Man’s Effect on the Environment
1) SOURCES OF POLLUTION
Freshwater Environments : Man pollutes freshwater all over the world in many ways there is much waste and pollution that ends up in rivers.
One of the main hazards is called eutrophication, this process becomes enriched with artificial nutrients from fertilisers which run off into the rivers and upset the natural nutrient cycle of the river, lake or pond. The water turns green because of the algae which when they die multifly using up all the oxygen.
Similar consequences occur if raw sewage is pumped into a river.
Chemical waste from factories dump their un wanted waste into rivers, lakes or ponds as well. One major component that effects the water wildlife is the insecticide DDT which damages animal tissue and is dangerous to humans , this can be passed along the foodchain.
Marine Environments : 80% of the waste which is pumped into the sea each year is produced by dredging, 10% is industrial waste and 10% is sewage. Some of the consiquences due to this are :- presence of toxic substances and the rapid uptake of contaminants by marine organisms to name but a few. Oil spillages either by tankers or offshore ridges cause devistating effects on the local environments. Oil is extremely dense which means it floats on top of the water and can kill fish and birds, ruin beaches but nothing as yet has been invented to deal with this major problem. Dangerous metals such as mercury, arsenic and lead are also dumped into the sea. All of these examples have the ability to kill and damage the environment around it.
Agricultural Environments : Unwanted plants or insects are nowadays killed with by herbicides and insecticides, in this case chemical rather than biological are used. Pesticides have the ability to damage the local environment, while herbicides may kill wild flowers as well as weeds and insecticides may kill
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harmful pests but it can also kill butterflies and moths. Some of these chemicals are even dangerous to humans as well.
2) FIVE MAJOR POLLUTANTS:
Sulphur Dioxide comes from both car and factory emissions.
Sulphur Dioxide is a poisonous gas which can kill plants and is the main gas that is involved in Acid Rain.
Oil can be spilt into our oceans by tankers and from Oilrigs themselves.
It is denser than water and therefore floats on it and is taken to shore by the sea. At this point the oil can seriously damage the beach and it’s wildlife eg fish.
The detergents that have been invented sometimes cause more damage than the oil itself but nowadays they use less destructive.
Lead is found in cars exhausts and some plants.
It can cause brain damage and various mental disabilities....