Table 1: Bad effects of nitrates in human body and on environment.

Effects

Brief description

Methemoglobinemia

[1, 2]

Nitrate contamination in drinking water causes methemoglobinemia; A disease in which oxygen-bearing capacity of blood is reduced. Haemoglobin in blood carries oxygen from the lungs to all other tissues but methaemoglobin is incapable of carrying oxygen. Even, formation of enough methaemoglobin (about 80% of total haemoglobin) causes death. Mainly, new born babies and nursing mothers are prone to suffer by methemoglobinemia.

Carcinogenic

[1, 2]

Nitrates may cause carcinogen effect in human body. Under abnormal circumstances nitrate is reduced to nitrite in the stomach and from N-nitrosamine, a postulated cause of stomach cancer.

Miscellaneous effects.

[4-7]

 Nitrate contamination in drinking water also has a negative effect on the human's health [3], which could result in many other diseases, such as birth defects, spontaneous abortion, increased infant mortality, diarrhoea, abdominal pain, vomiting, diabetes, hypertension, respiratory tract infections and changes in the immune system.

Environmental effects

[8]

High nitrate concentration in closed water body promotes algal blooms and water pollution with eutrophication. Nitrate concentrations in surface waters are usually below 5 ppm, but higher concentrations are often observed in groundwater in different places around the world. Moreover, nitrate levels in drinking water in all developed countries are increasing day by day, which is a global and serious issue.