Occurrence of emerging organic contaminants and endocrine disruptors in different water compartments in Mexico - A review

This review compiles the studies (2007-2021) regarding the occurrence of emerging organic contaminants (EOCs) and endocrine disruptors (EDs) in wastewater, surface water and groundwater in Mexico. A total of 174 compounds were detected, including pharmaceuticals, hormones, plasticizers, personal care products, sweeteners, drugs, and pesticides considered as EDs. The levels of EOCs and EDs varied from ng/L to 140 mg/L, depending on the compound, location, and compartment. Raw wastewater was the most studied matrix, showing a greater abundance and number of detected compounds. Nevertheless, surface waters showed high concentrations of bisphenol-A, butylbenzil-phthalate, triclosan, pentachlorophenol, and the hormones estrone, 17 alpha-ethinylestradiol, and 17 beta-estradiol, which exceeded the thresholds set by international guidelines. Concentrations of 17 alpha-ethinylestradiol and triclosan exceeding the above-mentioned limits were reported in groundwater. Cropland irrigation with raw wastewater was the principal activity introducing EOCs and EDs into groundwater. The groundwater abundance of EOCs was considerably lesser than that of wastewater, highlighting the attenuation capacity of soils/aquifers during wastewater infiltration. However, carbamazepine and N,Ndiethyl-meta-toluamide showed higher concentrations in groundwater than those in wastewater, suggesting their accumulation/concentration in soils/pore-waters. Although the contamination of water resources represents one of the most environmental concerns in Mexico, this review brings to light the lack of studies on the occurrence of EOCs in Mexican waters, which is important for public health policies and for developing legis-lations that incorporates EOCs as priority contaminants in national water quality guidelines. Consequently, the development of legislations will support regulatory compliance for wastewater and drinking water, reducing the human exposure.

Automated summary

This review examines the occurrence of emerging organic contaminants and endocrine disruptors in wastewater, surface water, and groundwater in Mexico. The study found that the types and concentrations of these contaminants varied in different samples and locations. While raw wastewater had the highest number of detected compounds, surface waters also showed concentrations of some compounds exceeding international guidelines. Groundwater was primarily affected by the irrigation of croplands with raw wastewater. However, soils and aquifers were found to have a capacity to attenuate the presence of contaminants from wastewater. Despite water pollution being a major environmental concern in Mexico, there is a lack of studies on the occurrence of emerging organic contaminants in Mexican waters.