Source identification and health risks of nitrate contamination in shallow groundwater: a case study in Subei Lake basin

Abstract

Nitrate pollution in groundwater has become a global concern as it can affect the drinking water quality and human health. In this paper, an extensive hydrochemical investigation and health risk were performed in the Subei Lake basin where shallow groundwater is the main available drinking water resource for residents. The prevalent pollutant, nitrate (NO 3 -), has been identi ed based on descriptive statistical method and box and whisker plots, and most of the other parameters of groundwater samples meet water standards and can be used for drinking purpose. Nearly 23.53% of groundwater samples had the NO 3 concentrations higher than the limit of 50 mg/L recommended by the World Health Organization, and the extremely high nitrate content (199 mg/L) was distributed around the Mukai Lake. Piper triangle diagram proposed that the dominated anions of hydrochemical types were observed with a gradual evolving trend from HCO 3 to SO 4 2and Clwith the increase of nitrate content. The results of correspondence analysis showed that agricultural activities were the most the possible source of nitrate contamination, while the higher content of other parameters in individual groundwater samples may be controlled by natural factors. The impacts of pollutant NO 3 on human health were quanti ed using health risk assessment model, and results showed that the order of non-carcinogenic health risk values from oral exposure was Infants Children Adult males Adult females, corresponding to 65%, 53%, 41% and 35% of samples exceeding the accepted limit for nitrate associated health risk (HQ 1), respectively.The detailed knowledge on groundwater quality characteristics obtained from this study can provide valuable reference for drinking water safety and groundwater pollution prevention.

Assessment of Groundwater Quality in Relation to Organic versus Mineral Fertilization

“…Concerning most physiochemical parameters, no significant differences are reported between samples corresponding to all experimental sites (Table 3). Li et al (2022) reported similar limits and content hierarchy in groundwater cations (Ca, Mg), iron, and major anions (HCO 3 − , SO 4 2− , Cl − , NO 3 − ), but higher contents in F − and NH 4 + in studies performed to emphasize the quality parameters of the groundwater collected from different sites [48]. Suthar et al (2009) reported greater groundwater contamination in rural areas of India due to mineral and organic fertilization practices, compared to our results, concerning nitrates(NO 3 − ), chlorine (Cl − ), and sulfates (SO 4 2− ) [49].…”

Optimized fertilization using online soil nitrate data

“…In addition, excessive nitrate in the environment leads to algal blooms that, in turn, cause eutrophication and hypoxia in surface water bodies, such as rivers, lakes, and even oceans (Bijay-Singh and Craswell, 2021;Górski et al, 2019;Zhang et al, 2021;Wang et al, 2018;Scavia and Bricker, 2006). Water resource pollution by nitrate is primarily attributed to intensive agricultural fertilizer application (Li et al, 2023;Rahmati et al, 2015;Gu et al, 2013;Zhang et al, 2014). Excessive fertilization results in the down-leaching of nitrate from the soil through the unsaturated zone to the groundwater.…”