NEET BIOLOGY

Detailed explanation-1: -Major agricultural contributors to water pollution (and the main targets for water-pollution control) are nutrients, pesticides, salts, sediments, organic carbon, pathogens, metals and drug residues.

Detailed explanation-2: -Many have severe problems with water services provision, sanitation, climate adaptation and pollution, with untreated wastewater, solid waste, pesticides and heavy metals being released into water supplies. Rising populations, urbanisation, rapid industrialisation and climate change all compound these threats.

Detailed explanation-3: -The main sources of pollution in any part of the region include point sources such as urban sewer and industrial effluents, and nonpoint sources comprising runoff from dispersed farms. Point sources still account for most of the river pollution in the region.

Detailed explanation-4: -Runoff is a major source of water pollution. As the water runs along a surface, it picks up litter, petroleum, chemicals, fertilizers, and other toxic substances. From California to New Jersey, beaches in the U.S. are regularly closed after heavy rainfall because of runoff that includes sewage and medical waste.