Comparative Quantification Study of Arsenic in the Groundwater and Biological Samples of Simri Village of Buxar District, Bihar, India.

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. Copyright:

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.[12]

Arsenic is a very poisonous metalloid and it has three allotropic forms.[34] 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).[6789] 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.[111213]

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),[2122] 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.[2526] The arsenic poisoning has caused lots of health hazards in the population of Bihar.[2728] 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

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

Figure 1

Thematic map showing synoptic view of high-arsenic level in water and blood using ArcGIS 10 software

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 2a and b].

Figure 2

(a) Arsenic concentration in water samples of hand pumps of village Simri analyzed through GF-AAS (b) Arsenic concentration in water samples percentage wise (Pie chart)

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 3a and b].

Figure 3

(a) Arsenic concentration in in blood samples of the village people of village Simri analyzed through GF-AAS (b) Arsenic concentration in blood samples percentage wise (Pie chart)

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

The correlation coefficient between blood arsenic levels and age of the subject (in years) (r = 0.049 and P < 0.05)

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

The correlation coefficient between blood arsenic levels and ground water arsenic levels (r = 0.003 and P < 0.05)

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

The correlation coefficient between ground water arsenic levels and age of the handpumps (r = 0.442 and P < 0.05)

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

The correlation coefficient between ground water arsenic levels and depth of the handpumps (r = 0.001 and P < 0.05)

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 8a and d]. Many village people exhibited suspected cancerous nodes in the neck region (suspected lymphoma cancer) [Figure 8b], while one subject exhibited severe cancerous growth over the neck region [Figure 8c]. On subject exhibited skin lesions in the head region [Figure 8e]. 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

(a) Hyperkeratosis of sole in 80 years old female. (b) Cervical enlarged node (Lymphoma Cancer) in 68 years old male. (c) Enlarged thyroid gland growth (Thyroid cancer) in 72 years old female. (d) Hyperkeratosis of palm in 60 years old male. (e) Lesion in the head region in 65 years old female

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.[33343536]

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.[3738]

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.[3940]

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.[4243]

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.[2728]

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.[2847484950] 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.

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.