A diverse nature of chemical pollutants are derived from industrial and agricultural wastes. These wastes are more commonly finding their way to water supply systems. These pollutants include cyanides, detergent solvents, organic acids and minerals, organ phosphorus compounds, dyes, bleaching agents, pigments nitrogenous substances, ammonia, sulphides, toxic and biological organic compounds. Chemical Pollutants can effect men’s health directly and indirectly (by accumulating in aquatic life like fish, which are consumed as food).
The main concern of water pollutants (chemical) is their long term effects that can occur even if present at small level and exposed to prolonged periods of months and years. Their long term effects are also non-specific and difficult to detect and determine. Some new chemical pollutants are difficult to remove with conventional water treatment methods. In developed countries, water-borne communicable disease are now rare and they are now focusing on chemical pollutants of water.
The water is associated to the following problems in addition to the above:
(1) Cardiovascular disease: Hardness of water have beneficial effect on cardiovascular system. Soft water can cause cardiovascular problems if consumed for prolonged period. Example of soft water is rain water.
(2) Dental health : The presence of fluoride (fluorine) at around 1mg per liter is essential in drinking water for dental and bone health. Fluorides below the above level causes dental caries and if it is in excess it causes dental fluorosis.
(3) Cyanosis in infants: High nitrate concentration in water can cause methemoglobinemia. This is rare but can occur if water from farmland gain access to public water supply.
(4) Some diseases are due to insects which carry the organism and they breed in water or nearby water. They are malaria, filarial, dengue fever, dengue hemorrhagic fever, onchocerosis, African trypanosomiasis, and arboviruses etc.
(5) Some diseases are transmitted due to inadequate filtration of water like, ascariasis, shigellosis etc. Some diseases are transmitted due to inadequate use of water, like scabies, trachoma, conjunctivitis.