Temporal Trends and Pattern Changes of Short- and Medium-Chain Chlorinated Paraffins in Marine Mammals from the South China Sea over the Past Decade

Abstract

Temporal trends of short-(SCCPs) and medium-chain chlorinated paraffins (MCCPs) were examined in blubber samples of 50 finless porpoises (Neophocaena phocaenoides) and 25 Indo-Pacific humpback dolphins (Sousa chinensis) collected from the South China Sea between 2004 and 2014. Elevated levels of SCCPs and MCCPs were detected in all blubber samples of both cetacean species. Concentrations of SCCPs ranged from 280 to 3900 ng·g −1 dry weight (dw) in porpoises and from 430 to 9100 ng·g −1 dw in dolphins, while concentrations of MCCPs ranged from 320 to 8600 ng·g −1 dw in porpoises and from 530 to 23 000 ng·g −1 dw in dolphins. Significantly higher concentrations were present in dolphins than porpoises due to their exposure levels in their living habitats. Strongly linear correlations existed between SCCPs and MCCPs, but there were no significant concentration differences between the genders of the two cetacean species in the same sampling year. Significantly temporal increasing trends of ∑SCCPs and ∑MCCPs have been observed in both porpoise and dolphin samples over the past decade, which reflect the influence of histories of production and usage on the bioaccumulation of CPs in marine mammals in China. An apparent temporal shift trend from SCCPs to MCCPs was also observed in CP accumulation profiles. Complex environmental fractionation from localized sources in the study region via atmospheric transport, oceanic/offshore water transport, and trophic transfer have resulted in different CP accumulation levels and homologue patterns in the two cetacean species. This is the first report of systematic temporal trends of SCCPs and MCCPs in marine mammals.

Short-chain chlorinated paraffins in marine organisms from the Pearl River Estuary in South China: Residue levels and interspecies differences

“…Regarding the chlorine content, Cl 7 and Cl 8 were the dominant congeners with the average percentages ranging from 25%-30% (27%, average) and from 21%-33% (26%, average) of the total SCCPs, respectively. This patterns of SCCPs were generally consistent with those in Indo-Pacific humpback dolphins from the study region in recent years (2012)(2013)(2014) (Zeng et al, 2015); but different from those reported in the surface sediment samples with higher abundance of short carbon chain (C 10 and C 11 ) in the Pearl River Estuary, although homologue groups with 7-8 chlorines dominated in the sediments (Chen et al, 2011). However, it was not clear whether this finding suggested selective accumulation of longer carbon chain SCCPs in these organisms; because Zeng et al (2015) found a more significant temporal shift trend in the SCCP homologue pattern from shorter-to longer-chain groups in dolphin from the Pearl River Estuary between 2004 and 2014.…”

“…A more recent study of SCCPs in Indo-Pacific humpback dolphin (Sousa chinensis) was conducted by Zeng et al (2015) in the Pearl River Estuary, and the measured ∑ SCCP concentrations in blubber samples ranged from 920 and 24,000 ng·g −1 lw with a mean value of 5500 ng·g −1 lw, which were higher than those detected in this study (210-21,000 ng·g −1 ). The levels of ∑ SCCPs in the dorsal muscle of fish species (210-2800 ng·g − 1 lw and 5.3-58 ng·g −1 wet weight, ww) from the Pearl River Estuary were higher than the concentrations reported for top predatory fish (2-10 ng·g −1 ww in the whole body homogenates) in Canada (Basconcillo et al, 2015), but lower than those in the muscles of marine fish from Liaodong Bay of North China (9700-33,000 ng·g − 1 lw) (Ma et al, 2014b), and marine fish (33-140 ng·g − 1 ww) from Ebro River Delta in Spain (Parera et al, 2013).…”

“…High levels of persistent halogenated compounds, including Dichlorodiphenyltrichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), have been detected in biota from the Pearl River Estuary (Sun et al, 2015a,b). Limited information, however, is available on the occurrence of SCCPs in marine species in this region (Zeng et al, 2015).…”

Occurrence, bioaccumulation and long-range transport of short-chain chlorinated paraffins on the Fildes Peninsula at King George Island, Antarctica

“…SCCPs are primarily released into the environment from anthropogenic sources as a type of high production volume chemical and are detected in the different environmental matrices, including air, water, sediments and biota (Barber et al, 2005;Bayen et al, 2006;Coelhan, 2010;Fridén et al, 2011;Marvin et al, 2003;Thomas et al, 2006;Zeng et al, 2015). The SCCPs travel to polar regions in a three-step process: release, transport and deposition (Wania, 2003).…”

Occurrences, sources and risk assessment of short- and medium-chain chlorinated paraffins in sediments from the middle reaches of the Yellow River, China

“…Besides, CPs may also enter the environment through waste incineration (Feo et al, 2009), sewage treatment (Zeng et al, 2012b) and e-waste dismantling (Lu et al, 2015). Up to now, CPs have been found to be widespread in the air , water (Coelhan, 2010), soil (Wang et al, 2014), sediment (Zeng et al, 2013), aquatic and terrestrial wildlife (Reth et al, 2006;Zeng et al, 2015), and even in human breast milk . So it's important to improve our understanding of the pollution status and potential risks posed by CPs.…”