Water Contamination Unit 4 PDF

 At the end of the Unit, students should be able to: Define contaminants Classify sources of water contaminants Classify water-related diseases Outline hazards associated with contaminated water  A contaminant is either a biological, chemical, physical or radical substa...

 At the end of the Unit, students should be able to: Define contaminants Classify sources of water contaminants Classify water-related diseases Outline hazards associated with contaminated water  A contaminant is either a biological, chemical, physical or radical substance that becomes harmful for humans when accidentally or deliberately introduced to water EXAMPLES OF CONTAMINANTS- nitrogen ,bleach, pesticides bacteria ,human drugs, parasites etc. Water is considered contaminated if it contains level of introduced pollutants which render it unsuitable for or unable to support a human use.  It is classified into two categories being; Direct sources- releasing pollutants directly into the water source. E.G mining activities, factories and refineries, waste treatment plants etc.. Indirect sources- pollutants enter the water source from the soil or underground water systems and from the atmosphere via the rain water. E.G human agricultural activities(pesticides and fertilizers), floods human and animal faecal matter. DIRECT SOURCES MINING ACTIVITIES There are chemicals that are used in processing the ore and after usage if these chemicals are not properly disposed they may end up contaminating water sources. E.g cyanide and sulphuric acid FACTORY AND REFINERY ACTIVITIES Factory activities are a huge source of water contamination. Usually the factories have a pipe that directly empty their waste products into the water sources such as dams, rivers INDIRECT SOURCES HUMAN AGRICULTURAL ACTIVITIES Runoff of fertilizers, pesticides, insecticides, herbicides can contaminate water bodies such as lakes and river. The fertilisers contain excess nitrates and phosphates in water that could be harmful to human health. FLOODS Floods may cause contamination and reduce the chances of having portable water through the disruption of water services. It contains physical, biological and chemical contaminants. Floods may damage the distribution system  Water related disease may result from both direct and indirect sources of water contamination. It includes waterborne diseases or water-associated pathogens and toxic substances. There are four types of water related diseases; Water borne diseases Water washed diseases Water based diseases Water related insect vector Others are hazards WATER BORNE DISEASES Are conditions caused by pathogenic microorganisms that are transmitted in water which often come from human or animal waste. Examples of water borne diseases include; cholera Causative; Eating or drinking water contaminated with a bacterium called vibrio cholera. Methods of transmission; eating food or drinking water contaminated by the faeces of an infected person WATER WASHED DISEASES These are infections that are caused by poor hygiene resulting from inadequate water availability. Examples; shigellosis Causative; bacteria shigella Transmission; through contaminated water and food through contact with contaminated faeces. WATER RELATED INSECT VECTORS These are diseases spread by insects which breed or feed near water. Examples; Malaria Causative; plasmodium parasites Transmission; anopheles mosquito bites Stagnant water becomes breeding place for mosquitos hence easy transmission of malaria. LEAD POISONING Lead poisoning occurs when one drinks water that is contaminated with lead from deteriorating pipes. lead is a toxic element that affect mostly children and can result In permanent adverse side effects like impaired development of the brain and the nervous system. Lead can also cause long-term harm in adults including increased risk of high blood pressure and kidney damage. ARSENIC POISONING Arsenic is a toxic element commonly used in pesticides Arsenicosis occurs due to elevated levels of arsenic in your body. Drinking water rich in arsenic over a long period results in health problems like skin cancer, cancer of the bladder and high blood pressure. NITRATES Fertilisers contain excess nitrates which can be a hazard to human lives when consumed. Nitrates result in health conditions like blue baby syndrome. PREVENTIONS Increase water accessibility and reliability Improve hygiene practices. Control vector population/Destroy breeding sites/Use bed nets. Remove and replace leaded pipes with unleaded ones. Educate the public about lead poisoning Use water that does not contain high levels of arsenic e.g. rain water