Hey as Water pollution is the contamination of water bodies (e.g. lakes,
rivers, oceans, aquifers and groundwater)

Causes

The specific contaminants leading to pollution in water include a wide
spectrum of chemicals, pathogens, and physical changes such as elevated
temperature and discoloration.

Water pollutant include

Detergents

Disinfection by-products found in chemically disinfected drinking water,
such as chloroform

Food processing waste, which can include oxygen-demanding substances,
fats and grease

Insecticides and herbicides, a huge range of organ and other chemical
compounds

Petroleum hydrocarbons, including fuels (gasoline, diesel fuel, jet fuels,
and fuel oil) and lubricants (motor oil), and fuel combustion by products,
from storm water runoff[17]

Volatile organic compounds, such as industrial solvents, from improper
storage.

Chlorinated solvents, which are dense non-aqueous phase liquids, may fall
to the bottom of reservoirs, since they don't mix well with water and are
denser.

Polychlorinated biphenyl (PCBs)

Trichloroethylene

Perchlorate

Various chemical compounds found in personal hygiene and cosmetic
products

Drug pollution involving pharmaceutical drugs and their metabolites

Inorganic water pollutants include:

Acidity caused by industrial discharges (especially sulfur dioxide from
power plants)

Ammonia from food processing waste

Chemical waste as industrial by-products

Fertilizers containing nutrients--nitrates and phosphates—which are found
in storm water runoff from agriculture, as well as commercial and residential

Heavy metals from motor vehicles acid mine drainage