Coming ecological risks of organochlorine pesticides and novel brominatedflame retardants in the Yellow River Basin br

To conduct ecological risk assessment, food, water and soil samples were collected fromfive densely populated irriga-tion areas in the Yellow River Basin (YRB), and analyzed for organochlorine pesticides (OCPs) and novel brominatedflame retardants (NBFRs). The results showed that the OCP residues ( n-ary sumation 14OCP were 0.748 ng L-1,13.1ngg-1dw and3.22 ng g-1dw in water, soil and maize) were generally within moderate levels in the YRB. Dichlorodiphenyltrichlo-roethane (DDT) residues dominated the OCPs, and potential ecological risks to aquatic and terrestrial organisms likelystemmed from dichlorodiphenyldichloroethylene (DDE) pollution in the upper reaches of the YRB in the Ningxia andHetao Plain. The NBFR concentrations in the YRB were 90.9 pg L-1in water, 21.1 pg g-1dw in soil and 3.81 pg g-1dw in maize. Positive correlations were observed between soil and maize contamination in thefive irrigated districts,indicating a potential threat to grain security and human health risks caused by OCPs and NBFRs. Pollutants detectedin soil and maize primarily originated from historical use (36.3 %), while the sources in water were more complex(64.4 %) and new inputs could not be excluded. Integrated health risks of human exposure to agricultural productsand water from the YRB were acceptable. However, the ecological risk of the Ningxia Plain would further deteriorateto the medium risk after 2032. The increasing ecological risk of DDT in water indicates that regular monitoring shouldstrengthen to ensure grain and water safety in the YRB.