|Year : 2019 | Volume
| Issue : 2 | Page : 132-138
Arsenic contamination in groundwater causing impaired memory and intelligence in school children of Simri village of Buxar district of Bihar
Arun Kumar1, Md Samiur Rahman2, Ranjit Kumar1, Mohammad Ali1, Pintoo Kumar Niraj1, Abhinav Srivastava1, Sushil Kumar Singh2, Ashok Kumar Ghosh1
1 Mahavir Cancer Institute and Research Centre, Patna, Bihar, India
2 Department of Biotechnology, Anugrah Narayan College, Patna, Bihar, India
|Date of Web Publication||22-Jul-2020|
Mahavir Cancer Institute and Research Centre, Patna, Bihar
Source of Support: None, Conflict of Interest: None
Background: Over the last few decades there has been increased health related issues due to arsenic poisoning worldwide. In India, in state of Bihar, 18 districts are affected from arsenic poisoning causing various health related problems in the exposed population. Arsenic poisoning in Buxar district of Bihar in the recent times has been identified as one of arsenic hotspot of Bihar due to serious health related problems including cancer. Aims and Objectives: The present study aims to find out that whether arsenic contamination in groundwater causes impaired memory and intelligence in school children of Simri village of Buxar district of Bihar or not? Materials and Methods: In the present study, water samples were collected from three hand pumps, which were utilized by the school children for drinking purpose since last ten years. Hair samples of 65 students enrolled in this school were also collected for the analysis of arsenic concentration and its correlation with the drinking water arsenic was done. The same students were interviewed for neuro-behavioural and memory tests for which various methods were utilized like continuous performance test (CPT), symbol digit test (SDT), pattern memory test (PMT) and switching attention behavior (SAB). Results: The study revealed high arsenic concentration in the water and hair samples. The correlation between high arsenic concentration in water and hair denotes high degree of exposure. Their neuro-behavioural analysis reflected very alarming observations like impaired intelligence memory pattern along with the inattention, loss of concentration and alertness. The highest arsenic concentration in drinking water observed was 857 μg/L while in the children hair sample the maximum value was 12.609 mg/Kg. Conclusion: The present study thus concludes that arsenic poisoning is causing changes in the neuro-behavioural activities in school children of Simri village. Therefore, a specific strategy is urgently required to control the present problem.
Keywords: Arsenic poisoning, low intelligence and memory, school children
|How to cite this article:|
Kumar A, Rahman MS, Kumar R, Ali M, Niraj PK, Srivastava A, Singh SK, Ghosh AK. Arsenic contamination in groundwater causing impaired memory and intelligence in school children of Simri village of Buxar district of Bihar. J Mental Health Hum Behav 2019;24:132-8
|How to cite this URL:|
Kumar A, Rahman MS, Kumar R, Ali M, Niraj PK, Srivastava A, Singh SK, Ghosh AK. Arsenic contamination in groundwater causing impaired memory and intelligence in school children of Simri village of Buxar district of Bihar. J Mental Health Hum Behav [serial online] 2019 [cited 2020 Aug 13];24:132-8. Available from: http://www.jmhhb.org/text.asp?2019/24/2/132/290512
| Introduction|| |
Arsenic, in the recent times, has posed a significant potential threat to the human health. About 105 countries in the world have been identified where a population of >200 million is estimated to be exposed to arsenic poisoning.,,,, In Asia, after Bangladesh, India is the second-largest country affected by the arsenic poisoning. The Ganga and Brahmaputra river basin regions are the largest arsenic exposed affected area. In Bihar, Bhojpur was the first district to be detected with arsenic poisoning leading to many health-related problems in the population. The population residing in this area are affected by the typical symptoms of arsenicosis such as hyperkeratosis on sole and palm, hyperpigmentation, and melanosis in skin of the body. The individuals also exhibited other diseases such as diabetes, hypertension, loss of appetite, loose motions, abdominal pain, breathlessness, hormonal imbalance, mental disability, and cancer.,, Subsequently, similar problems have also been observed in the adjacent district Buxar. The arsenic caused visible symptoms such as hyperkeratosis and melanosis in sole and palm of the individuals, loss of appetite, constipation, cardiac problems, hormone-related problems – thyroid, infertility, and even cases of cancer in the population of Buxar District of Bihar has been reported.,
The groundwater sources were considered safe for drinking water once on time, but over the past few years, there has been arsenic contamination reporting and pollution problems in its root due to rapid urbanization, increase in population, industrialization, and excess and uncontrolled extraction of groundwater for irrigation and other purposes. About 48% of districts of Bihar have been reported with arsenic contamination in groundwater. This comprises more than 67 blocks from 18 districts and covering more than 1600 habitations across the state where arsenic contamination in groundwater exceeds the Bureau of Indian Standard (BIS) limits for safe drinking water of 50 μg/L and more. If we consider the WHO limits of 10 μg/L, the coverage area will be much more, and the population, which is facing the danger of arsenic hazard, will be more than the BIS standard limit. It is estimated that more than 13.85 million people could be under the threat of contamination level above 10 μg/L, out of which more than 6.96 million people could be above 50 μg/L, against the total population of this area is around 50 million. The actual problem of arsenic menace among the population will be more than the estimate due to increase in the affected area after every new survey.,,
In Bangladesh, various studies have been reported confirming increased arsenic exposure through drinking water, which caused abnormal neurobehavioral function in the young school-going children., A study in Mexico reported urinary arsenic concentration is inversely associated with verbal IQ and long-term memory. Furthermore, they also found that long-term memory; attention and the ability to understand speech may be affected by exposure to arsenic in persons with chronic malnutrition., A similar study in India has also reported that there is a positive correlation between arsenic exposure and poor mental performance, such as focusing on vocabulary, mathematical skills, memory, and overall cognition. Arsenic causes hormonal imbalance and oxidative stress, which in turn lead to decrease in the levels of dopamine [Figure 1]. Decreased dopamine levels cause impaired brain development and neurobehavioral changes such as inattention, impulsivity, and loss of concentration and alertness.,
Arsenic determination in urine, hair, and nail are considered as the most reliable indicator of exposure. Hair samples are used as a biomarker for arsenic exposure because inorganic arsenic and dimethylarsinic acid are stored in hair root and thus reflect the past exposure. Elevated arsenic levels in hair indicate the past exposure of 6–12 months.
In the present study, 23 children were observed with mental disability in Simri village of Buxar district of Bihar. Some photographs of the children and adults are provided, which are apart from the present study group and were found in the village during the survey of the population [Figure 2]. Hence, the study throws light on the population already affected with mental disability and the children who are at risk due to drinking arsenic-contaminated water. The study was also carried out to know whether increased arsenic poisoning through drinking water has caused any neurological impairment leading to neuro-behavioral imbalance or loss of memory in the children or not?
| Materials and Methods|| |
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 January 08, 2016.
Study area and population
The study was conducted in Simri Block of Buxar District (Bihar, India) which is located very close to the southern bank of river Ganges (25°38'17.6“N 84°06'49.4”E) [Figure 3]. The study was carried out in Khaira Patti strip of Simri village. This research group is in the same area where extensive study related to the extent of arsenic contamination in drinking water sources along with health issues., The study was carried out from February 2016 to January 2017. For determining the exact location of the hand pump, handheld Global Positioning System receivers (Garmin etrex 10, of the USA) with an estimated accuracy of ≈10 m were utilized. Simultaneously, the health assessment of the children was also conducted through a health survey questionnaire. The demographic data, arsenic levels in the hand pump water with the duration of drinking hand pump water, and the averaged water intake per day by the students were recorded. For neurobehavioral and memory tests, multiple methods were used, such as continuous performance test (CPT), symbol digit, pattern memory (PM), and switching attention. For this Neurobehavioral Evaluation System 2, Taiwanese version, a neurobehavioral test battery, which has been applied in many studies,, was performed by each student. These tests were carried out through the Indian standardized Test Battery system (PGI Memory Scale). This resulted in very significant data set showing the test results.
The water sample bottles (500 ml polypropylene bottles) were well cleaned and pretreated with hydrochloric acid, and drinking water from three water sources of the school was collected for arsenic estimation. A total of 65 hair samples of children aged between 4 years and 15 years (of standard 1–10) were collected. After collection of water and hair samples, all the samples were estimated for arsenic as per the protocol of, NIOSH through Graphite furnace atomic absorption spectrophotometer (Pinnacle 900T, Perkin Elmer, Singapore).
For the analytical quality control, the standards, the calibration, and the correlation coefficient (at 0.999) were maintained during the study in the atomic absorption spectrophotometer. The known standard concentration of arsenic was prepared from the standard arsenic stock solution (1000 μg/L) procured from PerkinElmer (CAS #: As 7440-38-2; Lot #: 20-85ASX1; PE #: N9300102), Singapore, before the start of the assay of the field samples. The hair arsenic detection limit was at 0.05 μg/l while for water the detection limit was 0.04 μg/l. Hence, all the standard norms were maintained during the analysis.
Data were analyzed with statistical software (GraphPad Prism 5), and values were expressed with P value, while scattered graphs were plotted through another statistical software SPSS-16.0 (SPSS Inc., Chicago, IL, USA) using linear regression analysis method. For the Indian Standardised Test Battery System (PGI Memory Scale) through ANOVA followed by Dunnett test was applied.
| Results|| |
In the population of the selected village and during the epidemiological study was observed various mental disability incidences in the same village strip where the arsenic exposure in the recent times had caused other serious health problems due to arsenic exposure [Figure 3]. The arsenic concentration in the hair samples of the individuals of the village school had very high arsenic concentration. The n = 29 individuals had arsenic concentration in their hair samples between 0.1 and 0.2 mg/kg, n = 21 individuals had arsenic concentration between 0.3 and 1.0 mg/kg, n = 8 individuals between 1.1 and 2.0 mg/kg, n = 5 individuals between 2.1 and 3.0 mg/kg and n = 1 between 3.1 and 4.0 mg/kg and above 4.0 mg/kg, respectively [Figure 4]. The hand pump of the school village was analyzed which showed very high arsenic concentration as 857 μg/L.
Correlation coefficient study
- Correlation coefficient of arsenic concentration in hand pump water and arsenic concentration in the hair samples of the individuals: The maximum arsenic concentration in the hand pump of the school was 857 μg/L while the maximum arsenic concentration in the hair sample was 12.609 mg/kg correlates the arsenic exposure [r = 0.23, P < 0.05; [Figure 5]
- Correlation coefficient of individual age and the hair arsenic concentration: The maximum individual age was 15 years, and the maximum arsenic concentration in the hair sample of the individual was 12.609 mg/kg correlates the arsenic exposure [r = 0.039, P < 0.05; [Figure 6].
|Figure 5: The correlation coefficient between arsenic concentration in drinking hand pump and arsenic concentration in the hair samples of the individuals (r = 0.23 and P < 0.05)|
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|Figure 6: The correlation coefficient between arsenic concentration in drinking hand pump and individual age (years) (r = 0.039 and P < 0.05)|
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Intelligence and memory assessment
Various questions were asked to the students related to memory and their intelligence test. All the 65 individuals showed very poor score in all the tests. The short and PM were the two important variables in which the individuals scored very poor performance. In the present study, in the CPT and long memory test, the average performance by the individuals was low while in the short memory and PM tests, the individuals scored an average very low performance. The queries like analytical, mathematical and speech tests the subjects on an average scored very low performance. The study also denotes that the individuals had high arsenic concentrations in their hair samples which correlates that arsenic exposure might have caused the poor performance of the individuals [Table 1].
|Table 1: Performance of intelligence and memory power of the individuals (n=65)|
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| Discussion|| |
Arsenic is considered as one of the carcinogen causing cancers to human beings in world., The Food and Agriculture Organization health limit for arsenic in drinking was until recently 50 μg/L, but taking view of the recent arsenic poisoning incidences in the Indian population, the standard level was decreased to 10 μg/L which was accepted by the various regulatory bodies throughout the world.,, The WHO guidelines for arsenic in drinking water have also been made to 10 μg/L. This is based on the skin cancer risk factor 6 × 10−4, which is 60 times higher than the factor normally used to protect human health. However, the WHO guidelines for arsenic in drinking water in reality should be 0.17 μg/L.,,,
In the present study, very high concentration of arsenic contamination was observed in the hair samples of the children. They were drinking water from three highly arsenic contaminated hand pumps. However, they did not exhibit any arsenicosis symptoms, but, their low intelligence and memory correlate the arsenic exposure effect. Since high arsenic exposure over more than 10–20 years exhibits typical arsenicosis symptoms in the individuals. However, in the present study, it is quite possible that the individuals were not exposed more than 8 years hence did not exhibit any arsenicosis symptoms. In addition the children also showed inattention, impulsivity, loss of concentration, and alertness in them. Furthermore, the reporting of mental disability cases in the village is one of the major concerns in this area. It is proposed that arsenic being the xenoestrogen disrupts the endocrine activity (estrogenic activity) and produces free radicals which lead to the suppression of dopamine secretion which in turn causes degenerated brain development along with the neurobehavioral changes such as inattention, impulsivity, and loss of concentration and alertness.,,,,
Various studies have been carried out which shows arsenic may affect the developing brain through various possible mechanisms. Arsenic as prooxidant causes oxidative stress in the developing brain as a direct effect.,, The second possible mode of action of arsenic is that it causes hormonal imbalance, especially the estrogen and thyroid hormones, and both are required for the development of the brain, and arsenic disrupts the dopaminergic system. Furthermore, arsenic lowers the levels of dopamine causing neural behavioral changes such as inattention, impulsivity, loss of concentration, and alertness.,,,,
In addition, it was also found that long-term memory, attention, and the ability to understand speech were affected in children due to exposure of arsenic with chronic malnutrition. Children's intellectual function decreases by increased arsenic exposure. This correlation was proportional to the dose, which means children who had arsenic exposure more than 50 μg/L had lower performance scores than children with <5.5 μg/L exposure. In an another study, long-term cumulative arsenic exposure was found more harmful for cognitive function, including alterations in PM, attention set shifting full-scale IQ, and functional memory, verbal IQ in teens.,
Various studies have shown that in population with no arsenic exposure, the arsenic concentration in hair is generally 0.02–0.2 mg/kg.,,,, The population drinking water with high arsenic concentration, their hair arsenic concentration is also increased. In West Bengal, India arsenic concentrations ranging from 3 to 10 mg/kg in hair were observed in the people drinking high arsenic contaminated water.
In an another study conducted in Nevada and California, arsenic concentration of 400 μg/L in drinking water corresponded to about 1.2 μg/g in hair and 100 μg/L in water corresponded to about 0.5 μg/g in hair., The present study also correlates the similar trends in the children's hair samples denotes the level of toxicity. In a study, in Alaska, an average of 400 μg/L in drinking water corresponded to 3.3 μg/g in hair. In a similar study carried out in Canada, about 50% of 86 individuals were drinking arsenic contaminated water with concentrations more than 50 μg/L had hair arsenic concentrations above 1 μg/g whereas 33 people drinking arsenic contaminated water with concentrations more than 100 μg/L, 94% had hair arsenic concentrations above 1 μg/g.
In the present study, high arsenic concentrations were observed in the hair samples of the school children. They were unknowingly drinking high arsenic concentrated hand pump water. The arsenic concentration in water samples was never analyzed before our study. The most unfortunate part was that the individuals had low intelligence and impaired memory due to drinking arsenic-contaminated water. Hence, proper strategy is urgently required otherwise it may harm the neural development leading to other neurobehavioral changes.
| Conclusion|| |
The present study shows very significant correlation between the arsenic exposure through drinking water and the neurobehavioral changes in the individuals of the village school. The hair samples of the individuals also showed high arsenic contamination. Hence, the health of the individuals has to be immediately monitored, and proper strategy has to be made by the state Government.
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 b'e 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.
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 institute for the entire infrastructural facilities.
Financial support and sponsorship
This study was supported by the 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.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]