1. Waterborne disease.
Human infection disease is among the most
serious effects of water pollution, waterborne disease occurs when parasites or
ether disease causing microorganisms are transmitted through the contaminated
water.
The disease includes typhoid, cholera and
dysentery, contaminated water also facilitates the spread of intestinal
parasites such as roundworms and hookworms. Polluted beach water can cause
rashes, respiratory infection, diarrhoea, vomiting and stomach aches.
2. Nutrient pollution
Excessive growth of waterweeds as a result of
nutrient pollution reduces water clarity. This makes it hard from water animal
to find food. The weeds also block the sunlight needed by sea grasses, which
serve as nursery for many important fish species.
The decomposition of the waterweeds takes a
lot of oxygen out of the water, in some cases , the oxygen level in the water
body may fall too low to support normal aquatic life, such as area become
coastal dead zone. Nutrient pollution can also trigger unusual outbreak of fish
disease.
3. Industrial chemical
Severe chemical spills and leaks into water
bodies kill aquatic life, such as fish. Presence of pesticides in drinking
water and in the food chain can result in damage to the nervous, endocrine and
reproductive systems, and the liver, it can also cause cancerous disease.
4. Oils spills
Exposure to oil or its constituent’s
chemical can alter the ecology of aquatic habitat and the physiology of marine
organisms.
The oils (or chemical components of the oil)
can seep into marsh and sub-tidal sediments and remain there for many years;
this negatively affects marsh grasses, marine worms and other aquatic life
forms that live in, on or near the sediments.
5. Marine debris
Some time, marine animal can swallow the trash
item in marine debris, mistaking them from prey, for example, sea turtles eat
plastics bags mistaking them jellyfish. The bags cause intestinal blockage and
sometimes death of the turtles.
Discarded or lost fishing gear (line, rope,
nets) and other trash items can get wrapped around marine animal’s fins or
flippers, causing them to down or injuring the limb. Marine debris can
also degrade coral reefs, sea grass beds, and other aquatic habitants.