Context:

• India ranks second in global phosphorus pollution by human activity.
• Phosphorus levels in our freshwater bodies are escalating and this could pose a serious threat to the ecosystem, warns a new report in Water Resources Research.
• Calculating the total global anthropogenic (caused by human activity) phosphorus pollution, China contributed the most with 30%, followed by India (8%), and the USA (7%).

Point pollution

• The researchers analysed the pollution from point sources first. i.e., the pollution from a single identifiable source like sewage pipes.
• Breaking it down by country, the largest contributor was China, followed by USA and then India.

Non-point sources of pollution

• Non-point sources of pollution like erosion, run-off and leaching contributed to the other half of the pollution.
• The domestic sector was the largest contributor of phosphorus accounting for 54%, followed by agriculture (38%) and industry (8%).
• The report points out that the phosphorus load from agricultural fields increased by 27% over the study period (2002 to 2010) due to the extensive use of mineral fertilizers and manure.

Grey-water footprints

• Grey-water footprint is the amount of freshwater required to dilute the pollutants.
• It can also indicate whether the water body can handle the pollution or get affected by it.
• Eutrophication (sudden increase in nutrients in a water body leading to outburst in algae, floating plants, microbes etc) due to phosphorus pollution causes algal blooms, which can lead to the mortality of fish and plants due to lack of oxygen and light.
• It also reduces the use of the water for human purposes.

Polluted river basins

• The Huang He river basin of China ranked first, followed by the Indus river basin.
• The Ganges basin ranked fourth in the list of polluted river basins.

Source:TH