Polybrominated dipheny ethers (PBDEs) and organochlorine compounds (OCs) in the blubber, liver, and kidney of Indo-Pacific humpback dolphins and finless porpoises stranded in Hong Kong coastal waters ...were determined. Among the organohalogen compounds analyzed, DDTs were the most dominant contaminants with concentrations ranging from 9.9 to 470 mu g/g lipid weight. Quantification of PCBs and most of organochlorine pesticides was performed using a GC equipped with a microelectron capture detector and an auto-injection system. The PCB standard used for quantification was a mixture of 62 PCB isomers and congeners. For all the contaminants, higher concentrations were found in humpback dolphins when compared to finless porpoises.
The present paper overviews the organochlorine contamination in marine mammals with ecotoxicological concern. From a geographical point of view, the organochlorine contamination is still spreading on ...a global terms, and tropical zones represent a major emission source of these toxic pollutants. In this context, oceans play a role as a final sink for persistent organochlorines and thus marine mammals seem to be housing a garbage of toxic contaminants. Due to the specific physiological functions such as the presence of large lipid pool(blubber)for accumulating organochlorines, lactational transfer of these contaminants in large quantities over generations and small capacity to degrade them, marine mammals can amplify much greater amounts of toxic organochlorines in the body through food chain. Therefore, long-term accumulation and chronic toxic effects are of great concern in marine mammals. Additionally, it is unlikely to decline the residue levels of toxic organochlorines in marine mammals in near future, suggesting that the adverse effect of these contaminants are steadily being extended to these animals.
Caprella spp. (Crustacea: Amphipoda) inhabiting the Sargassum algal community in Otsuchi Bay near unpopulated areas of northern Japan, were collected from 1994 to 2001 and subjected to analysis of ...butyltin (BT) concentrations. The period from 1994 to 2001 corresponds to four to 11 years after legislation limiting the use of tributyltin (TBT) on small boats and aquaculture facilities was passed in Japan. Butyltin compounds including TBT, dibutyltin (DBT) and monobutyltin (MBT) were detected in all samples of Caprella spp., although the three BTs were not detected in seawater samples collected from the same area between 1997 and 1999. The concentration of total BTs (BTs=MBT+DBT+TBT) in Caprella spp. significantly decreased from 84 ng BTs/g wet wt in 1994 to 7·4 ng/g wet wt in 2001. The concentrations of BTs in Caprella spp., which have a high bioconcentration factor for TBT, are thought to reflect the average concentrations of BTs in the surrounding seawater in the previous few months. The half-life of BTs and TBT in Caprella spp. was 2·38 years and 2·07 years, respectively, which are less than half of that of TBT in seawater based on the national survey of The Ministry of the Environment, Japan. Illegal usage of TBT near the studied area may have decreased due to monitoring of BTs.
The 21st Century's Center of Excellence (COE) Program “Coastal Marine Environmental Research” in Ehime University, funded by the Ministry of Education, Culture, Sports, Science and Technology, ...Government of Japan, started its activities in October 2002. One of the core projects of the COE Program in Ehime University is “studies on environmental behavior of hazardous chemicals and their toxic effects on wildlife”. This core project deals with studies of the local and global distribution of environmental contaminants in aquatic ecosystems, retrospective analysis of such chemicals, their toxicokinetics in humans and wildlife, molecular mechanisms to determine species-specific reactions, and sensitivity of chemically induced effects, and with the development of methodology for risk assessment for the conservation of ecological and species diversity. This presentation describes our recent achievements of this project, including research on contamination by arsenic and organohalogen pollutants in the Mekong River basin and molecular mechanisms of morphologic deformities in dioxin-exposed red seabream (Pagrus major) embryos. We established the Environmental Specimen Bank (es-BANK) in Ehime University in 2004, archiving approximately 100000 cryogenic samples containing tissues of wildlife and humans that have been collected for the past 40 years. The CMES homepage offers details of samples through online database retrieval. The es-BANK facility was in operation by the end of 2005.
Butyltin concentrations along the Japanese coast were monitored during 1997-99, 7-9 yr after legislation limited the use of tributyltin (TBT) in Japan. Butyltins were detected in 32 of 63 seawater ...samples with average mono- (MBT), di- (DBT), and TBT concentrations of 4.6, 4.5, and 6.8 ng/l, respectively. Butyltin hotspots were identified along western Japan, even in unpopulated areas. MBT, DBT, and TBT were measured in samples of the crustacean Caprella spp.. The regulation governing TBT usage since 1990 has not been effective in terms of shallow water ecosystem recovery throughout Japan.
The determination of the total tin inbiological materials was studied using a calibration method involving ICP-MS. Prior to an ICP-MS determination, samples were subjected to microwave-digestion with ...HNO3. The detected intensities for all tin isotopes increased along with an increase in the HCl concentration, while the intensities did not vary with the HNO3 concentration. The addition of HNO3 acted to control the interference by 0.02 M of HCl. The total tin concentrations in biological reference materials (NIES No.11, No.6, and No. 5) were examined by the present method, and agreed well with the reported reference values. In the case of preparing 100 mg of dry samples, and obtaining a final extract volume of 10 ml, the detection limit was 10 ng Sn/g-d.w. in the present study. Considering all of these results, it can be concluded that the present method is applicable with high accuracy and sensitivity for determining the total tin in biological samples.
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.
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