Water has been considered the ultimate dumping ground for the waste of human societies. Water is polluted when dissolved or entrained substances (from human activities) are present in amounts that make the water unfit or undesirable for specific uses. These activities are attributed to the addition of industrial, municipal and agricultural pollutants to the receiving waters in form of pesticides, fertilizers, oil, gasoline, additives, plastics, sewage, garbage, sediment etc.
During the sedimentation process, chemical species that were found in the water column and adsorbed to the suspended sediment will also be trapped in the bottom sediments. As a result of this process, sediments serve as a valuable sink for pollutants, eliminating them from the water column and reducing their potential toxicity to aquatic organisms.
Although sediment is the part of the natural environment where streams transport sediments washed in from the water shed and deposit it on natural bars or into the larger rivers and lakes that they empty into. Problems occur however, when human activities sometimes increase the amounts that end up in rivers. When activities such as road construction, building construction, landscaping, logging or poorly managed farming remove the protective vegetative covering from soils, loose sediments are then free to wash into the streams with surface water runoff during rain storms.
The streams, themselves can also be source of excess sediment. As stream flows increase, the increased amount of water leads to stream bank erosion. The sediment that was a part of the stream bank then enters the stream, further increasing the suspended sediment concentration and loads. Stream flows increase when forests are removed, wetland filled or impervisions surface area is increased.
Large amounts of untreated water are being discharged into rivers by some industries located near the rivers, without consideration of the adverse effects this may have on aquatic life and quality of the receiving water bodies. This practice appears inexpensive, though not without consequences.
The resultant effects of this obnoxious waste disposal and sedimentation process include water sediment pollution, leading to denial of surface water amenities to majority of the people who rely on them for drinking and domestic chores and phenomenal increase in incidents of organic diseases such as cancer. And water borne disease like gastroenteritis, typhoid fever, salmonellosis, shigellosis etc. Excess sediments damages river environments by smothering the organisms that live on the bottom. Sediments blocks sunlight, which means that algae cannot grow (by photosynthesis).
With over 70% of the planet covered by oceans, people have long acted as if these very bodies of water could serve as a limitless dumping ground for waters. Raw sewage garbage and oil spills have begun to overwhelm the diluting capabilities of the ocean and most coastal are now polluted. Beaches are closed regularly often because of high amounts of bacteria from sewage disposal and life’s in water body are beginning to suffer.
Either directly or indirectly, sediments are usually the final repository for the multitude of known and unknown chemicals entering the aquatic ecosystem. Sediment is considered a form of pollution when there is too much of it. Excess sediment found at the bottom of rivers is caused by erosion. It occurs when soil sediments are exposed and swept away by wind or water. Excess sediment can also be caused by improper management of construction site eroding stream bunks and improper plant cover on urban and rural land.
sediments is defined as any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of water or other liquid.
The end result of all pollution affects the water and consequently the sediment bodies. The pollutants in the air fall on land together with rain, and are washed down with run off waters to the rivers, stream, bikes and other bodies of water. These pollutants undergo sedimentation and get attached to bottom sediments. This concludes the fact that pollutant that affects water body also affects sediments. Water is polluted from various sources and can be said to be the most polluted.