World Water week 2022 will be held on the theme ‘Seeing the Unseen: The value of water,” and is built on a global need to not only see, but understand, and more importantly- value water. Most of the water, about 97% on earth is present in the seas and oceans. It is too salty to be of any use for drinking and industrial purposes. The remaining 3% fresh water, 75% of which is locked up in the polar ice caps and in glaciers and quite deep under the earth’s surface as underground water. The freshwater, which we can use comes from two sources namely, surface water and ground water.
Water pollution is generally induced by humans. It results from actions of humans carried on to better self. These could be treated under the various activities that man engages in, that lead to pollution. The growth of human population, industrial and agricultural practices is the major causes of pollution. Water pollution becomes worse as a result of overcrowding in urban areas. Agricultural, domestic and industrial wates are the major pollutants of agnatic habitats. Sewage is the biggest pollutant of fresh water when discharged into them. Sewage is the waterborne water of society and the discharge of untreated sewage into river is very enormous and unhealthy. The striking consequences is a substantial and immediate drop in the amount of dissolved oxygen in the water. This happens because organic matter stimulates decomposers especially bacteria which break down suspended solids in the sewage. As they respire, the decomposers use up dissolved oxygen and the biological oxygen demand reduces. The flora and fauna of the rivers experience change and reduction in number due to death by suffocation. Highly polluted brivers have obnoxious smell and contain little or no flora and fauna. Another source of water pollution is the discharge of hot water from cooling engines in the industries. This increases water temperature and lower metabolic rate of organisms. This then raises their oxygen demand. The effects of pollution are greater in shallow, enclosed or slow flowing streams. Excess fertilizers, herbicides and pesticides when washed are greater in shallow, enclosed or slow flowing streams. Excess fertilizer, herbicides and pesticides when washed by rain into rivers causes serious danger to life. Excess phosphorus in fertilizer causes serious eutrophication. Apart from fertilizers, detergent is also very toxic to marine life when washed into water. Chemical pollutants from distaffs have been found to be animal carcinogens. The dyeing industries in Nigeria produce chemicals such as zinc sulphate and copper salts which are non-biodegradable, when they are discharged into rivers producing devasting effects on aquatic environments.
St. Xavier’s Bangalore spreads the message that pollution poses a serious risk to life especially when the water is a source of drinking and for domestic purposes for humans polluted waters are potent agents of disease such as cholera, typhoid, and tuberculosis. Since water pollution has direct consequences on human well beings, an effective teaching strategy in the formal education sector is essential for a better understanding so as to develop the right attitude towards water. This is why the economic solutions have to be implemented and combined with other methods of science teaching will leave lasting impression on the learner as well as help to solve the problems of the environment.