ABSTRACT
“Emerging contaminants” (ECs) are synthetic or natural chemicals that have been in focus since 1990. Globally, their concentrations range from nanogram to microgram per liter in groundwater. Based on reviewed studies (29) from 2015, the most commonly reported ECs continued to be carbamazepine, sulfamethoxazole, caffeine, and bisphenol A. The maximum concentrations of 13 ECs exceed 397.4 ng/L, which are the outliers detected by the interquartile range (IQR). According to this, 30 values of these compounds lie above the upper limit with carbamazepine and acesulfame representing the highest counts. In India, three studies report a variety of organic contaminants in aquifers of the Ganga Basin. A mixture of sources is recognized and classified as point and non-point/diffuse sources. Groundwaters near urban centers and agricultural lands are found to be more susceptible to contamination. Elevated concentrations of many contaminants are very frequent in shallow aquifers with sandy gravel and sandy texture due to higher permeability. Toxicological studies have shown their presence in aquatic animals due to their bio-accumulative nature and possible health effects. More extensive research is required on sources identification, transport routes, fate, and toxicity for their risk assessment.
