Global Status of Nitrate Contamination in Groundwater: Its Occurrence, Health Impacts, and Mitigation Measures

Abstract

Nitrate has emerged as one of the most alarming and widespread contaminant of groundwater and surface water resources reported around the globe. Nitrate formation is an integral part of nitrogen cycle and is added either by the natural processes (atmospheric fixation, lightning storms) or through anthropogenic activities (fertilizer applications, septic tanks). Nitrate enters the hydrosphere easily, and its ingestion causes various health risks such as methemoglobinemia, cancer, diabetes, etc. on humans and to some extent on livestock populations as well. Agricultural practices and subsequent fertilizer application along with other anthropogenic activities are assumed to be the primary reason behind elevated levels of nitrate in groundwater. However, even under the similar ecological conditions, the reported occurrence of nitrate in groundwater is sporadic in nature, indicating the possible interference from other complex factors (including geogenic factors) and a dynamic release mechanism. Various concepts for the different sources and occurrence of nitrate in groundwater along with its health impacts are discussed in this chapter. Several existing and upcoming technologies are there to remove excess nitrate from potable water; these are also discussed in the chapter.