The metals which are toxic to human heath and those that cause cancer when exposed to human beings include, mercury, lead, acetic, nickel, chromium and cardinium. These metals cause cancer at very low concentrations. Those metals are highly persistent and are likely to be bio – magnified along the food chains reaching very dangerous concentration or levels. their sources in water include atmospheric fallout or are brought to a water body with run off that passes through mines, where these heavy metals are mined, run offs from urban areas, industrial discharge or they can get into the water from their places of use.
TOXIC ORGANIC CHEMICALS. Toxic organic chemicals expose human being s to cancer through improper disposal of industrial and house hold wastes, pesticides, from run offs, leachates, from hazardous waste, dump disposal waste or other places where they are used. iii. GROUND WATER POLLUTION There are many sources ;of ground water pollution that accelerate the spread of cancer. These are: (a). Pollutants from agricultural activities like pesticides, fertilizer, (b) leachates from waste disposal site . (c) industrial heavy metals iv. OCEAN POLLUTION.
Pollutants due to ocean pollution that cause cancer include hazardous wastes through illegal dumping of wastes. Other contributors to the spread of cancer are agricultural and urban run offs such as fertilizer and heavy metals which are carried to the ocean from rivers. Harmful substances can bio – accumulate or become bio – magnified in the ocean . v. LAND POLLUTION. Addition of chemical substances to soil can affect plant life and later migrate to streams and rivers or enter into food chain thus those chemicals can affect people and other organisms. The sources of pollutants in the soil that can cause cancer to human beings include.
(a) Agricultural sources Pesticides used on agricultural crops can introduce heavy metals such as zinc, copper, manganese and persistent organic pesticides like DTT, acenic, mercury to the soil. Fertilizers also introduce heavy metals in the soil. Such as acenic, candinium, zinc and copper are also responsible to the spread of cancer. (b) Wastes like heavy metals from land fills and radioactive materials. Contamination of soil by agricultural inputs. (i) Pesticides: Pesticides are any chemical that kills pests, either animal pests or weed pests that are herbicides.
Animal pesticides include insecticides, acaricides and fungicides. Types of pesticides. Inorganic pesticides. They contain inorganic substances such as acenic, copper, lead and mercury. they are highly toxic, non – biodegradable and persist in the environment for a long time. They hare used to coat seeds to prevent insect attack after planting. (c) Chlorinated hydrocarbons. These are synthetic pesticides and include all the following categories: (i) Organo chlorine (ii) Organo phosphates (iii) Carbamates ORGANOCHLORINE. They were sensitized in 1934 as the first compound of DTT.
It was toxic to insects. It persisted in the environment and therefore could kill insects over a long time. DTT can be bio –magnified along the food chain. Due to the persistent and toxicity of organ chlorine most of them have been banned in developed countries. ORGANOPHOSPHATES. They are not as persistent as organ chlorine, however they are every toxic that is 10 to 100 times more toxic than organ chlorines. Organophosphates include malathium, parathium and diazonine. CARBAMATES. They are comparatively safe and are reasonably degradable. They include Aid carp and Carbofron.
Pesticides have a chronic effects including cancer when exposed to human beings. AIR POLLUTIOIN. Pollutants in the air that cause cancer include: Suspended particulate matter Volatile organic compounds Radioactive materials Heavy metal SUSPENDED PARTICULATE MATTER. These are the major pollutants in the air that cause cancer. Suspended particulate matter is any solid or liquid droplets that are suspended in the air. Some are very small and invisible while others are visible. Some of the metallic dust that causes cancer includes asbestos, acenic, mercury and nickel. INDOOR AIR POLLUTION.
It is the pollution that occurs inside buildings such as houses and work places. Exposures of asbestos cause cancer. The sources of cancer include seedling, insulation of boilers, fire prove clothing and also clothing of asbestos clothing. Asbestos are known to cause lung cancer. Exposures of radon gas (Radon 22) causes lung cancer. Radon cancer is a radio active gas and its sources are rocks and soils that contain uranium 238. When uranium undergoes radioactive decay it gives rise to radon gas. Radon gas enters into building in the cracks in house cracks or house foundation.
When radon gas is inhaled it undergoes radioactive decay in the lungs forming polonium 214, plutonium 2. 8 and lead 214 which cause lung cancers. Pollution by radioactive substances. Radiations can cause cancer. Cancer is the abnormal division or multiplication of cells that is the abnormal multiplication of blood cells may cause leukemia. All living things are exposed to small amounts of ionizing radiations known as natural radiations, like alpha particles, beta particles and gamma rays. Exposure to radiations from man made sources include: (i) The x –rays (ii) By living 5 to 8km from approaching nuclear power plant
(iii) From mining, transport, processing of uranium 235 (iv) From radiotherapy (v) Medicine (vi) Nuclear power accident (vii) From TV and computers (viii) The disposal of radioactive wastes. CONCLUSION. Although environmental pollution is undesirable and even expensive, it is inevitable and necessary part of life for people who rely on technology. Ion a community that relies on technology pollution cannot be eliminated completely. The only measures that can be taken to curb and reduce the spread of cancer are by reducing the amounts of pollution to air, land and water.