DST/SSTP/Bihar/155/2011 (G).

Conflicts of interest

There are no conflicts of interest.

References

1Donselaar ME, Bhatt AG, Bose N, Bruining J, Ghosh AK. Entrapment of arseniccontaminated groundwater in point bars: Case study of holocene ganges river deposits, Bihar, India, proceedings of 10th international conference on fluvial sedimentology, University of Leeds, UK; 2013.
2Winkel L, Berg M, Amini M, Hug SJ, Johnson CA. Predicting groundwater arsenic contamination in Southeast Asia from surface parameters. Nat Geosci 2008;1:536-42.
3ATSDR US. Toxicological profile for arsenic. Agency for toxic substances and diseases registry; 2005.
4ATSDR/DTEM. Division of toxicology and environmental medicine. ToxFAQs: CABSTM/chemical agent briefing sheet arsenic. Agency for Toxic Substances and Disease Registry; 2006.
5IPCS. Arsenic and Arsenic Compounds. 2nd ed. Geneva, World Health Organization, International Programme on Chemical Safety (Environmental Health Criteria); 2001. p. 224.
6Straif K, Benbrahim-Tallaa L, Baan R, Grosse Y, Secretan B, El Ghissassi F, et al. WHO, International agency for research on cancer monograph working group. A review of human carcinogens-Part C: Metals, arsenic, dusts, and fibres. Lancet Oncol 2009;10:453-4.
7Karagas MR, Stukel TA, Tosteson TD. Assessment of cancer risk and environmental levels of arsenic in new Hampshire. Int J Hyg Environ Health 2002;205:85-94.
8Valko M, Rhodes CJ, Moncol J, Izakovic M, Mazur M. Free radicals, metals and antioxidants in oxidative stress-induced cancer. Chem Biol Interact 2006;160:1-40.
9International Agency for Cancer Research (IARC). Some drinking-water disinfectants and contaminants including arsenic, in IARC: Monographs on the Evaluation of Carcinogenic Risks to Humans. Vol. 84. IARC; 2004.
10ACSH. Arsenic, drinking water, and health: A position paper of the American Council on Sciences and Health. American Council on Sciences and Health, New York. Regul Toxicol Pharmacol 2002;36:162-74.
11WHO. Arsenic and arsenic compounds. Environmental health criteria. Geneva: WHO; 2001. p. 224.
12WHO. Guidelines for drinking-water quality, 3rd ed., vol. 1. Incorporating 1st and 2nd agenda. Recommendations. Geneva, World Health Organization; 2008. p. 306-8b.
13WHO. Exposure to arsenic: A major public health concern, In: Preventing disease through healthy environments. WHO; 2010. p. 1-5.
14Hassan M. Arsenic in groundwater. Boca Raton: CRC Press; 2018.
15ATSDR. Toxicological profile for arsenic. Draft for public comment. Atlanta GA: Agency for Toxic Substances and Disease Registry; 2007.
16Nordstrom DK. Public health. Worldwide occurrences of arsenic in ground water. Science 2002;296:2143-5.
17Datta DV, Kaul MK. Arsenic content of drinking water in villages in northern India. A concept of arsenicosis. J Assoc Physicians India 1976;24:599-604.
18Garai R, Chakraborty AK, Dey SB, Saha KC. Chronic arsenic poisoning from tube-well water. J Indian Med Assoc 1984;82:34-5.
19Dhar RK, Biswas BK, Samanta G, Mandal BK, Chakraborti D, Roy S, et al. Groundwater arsenic calamity in Bangladesh. Curr Sci 1997;73:48.
20Shrestha RR, Shrestha MP, Upadhyay NP, Pradhan R, Khadka R, Maskey A, et al. Groundwater arsenic contamination, its health impact and mitigation program in Nepal. J Environ Sci Health A Tox Hazard Subst Environ Eng 2003;38:185-200.
21Chakraborti D, Mukherjee SC, Pati S, Sengupta MK, Rahman MM, Chowdhury UK, et al. Arsenic groundwater contamination in Middle Ganga Plain, Bihar, India: A future danger? Environ Health Perspect 2003;111:1194-201.
22Chakraborti D, Rahman MM, Paul K, Chowdhury UK, Sengupta MK, Lodh D, et al. Arsenic calamity in the Indian subcontinent: What lessons have been learned? Talanta 2002;58:3-22.
23Bhattacharjee S, Chakravarty S, Maity S, Dureja V, Gupta KK. Metal contents in the groundwater of Sahebgunj district, Jharkhand, India, with special reference to arsenic. Chemosphere 2005;58:1203-17.
24Chakraborti D, Sengupta MK, Rahman MM, Ahamed S, Chowdhury UK, Hossain MA, et al. Groundwater arsenic contamination and its health effects in the Ganga–Meghna–Brahmaputra Plain. J Environ Monit 2004;6:74N-83N.
25Saha D. Arsenic groundwater contamination in parts of middle Ganga plain, Bihar. Curr Sci2009;97:753-5.
26Chakraborti D, Rahman MM, Ahamed S, Dutta RN, Pati S, Mukherjee SC. Arsenic groundwater contamination and its health effects in Patna district (capital of Bihar) in the middle Ganga plain, India. Chemosphere 2016;152:520-9.
27Kumar A, Ali Md, Rahman S Md, Iqubal A Md, Anand G, Niraj PK, et al. Ground water arsenic poisoning in “Tilak Rai Ka Hatta” village of Buxar district, Bihar, India causing severe health hazards and hormonal imbalance. J Environ Anal Toxicol 2015;5:290.
28Kumar A, Rahman M, Iqubal M, Ali M, Niraj PK, Anand G, et al. Ground water arsenic contamination: A local survey in India. Int J Prev Med 2016;7:100.
29Census. Interim Report of Population Census of India; 2011.
30APHA. Method 3114: Standard methods for the examination of water and wastewater, 18th ed., v. American Public Health Association. 1992. p. 28-33.
31Cornelis R, Heinzow B, Herber RFM, Molin Christensen J, Paulsen OM, Sabbioni E, et al. Sample collection guidelines for trace elements in blood and urine, technical report of IUPAC. Pure Appl Chem 1995;67:1575-608.
32NIOSH (National Institute for Occupational Safety and Health). Elements in blood or tissue. Method: 8005. In: NIOSH manual of analytical methods. 4th ed. O.H. Cincinnati, department of health and human service, national institute of occupational safety and health. DHHS Publication;. p. 94-113.
33Rembert N, He K, Judd SE, McClure LA. The geographic distribution of trace elements in the environment: The REGARDS study. Environ Monit Assess 2017;189:84.
34Shankar S, Shanker U, Shikha null. Arsenic contamination of groundwater: A review of sources, prevalence, health risks, and strategies for mitigation. Sci World J 2014;2014:304524.
35Li Y, Ye F, Wang A, Wang D, Yang B, Zheng Q, et al. Chronic arsenic poisoning probably caused by arsenic-based pesticides: Findings from an investigation study of a household. Int J Environ Res Public Health 2016;13:133.
36Waldman L, Bisht R, Saharia R, Kapoor A, Rizvi B, Hamid Y, et al. Peri-urbanism in globalizing India: A study of pollution, health and community awareness. Int J Environ Res Public Health 2017;14:980.
37Sattar A, Xie S, Hafeez MA, Wang X, Hussain HI, Iqbal Z, et al. Metabolism and toxicity of arsenicals in mammals. Environ Toxicol Pharmacol 2016;48:214-24.
38Moe B, Peng H, Lu X, Chen B, Chen LW, Gabos S, et al. Comparative cytotoxicity of fourteen trivalent and pentavalent arsenic species determined using real-time cell sensing. J Environ Sci (China) 2016;49:113-24.
39Bates MN, Smith AH, Hopenhayn RC. Arsenic ingestion and internal cancers: A review. Am J Epidemiol 1992;135:462-76.
40Bagla P, Kaiser J. India's spreading health crisis draws global arsenic experts. Science 1996;274:174-5.
41Rossman TG. Mechanism of arsenic carcinogenesis: An integrated approach. Mutat Res 2003;533:37-65.
42Ahmad SA, Sayed MH, Barua S, Khan MH, Faruquee MH, Jalil A, et al. Arsenic in drinking water and pregnancy outcomes. Environ Health Perspect 2001;109:629-31.
43Krassas GE. Thyroid disease and female reproduction. Fertil Steril 2000;74:1063-70.
44Nath A, Vendan PSE, Kumar S, Kumar A, Singh JK. Toxicity due to arsenic in gangetic zone of Patna, India and its linkage with cancer. J Environ Anal Toxicol 2013;3:192.
45Guillot S, Charlet L. Bengal arsenic, an archive of Himalaya orogeny and paleohydrology. J Environ Sci Health (Part A) 2007;42:1785-94.
46Shen S, Li X, Cullen W, Weinfeld M, Le X. Review: Arsenic binding to proteins. Chem Rev 2013;113:7769-92.
47Hall M, Chenb Y, Ahsan H, Slavkovich V, Geenc AV, Parvez F, et al. Blood arsenic as a biomarker of arsenic exposure: Results from a prospective study. Toxicology 2006;225:225-33.
48Katiyar S, Singh D. Prevalence of arsenic exposure in population of Ballia district from drinking water and its correlation with blood arsenic level. J Environ Biol 2014;35:589-94.
49Kumar A, Kumar R, Ali M, Gahlot V, Ghosh AK. Groundwater arsenic poisoning in Buxar district of Bihar. Proceedings of the 6th International congress on arsenic in the environment, Stockholm, Sweden, 19-23 June 2016, Arsenic Research and Global Sustainability As2016, Taylor and Francis group, London; 2016. p. 378-9.
50Kumar A, Ghosh AK, Singh N. Arsenic on drinking water: An emerging human right challenge in India (Chapter 4). In: Singh N, editor. The Human Right to water – From Concept To Reality. Switzerland: Springer International Publishing; 2016.