Arsenic contamination of drinking water occurs due to excessive use of arsenic containing chemical pesticides viz copper arsenate and lead arsenate in the modern agriculture. Arsenic is a natural component of the earth’s crust and is widely distributed throughout the environment in the air, water and land. It is highly toxic in its inorganic form. Arsenic contaminated drinking water cause Arsenicosis or Black foot disease.
High levels of arsenic + Groundwater (drinking water) –> Arsenicosis or Black foot disease
Sources of exposure
People are exposed to elevated levels of inorganic arsenic through drinking contaminated water, using contaminated water in food preparation and irrigation of food crops, industrial processes, eating contaminated food and smoking tobacco.
Long-term exposure to inorganic arsenic, mainly through drinking of contaminated water, eating of food prepared with this water and eating food irrigated with arsenic-rich water, can lead to chronic arsenic poisoning. Skin lesions and skin cancer are the most characteristic effects.
The patients of arsenicosis suffer from following problems:
- Black spots on chest, back, limbs (hands and legs) known as melanosis.
- Severe toxicity can lead to Cancer.
- The skin becomes hard and fibrous.
- Complications of liver, spleen, goiter and skin cancer may also develop due to arsenic poisoning.
Areas Reported with Arsenic Toxicity
- India: Arsenic pollution of ground water has been reported from West Bengal, Orissa, Bihar, Western U.P. Consumption of such arsenic polluted water leads to accumulation of arsenic in the body parts like blood, nails and hairs causing skin lesions, rough skin, dry and thickening of skin and ultimately skin cancer.
- World: Bangladesh has some of the most polluted ground water in the world 85 per cent of the area of Bangladesh’s ground water is arsenic contaminated. 1.2 million people of the country of Bangladesh is suffering from arsenic poisoning.
Prevention and control
The most important action in affected communities is the prevention of further exposure to arsenic by the provision of a safe water supply for drinking, food preparation and irrigation of food crops. There are a number of options to reduce levels of arsenic in drinking-water.
- Substitute high-arsenic sources such as groundwater, with low-arsenic, microbiologically safe sources such as rain water and treated surface water. Low-arsenic water can be used for drinking, cooking and irrigation purposes, whereas arsenic-rich water can be used for other purposes such as bathing and washing clothes.
- Discriminate between high-arsenic and low-arsenic sources. For example, test water for arsenic levels and paint tube wells or hand pumps different colours. This can be an effective and low-cost means to rapidly reduce exposure to arsenic when accompanied by effective education.
- Blend low-arsenic water with higher-arsenic water to achieve an acceptable arsenic concentration level.
- Install arsenic removal systems – either centralized or domestic – and ensure the appropriate disposal of the removed arsenic. Technologies for arsenic removal include oxidation, coagulation–precipitation, absorption, ion exchange and membrane techniques. There are an increasing number of effective and low-cost options for removing arsenic from small or household supplies.
Long-term actions are also required to reduce occupational exposure from industrial processes.
Education and community engagement are key factors for ensuring successful interventions. There is a need for community members to understand the risks of high arsenic exposure and the sources of arsenic exposure, including the intake of arsenic by crops (e.g. rice) from irrigation water and the intake of arsenic into food from cooking water.
High-risk populations should also be monitored for early signs of arsenic poisoning – usually skin problems.
Current Affairs by Simran IAS Academy