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Nutrient pollution, a form of water pollution, refers to contamination by excessive inputs of nutrients.It is a primary cause of eutrophication of surface waters (lakes, rivers and coastal waters), in which excess nutrients, usually nitrogen or phosphorus, stimulate algal growth. [1]
Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water. [1] [2] Eutrophication may occur naturally or as a result of human actions.
With primary causes being warming ocean waters, ocean acidity, and pollution. [3] In 2008, a worldwide study estimated that 19% of the existing area of coral reefs had already been lost. [ 4 ] Only 46% of the world's reefs could be currently regarded as in good health [ 4 ] and about 60% of the world's reefs may be at risk due to destructive ...
It is a primary cause of eutrophication of surface waters (lakes, rivers and coastal waters), in which excess nutrients, usually nitrogen or phosphorus, stimulate algal growth. [44] Sources of nutrient pollution include surface runoff from farm fields and pastures, discharges from septic tanks and feedlots , and emissions from combustion.
Phosphates have low toxicity in the environment but cause nutrient pollution, a major water quality problem in many watersheds. [17] Phosphates in water cause eutrophication of algae which creates conditions favorable to formation of harmful algal blooms. These blooms prevent light and oxygen from getting into the water, leading to the death of ...
Global map of low and declining oxygen levels in coastal waters (mainly due to eutrophication) and in the open ocean (due to climate change).The map indicates coastal sites where oxygen levels have declined to less than 2 mg/L (red dots), as well as expanding ocean oxygen minimum zones at 300 metres (blue shaded regions).
Diffuse source pollution from agricultural fertilizers is more difficult to trace, monitor and control. High nitrate concentrations are found in groundwater and may reach 50 mg/litre (the EU Directive limit). In ditches and river courses, nutrient pollution from fertilizers causes eutrophication. This is worse in winter, after autumn ploughing ...
Elevated nitrate in groundwater is a concern for drinking water use because nitrate can interfere with blood-oxygen levels in infants and cause methemoglobinemia or blue-baby syndrome. [30] Where groundwater recharges stream flow, nitrate-enriched groundwater can contribute to eutrophication , a process that leads to high algal population and ...