Screening of 484 trace organic contaminants in coastal waters around the Liaodong Peninsula, China: Occurrence, distribution, and ecological risk * Huaijun Xie a , Jingwen Chen a , Yang Huang a , Ruohan Zhang a , Chang-Er Chen b , Xuehua Li a, * , Kiwao Kadokami c a Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China b Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Environmental Theoretical Chemistry, South China Normal University, Guangzhou, 510006, China c Institute of Environmental Science and Technology, The University of Kitakyushu,1-1 Hibikino, Wakamatsu, Kitakyushu, Fukuoka, 808-0135, Japan article info Article history: Received 19 April 2020 Received in revised form 10 August 2020 Accepted 11 August 2020 Available online 18 August 2020 Keywords: Trace organic contaminants Coastal waters Comprehensive analytical method Risk assessment abstract Human activities such as agriculture, aquaculture, and industry can lead to the pollution of coastal waters by trace organic contaminants (TrOCs), and the TrOCs can pose a threat to marine ecosystems. Therefore, it is essential to investigate the occurrence, distribution, and ecological risk of the TrOCs in coastal waters. Previous studies adopting conventional analytical methods have focused on a limited number of targets. Herein, a comprehensive and systematic determination was undertaken to target 484 TrOCs in the waters around the Liaodong Peninsula, China. Eighty-six TrOCs were detected at concentrations of up to 350 ng L 1 , and 25 TrOCs were detected at a frequency of >50%. Pesticides were the predominant pollutants, occurring at high concentrations with large detection frequencies. Ecological risks were assessed for single pollutants and mixtures based on the risk quotient and concentration addition modeling, respectively. The detected pesticides posed relatively high risk to aquatic organisms, while pharmaceuticals, consumer products, and other pollutants posed little or no risk. TrOC mixtures posed extremely high risk to aquatic organisms, which represented a significant threat to the marine envi- ronment and local communities. The results described here provide useful information that can inform China’s “Action Plan for Prevention and Control of Water Pollution”. © 2020 Elsevier Ltd. All rights reserved. 1. Introduction Coastal areas are dynamic ecosystems and represent some of the most biodiverse and biologically productive environments in the world. Coastlines are also often considered to be “elite areas” that support economic development and human habitation (Martínez et al., 2007; Wie˛ ski et al., 2009). Indeed, more than 50% of the world’s population lives within 100 km of the coast (Gommes et al., 2005). However, human activities such as agriculture, aquaculture, and industry can lead to pollution of the marine environment (Bonsignore et al., 2018; Chitrakar et al., 2019). In China, for example, more than 8.6 billion tons of sewage containing various pollutants were discharged to the coast in 2018 from 453 direct discharge sources (Bulletin on the state of marine ecological environment in China, 2019). Among the numerous pollutants found in coastal waters, trace organic contaminants (TrOCs) have received increasing attention in recent years. Many TrOCs can be persistent in coastal waters and lead to a series of adverse effects on marine organisms, even at extremely low concentrations (Dachs and M ejanelle, 2010; Klumpp et al., 2002; Pelletier et al., 2006). For example, carbaryl and dichlorvos can inhibit enzyme activity in mussel gills and, conse- quently, affect their behavior (Donkin et al., 1997). In addition, antibiotic pollution can promote the selection of resistance genes, which represents a threat to human health (Harnisz and Korzeniewska, 2015; Knapp et al., 2008). It is, therefore, essential to fully understand the status and ecological risk posed by the * This paper has been recommended for acceptance by Eddy Y. Zeng. * Corresponding author. E-mail address: lixuehua@dlut.edu.cn (X. Li). Contents lists available at ScienceDirect Environmental Pollution journal homepage: www.elsevier.com/locate/envpol https://doi.org/10.1016/j.envpol.2020.115436 0269-7491/© 2020 Elsevier Ltd. All rights reserved. Environmental Pollution 267 (2020) 115436