NEET BIOLOGY

Detailed explanation-1: -Fertilization of surface waters (eutrophication) results in, for example, explosive growth of algae which causes disruptive changes to the biological equilibrium [including fish kills]. This is true both for inland waters (ditches, river, lakes) and coastal waters. Groundwater is being polluted mainly by nitrates.

Detailed explanation-2: -Too much fertilizer can actually kill the plant and excess fertilizer can runoff into streams and lakes causing toxic algal blooms that are harmful to aquatic life and even people and their pets. Excess fertilizer runoff from lawns and agricultural applications also contribute to aquatic “dead zones” in coastal areas.

Detailed explanation-3: -High levels of nitrogen and phosphorus can cause eutrophication of water bodies. Eutrophication can lead to hypoxia (“dead zones”), causing fish kills and a decrease in aquatic life.

Detailed explanation-4: -Agriculture, which accounts for 70 percent of water withdrawals worldwide, plays a major role in water pollution. Farms discharge large quantities of agrochemicals, organic matter, drug residues, sediments and saline drainage into water bodies.