19. Answer in detail IV

a. Domestic Sewage :Sewage that has not been treated contains impurities such as organic materials from food waste, toxic chemicals from household items, and disease-causing bacteria.

b. Domestic waste and plastics: 
Plastics clog drains, allowing diseases like dengue fever and choleramalaria and choleramalaria and dengue fever typhoid and cholera to spread. Aquatic life is harmed by waste in water bodies.

c. Agricultural activities: Agriculture-related fertilisers, herbicides, and insecticides can dissolve in rains and flow into water bodies like rivers and lakes. This results in an excess of nutrients, such as nitrates and phosphatesphosphates and carbonatesnitrates and carbonates, as well as toxic chemicals, which can be harmful to aquatic life.

Industrial waste are

 

 

and other harmful wastes are released by many industries. If this waste is not properly managed and is released into water bodies, it has negative impacts on humans, plants, animals, and aquatic life.

 

e. Oil spills: Oil spills cause water pollution which is harmful to plantshumansanimalsaquatic life.

f. Thermal pollution: Water used for cooling is discharged at a higher temperature and sometimes with chemicals back to a river or original water source. The amount of nitrogencarbon dioxideoxygenhydrogen dissolved in water reduces as the temperature rises, negatively affecting aquatic life.