Badal K. Mandal

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.

Arsenic in ground water in six districts of West Bengal, India: the biggest arsenic calamity in the world. Part I. Arsenic species in drinking water and urine of the affected people

Arsenic in ground water has been found above the maximum permissible limit in six districts of West Bengal covering an area of 34 000 km2 with a population of 30 million. At present 37 blocks of these six districts by the side of the River Ganga are affected and about 800 000 people from 312 villages/wards are drinking arsenic contaminated water and amongst them at least 175 000 people are showing arsenical skin lesions. The source of arsenic is geological. We have analysed thousands of tube-well water samples from these six districts for four arsenic species namely, arsenite, arsenate, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA). We could detect no MMAA or DMAA in any of these samples. In urine, DMAA and MMAA are the predominant species along with arsenite and arsenate. The techniques we used for the determination and speciation of arsenic are: (i) separation of arsenite and arsenate from water by sodium diethyldithiocarbamate in chloroform followed by FI-HGAAS; (ii) spectrophotometry using Ag–DDTC in chloroform with hexamethylenetetramine as absorbing solution; (iii) ion-exchange separation of arsenite and arsenate from water followed by FI-HGAAS; and (iv) for analysis of inorganic arsenic and its metabolites in urine, FI-HGAAS was used after separation of the species by a combined cation–anion-exchange column. Total arsenic in urine was determined by FI-HGAAS after acid decomposition. The most toxic species, arsenite, is present in ground water at about 50% of the total arsenic level, and more than 90% of the total arsenic in urine is inorganic arsenic and its metabolites.

Arsenic in ground water in six districts of West Bengal, India: the biggest arsenic calamity in the world. Part 2. Arsenic concentration in drinking water, hair, nails, urine, skin-scale and liver tissue (biopsy) of the affected people

In six districts of West Bengal arsenic has been found in ground water above the maximum permissible limit recommended by the WHO of 0.05 mg l-1. This water is used by the villagers for drinking, cooking and other household purposes. These six districts have an area of 34,000 km2 and hold a population of 30 million. Over the last five years we have surveyed only a few small areas of these six affected districts and our survey revealed that, at present, at least 800,000 people from 312 villages in 37 blocks are drinking contaminated water and more than 175,000 people are showing arsenical skin lesions that are the late stages of manifestation of arsenic toxicity. Most of the three stages of arsenic-related clinical manifestations are observed amongst the affected people. The common symptoms are conjunctivitis, melanosis, depigmentation, keratosis and hyperkeratosis; cases of gangrene and malignant neoplasms are also observed. The source of arsenic is geological. We have analysed thousands of arsenic contaminated water samples. Most of the water samples contain a mixture of arsenite and arsenate and in none of them could we detect methylarsonic or dimethylarsenic acid. We have also analysed a large number of urine, hair and nail samples, several skin-scales and some liver tissues (biopsy samples) of the people drinking the arsenic contaminated water and showing arsenical skin lesions. Flow injection hydride generation atomic absorption spectrometry (FI-HGAAS) was used for the analysis of hair, nails, urine and skin-scale after decomposition by various techniques. The liver tissues were analysed by Zeeman corrected-ETAAS using a few milligrams of the biopsy samples.

Arsenic in groundwater in six districts of West Bengal, India.

Arsenic in groundwater above the WHO maximum permissible limit of 0.05 mg l−1 has been found in six districts of West Bengal covering an area of 34 000 km2 with a population of 30 million. At present, 37 administrative blocks by the side of the River Ganga and adjoining areas are affected. Areas affected by arsenic contamination in groundwater are all located in the upper delta plain, and are mostly in the abandoned meander belt. More than 800 000 people from 312 villages/wards are drinking arsenic contaminated water and amongst them at least 175 000 people show arsenical skin lesions. Thousands of tube-well water in these six districts have been analysed for arsenic species. Hair, nails, scales, urine, liver tissue analyses show elevated concentrations of arsenic in people drinking arsenic-contaminated water for a longer period. The source of the arsenic is geological. Bore-hole sediment analyses show high arsenic concentrations in only few soil layers which is found to be associated with iron-pyrites. Various social problems arise due to arsenical skin lesions in these districts. Malnutrition, poor socio-economic conditions, illiteracy, food habits and intake of arsenic-contaminated water for many years have aggravated the arsenic toxicity. In all these districts, major water demands are met from groundwater and the geochemical reaction, caused by high withdrawal of water may be the cause of arsenic leaching from the source. If alternative water resources are not utilised, a good percentage of the 30 million people of these six districts may suffer from arsenic toxicity in the near future.

Impact of safe water for drinking and cooking on five arsenic-affected families for 2 years in West Bengal, India

The groundwater in seven districts of West Bengal, India, covering an area of 37,000 km2 with a population of 34 million, has been contaminated with arsenic. In 830 villages/wards more than 1.5 million people, out of the total population, drink the arsenic-contaminated water. Safe water from a source having < 0.002 mg 1(-1) arsenic has been supplied for 2 years to five affected families comprising 17 members (eight of them with arsenical skin-lesions) of different age groups for impact assessment study in terms of loss of arsenic through urine, hair and nail. The study indicates random observable fluctuations of arsenic concentration in urine among members on different scheduled sampling days with a declining trend, particularly during the first 6 months. Furthermore, the investigation showed that despite having safe water for drinking and cooking, the study group could not avoid an intake of arsenic, time and again, through edible herbs grown in contaminated water, food materials contaminated through washing, and the occasional drinking of contaminated water. After minimizing the level of contamination, a noteworthy declining trend after 8 months was observed in urine, hair and nails in all the cases, but not to that level observed in a normal population, due to prevailing elevated background level of arsenic in the area. The eight members, who had already developed skin lesions, are far from recovering completely, indicating a long-lasting damage. Statistical interpretation of the data are considered.

Arsenic Groundwater Contamination and Sufferings of People in North 24-Parganas, One of the Nine Arsenic Affected Districts of West Bengal, India

Abstract To understand the magnitude of the arsenic calamity in West Bengal, a detailed study spanning 7 years was made in North 24-Parganas, one of the nine arsenic affected districts. Area and population of North 24-Parganas district are 4093.82 sq. km and 7.3 million, respectively. Fourty eight thousand and thirty water samples were analyzed from hand tubewells of North 24-Parganas in use for drinking, cooking and 29.2% of the tubewells were found to have arsenic above 50 µg/L, the maximum permissible limit of World Health Organization (WHO) and 52.8% have arsenic above 10 µg/L, WHO recommended value of arsenic in drinking water. Out of the 22 blocks of North 24-Parganas, in 20 blocks arsenic has been found above the maximum permissible limit and so far in 16 blocks people have been identified as suffering from arsenical skin lesions. From the generated data, it is estimated that about 2.0 million and 1.0 million people are drinking arsenic contaminated water above 10 µg/L and 50 µg/L level, respectively in North 24-Parganas alone. So far, in our preliminary study 33,000 people have been examined at random from arsenic affected villages in North 24-Parganas and 2274 people have been registered with arsenical skin lesions. Extrapolation of the available data indicates about 0.1 million people may be suffering from arsenical skin lesions from North 24-Parganas alone. A sum of 21,000 hair, nail, and urine samples analyses from arsenic affected villages show 56%, 80%, and 87% people have arsenic in biological specimen more than normal/toxic (hair) level, respectively. Thus, many may be subclinically affected. Due to use of arsenic contaminated groundwater for agricultural irrigation, rice and vegetable are getting arsenic contaminated. Hence there is an additional arsenic burden from food chain. People from arsenic affected villages are also suffering from arsenical neuropathy. A followup study indicates that many of the victims suffering from severe arsenical skin lesions for several years are now suffering from cancer or have already died of cancer.

High performance liquid chromatography inductively coupled plasma mass spectrometry for speciation of arsenic compounds in urine

Abstract Speciation of urinary arsenic is very important to know the extent of human exposure to inorganic arsenic and also from toxicity point of view. A high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) system for speciation of arsenite, arsenate, monomethyl arsonic acid (MMAA), dimethyl arsenic acid (DMAA) and arsenobetaine (AB) in a single run in urine samples has been developed. The method is based on anion exchange high performance liquid chromatography (HPLC) coupled on-line to inductively coupled plasma mass spectrometer (ICP-MS). Detection limits for the five arsenic species in urine samples are between 0.01 and 0.04 μg l −1 . To validate the method, Standard Reference Material, toxic metals in freeze-dried urine SRM 2670 containing both normal and elevated levels of arsenic have been analyzed for arsenic species. Our results of arsenic species in Standard Reference Material SRM 2670 have been compared with the results of seven other laboratories. The method has been applied to determine the arsenic species in urine samples of two groups of people from two arsenic-affected villages of two districts, out of the nine affected districts of West Bengal, India. These two groups were using arsenic-contaminated water a few years ago, but are now supposed to be using safe water for drinking and cooking, as safe sources have been installed. From their urine speciation, the nature of exposure of individuals to arsenic compound could be predicted. It is concluded that, even though these groups are using safe water, they cannot avoid, from time to time, arsenic contamination as many water sources of the surrounding areas are arsenic contaminated.

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.