Yoko Ochi

Ehime University, Matsuyama-shi, Ehime, Japan

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Publications (6)8.79 Total impact

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    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.
    Marine Pollution Bulletin 01/2009; 58(3):396-401. · 2.53 Impact Factor
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    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).
    Environmental Pollution 01/2009; 157(3):737-47. · 3.73 Impact Factor
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    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.
    01/2009;
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    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.
    Marine Pollution Bulletin 10/2006; 52(9):1066-76. · 2.53 Impact Factor
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    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.
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    ABSTRACT: Introduction Mass mortality of seven adult striped dolphins (Stenella coeruleoalba) was found at Gogo-shima Island, Matsuyama, Japan in 2003. Some parasites were found in all the six analyzed specimens by pathological diagnosis, although the main cause of death was undetermined. A goiter was also observed in three of the six individuals, suggesting thyroid hypofunction by anthropogenic contaminants accumulated in the dolphins (Makara et al. 2006). It is well known that some of the organochlorines (OCs), brominated flame retardants (BFRs) and their metabolites have immunotoxic or endocrine disrupting potential. OCs including PCBs and organochlorine pesticides such as DDTs were extensively used until the early-1970s in Japan. Because of persistence and lipophilicity of these compounds, their ubiquitous contamination and extreme biomagnification in marine mammals have been reported. Concern about environmental contamination by BFRs, especially by polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs), have increased in recent years due to their persistence, bioaccumulative nature, and possible adverse effects on humans and wildlife. Both chemicals are used as additive flame retardants in a wide variety of commercial products such as plastics, textiles, and electronic appliances including computers, and televisions. Statistical data demonstrated that Asian countries shared about 40% and 23% of the global PBDEs and HBCDs consumption in 2001, respectively (BSEF 2003). Although many reports on the environmental behavior and fate of PBDEs have been published (Hites 2004, Kajiwara et al. 2004, Rahman et al. 2001, Ueno et al. 2004), only limited information on other BFRs such as HBCDs are available so far (Covaci et al. 2006). In this regard, OCs and BFRs were analyzed in striped dolphins found stranded at Gogo-shima Island to evaluate the present status of contamination and toxicological risks by organohalogen compounds. Figure 1. Sampling location Materials and Methods Samples Five male and one female striped dolphin specimens analyzed in this study were found stranded at Gogo-shima Island, Matsuyama, Japan in 2003 (Fig. 1). Biological data of the animals analyzed are given in Table 1. Blubber samples were excised from the dead animals, wrapped in aluminum foil, and stored at –2C until chemical analysis. Chemical analysis Analysis of OCs and BFRs were performed following the procedures described elsewhere with slight modifications. Briefly, 2-10 g (wet wt) of the sample was ground with anhydrous sodium sulfate and Soxhlet extracted with diethyl ether/hexane (3:1, v/v) for 7-8 h. An aliquot of the extract, after spiking 13 C 12 -BDEs (13 C 12 -BDE-3, 15, 28, 47, 99, 153, 154, 183, 197, 207, 209) and 13 C 12 -HBCDs (-, -, -13 C 12 -HBCD), was loaded to a gel permeation chromatography (GPC, Bio-Beads S-X3, Bio-Rad, CA, 2 cm i.d., x 50 cm) column for lipid removal. The GPC fraction containing BFRs was concentrated and subjected to an activated silica gel column (Wakogel DX, 4 g, Wako Pure Chemicals, Tokyo) for clean-up and fractionation. PBDEs were eluted with 80 ml of dichloromethane/hexane (5:95, v/v) from the silica gel column and HBCDs were eluted with following 100 ml of dichloromethane/hexane (25:75, v/v). 13 C 12 -BDE-139 was spiked as an internal standard and subjected to GC-MS analysis. Concentrations of all the targeted BDE congeners, except BDE-209, were summed to obtain concentration of PBDEs. The HBCDs fraction was evaporated and spiked with HBCD-d 18 (-, -, -HBCD-d 18) prior to LC-MS-MS analysis. The diastereoisomer specific analysis was performed on the basis of the reported analytical method (Tomy et al., 2005). For analysis of OCs including PCBs, DDTs, HCHs, CHLs, and HCB, another aliquot of the Soxhlet extract was purified and fractionated using a GPC and an activated florisil column. Identification and quantification of OCs were performed using a GC-ECD. Concentrations of analytes were expressed as ng/g in lipid weight unless stated elsewhere.