Ganga-Meghna Brahmaputra || West Bengal || Bangladesh || Middle Ganga Plain, Bihar || Uttarpradesh
Jharkhand || North-East Hilly States || Rajnandgaon, Chattisgarh || Behala, Kolkata, WB || As toxicity- Homeopathic Treatment
Effectiveness & Reliability - As Field Testing Kits || Utility Of Treatment Plant
Causes, Effects & Remedies - Groundwater As Calamity || References

Arsenic Poisoning in Bihar : Environmental Health

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ARSENIC IN DRINKING WATER AND OBSTETRIC OUTCOME

The sample of 550 subjects included 16 adult females who were examined clinically and had their obstetric history analyzed in detail. Twelve women were pregnant when we?examined them. Table 5 summarizes the reproductive history of the 16 women categorized by the drinking water arsenic. The 5 subjects exposed to 463–1025 µg/L had an excess of miscarriage, stillbirths, preterm birth, and low birth weight infants. Data on the 3 women with the most adverse histories are given in Table 6; all 3 had severe skin lesions and were exposed to drinking water arsenic 1025 µg/L. The normal first pregnancy of all 3 women is noted. In this area, it is a social taboo to remain in the parent’s home after first conception and it is possible that they drank arsenic safe water until the first conception (all three women reported that skin lesions similar to theirs were not observed in their native villages).

DISCUSSION

The manifestations of arsenicosis after exposure to contaminated groundwater in this small village at the western border of the Middle Ganga Plain are remarkably similar to our initial studies of the index villages in the Ganga Delta of West Bengal and Bangladesh where the finding of an intensely afflicted population led to the recognition of a pandemic. In retrospect the first case of arsenicosis was recognized in West Bengal in the 1980s (Chakraborti et al. 2002; Chakraborty et al. 1987; Garai et al. 1984; Saha 1983; Saha 1984) but widespread contamination was not defined until 1995. A similar pattern attended the evolving recognition of the groundwater contamination in the eastern Ganga delta of Bangladesh. Understanding of the processes controlling the transfer of arsenic between aquifer sediments and groundwater is incomplete (Acharya et al. 1999, 2000; Akai et al. 1998; Bhattacharya et al. 1997; Chakraborti et al. 2001; Das et al. 1996; Nickson et al. 1998, 2000; Roy Chowdhury et al. 1999). According to Nickson et al. (1998) the primary source of arsenic is in association with iron oxyhydroxide in aquifer sediment and the key process of arsenic mobilization is desorption and dissolution of iron-oxides due to the reducing conditions of the aquifer and low hydraulic gradients. This theory does not explain the?increasing arsenic concentration in existing tube wells, previously safe but now progressively contaminated (Chakraborti et al. 2001). Das et al. (1996), Roy Chowdhury et al. (1999), and Chakraborti et al. (2001) proposed, on the basis of sediment analysis, that oxygen entering the aquifer due to heavy groundwater withdrawal for irrigation favors the oxidation of arsenic rich iron sulfide and mobilization of arsenic to the aquifer. The source of arsenic for West Bengal was considered by Acharya et al (2000), Saha et al. (1997) as the Rajmahal and Chotonagpur plateau of West Bengal. However, it appears the source of arsenic for Chandigarh, West Bengal, Bangladesh and Terai, Nepal is Himalaya (Chakraborti et al. 2001; Foster et al. 2000) and for Bihar, the source should also be the Himalaya. Although it was reported (Acharya et al. 1999) that groundwater of Uttar Pradesh and Bihar has low concentrations of iron (0–700 µg/L), our study of iron in groundwater of Semria Ojha Patti and its surrounding 5 villages of Bihar shows elevated concentrations of iron (145–8624 µg/L). Arsenic rich sediments derived from the Himalaya Mountains and foot hills of Shillong Plateau are deposited in Gangetic Plain, PMB delta of Bangladesh, Terai region of Nepal, Chandigarh area and, now, Bihar. Most of the arsenic contaminated tubewells are in the depth range 20–55m, similar to that of the West Bengal and Bangladesh. The deposition is expected to be in the Holocene type deposits. The meandering pattern of the river is
responsible for the localized depositions of arsenic rich sediment in selected areas along the course of the river Ganga. Whether the huge groundwater withdrawal, pivotal to the green revolution, allows oxygen to enter into the aquifer initiating microbial activities, or has any relation to localized increases in arsenic mobilization is yet to be understood. As we reported (Chakraborti et al. 1999b; Rahman et al. 2001) on the basis of around 125,000 tube well analyses, some portions of Bangladesh and West Bengal are geologically free of arsenic. Similarly, the entire Ganga Plain, home of 449 million may not be uniformly affected despite?our expectations that groundwater will be arsenic contaminated over a wide region. Other toxic metals/metalloids in groundwater will also vary with the geological conditions and sedimentary deposits. The extreme severity of the exposure in Semria Ojha Patti is typical of index villages with lesser exposures defined later. This preliminary study has the obvious deficits of a volunteer study population lacking full demographic representation. We captured relatively few women and missed many of the men working outside the village. We have no assurance that the childhood population was appropriately represented. The unverified obstetric histories were obtained from an extremely small sample with no control population. It is only by comparison with similar preliminary studies in West Bengal and Bangladesh that we can infer the severity of the exposure.
Those suffering from arsenical skin lesions (n=60) in Semria Ojha Patti village were drinking water with high concentrations of arsenic (mean 475 µg/L, median 431 µg/L, range 202–1654 µg/L). The World Health Organization (WHO) recommended maximum for arsenic in drinking water is 10 µg/L and the Indian standard is 50 µg/L. The finding of skin lesions in 13% of the adults group and a surprising 6.3% of children support severe exposure
beginning with the transition to tube wells. The comparably high concentrations of arsenic in urine, hair and nails of the subjects (Table 3) are consistent with studies from West Bengal and Bangladesh (Biswas et al. 1998; Chowdhury et al. 1999, 2000b, 2003; Mandal et al. 1996; Rahman et al. 2001; Roy Chowdhury et al. 1997). The particularly high prevalence of neuropathy in women is consistent with their more continuous exposure since many men work outside the home or village. As in our other studies (Mukherjee et al. 2003, Rahman et al. 2001) the extent and severity of the neuropathy increased with the arsenic concentrations in the drinking water. Although relatively few children had overt neuropathy they need to be tested for neurobehavioral and cognitive?effects. The effects of arsenic on the developing brain and nervous system may begin in utero, perinatally, or later and the severity is also dependent on other factors such as pre-maturity, intrauterine growth retardation, malnutrition and infection. The anecdotal obstetric histories, suggesting reproductive toxicity at exposures sufficient to cause maternal toxicity, are highly provocative and consistent with the limited human data. An increase in spontaneous abortion, still birth, and perinatal mortality was reported from Karcag, Hungary, due to drinking water arsenic (Rudnai and Gulyas 1998). High perinatal and neonatal mortality have been reported from the mining area of northern Chile in association with arsenic contaminated water (Hopenhayn-Rich et al. 1998). In Bangladesh, Ahmad et al. (2001) reported a significant increase in spontaneous abortion, stillbirth and preterm birth. Increased arsenic in the cord blood and placental arsenic was reported for Argentine women drinking water with arsenic 200 µg/L (Concha et al. 1998). Studies implicating arsenic as a teratogen as well as a reproductive toxin are still inconclusive (Golub et al. 1998).

 

CONCLUSION

Groundwater arsenic contamination in West Bengal, India, surfaced during 1983 and that of Bangladesh in 1995 (Post Conference Report 1995). International attention focused on the arsenic problem in West Bengal and Bangladesh after the International Conference on Arsenic in Groundwater held in Calcutta, 1995 and the International Conference on Arsenic Pollution of Groundwater held in Dhaka, Bangladesh, 1998. The arsenic calamity of Bangladesh is considered to be world’s biggest mass poisoning with millions of people exposed (Smith et al. 2000) and that of West Bengal has been compared with the Chernobyl disaster (Post Conference Report 1995). The question of how much of Bihar and Uttar Pradesh are affected by groundwater arsenic contamination can be answered only by detailed surveys and water analyses. It is?relevant to recall that in 1984, only one village in West Bengal was known as arsenic affected; the present count is more than 3000 villages. For Bangladesh, it was 3 villages in 2 districts in 1995 and at present it is more than 2000 villages in 50 districts. Even after 15 years in West Bengal and 7 years in Bangladesh additional villages are identified by virtually every new survey. The geologic similarities of the Middle and Upper Ganga Plains support a test of the hypothesis that the risk may involve the entire Gangetic Plain. Twenty years ago and 7 years ago when the West Bengal government and Bangladesh were first informed of arsenic contamination it was considered a sporadic, easily remedied matter with little realization of the magnitude of the problem (Chakraborti et al. 2002). Even international aid agencies working in the subcontinent simply did not consider that arsenic could be present in groundwater (Chakraborti et al. 2002). The arsenic problem of West Bengal and Bangladesh intensified during a long period of neglect. Bihar’s arsenic issue may not be a localized contamination. The magnitude of the problem should be assessed. Our earlier mistakes should not be repeated.?

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