Ryo Tatsukawa

Species-specific distribution of heavy metals in tissues and organs of loggerhead turtle (Caretta caretta) and green turtle (Chelonia mydas) from Japanese coastal waters

Concentrations of heavy metals (Fe, Mn, Zn, Cu, Pb, Ni, Cd, Co and Hg) were determined in tissues and organs of loggerhead (Caretta caretta) and green turtles (Chelonia mydas) collected from Japanese coastal waters, in order to elucidate body distribution and to develop a non-lethal monitoring technique using the carapace. A majority of the metal burdens was present in the muscle, liver, bone and carapace of sea turtles. High Cu concentrations exceeding 10 μg/g wet wt were observed in the liver of these two turtle species. Mean Zn concentrations in fat tissues of loggerhead and green turtles were 94.6 and 51.3 μg/g wet wt respectively, which were about 10-fold higher than those reported in other marine animals. Concentrations of Mn, Zn and Hg in the carapace were correlated with whole body burdens, indicating that the carapace is a useful non-lethal indicator for monitoring heavy metal levels in the body of the sea turtle.

Persistent organochlorines in minke whale (Balaenoptera acutorostrata) and their prey species from the Antarctic and the North Pacific.

Persistent organochlorines such as polychlorinated biphenyls (PCBs), DDTs, chlordane compounds (CHLs), hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were determined in the blubber of minke whale and its diet collected from the Antarctic and the North Pacific Oceans. Residue levels of these compounds (except HCB) in minke whale from the Antarctic were apparently lower than those from the North Pacific. This is due to the lower levels of these pollutants in the southern hemisphere than in the northern hemisphere and the specific feeding habit of the minke whale from the Antarctic which feeds on lower trophic organisms, primarily euphausiids. The north-south difference for HCB residue levels was small, reflecting its dispersible nature through long-range atmospheric transport. Compositions of DDT and CHL compounds in minke whale from the Antarctic were similar to those from the North Pacific. However, the composition of HCH isomers was different between the Antarctic and the North Pacific as was observed in their diet, suggesting a larger or on-going usage of lindane in the southern hemisphere countries. In minke whale from the Antarctic, the elevated level of PCBs residues was noted during a period of 1984 to 1993, implying a continuous discharge of PCBs in the southern hemisphere. A similar discharge was also suggested in the North Pacific, while a decreasing contamination by DDTs was apparent.

ORGANOCHLORINE CONTAMINATION IN SOME ODONTOCETI SPECIES FROM THE NORTH PACIFIC AND INDIAN OCEAN

Abstract Concentrations of persistent organochlorines were determined in the blubber and melon of 11 species of adult male odontocetis collected from the North Pacific, Indian Ocean and nearby seas. Mean concentrations of DDs (33 μg/g wet wt) were the highest followed by PCBs (32 μg/g wet wt), chlordane compounds (CHLs: 3.7 μg/g wet wt), HCHs (1.1 μg/g wet wt), and HCB (0.32 μg/g wet wt). Odontoceti species inhabiting temperate waters revealed maximum residual concentrations of these contaminants, and the elevated DDT and PCB residues detected seem to suggest that some of the present species might potentially be at high risk. Relatively high DDT concentrations were found in tropical water species, which could be attributed to the current usage of DDT in the tropics and the less movable nature of this compound via long-range atmospheric transport. The HCH levels in animals inhabiting cold and temperate waters were higher than those inhabiting tropical waters, a result that was perhaps reflective of atmospheric transport from the tropical source to the northern sinks. A similar pattern was also observed in PCBs, CHLs and HCB, probably indicating the ongoing discharge of these compounds from mid-latitudes as well as those originating in tropical regions.

Mercury and cadmium in common cormorants (Phalacrocorax carbo).

Mercury (Hg) and cadmium (Cd) in common cormorants (Phalacrocorax carbo) collected in Lake Biwa, Japan and Tokyo, Japan, were investigated to elucidate the biological behaviors of these elements, and to assess exposure to these pollutants of wild, fish-eating birds. Hg and Cd concentrations were highest in the liver and kidneys, respectively. The lowest levels of both elements were observed in chicks. Hg concentrations in all tissues except brain increased significantly with growth from chicks to juveniles (p<0.05, U-test). Cd concentrations in the kidneys and liver also increased significantly during growth from juvenile to adult (p<0.005, U-test). When comparing hepatic Hg and Cd in adult birds between 10 samples from Lake Biwa and nine samples from Tokyo, the Cd concentrations in the Lake Biwa samples (1.4+/-0.37 microg/g dry wt) (mean+/-SD) were significantly higher than those from Tokyo (0.32+/-0.16 microg/g dry wt) (p<0.005, U-test), while no statistically significant difference was found in the Hg concentrations. Possible causes of these differences were discussed in relation to their prey.

Bioaccumulation of Butyltin Compounds in Marine Mammals: The Specific Tissue Distribution and Composition

Although organotins are notorious man-made organometallic species introduced into the aquatic environment, no investigation had been concerned with contamination of higher trophic animals such as marine mammals until the last few years. Our recent work demonstrated the detection of butyltin compounds (BTCs), including mono- (MBT), di-(DBT), and tri-butyltin (TBT) in marine mammals. This paper reviews BTC contamination in higher trophic animals, based on our recent publications. Analysis for BTCs showed significant accumulation in tissues and organs of three finless porpoises (Neophocaena phocaenoides) collected from Japanese coastal waters. More than 10u2009μg of butyltin ions per gram on a wet weight basis were detected in the liver of a porpoise collected in the semi-closed sea. Distribution of BTCs in the tissues and organs of the porpoises showed a similar pattern to several other marine mammal species: higher concentrations in liver and kidney, and lower in muscle and blubber. In addition, tissues and organs from two water birds and one sea turtle species were also analyzed for BTCs, and their concentrations and compositions were compared among the species. The results showed that the distribution of these contaminants extends widely, not only to marine mammals but also to other higher trophic species. On the other hand, the composition of the BTCs exhibited a specific profile in each species. The ratios of hepatic concentrations of DBT or MBT to TBT for marine mammals were relatively lower than those of water birds and the sea turtle, indicating that metabolism and excretion of TBT may be less efficient in the mammalian species.

Accumulation pattern of persistent organochlorine residues in common cormorants (Phalacrocorax carbo) from Japan

Concentrations of organochlorines such as PCBs, DDTs, chlordanes (CHLs), HCHs and HCB were determined in the liver of common cormorants from two different colonies to understand the current status of contamination and geographical differences. The birds from Shinobazu pond, central Tokyo, exhibited significantly higher OC levels than those in the Lake Biwa. Residue level of PCBs was the highest followed by the DDTs regardless of the locations and growth stages. CHLs and HCB were also higher in the Shinobazu pond adults and juveniles, whereas HCHs were comparable with the Lake Biwa. The OC levels, excluding PCBs, were relatively higher in regurgitated fish in Lake Biwa than Tokyo Bay fish. The inverse relation of bioaccumulation between fish and birds emphasized that cormorants from both colonies, at least, would have seasonal and preferential feeding habits in a widely extended area. The calculated biomagnification values showed that DDTs and CHLs had lowest and highest metabolic capacities, respectively. This study also made evident that present OC contamination levels in common cormorants may not pose a serious threat to their reproduction. However, contaminant related risk in cormorants, if any, could be higher in Shinobazu pond than that in Lake Biwa.

Isomer-specific analysis of polychlorinated biphenyls in harbour porpoise (Phocoena phocoena) from the Black Sea

Abstract The highly toxic coplanar PCBs and other isomers were determined in harbour porpoises and fish (porpoise diet) collected from the Turkish coastal water of the Black Sea, during 1993. The concentrations of total PCBs were found in the range of 5.0–34 μg g−1 wet wt in the blubber of porpoises. Highly chlorinated members such as IUPAC Nos 138, 153 and 180 were the dominant congeners, consisting of 41% of the total PCB concentrations. The mean total 2,3,7,8-TCDD toxic equivalents (TEQs) of 13 coplanar PCBs including non-, mono- and di-ortho congeners were 1400 pg g−1 wet wt in the blubber of males and 300 pg g−1 wet wt in females. The IUPAC No. 118 was the most contributing congener occupying about 60% of the total TEQs. The most toxic non-ortho chlorine substituted coplanar PCBs such as IUPAC No. 77, 126 and 169 were minor contributors and accounted for 7.8, 4.2 and 0.7%, respectively, of the total TEQs. The activities of PB and MC-type enzymes were found to be low in Black Sea harbour porpoises, suggesting long term accumulation and possible toxic effects of PCBs in this species.