A preliminary screening of HBCD enantiomers transported by microplastics in wastewater treatment plants

Yuefei Ruan; Kai Zhang; Chenxi Wu; Rongben Wu; Paul K S Lam

doi:10.1016/j.scitotenv.2019.04.007

A preliminary screening of HBCD enantiomers transported by microplastics in wastewater treatment plants

Sci Total Environ. 2019 Jul 15:674:171-178. doi: 10.1016/j.scitotenv.2019.04.007. Epub 2019 Apr 4.

Authors

Yuefei Ruan¹, Kai Zhang², Chenxi Wu³, Rongben Wu⁴, Paul K S Lam⁴

Affiliations

¹ State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China.
² State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China. Electronic address: zhangkaibill@foxmail.com.
³ State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
⁴ State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China; Department of Chemistry, City University of Hong Kong, Hong Kong, China.

PMID: 31004893
DOI: 10.1016/j.scitotenv.2019.04.007

Abstract

Hexabromocyclododecane (HBCD), a commonly used flame retardant, causes public concern due to its potential negative effects on organisms. Microplastics are suspected to contain certain amounts of HBCD. Wastewater treatment plants (WWTPs) are believed to be one of the largest sources of microplastics and a sink for micropollutants, providing opportunities for interactions between them, especially for hydrophobic micropollutants such as HBCD. There is a lack of studies focusing on the prevalence of microplastics and HBCD they carry. The present study investigated two typical WWTPs in Hong Kong, Stonecutters Island WWTP (SCI) and Shek Wu Hui WWTP (SWH), which employ different treatment technologies. The abundance of microplastics decreased with the treatment flow, and the microplastic concentrations in effluent were at intermediate levels (0.40 and 0.27particles/L) compared with the levels reported in previous studies. The concentrations of HBCD transported by microplastics reached 4184.4 ng/g in the effluent, whereas that in sewage water (dissolved phase) was 0.8 pg/L. For microplastics, 7.32 × 10⁷ and 2.24 × 10⁷ particles per day were estimated to be released from SCI and SWH, respectively into the environment; the release of HBCD carried by microplastics potentially reached 15.5 g per day, whereas the dissolved HBCD in the effluent may reach 0.067 g per day. A preliminary risk assessment of HBCD transported by microplastics showed that HBCD posed negligible risk; nevertheless, attention should be paid to the continual discharge of microplastics from WWTPs.

Keywords: Enantiomer; Flux; HBCD; Microplastics; WWTP.