ZOU Bin ¹ , ZHANG Han ¹ , WANG Zhilin ¹ , GUO Jipu ² , CHEN Wenwu ³ ,CHANG Chao ³ , GUO Jiahua³

(1. State Grid Shaanxi Electric Power Company, Xi′an 710048, China;

2. Electric Power Research Institute of State GridShaanxi Electric Power Company, Xi′an 710100, China; 

3. Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi′an 710127, China)

Abstract: Organochlorine pesticides (OCPs) as typical persistent organic pollutants ( POPs) in river sediments have drawn much public attention. To explore the spatial distribution, sources and ecological risks of OCPs in the sediments of the Beiluo River, a typical river in the Loess Plateau, 17 surface sediment samples were collected in June 2021 and subsequently analyzed for the concentrations of OCPs using agas chromatography-triple quadrupole tandem mass spectrometer (GC-MS / MS) . On this basis, the sources of OCPs were revealed via the isomer ration method, whereas the ecological risk of OCPs was assessed with the risk quotient method. A total of 25 OCPs in the surface sediments of the Beiluo River were detected, with the ∑OCPs content ranging from 0. 53 ng / g to 61. 68 ng / g. The average content of DDTs was the highest, accounting for 50. 11% of ∑OCPs, followed by DRINs with 23. 01% of ∑OCPs. Compared to other watersheds in China, OCPs in surface sediments of the Beiluo River were at a moderately low level. HCHs pollution in surface sediments was mainly caused by the application of lindane in agricultural as well as the mixed input of agricultural lindane and industrial HCHs. DDTs were predominately decomposed into DDE in oxic environments and their pollution was primarily duo to the industrial use of DDTs, the mixed input of industrial DDTs and dicofol. Historical residues were the principal source for OCPs in sediments, rather than recent inputs. OCPs are mainly historical residues in the environment, with less recent input of OCPs. Ecological risk assessment highlights that endosulfan I dieldrin posed high ecological risks to the Beiluo River. Accordingly, a more intensive monitoring and control of organic pollution in the investigated regions are highly recommended.

Key words: organochlorine pesticides; sediment; distribution; source; ecological risk assessment; Beiluo River