Cause

What Causes That Makes Water Pollution?
Actually the Causes of Water Pollution happened it's not chemical from the water actually but the Water Pollution will happened because of the land like example when farmers fertilize the fields, the chemicals they use are gradually washed by rain into the groundwater or surface waters nearby. But sometimes the Water Pollution will happened chemicals released by smokestacks can enter the atmosphere and then fall back to earth as rain, entering seas, rivers, and lakes and causing water pollution and it will called as atmospheric deposition.

Reason of Water Pollution

The Causes...
1)Sewage-Sewage disposal affects people's immediate environments and leads to water-related illnesses such as diarrhea that kills 3-4 million children each year.
2)Nutrients-Suitably treated and used in moderate quantities, sewage can be a fertilizer: it returns important nutrients to the environment, such as nitrogen and phosphorus, which plants and animals need for growth. The trouble is, sewage is often released in much greater quantities than the natural environment can cope with. Chemical fertilizers used by farmers also add nutrients to the soil, which drain into rivers and seas and add to the fertilizing effect of the sewage.

3)Waste Water-A few statistics illustrate the scale of the problem that waste water it is chemicals washed down drains and discharged from factories can cause. Around half of all ocean pollution is caused by sewage and waste water.

4)Chemical Waste- At the opposite end of the spectrum are highly toxic chemicals such as poly chlorinated biphenyls (PCBs). They were once widely used to manufacture electronic circuit boards, but their harmful effects have now been recognized and their use is highly restricted in many countries.

5)Radioactive waste-People view radioactive waste with great alarm—and for good reason. At high enough concentrations it can kill; in lower concentrations it can cause cancers and other illnesses. The biggest sources of radioactive pollution in Europe are two factories that reprocess waste fuel from nuclear power plants: Sell afield on the north-west coast of Britain and Cap La Hague on the north coast of France. Both discharge radioactive waste water into the sea, which ocean currents then carry around the world. 

6)Oil Pollution-When we think of ocean pollution, huge black oil slicks often spring to mind, yet these spectacular accidents represent only a tiny fraction of all the pollution entering our oceans. Even considering oil by itself, tanker spills are not as significant as they might seem: only 12% of the oil that enters the oceans comes from tanker accidents; over 70% of oil pollution at sea comes from routine shipping and from the oil people pour down drains on land. However, what makes tanker spills so destructive is the sheer quantity of oil they release at once — in other words, the concentration of oil they produce in one very localized part of the marine environment.

7)Plastic-There are three reasons for this: plastic is one of the most common materials, used for making virtually every kind of manufactured object from clothing to automobile parts; plastic is light and floats easily so it can travel enormous distances across the oceans; most plastics are not biodegradable (they do not break down naturally in the environment), which means that things like plastic bottle tops can survive in the marine environment for a long time.