Are the current methods of remediation to reduce nitrate contamination in groundwater in the developing world effective? A systematic review

Abstract

Nitrate contamination of groundwater has become a growing problem, particularly in the developing world as a result of agricultural intensification and rapid urbanisation leading to leaching and run off. Large numbers of people depend on groundwater for drinking and ingestion of nitrate contaminated waters can lead to methaemoglobinemia and cancers. This review examines biological, chemical and physical methods currently employed to remove nitrate contamination from groundwater. Review of these methods is achieved by extensive literature searching and utilisation of inclusion criteria and quality assessments to obtain relevant results. The review found that all of the methods examined are effective. Effectiveness was measured against the WHO guideline of 50 mg/L nitrate concentration in groundwater. No one method was found to be more effective than any of the others. The operating parameters are variables that are known to affect the efficiency were also examined. It was found that these affect efficiency and also removal rate and the products formed. The review also discusses the biases associated with a systematic review, and the limitations involved.