[Show abstract][Hide abstract] ABSTRACT: Organohalogen contaminants including PCBs, DDTs, CHLs, HCHs, HCB, PBDEs and HBCDs were determined in striped dolphins (Stenella coeruleoalba) found stranded at Gogo-shima (n=6, 2003) and collected from Taiji (n=15, 1978-1992) in Japan. All target compounds were significantly detected in all the specimens, indicating ubiquitous contamination of oceanic cetaceans in northwest Pacific Ocean. Examination of body distribution of organohalogens in the six specimens from Gogo-shima showed no significant difference in concentrations among the analyzed tissues, except for brain, which had lower levels possibly due to the existence of blood-brain barrier. For evaluating temporal trends, archived blubber samples of adult male stripped dolphins collected in 1978, 1979, 1986 and 1992 were analyzed. Concentrations of PCBs, DDTs and HCHs did not change significantly during 1978-2003. In contrast, remarkable increasing trends of PBDEs and HBCDs were observed, suggesting growing consumption in Japan and surrounding countries in recent years.
[Show abstract][Hide abstract] ABSTRACT: This study investigated the accumulation features and temporal trends of PCDD/Fs, dioxin-like PCBs (DL-PCBs) and non-dioxin-like PCBs (NDL-PCBs) in the blubber of Baikal seals collected in 1992 and 2005. DL-PCBs (480-3600ng/g) and NDL-PCBs (980-35,000ng/g) were dominant contaminants. Concentrations of PCDDs and PCBs in males were significantly higher than in females. In males, age-dependent accumulation was observed for PCDDs, mono-ortho PCBs and NDL-PCBs. PCDFs and non-ortho PCBs showed no such trends, implying that exposure of seals to these contaminants has been decreasing in recent years. No decreasing temporal trend was observed for PCDDs, mono-ortho PCBs and NDL-PCBs, suggesting that Baikal seals are still exposed to PCDDs and PCBs. TEQs of PCDDs and mono-ortho PCBs in seals collected in 2005 accounted for 62-77% of total TEQs. The TEQ levels in 40% of the specimens exceeded the threshold level for immunosuppression observed in harbor seals (209pg/g).
[Show abstract][Hide abstract] ABSTRACT: Brominated flame retardants (BFRs) including polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) were determined in Baikal seals (Pusa sibirica) collected from Lake Baikal to reveal their contamination status, accumulation features and temporal trends. Organohalogen compounds analyzed were detected in all the blubber samples of Baikal seals. DDTs were the most abundant contaminants followed by PCBs, CHLs, HCHs, PBDEs, HBCDs, and HCB. BFR levels found in Baikal seals were lower than those in other marine mammals from European or American coastal waters, implying that seals in this region were less exposed to BFRs. This suggests that there is no heavy industry producing or using BFRs in the watershed of Lake Baikal and the contamination might have resulted from long-range atmospheric transport. Concentrations of PBDEs and HBCDs in the blubber of Baikal seals collected in 2005 were significantly higher in males than in females. This gender dependent difference could be due to transfer of these contaminants from mother to pup during gestation and lactation. In addition, temporal trends of organohalogen contamination in Baikal seals were investigated using the blubber of male juvenile seals collected in 1992, 1995, 1998, and 2005. No obvious trend was observed for PBDEs, whereas HBCDs showed a significant increasing trend during this period, suggesting that contamination by these organohalogen compounds, particularly HBCDs, is ongoing.
[Show abstract][Hide abstract] ABSTRACT: Blubber and liver samples were obtained for analysis of wide ranges of contaminants from killer whales (Orcinus orca) which were locked away in drifting sea ice on the coast of Rausu, the Shiretoko Peninsula in Eastern Hokkaido, Japan in February 2005. Among the organohalogen compounds analyzed, DDTs were the predominant contaminants with concentrations ranging from 28 to 220 microg/g on a lipid-weight basis followed by PCBs and other organochlorine pesticides. PBDEs levels were two or three orders of magnitude lower than those of PCBs and DDTs. 2,3,7,8-Tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) derived by WHO mammal-TEF in killer whales were in the range of 110-440 pgTEQ/g. Mono-ortho coplanar PCBs contributed to 75-98% of total TEQs, indicating coplanar PCBs are significant contaminants for risk assessment in this species. The fact that hepatic residue levels of butyltins (from 13 to 770 ng/g wet weight) were much higher than those of phenyltins may be reflecting extensive use of tributyltin as antifouling paint.
[Show abstract][Hide abstract] ABSTRACT: This study investigated accumulation features and temporal trends of dioxins and related compounds (DRCs), such as PCDD/Fs, dioxin-like PCBs (DL-PCBs), and non dioxin-like PCBs (NDL-PCBs) in the blubber of Baikal seals collected in 1992 and 2005. PCBs including DL-and NDL-congeners were dominant. Concentrations of PCDD and PCB congeners in males were significantly higher than in females. However, such a trend was not observed for PCDFs. In males, age-dependent accumulations were observed for PCDD, mono-ortho PCB and NDL-PCB congeners. PCDFs and non-ortho PCBs showed no such trend, implying that exposure of seals to these contaminants has been decreasing in recent years. No decreasing temporal trend was observed for PCDDs, mono-ortho PCBs and NDL-PCBs, suggesting that Baikal seals are still exposed to relatively high levels of PCDDs and PCBs. TEQs of PCDDs and mono-ortho PCBs in seals collected in 2005 were within 62–77% of total TEQs. The TEQ levels in 40% of the specimens exceeded the threshold level for immunosuppression observed in harbor seals.