Temporal Trends of Short- and Medium-Chain Chlorinated Paraffins in Mollusks from the Chinese Bohai Sea during 2011–2018

Abstract

Short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) are among the most complex and commonly used chlorinated pollutants in the environment. Their temporal and spatial trends can be used to evaluate the effectiveness of regulations on their production and usage. In this study, mollusks (n = 308) were collected to study their temporal and spatial trends (as well as congener patterns) in different species collected from the Chinese Bohai Sea during 2011–2018. The total concentrations of SCCPs and MCCPs were 28.2–6026 ng/g of dry weight (dw) (mean of 578 ng/g of dw) and nd–4342 ng/g of dw (mean of 356 ng/g of dw), respectively. No obvious temporal or spatial trends of CPs in mollusks were found. However, the homologue profile variance and temporal trends of SCCPs and MCCPs across sampling years suggested changes in the composition of CP industrial products. Compared to the other species, oysters had the highest concentrations of CPs, implying that their bioaccumulation activity might be higher than those of other species. Upon combination of results of biological accumulative capacity and the correlation of CP concentrations among the different species, Neverita didyma, Meretrix meretrix, and Crassostrea talienwhanensis are more appropriate than other species for indicating the pollution of CPs in the Chinese Bohai Sea.

Chlorinated Paraffin Pollution in the Marine Environment

“…Also, time-dependent differences in CPs concentrations have been observed in marine organisms in specific regions. For example, concentrations of ∑SCCPs and ∑MCCPs in mollusks varied between 2011 and 2018 on the BS coast, whereas no variance patterns were observed . By contrast, SCCPs, MCCPs, and LCCPs did not show an evident change in concentrations in herring muscles from Landsort, Sweden between 2011 and 2017 …”

“…Species−dependent differences in CPs concentrations are observed in marine organisms, with concentrations higher in crabs and oysters than in fish and shrimp. Data from refs ,,,,, . Concentration units are ng/g lw in the East China Sea, Pearl River Estuary, Yangtze River Delta, Liaodong Bay, ng/g dw in the Bohai Sea, and ng/g ww in the North Sea and Baltic Sea.…”

Bioaccumulation and Trophic Transfer of Short-, Medium-, and Long-Chain-Chlorinated Paraffins in Benthic Biotas of the Haima Cold Seep, South China Sea

“…19 Different from our results of higher ∑SCCP concentrations in mussels than clams, ∑SCCP concentrations were lower in mussels than clams on the Bohai Sea coast, China. 18,46 The above results indicated that bioaccumulation behaviors of CPs changed substantially among the varied ecosystems, which was probably ascribed to differences in food web structures, biota's metabolic processes, microbial degradation processes, local CP sources, and environmental parameters. 5,20 We compared ∑SCCP concentrations in the same species from different regions.…”

Assessing Safety of Market-Sold Fresh Fish: Tracking Fish Origins and Toxic Chemical Origins

“…(2) While SCCP tended to be replaced by medium-chain chlorinated paraffin (MCCP) because SCCP was listed as a persistent organic pollutant in Annex A of the Stockholm Convention in 2017, the atmospheric level of SCCP (94 ± 105 ng m –3 ) was still markedly higher than that of MCCP (59 ± 93 ng m –3 ) averaged over 10 megacities in China in 2019. Much higher SCCP levels in fish than MCCP levels have also been identified across China. , It should be noted that lighter CPs with a short chain tend to be more easily volatilized, resulting in higher levels than the CPs with a longer chain in the atmosphere. Recent field evidence has revealed growing MCCP concentrations in the biotic and abiotic environments in China .…”

“…Much higher SCCP levels in fish than MCCP levels have also been identified across China. 18,19 It should be noted that lighter CPs with a short chain tend to be more easily volatilized, resulting in higher levels than the CPs with a longer chain in the atmosphere. Recent field evidence has revealed growing MCCP concentrations in the biotic and abiotic environments in China.…”