Bhajan Kumar Biswas

Arsenic poisoning in the Ganges delta.

We have been studying the contamination of groundwater by arsenic and the attend-ant human suffering in West Bengal, India, for a decade, and in Bangladesh for the past four years. From our analysis of thousands of samples of water and sediment, we have been able to test the course of events proposed by Nickson et al. to account for the poisoning of Bangladesh groundwater. We disagree with Nickson et al.s claim that arsenic concentrations in shallow (oxic) wells are mostly below 50 μg per litre. In our samples from Bangladesh (n=9,465), 59% of the 7,800 samples taken at known depth and containing arsenic at over arsenic 50 μg per litre were collected from depths of less than 30 m, and 67% of the 167 samples with arsenic concentrations above 1,000 μg per litre were collected from wells between 11 and 15.8 m deep.

Chronic Arsenic Toxicity in Bangladesh and West Bengal, India—A Review and Commentary

Fifty districts of Bangladesh and 9 districts in West Bengal, India have arsenic levels in groundwater above the World Health Organizations maximum permissible limit of 50 μg/L. The area and population of 50 districts of Bangladesh and 9 districts in West Bengal are 118,849 km2 and 104.9 million and 38,865 km2 and 42.7 million, respectively. Our current data show arsenic levels above 50 μg/L in 2000 villages, 178 police stations of 50 affected districts in Bangladesh and 2600 villages, 74 police stations/blocks of 9 affected districts in West Bengal. We have so far analyzed 34,000 and 101,934 hand tube-well water samples from Bangladesh and West Bengal respectively by FI-HG-AAS of which 56% and 52%, respectively, contained arsenic above 10 μg/L and 37% and 25% arsenic above 50 μg/L. In our preliminary study 18,000 persons in Bangladesh and 86,000 persons in West Bengal were clinically examined in arsenic-affected districts. Of them, 3695 (20.6% including 6.11% children) in Bangladesh and 8500 (9.8% including 1.7% children) in West Bengal had arsenical dermatological features. Symptoms of chronic arsenic toxicity developed insidiously after 6 months to 2 years or more of exposure. The time of onset depends on the concentration of arsenic in the drinking water, volume of intake, and the health and nutritional status of individuals. Major dermatological signs are diffuse or spotted melanosis, leucomelanosis, and keratosis. Chronic arsenicosis is a multisystem disorder. Apart from generalized weakness, appetite and weight loss, and anemia, our patients had symptoms relating to involvement of the lungs, gastrointestinal system, liver, spleen, genitourinary system, hemopoietic system, eyes, nervous system, and cardiovascular system. We found evidence of arsenic neuropathy in 37.3% (154 of 413 cases) in one group and 86.8% (33 of 38 cases) in another. Most of these cases had mild and predominantly sensory neuropathy. Central nervous system involvement was evident with and without neuropathy. Electrodiagnostic studies proved helpful for the diagnosis of neurological involvement. Advanced neglected cases with many years of exposure presented with cancer of skin and of the lung, liver, kidney, and bladder. The diagnosis of subclinical arsenicosis was made in 83%, 93%, and 95% of hair, nail and urine samples, respectively, in Bangladesh; and 57%, 83%, and 89% of hair, nail, and urine samples, respectively in West Bengal. Approximately 90% of children below 11 years of age living in the affected areas show hair and nail arsenic above the normal level. Children appear to have a higher body burden than adults despite fewer dermatological manifestations. Limited trials of 4 arsenic chelators in the treatment of chronic arsenic toxicity in West Bengal over the last 2 decades do not provide any clinical, biochemical, or histopathological benefit except for the accompanying preliminary report of clinical benefit with dimercaptopropanesulfonate therapy. Extensive efforts are needed in both countries to combat the arsenic crisis including control of tube-wells, watershed management with effective use of the prodigious supplies of surface water, traditional water management, public awareness programs, and education concerning the apparent benefits of optimal nutrition.

Status of groundwater arsenic contamination in the state of West Bengal, India: a 20-year study report.

Since 1988 we have analyzed 140 150 water samples from tube wells in all 19 districts of West Bengal for arsenic; 48.1% had arsenic above 10 microg/L (WHO guideline value), 23.8% above 50 microg/L (Indian Standard) and 3.3% above 300 microg/L (concentration predicting overt arsenical skin lesions). Based on arsenic concentrations we have classified West Bengal into three zones: highly affected (9 districts mainly in eastern side of Bhagirathi River), mildly affected (5 districts in northern part) and unaffected (5 districts in western part). The estimated number of tube wells in 8 of the highly affected districts is 1.3 million, and estimated population drinking arsenic contaminated water above 10 and 50 microg/L were 9.5 and 4.2 million, respectively. In West Bengal alone, 26 million people are potentially at risk from drinking arsenic-contaminated water (above 10 microg/L). Studying information for water from different depths from 107 253 tube wells, we noted that arsenic concentration decreased with increasing depth. Measured arsenic concentration in two tube wells in Kolkata for 325 and 51 days during 2002-2005, showed 15% oscillatory movement without any long-term trend. Regional variability is dependent on sub-surface geology. In the arsenic-affected flood plain of the river Ganga, the crisis is not having too little water to satisfy our needs, it is the crisis of managing the water.

Status of groundwater arsenic contamination in Bangladesh: A 14-year study report

Since 1996, 52,202 water samples from hand tubewells were analyzed for arsenic (As) by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) from all 64 districts of Bangladesh; 27.2% and 42.1% of the tubewells had As above 50 and 10 μg/l, respectively; 7.5% contained As above 300 μg/l, the concentration predicting overt arsenical skin lesions. The groundwater of 50 districts contained As above the Bangladesh standard for As in drinking water (50 μg/l), and 59 districts had As above the WHO guideline value (10 μg/l). Water analyses from the four principal geomorphological regions of Bangladesh showed that hand tubewells of the Tableland and Hill tract regions are primarily free from As contamination, while the Flood plain and Deltaic region, including the Coastal region, are highly As-contaminated. Arsenic concentration was usually observed to decrease with increasing tubewell depth; however, 16% of tubewells deeper than 100 m, which is often considered to be a safe depth, contained As above 50 μg/l. In tubewells deeper than 350 m, As >50 μg/l has not been found. The estimated number of tubewells in 50 As-affected districts was 4.3 million. Based on the analysis of 52,202 hand tubewell water samples during the last 14 years, we estimate that around 36 million and 22 million people could be drinking As-contaminated water above 10 and 50 μg/l, respectively. However for roughly the last 5 years due to mitigation efforts by the government, non-governmental organizations and international aid agencies, many individuals living in these contaminated areas have been drinking As-safe water. From 50 contaminated districts with tubewell As concentrations >50 μg/l, 52% of sampled hand tubewells contained As <10 μg/l, and these tubewells could be utilized immediately as a source of safe water in these affected regions provided regular monitoring for temporal variation in As concentration. Even in the As-affected Flood plain, sampled tubewells from 22 thanas in 4 districts were almost entirely As-safe. In Bangladesh and West Bengal, India the crisis is not having too little water to satisfy our needs, it is the challenge of managing available water resources. The development of community-specific safe water sources coupled with local participation and education are required to slow the current effects of widespread As poisoning and to prevent this disaster from continuing to plague individuals in the future.

Groundwater arsenic contamination in the Ganga-Padma-Meghna-Brahmaputra plain of India and Bangladesh.

magnitude of arsenic groundwater contamination, and its related health effects, in the Ganga-MeghnaBrahmaputra (GMB) plain—an area of 569,749 km2, with a population of over 500 million, which largely comprises the flood plains of 3 major river systems that flow through India and Bangladesh. Design: On the basis of our 17-yr–long study thus far, we report herein the magnitude of groundwater arsenic contamination, its health effects, results of our analyses of biological and food samples, and our investigation into sources of arsenic in the GMB plain Setting: The GMB plain includes the following states in India: Uttar Pradesh in the upper and middle Ganga plain, Bihar and Jharkhand in the middle Ganga plain, West Bengal in the lower Ganga plain, and Assam in the upper Brahmaputra plain. The country of Bangladesh is located in the Padma-Meghna-Brahmaputra plain. In a preliminary study,1 we identified arsenic in water samples from hand-operated tubewells in the GMB plain. Levels in excess of 50 ppb (the permissible limit for arsenic in drinking water in India and Bangladesh) were found in samples from 51 villages in 3 arsenic-affected districts of Uttar Pradesh, 202 villages in 6 districts in Bihar, 11 villages in 1 district in Jharkhand, 3,500 villages in 9 (of a total of 18) districts in West Bengal, 2,000 villages in 50 (of a total of 64) districts in Bangladesh, and 17 villages in 2 districts in Assam. Study Populations: Because, over time, new regions of arsenic contamination have been found, affecting additional populations, the characteristics of our study subjects have varied widely. We feel that, even after working for 17 yr in the GMB plain, we have had only a glimpse of the full extent of the problem. Protocol: Thus far, on the GMB plain, we have analyzed 145,000 tubewell water samples from India and 52,000 from Bangladesh for arsenic contamination. In India, 3,781 villages had arsenic levels above 50 ppb and 5,380 villages had levels exceeding 10 ppb; in Bangladesh, the numbers were 2,000 and 2,450, respectively. We also analyzed 12,954 urine samples, 13,560 hair samples, 13,758 nail samples, and 1,300 skin scale samples from inhabitants of the arsenic-affected villages. Groundwater Arsenic Contamination in the Ganga-Padma-

Groundwater Arsenic Contamination and Suffering of People in Bangladesh

Publisher Summary The total area and population of Bangladesh are 148,393 km2 and 120 million respectively. To date, 9089 water samples collected from 60 districts have been analyzed and arsenic (As) concentrations in 41 districts have been found to be above 50 μg/l. The area and population of these 41 districts are 89,186 km2 and 76.9 million respectively. This does not mean the total population in these 41 districts are drinking contaminated water and suffering from aresenicosis, but no doubt they are at risk. About 3000 each of hair and nail samples from people living in As-affected villages (including patients) have so far been analyzed and 97% of the hair samples contain aresenic above the toxic level and 95% of the nail samples contain above the normal level. Out of the 41 districts where As has been found above 50 μg/l authors have, so far, 22 districts have been surveyed for arsenicosis patients, and in 21 districts people suffering from As-induced skin lesions have been identified.

Arsenic Groundwater Contamination and Sufferings of People in West Bengal-India and Bangladesh

Working on West Bengal—s arsenic calamity for last 10 years & in Bangladesh for last 4 years even now we feel we are at the tip of the iceberg. Thus we need to know as early as possible the real magnitude of the arsenic calamity. According to WHO, the possibility of getting skin lesions exists among those drinking 1,000μg of arsenic per day for several years. & our analytical report on water indicates that a large sum of population are consuming above 1,000μg of arsenic per day. Our thousands of hair, nail & urine analyses from the affected villages indicate that more than 80% of population have higher arsenic body burden. Thus many may not be showing arsenical skin lesions but may be sub-clinically affected. Further if it is true that arsenic toxicity appears after several years of exposure, then the picture may actually be far more grim than it appears at present, & children our future generations are at a greater risk.