Biomedical subjects

Shinsuke Tanabe

Publications and source records attributed to Shinsuke Tanabe.

At least 19 recordsLinked to original sources

PubMed2007

Pollution sources and occurrences of selected persistent organic pollutants (POPs) in sediments of the Mekong River delta, South Vietnam.

The Mekong River delta is one of the largest agricultural land in the Southeast Asia. It plays a very important role for agriculture and fisheries in South Vietnam. However, comprehensive studies on the environmental pollution of persistent organic pollutants (POPs) in Mekong River delta have not been carried out in recent years. In this study, we collected sediment samples from the Mekong River to evaluate the contamination and ecological risks caused by several POPs. The contamination pattern of POPs was DDT>PCBs>CHLs>HCHs>HCB. DDTs are the most abundant pollutants, their concentration ranging from 0.01 to 110 ng/g dry wt, followed by PCBs (0.039-9.2 ng/g dry wt). DDTs and PCBs concentrations were higher in sediment from adjacent to urban areas than those from rural and agricultural sites, suggesting urban areas as important point sources of DDTs and PCBs to the river. Ratio of p,p'-DDT/p,p'-DDE was lower compared to those previously reported. However, some samples still had the ratio higher than 0.5, indicating recent input of DDT into the aquatic environments. This result shows that although the magnitude of contamination decreased over time, recent inputs of DDTs to the river still occur. Some sediment samples had concentrations of DDT compounds higher than the standards from the Canadian Environmental Quality Guideline, suggesting continuous monitoring for POPs contamination in the Mekong River is necessary.

Cities↗

PubMed2007

Trace element accumulations in 13 avian species collected from the Kanto area, Japan.

In the present study, concentrations of 13 elements (Li, Cr, Mn, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Hg) were measured in the tissues of the livers, the kidneys, pectoral muscles, lungs and brains of 13 avian species collected from the Kanto area of Japan. The difference in hepatic heavy metal levels of the grey herons from the two sites was compared. Metal levels in the sediment of the Tama River estuary, situated in the Haneda area, were also measured. These results revealed that heavy metal pollution is present in an aquatic area of Haneda. The accumulation patterns of Cu and Zn in the livers of grey herons appeared to be separated into two groups. Additionally, the present study includes the properties of other metal accumulations and their relationships in avian species.

Animals↗

PubMed2006

Assessment of polybrominated diphenyl ethers in eggs of waterbirds from South China.

Concentrations of total polybrominated diphenyl ethers (PBDEs) in Ardeid eggs from Hong Kong, Xiamen and Quanzhou in south China ranged from 140-1000, 30-550 and 140-380ngg(-1), lipid wt., respectively. There were spatial and interspecies variations in the abundance and congeneric profiles of PBDEs. The different congeneric profiles observed among the study sites may be associated with the developmental phases of the cities, as well as a possible consequence of debromination of BDE209. Marked concentrations of higher-brominated diphenyl ethers (BDEs 183, 196, 197, 206, 207 and 209) were detected in the egg samples from all sites, probably indicating uptake of BDE209 by top predators, and that there is widespread occurrence of BDE209 in south China. Comparisons of egg concentrations of BDEs 47, 99, 153 and 209 with tentative critical concentrations for neurobehavioral effects and oxidative stress indicated some potential risks for BDE99 and BDE209 in the Ardeid populations.

Animals↗

PubMed2006

Dioxins and related compounds in albatrosses from the Torishima Island, Japan: accumulation features by growth stage and toxicological implications.

Concentrations of dioxins and related compounds (DRCs), such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs), were determined in eggs, nestlings, and adults of black-footed albatross (BfA; Diomedea nigripes) and short-tailed albatross (StA; Diomedea albatrus) collected from the Torishima Island in Japan during 2002, which is one of their breeding grounds. Observed DRC concentrations, especially PCDFs and non-ortho Co-PCBs, in eggs of BfA and StA were relatively higher than those in other oceanic, coastal, and inland wild birds reported recently and were comparable to those in a pooled BfA egg from Midway Atoll in 1993, implying continuous input of these contaminants into open ocean and possible albatross-specific exposure. Concentrations of PCDDs except 12378-P5CDD and high-chlorinated PCDFs in 3-month-old BfA nestling were lowerthan those in 1-month-old nestling, indicating their developmental dilution. On the other hand, higher levels of T4-H6CDFs and Co-PCBs, especially low-chlorinated congeners such as 2378-T4CDF and T4CB77, were found in 3-month-old BfA nestling, suggesting specific exposure to these contaminants, possibly due to their higher transportability than high-chlorinated congeners. Estimated biomagnification factors of almost all the congeners in adults were apparently greater than those in nestlings, except 2378-T4CDF, T4CB77, and H7-O8-CDD/Fs. This could be due to preferential metabolism of 2378-T4CDF and T4CB77 and lower uptake efficiency of high-chlorinated congeners through the gastrointestinal tract in adults. Toxic equivalents in BfA and StA eggs estimated using WHO-avian toxic equivalency factors exceeded some toxicity thresholds for avian embryos, indicating possible adverse effects of DRCs to albatross embryos.

Age Factors↗

PubMed2006

Contamination status of arsenic and other trace elements in drinking water and residents from Tarkwa, a historic mining township in Ghana.

This study was conducted to assess the contamination status of 22 trace elements, especially As in water and residents in Tarkwa, a historic mining town in Ghana. Drinking water and human urine samples were collected from Tarkwa in addition to control samples taken from Accra, the capital of Ghana in March, 2004. Concentrations of As and Mn in some drinking water samples from Tarkwa were found above the WHO drinking water guidelines posing a potential health risk for the people. A potential health risk of As and Mn is a concern for the people consuming the contaminated water in this area. No significant difference of As concentrations in human urine between mining town (Tarkwa) and control site (Accra) was observed. Although As concentrations in drinking water in Tarkwa were low, urinary As levels were comparable to those reported in highly As-affected areas in the world. These results suggest the presence of other sources of As contamination in Ghana. This is the first study on multi-elemental contamination in drinking water and human from a mining town in Ghana.

Arsenic↗

PubMed2006

Occurrence of organochlorine pesticides, polychlorinated biphenyls and polybrominated diphenyl ethers in deep-sea fishes from the Sulu Sea.

Explore the source record for details and available documents.

Animals↗

PubMed2006

Toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in developing red seabream (Pagrus major) embryo: an association of morphological deformities with AHR1, AHR2 and CYP1A expressions.

The toxicity of dioxins such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is mainly mediated by the aryl hydrocarbon receptor (AHR), which regulates the multiple target genes including cytochrome P4501A (CYP1A). In general, bony fishes, which possess at least two distinct AHRs are one of the most sensitive vertebrates to TCDD in early life stage. However, the physiological and toxicological roles of piscine multiple AHRs are not fully understood, especially in marine fish. To understand which AHR is responsible for TCDD toxicity in a marine fish species, we characterized the early life stage toxicity related to the expression of AHRs and CYP1A in red seabream (Pagrus major). The embryos at 10h post-fertilization (hpf) were treated with 0-100 microg/L TCDD for 80 min waterborne exposure. TCDD dose-dependently elicited developmental toxicities including mortality, yolk sac edema, retarded body growth, spinal deformity, reduced heart rate, shortened snout, underdeveloped fin, heart, and lower jaw. Intriguingly, hemorrhage and pericardium edema, typical TCDD developmental defects noticed in other fish species, were not found in red seabream until test termination. The EC(egg)50s for yolk sac edema, underdeveloped fin, and spinal deformity were 170, 240, and 340 pg/g, respectively. The LC(egg)50 was 360 pg/g embryo, indicating that this species is one of the most sensitive fishes to TCDD toxicity. The expression levels of rsAHR1, rsAHR2 and CYP1A mRNAs were also determined in different developmental stages. The rsAHR2 mRNA expression dose-dependently increased following TCDD exposure, while rsAHR1 mRNA level was not altered. Level of rsAHR2 mRNA measured by two-step real-time PCR was 30 times higher than rsAHR1 in embryos treated with the highest dose. Temporal patterns of rsAHR2 and CYP1A mRNAs were similar in TCDD-treated embryos, representing a significant positive correlation between rsAHR2 and CYP1A mRNA levels, but not between rsAHR1 and CYP1A. In comparison of temporal trends of TCDD-induced AHRs and CYP1A expression, and developmental toxicities, the highest expression of rsAHR2 and CYP1A mRNA were detected prior to the appearance of maximal incidence of TCDD toxic manifestations. These results suggest that rsAHR2 may be dominantly involved in the transcriptional regulation of CYP1A, and several TCDD defects are dependent on the alteration of rsAHR2 and/or rsAHR2-CYP1A signaling pathway that is controlled through their expression levels.

Animals↗

PubMed2006

Persistent organic pollutants in human breast milk from Asian countries.

In this paper, we concisely reviewed the contamination of persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB) in human breast milk collected from Asian countries such as Japan, China, Philippines, Vietnam, Cambodia, India, Malaysia, and Indonesia during 1999-2003. Dioxins, PCBs, CHLs in Japanese, and DDTs in Vietnamese, Chinese, Cambodian, Malaysian, and HCHs in Chinese, Indian, and HCB in Chinese breast milk were predominant. In India, levels of dioxins and related compounds (DRCs) in the mothers living around the open dumping site were notably higher than those from the reference site and other Asian developing countries, indicating that significant pollution sources of DRCs are present in the dumping site of India and the residents there have been exposed to relatively higher levels of these contaminants possibly via bovine milk.

Asia↗

PubMed2006

Constitutive androstane receptor (CAR) as a potential sensing biomarker of persistent organic pollutants (POPs) in aquatic mammal: molecular characterization, expression level, and ligand profiling in Baikal seal (Pusa sibirica).

To characterize the function of constitutive active/androstane receptor (CAR) in aquatic mammals, CAR complementary DNA (cDNA) was cloned from the liver of Baikal seal (Pusa sibirica) from Lake Baikal, Russia, and the messenger RNA (mRNA) expression levels in various tissues/organs of the wild population and the CAR ligand profiles were investigated. The seal CAR cDNA had an open reading frame of 1047 bp encoding 348 amino acids that revealed 74-84% amino acid identities with CARs from rodents and human. The mRNA expression profile of tissues/organs represented that Baikal seal CAR was predominantly expressed in the liver followed by heart and intestine. The expression analysis of hepatic CAR mRNA showed no correlation with expression of cytochrome P450 (CYP) 1A, 1B, 2B, 2C, and 3A-like proteins, indicating that the CAR expression level may not be the sole determinant of the regulation of these CYP expressions in the seal liver. There was no significant correlation between CAR expression and any of the persistent organic pollutants (POPs) levels. Furthermore, we performed an in vitro CAR transactivation assay using MCF-7 cells transfected with Baikal seal CAR expression plasmid and (NR1)(3)-luciferase reporter gene plasmid. In the transactivation analysis of Baikal seal CAR, neither repression by androstanol and androstenol, nor activation by estrone and estradiol, which are recognized as endogenous ligands for mouse and human CARs, was detected. On the other hand, bile acids such as chenodeoxycholic acid, deoxycholic acid, and lithocholic acid activated the seal CAR as well as mouse CAR. As for exogenous chemicals, the seal CAR was transactivated by a human CAR agonist, 6-(4-chlorophenyl)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime), but not by a mouse CAR agonist, (1,4-bis[2-(3,5-dichloropyridyloxy)]benzene). In addition, the seal CAR was also activated by polychlorinated biphenyls (PCBs) (Kanechlor-500, International Union of Pure and Applied Chemistry No. PCB153; 2,2',4,4',5,5'-hexachlorobiphenyl and PCB180; 2,2',3,4,4',5,5'-heptachlorobiphenyl), and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) and its metabolite, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE). The seal CAR responded more sensitively to PCBs than the mouse CAR. Based on the results of CAR transactivation assay, the lowest observable effect levels of Kanechlor-500, PCB153, PCB180, p,p'-DDT, and p,p'-DDE in Baikal seal were estimated to be 10, 20, 20, 10, and 10 ppm on wet weight basis, respectively. These results suggest that CAR is conserved in diverse mammalian species including seals. Whereas the seal CAR-mediated gene transcription may potentially be a sensitive response to the exposure of certain POPs, the ligand profile of seal CAR may be different from those of other mammalian CARs. This study indicates that CAR-mediated responses may be useful information to assess the ecotoxicological risk of xenobiotics such as POPs in wildlife but the previous results derived from rodent and human CAR may not be applicable to the risk assessment in wild species.

Amino Acid Sequence↗

PubMed2006

Organohalogen compounds in human breast milk from Republic of Buryatia, Russia.

Human breast milk samples collected during 2003/04 in Buryatia, a Russian autonomous republic, were analyzed in order to assess human exposure to organohalogen compounds including organochlorine pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). When compared with available worldwide data, levels of HCB (23-880 ng/g lipid wt.), PCBs (69-680 ng/g lipid wt.), and HCHs (100-3700 ng/g lipid wt.) were relatively high, indicating elevated human exposure to these organochlorines (OCs) in Buryatia. In contrast to OCs, PBDE concentrations were low (0.46-1.7 ng/g lipid wt.). Out of 14 BDE congeners analyzed, BDE-28, BDE-47, BDE-100, BDE-153, BDE-197, and BDE-207 were detected. Estimated daily intakes (EDIs) of HCHs, HCB, CHLs, and PCBs by infants solely from human milk for 100%, 43%, 34%, and 17% of the samples, respectively, exceeded guideline thresholds. Although high EDIs raise concern for possible toxic effects of OCs, women in Buryatia are recommended to breastfeed due to numerous advantages of breastfeeding for mother and child.

Adult↗

PubMed2006

Comparison of trace element concentrations in livers of diseased, emaciated and non-diseased southern sea otters from the California coast.

Infectious diseases have been implicated as a cause of high rates of adult mortality in southern sea otters. Exposure to environmental contaminants can compromise the immuno-competence of animals, predisposing them to infectious diseases. In addition to organic pollutants, certain trace elements can modulate the immune system in marine mammals. Nevertheless, reports of occurrence of trace elements, including toxic heavy metals, in sea otters are not available. In this study, concentrations of 20 trace elements (V, Cr, Mn, Co, Cu, Zn, Rb, Sr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, Pb, and Bi) were measured in livers of southern sea otters found dead along the central California coast (n=80) from 1992 to 2002. Hepatic concentrations of trace elements were compared among sea otters that died from infectious diseases (n=27), those that died from non-infectious causes (n=26), and otters that died in emaciated condition with no evidence of another cause of death (n=27). Concentrations of essential elements in sea otters varied within an order of magnitude, whereas concentrations of non-essential elements varied by two to five orders of magnitude. Hepatic concentrations of Cu and Cd were 10- to 100-fold higher in the sea otters in this study than concentrations reported for any other marine mammal species. Concentrations of Mn, Co, Zn, and Cd were elevated in the diseased and emaciated sea otters relative to the non-diseased sea otters. Elevated concentrations of essential elements such as Mn, Zn, and Co in the diseased/emaciated sea otters suggest that induction of synthesis of metallothionein and superoxide dismutase (SOD) enzyme is occurring in these animals, as a means of protecting the cells from oxidative stress-related injuries. Trace element profiles in diseased and emaciated sea otters suggest that oxidative stress mediates the perturbation of essential-element concentrations. Elevated concentrations of toxic metals such as Cd, in addition to several other organic pollutants, may contribute to oxidative stress-meditated effects in sea otters.

Animals↗

PubMed2006

Persistent organochlorines in raccoon dogs (Nyctereutes procyonoides) from Japan: Hepatic sequestration of oxychlordane.

The present study determined the accumulation features of persistent organochlorines (OCs) such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), and chlordane compounds (CHLs) in wild raccoon dogs (RDs; Nyctereutes procyonoides) collected from Kanagawa prefecture in Japan during 2001. In livers of RDs, CHLs were remarkably dominant (20 times higher than PCBs) followed by PCBs>DDTs>HCHs>HCB, whereas the chemicals in muscles were in the order of CHLs>PCBs>HCHs>DDTs>HCB. The accumulation pattern of OCs in RDs was different from those in Japanese humans and avian species reported previously, which generally accumulate higher levels of DDTs and PCBs than CHLs. This result indicates that RDs have been exposed to relatively high levels of CHLs and have high metabolic and elimination capacity for DDTs. In fact, CHL levels in RDs were higher than those in humans and some avian species, while DDT levels in RDs were much lower than other animals. In particular, extremely high accumulation levels of oxychlordane, which is a metabolite from chlordanes and nonachlors, were observed in RD livers. The higher toxic potency of oxychlordane than parent compounds may suggest that RDs are at high risk by this metabolite. On lipid weight basis, PCBs, HCHs and HCB levels were almost similar in livers and muscles, suggesting that the tissue distribution of these compounds principally followed the lipid-dependent accumulation. However, accumulation levels of oxychlordane and p,p'-DDD in livers were significantly higher than those in muscles, and concentration ratios of liver to muscle (L/M ratios) of these compounds were greater than 1.0 in all the specimens. This phenomenon was similar to PCDD/DF congener accumulation patterns observed previously in RDs. When relationships between hepatic TEQs and L/M ratios were examined for oxychlordane and p,p'-DDD, L/M ratios for these compounds significantly increased with hepatic TEQ levels, suggesting their hepatic sequestration in TEQs-dependent manner.

Animals↗

PubMed2006

Exposure assessment for trace elements from consumption of marine fish in Southeast Asia.

Concentrations of 20 trace elements were determined in muscle and liver of 34 species of marine fish collected from coastal areas of Cambodia, Indonesia, Malaysia and Thailand. Large regional difference was observed in the levels of trace elements in liver of one fish family (Carangidae): the highest mean concentration was observed in fish from the Malaysian coastal waters for V, Cr, Zn, Pb and Bi and those from the Java Sea side of Indonesia for Sn and Hg. To assess the health risk to the Southeast Asian populations from consumption of fish, intake rates of trace elements were estimated. Some marine fish showed Hg levels higher than the guideline values by U.S. Environmental Protection Agency and Joint FAO/WHO Expert Committee on Food Additives (JECFA). This suggests that consumption of these fish may be hazardous to the people.

Animals↗

PubMed2006

Cytochrome P450 1A4 and 1A5 in common cormorant (Phalacrocorax carbo): evolutionary relationships and functional implications associated with dioxin and related compounds.

The present study characterized cytochrome P4501A (CYP1A) isoforms from common cormorant (Phalacrocorax carbo) with regard to their evolutionary relationships and their roles in disposition of dioxin and related compounds (DRCs). Two clones isolated from a cormorant liver cDNA library were named CYP1A4 and CYP1A5 on the basis of greatest overall amino acid identity shared with chicken (Gallus gallus) CYP1A4 (78%) and CYP1A5 (78%), respectively. Spatial heterogeneity in phylogenetic signal along the sequences strongly indicated that cormorant CYP1A4 and CYP1A5 have undergone partial interparalog gene conversion, similar to chicken and mammalian CYP1As. Phylogenetic analysis of a putatively unconverted region produced a tree topology consistent with the orthology of avian CYP1A5s with mammalian CYP1A2s and avian CYP1A4s with mammalian CYP1A1s. Hepatic CYP1A4 and CYP1A5 mRNA levels in wild cormorants from Lake Biwa, Japan, were quantified to examine the effects of DRCs on isoform-specific expression and to evaluate the toxicokinetics of DRCs in which CYP1A expression is involved. Both CYP1A4 and CYP1A5 mRNA levels were positively correlated with total tetrachlorodibenzo-p-dioxin toxic equivalents and concentrations of each congener in most cases in the liver, suggesting the induction of both enzymes through a shared transcriptional mechanism. The lack of correlation of 2,3,7,8-tetrachlorodibenzofuran and 3,3',4,4'-tetrachlorobiphenyl (PCB77) to CYP1A gene expression is likely due to the rapid metabolism of these two congeners. Liver-to-muscle concentration ratios for most DRC congeners except PCB77 and mono-ortho coplanar polychlorinated biphenyls significantly increased with an elevation of CYP1A4 and CYP1A5 mRNA levels. The present data suggest that hepatic sequestration of some DRCs occurs in cormorant via binding to either CYP1A5 or both CYP1A4 and CYP1A5.

Amino Acid Sequence↗

PubMed2006

Levels of trace elements in green turtle eggs collected from Hong Kong: Evidence of risks due to selenium and nickel.

Concentrations of 22 trace elements were determined in green turtle (Chelonia mydas) eggs collected from Hong Kong. Concentrations of selenium, lead and nickel in these eggs were generally higher than those reported in other studies. The predicted no effect concentrations (PNEC; ng/g wet weight) of Pb (1000), Se (340 and 6000 for the worst-case and best-case scenarios, respectively) and Ni (17) in the green turtle eggs were estimated. Hazard quotients (HQs) estimate that Se (HQs: 0.2-24.5) and Ni (HQs: 4.0-26.4) may pose some risks to the turtles. Our study also found that concentrations of Ag, Se, Zn, Hg and Pb in the shell of the turtle eggs were significantly correlated with levels in the whole egg contents (yolk+albumen). Once the precise relationships of specific elements are established, egg-shell concentrations may be used as a non-lethal, non-invasive, surrogate for predicting whole egg burden of certain contaminants in marine turtles.

Animals↗

PubMed2006

Environmental Specimen Bank in Ehime University (es-BANK), Japan for global monitoring.

During the last 40 years, The Center for Marine Environmental Studies (CMES), Ehime University collected a variety of environmental and biological material comprising about 1000 species and 100,000 samples from many developing and developed countries and also open seas and oceans all over the world. They were categorically archived, catalogued and stocked in our Environment Specimen Bank (es-BANK) facility equipped with a -25 degrees C cold room. We have already exchanged specimens with many scientific institutions and are also eager to widen our collaboration with other specimen banks. In our survey using the air, water, wildlife and human samples, we found that the major emission sources for the industrial chemicals like polychlorinated biphenyls (PCBs) are in the developed nations while those of organochlorine (OC) pesticides like dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), etc. are located in developing countries. However, significant emission of modern environmental contaminants such as polybrominated diphenyl ethers (PBDEs) also seems to occur predominantly in countries with high economic growth rates. Apart from the modern incinerators and other industrial installations in developed nations, the compounds, like dioxins and related compounds (DRCs), were also found to be released in significant levels from the municipal solid waste dumping sites of developing countries. By evaluating the distribution patterns of various persistent toxic substances (PTSs) in our studies, we could conclude that DRCs and DDTs are regional contaminants, while PCBs, PBDEs, HCHs and hexachlorobenzene (HCB) are global contaminants. We also found that the pollution by PBDEs has been increasing in the last two decades while that of the legacy OCs has been decreasing.

Environmental Monitoring↗

PubMed2006

Temporal variation and biomagnification of organohalogen compounds in finless porpoises (Neophocaena phocaenoides) from the South China Sea.

Polybrominated diphenyl ethers (PBDEs) and organochlorine compounds (OCs) were determined in the blubber of male finless porpoises (Neophocaena phocaenoides) collected in 1990 and 2000/01 from the South China Sea. Among the organohalogen compounds analyzed, DDTs and PCBs were the predominant contaminants in the porpoises, ranging from 26,000 to 260,000 and 1400 to 28,000 ng/g lipid wt., respectively. PBDEs ranged from a minimum of 84 ng/g lipid wt., in 1990 to a maximum of 980 ng/g lipid wt., in 2001, showing a significant increase during the time period investigated. Congener profiles in finless porpoises did not shift to higher BDE congeners during these years, implying a continuous discharge of lower BDE commercial mixtures, such as PentaBDE. For OCs, HCHs concentrations decreased significantly, while others did not exhibit any significant temporal variation. Biomagnification factors (BMFs) were found to be highest for CHLs and lowest for HCB. PBDEs and PCBs had comparable BMFs, indicating a similar potential for biomagnification through the food web.

Adipose Tissue↗

PubMed2006

Organohalogen and organotin compounds in killer whales mass-stranded in the Shiretoko Peninsula, Hokkaido, Japan.

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.

Adipose Tissue↗