Coastal biomonitoring survey on persistent organic pollutants using oysters (Saccostrea mordax) from Okinawa, Japan: Geographical distribution and polystyrene foam as a potential source of hexabromocyclododecanes

• Published in: The Science of the total environment 2020-10, Vol.739, p.140049-140049, Article 140049
• Main Authors: Mukai, Yukino, Goto, Akitoshi, Tashiro, Yutaka, Tanabe, Shinsuke, Kunisue, Tatsuya
• Format: Article
• Language: English
• Subjects: Hexabromocyclododecanes; Okinawa; Oyster; Polystyrene foam; POPs
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.140049

The present study determined contamination levels of POPs, such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs), in oysters (Saccostrea mordax) collected throughout the seacoast of Okinawa, Japan and their geographic distribution. PCBs, DDTs, CHLs, PBDEs and HBCDs were detected in almost all the oyster samples analyzed and higher concentrations of PCBs, DDTs and CHLs were found in oysters from southwestern populated areas. On the other hand, HBCDs in oysters showed similar levels throughout Okinawa and the highest concentration in a northern rural site with less human and industrial activities, although oyster concentrations of PBDEs were relatively lower. When POPs in expanded polystyrene (EPS) buoys and polystyrene foam debris floated and drifted on coastal seawater were analyzed, extremely high concentrations of HBCDs were detected in some of these EPS buoys and polystyrene foam debris but other POPs were below the limit of detection in all the samples. To evaluate the specific exposure route of HBCDs for oysters, we further analyzed HBCD diastereomers, and PCB congeners by way of comparison, in seawater and sediment samples collected at an urban site and a rural site and estimated their biota (oyster)-sediment accumulation factors (BSAF) and bioaccumulation factors (BAF). Interestingly, the highest log BAF values were found for α-HBCD despite its lower log Kow than those of γ-HBCD and PCB congeners, although log BSAF values for HBCDs were lower than those for PCBs. Considering that α-HBCD was detected in a few polystyrene foam samples as the predominant diastereomer, oysters inhabiting the coastal region of Okinawa might be frequently exposed to micronized polystyrene foam particles containing HBCDs. [Display omitted] •A coastal biomonitoring survey on POPs was conducted using oysters from Okinawa.•Concentrations of PCBs, DDTs and CHLs were higher in oysters from populated areas.•The highest concentration of HBCDs was found in oysters from a northern rural site.•Elevated HBCD levels were detected in EPS buoys and polystyrene foam debris.•Polystyrene foam might be a potential source of HBCDs in the Okinawa's coast.