Pollution history of perfluorinated compounds (PFCs) in sediment cores from Jinhae Bay, Korea

Abstract

Jinhae Bay is a representative semi-enclosed bay, located on the southern part of Korea. Due to the discharge of untreated chemicals and wastewater treatment plants (WWTPs) activities, previous studies have reported that Jinhae Bay has contaminated by persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). However, no reports are available on historical trends of perfluorinated compounds (PFCs) in Korean coastal environment. The specific characteristics of PFCs such as repellent to water and oil, PFCs have been widely used in industrial and consumer applications. In this study, to investigate the pollution history of perfluorinated compounds (PFCs), we collected four sediment cores from Jinhae Bay. Sediment dating was measured by using the 210Pb and 226Ra specific activities. The total concentrations of PFCs in sediment core for Masan Bay (JC1), Haengam Bay (JC2), Gohyeon Bay (JC3) and Jindong Bay (JC4) ranged from 0.01 to 0.58 ng/g dry weight, from 0.01 to 0.82 ng/g dry weight, from 0.02 to 0.17 ng/g dry weight, and from 0.01 to 0.82 ng/g dry weight, respectively. The concentrations of PFCs in surface sediment of Jinhae Bay were comparable or lower than other areas around the world. The concentrations of PFCs showed increasing trends closing to the surface sediment in all of the sampling bays. The highest concentrations were detected in the subsurface sediment (15-17) cm of JC1 and in the surface sediment (0-1) cm of JC2, JC3 and JC4. This indicates that there is ongoing discharge of PFCs into Jinhae Bay. The concentrations of PFCs began to increase from the 1970s in JC1, JC2 and JC4 sediment cores. These temporal trends of PFCs in the sediment cores were consistent with the global production trend, which sharply increased from 1970s. Perfluorooctanesulfonate (PFOS), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA) and perfluorotridecanoic acid (PFTrDA) were the major compounds in all sediment cores. The composition profile of each sites showed similar pattern and have a positive correlation among these chemicals (p < 0.05). It indicates that they shared the similar sources. In Gohyeon Bay, the overall concentrations of PFCs showed several times lower than other three bays. Because of Gohyeon Bay far away from the densely populated cities and industry complexes. The input fluxes of total PFCs were 330.9 pg/cm2 yr in JC1 sediment core, 85.5 pg/cm2 yr in JC2 sediment core, 18.9 pg/cm2 yr in JC3 sediment core and 98.5 pg/cm2 yr in JC4 sediment core, respectively. Considering the still deposited of PFCs into Jinhae Bay and increasing concentrations of PFCs observed in surface sediment of Jinhae Bay, continuous monitoring of PFCs in Korean coastal waters will be needed.