Modification of DNMTs Gene Expressions by GST O1 and GST O2 Polymorphism in Chronic Arsenic Exposed People with and without malignancy from West Bengal, India.

Background: Chronic Arsenic exposure causes skin manifestations and even cancer. However, the response varies widely among persons despite receiving similar cumulative exposure through their food or drinking water or both. These differentiations in manifestations may be due to polymorphic distribution of arsenic metabolizing genes among exposed people. Method: Polymorphism of GSTO1, GSTO2 and their frequency distribution may modify skin manifestations and development of arsenic induced cancer in exposed persons through food chain. Polymorphic variations of GSTO1 and GSTO2 have been studied on 112 subject including control. They were recruited from one of major arsenic affected district, Nadia of West Bengal, India, having high arsenic content in their food. Exposed subjects were categorized into three groups, i.e, with arsenical skin lesions and with out arsenical skin lesions and arsenic induced cancer. Control subjects were 33 in number. Concentration of arsenic in their urine, hair, drinking water, food, extent of clinical manifestations, GST O1and O2status was determined. DNMT1, 3A, and 3B were studied for their expression profile and analyzed with GSTO1 and O2 polymorphisms. Result: Genetic polymorphism of GSTO1 gene polymorphism is significantly associated with arsenic induced skin scores in skin lesion positive cases and arsenic induced cancer cases and also significant increase is seen in DNMT expression and MDA level in exposed cases with homozygous wild type variants. Total urinary arsenic decreases significantly in wild type GSTO1 genotype, although, GSTO2 polymorphism showed no statistically significant differences in skin manifestations, and DNMTs expression. Frequency of GSTO1 and O2 polymorphic variety showed prevalence of wild type homozygous in arsenic induced cancer cases.Conclusion: GSTO1 polymorphism shows significant association with DNMT expression profile in arsenic exposed people.

ARSENIC POLLUTION AND REMEDIAL MEASURES IN WEST BENGAL: AN OVERVIEW

During the past twenty years, Arsenic (As) contamination via groundwater has become a significant issue worldwide and is now a serious concern within the Indo-Bangladesh Gangetic delta. Arsenic enters physical body through contaminated groundwater consumed as beverage. Food safety in this region is facing severe consequences as bio-accumulation of Arsenic is happening through food crops irrigated with As-contaminated water. Chronic exposure to Arsenic may cause not only cancerous and non-cancer health effects. Reports suggest that about 20% population in West Bengal is very affected. Various techniques are being introduced to supply arsenic-free beverage at a reasonable cost. But a rigorous change in habit and state of mind for procuring safe beverage in those surviving in As-contaminated zones is that the most essential step towards curbing the fatal consequences of arsenic exposure. Harvesting rain water and utilization of proper purification techniques are often considered a possible alternative of safe beverage. Arsenic in groundwater above the WHO maximum permissible limit of 0.01 mg l−1 has been found in six districts of West Bengal covering a neighborhood of 34 000 km2 with a population of 30 million. at the present, 37 administrative blocks by the side of the River Ganga and adjoining areas are affected. Areas suffering from arsenic contamination in groundwater are all located within the upper delta plain, and are mostly within the abandoned meander belt. Quite 8,00,000 people from 312 villages/wards are affected with arsenic contaminated beverage and amongst them a minimum of 175 000 people show arsenical skin lesions. Thousands of tube-well waters in these six districts are analyzed for arsenic species. Hair, nails, scales, urine, liver tissue analyses show elevated concentrations of arsenic in people drinking arsenic-contaminated water for an extended period. The source of the arsenic is geological. Bore-hole sediment analyses show high arsenic concentrations in just few soil layers which is found to be related to iron-pyrites. Various social problems arise thanks to arsenical skin lesions in these districts. Poor socio-economic conditions, malnutrition, illiteracy, food habits and intake of arsenic-contaminated water for several years have aggravated the arsenic toxicity. altogether these districts, major water demands are met from groundwater and therefore the geochemical reaction, caused by high withdrawal of water could also be the explanation for arsenic leaching from the source. If alternative water resources aren't utilised, an honest percentage of the 30 million people of those six districts may suffer from arsenic toxicity within the near future.

Nutritional deficiency and arsenical manifestations: a perspective study in an arsenic-endemic region of West Bengal, India

ObjectiveTo assess whether nutritional deficiency increases susceptibility to arsenic-related health effects.DesignAssessment of nutrition was based on a 24 h recall method of all dietary constituents.SettingEpidemiological cross-sectional study was conducted in an arsenic-endemic area of West Bengal with groundwater arsenic contamination.SubjectsThe study was composed of two groups – Group 1 (cases,n108) exhibiting skin lesions and Group 2 (exposed controls,n100) not exhibiting skin lesions – age- and sex-matched and having similar arsenic exposure through drinking water and arsenic levels in urine and hair.ResultsBoth groups belonged to low socio-economic strata (Group 1 significantly poorer,P< 0·01) and had low BMI (prevalence of BMI < 18·5 kg/m2: in 38 % in Group 1 and 27 % in Group 2). Energy intake was below the Recommended Daily Allowance (set by the Indian Council of Medical Research) in males and females in both groups. Increased risk of arsenical skin lesions was found for those in the lowest quintile of protein intake (v. highest quintile: OR = 4·60, 95 % CI 1·36, 15·50 in males; OR = 5·62, 95 % CI 1·19, 34·57 in females). Significantly lower intakes of energy, protein, thiamin, niacin, Mg, Zn and choline were observed in both males and females of Group 1 compared with Group 2. Significantly lower intakes of carbohydrate, riboflavin, niacin and Cu were also observed in female cases with skin lesions compared with non-cases.ConclusionsDeficiencies of Zn, Mg and Cu, in addition to protein, B vitamins and choline, are found to be associated with arsenical skin lesions in West Bengal.

Status of groundwater arsenic contamination and human suffering in a Gram Panchayet (cluster of villages) in Murshidabad, one of the nine arsenic affected districts in West Bengal, India

A detailed study was carried out in a cluster of villages known as Sagarpara Gram Panchayet (GP), covering an area of 20 km2 and population of 24,419 to determine the status of groundwater arsenic contamination and related health effects. The arsenic analysis of all hand tubewells (n = 565) in working condition showed, 86.2% and 58.8% of them had arsenic above 10, and 50 μg l−1, respectively. The groundwater samples from all 21 villages in Sagarpara GP contained arsenic above 50 μg l−1. In our preliminary clinical survey across the 21 villages, 3,302 villagers were examined and 679 among them (20.6%) were registered with arsenical skin lesions. A total of 850 biological samples (hair, nail and urine) were analysed from the affected villages and, on average, 85% of them contained arsenic above the normal level. Thus, many people of Sagarpara might be sub-clinically affected. Our data was compared with the international one to estimate population in Sagarpara GP at risk from arsenical skin lesions and cancer. Proper watershed management and economical utilization of available surface water resources along with the villagers' participation is urgently required to combat the present arsenic crisis.