Water-related disease is a major cause of morbidity and mortality in many parts of the world, including India. Water may be polluted with pathogenic bacteria by excreta or sewage, which is certain to contain pathogenic microorganisms. Over and above Rotavirus, other major bacterial agents in water include E. coli, Shigella, Campylobacter, Salmonella, and V. cholera which can cause diarrheal disease, mostly in children. Chemical contamination in water can be caused by its natural occurrence or could be introduced by human interference and can produce serious health effects. Fluoride and arsenic are the two important chemical contaminants which affect large population in India.
Chronic arsenic toxicity (arsenicosis) caused by drinking of arsenic-contaminated groundwater has resulted in a major environmental health hazard that affected many states in Eastern India. Specific characteristic skin lesions of chronic arsenic toxicity are pigmentation and keratosis. However, studies carried out during the last 28 years in West Bengal reported various systemic manifestations associated with chronic arsenic toxicity in humans. Chronic lung disease, liver fibrosis (non-cirrhotic portal fibrosis), polyneuropathy, peripheral vascular disease, hypertension, non-pitting edema of limbs, conjunctival congestion, weakness, and anemia are also associated with arsenicosis. Cancer of skin, lung, and urinary bladder are important cancers found in arsenicosis cases.