Environmental Concerns and Toxicogenetic Endpoints of Priority Substances (PSs) and Contaminants of Emerging Concerns (CECs): A Comprehensive Review

Priority Substance (PSs) and Contaminant of Emerging Concerns (CECs) exhibited a wide range of environmental and public health concerns worldwide. This review summarized the documented studies related to the current surface water occurrence, spatial distribution, ecological risks and toxicity of selected PSs, such as polycyclic aromatic hydrocarbons (PAHs) and CECs, such as Di(2-Ethylhexyl) Phthalate (DEHP) and Pharmaceuticals and Personal Care Products (PPCPs). The spatial distribution analysis revealed alarming levels of PAHs in the surface waters of Asian counties, e.g., 84210 ng L-1 in Gomti River, India, 29325 ng L-1 in Daya Bay, China and 1287 ng L-1 in Chenab River, Pakistan. As for DEHP, the highest concentrations of 13050 µg L-1 in Liao River, China, and 2306 µg L-1 in Rivers of Eastern Cape, South Africa were reported. These environmental levels of PAHs and DEHP were many folds higher than the surface water permissible levels devised by WHO and USEPA. Contrarily, the emerging PPCPs were reported in relatively lower levels in the surface waters globally, compared to that of PAHs and DEHP. Consistent with the environmental levels, PAHs and DEHP revealed alarming ecological risks in the surface water sources, compared to that of PPCPs. Regarding to the sources of PSs and CECs, PAHs emissions were mostly linked to the incomplete combustion of petroleum products, DEHP contamination was associated to its applications in consumption and production of plastic appliances and PPCPs emissions were largely related to the domestic and industrial effluents. As for toxic endpoints of PAHs, DEHP and PPCPs, all of these were reported to cause DNA damage, genotoxicity, reproductive toxicity, developmental toxicity and immunotoxicity, as revealed in reviewed in vitro/vivo studies. In addition, the current review also highlighted the existing environmental regulations to control the emissions of these pollutants to the environmental matrices. Taken together, this review concluded that despite the existing environmental regulations, the current levels of organic pollutants are still on rising, especially in Asian countries. Therefore, the strict implementation of the existing regulations is highly necessary to control these pollutants to ensure public health and ecological integrity.