Status of groundwater arsenic contamination in the state of West Bengal, India: A 20‐year study report

Abstract

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.

Natural Arsenic in Global Groundwaters: Distribution and Geochemical Triggers for Mobilization

“…High levels of As concentrations (>10 μg/L, the WHOrecommended guideline) have been reported in the groundwaters of 14 (of 19) districts in West Bengal, including Kolkata metropolitan city (India) [144]. More than 9.2 million inhabitants in West Bengal are drinking Ascontaminated groundwater (>10 μg/L) [144].…”

Accumulation of arsenic in plants from arsenic contaminated irrigation water

“…Türkiye'nin de içerisinde yer aldığı dünyanın birçok ülkesinde (ABD, Arjantin, Bangladeş, Şili, Hindistan, Meksika, Çin, Moğolistan, Myanmar, Nepal, Yeni Zelanda, Tayland, Vietnam ve Tayvan gibi) çoğu içme ve kullanma suyu kaynağında, arsenik derişimi ulusal ve uluslararası içme suyu standartlarının üzerindedir [8], [17], [22], [23]. Bangladeş, Batı Bengal'de yeraltı suyu örneklerinin, %48.1'inde 10 µg/L'nin üzerinde, %23.8'inde 50 µg/L µg/L ve %3.3'ünün 300 µg/L, %0.13 örnekte 1000 µg/L (1333-3700 µg/L) üzerinde As tespit edilmiştir [22]. Hindistan, Brahmaputra'da yeraltı sularında As ölçülebilir seviye ile 500 µg/L arasında belirlenmiştir [24].…”

“…As -3 ve As +5 iyonları ortam şartlarına bağlı olarak kolayca elektron transferi ile (yükseltgenme ve indirgenme) diğer oksidasyon basamağındaki bileşiklerine dönüşebilir [29]. Su kaynaklarındaki arsenik türleri ve oksidasyon seviyeleri, suyun pH değerine, redoks potansiyeline, sülfür, demir ve kalsiyum gibi iyonlarının varlığına ve mikrobiyal aktiviteye bağlı olarak değişmektedir [22]. Yeraltı ve yüzeysel su kaynaklarında arsenik genellikle üç değerli arsenit (AsIII) ya da beş değerlikli arsenat (AsV) olarak inorganik şekillerde bulunur [9].…”

Arsenic, Copper, Molybdenum, and Selenium Exposure through Drinking Water in Rural Eastern Croatia

“…Population in the rural areas is particularly sensitive because of their low socio-economic and educational status [8,30]. The concentrations of arsenic in groundwater vary considerably among different countries [4,31,32]. Even in the same district, arsenic concentrations may vary signifi cantly [33].…”