The concentration of persistent organic pollutants in water resources: A global systematic review, meta-analysis and probabilistic risk assessment

The persistent organic pollutants (POPs) are environmentally stable and highly toxic chemicals that accumulate in living adipose tissue and have a very destructive effect on aquatic ecosystems. To analyze the evolution of the con-centration and prevalence of POPs such as alpha-HCH, beta-HCH, gamma-HCH, n-ary sumation -HCH, Heptachlor, Aldrin, p,p '-DDE, p,p '-DDT, n-ary sumation -DDT, and n-ary sumation -OCP in water resources, a search between January 01, 1970, to February 10, 2020, was followed using a systematic review and meta-analysis prevalence. Among the 2306 explored articles in the reconnaissance step, 311 articles with 5315 exemplars, 56 countries, and 4 types of water were included in the meta-analysis study. Among all studied POPs, the concentration of p,p '-DDT in water resources was the highest, especially in drink -ing water resources. The overall rank order based on the concentration and prevalence of POPs were surface water > drinking water > seawater > groundwater. To identify POPs-contaminated areas, the distance from the mean rela-tive to their distribution was considered. The most to the least polluted areas included: South Africa, India, Turkey, Pakistan, Canada, Hong Kong, and China. The highest carcinogenic risk was observed for beta-HCH (Turkey and China), followed by alpha-HCH (Mexico). The highest non-carcinogenic risk was identified for Aldrin (all analyzed countries), followed by Dieldrin (Turkey) and gamma-HCH (Mexico). The Monte Carlo analysis (under the assumption that gamma-HCH has a normal distribution), the mean obtained was 8.22E-07 for children and 3.83E-07 for adults. This is in accor-dance with the standard risk assessment approach. In terms of percentiles, the Monte-Carlo approach indicates that 75% of child population is under the 1.07E-06 risk and 95% of adults under 7.35E-06. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Persistent organic pollutants (POPs) have destructive effects on aquatic ecosystems, affecting the concentration and distribution in water resources. Studies have shown that p,p'-DDT has the highest concentration in water resources, and the most heavily polluted countries with POPs include South Africa, India, and Turkey.