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ABSTRACT: By field sampling and laboratory experiments we compared the mechanisms by which polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are biomagnified. We measured PBDEs and PCBs, together with stable carbon and nitrogen isotopes as an index of trophic level, in low-trophic-level organisms collected from a coastal area in Tokyo Bay. PBDEs were biomagnified to a lesser degree than PCBs. The more hydrophobic congeners of each were biomagnified more. However, the depletion of BDE congeners BDE99 and BDE153 from fish was suggested. To study congener-specific biotransformation of halogenated compounds, we conducted an in vitro experiment using hepatic microsomes of two species of fish and five BDE congeners (BDE47, 99, 100, 153, and 154) and five CB congeners with the same substitution positions as the PBDEs. BDE99 and 153 were partially debrominated, but BDE47 and 154 were not debrominated. This congener-specific debromination is consistent with the field results. Both in vitro and field results suggested selective debromination at the meta position. The CB congeners were not transformed in vitro. This result is also consistent with the field results, that PCBs were more biomagnified than PBDEs. We conclude that metabolizability is an important factor in the biomagnification of chemicals, but other factors must be responsible for the lower biomagnification of PBDEs in natural ecosystems.
Science of The Total Environment 02/2013; 449C:401-409. · 3.29 Impact Factor
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ABSTRACT: In order to estimate the nitrogen loading from fish aquaculture facilities, we studied the nitrogen and carbon stable isotope
ratios (δ15N and δ13C, respectively) in the brown macroalga Sargassum piluliferum and small amphipod crustaceans Caprella spp., both of which are lower trophic level biota found at fish and pearl oyster aquaculture facilities situated along the
eastern coast of the Uwa Sea, Japan. This coastal region is one of the least populated areas along the Japanese coast. The
mean concentrations of chlorophyll a, dissolved inorganic nitrogen, dissolved inorganic phosphate, and dissolved silicate-Si were 1.5- to 2-fold higher in samples
from the fish aquaculture facilities than in those from the pearl oyster aquaculture facilities, indicating that the fish
aquaculture facilities were associated with nitrogen loading. The δ15N abundance level in S.
piluliferum collected from the fish aquaculture facilities was significantly higher (1.3‰) than that in macroalga collected at the pearl
oyster aquaculture facilities, whereas that in Caprella spp., primary consumers, was only slightly higher (0.3‰). The feeding style of Caprella spp., which depends on suspended particulate organic matter and attached microalgae, is considered to the primary causal
factor for the lack of a significant difference in δ15N abundance level between the two types of aquaculture facilities. Based on these results, we conclude that S.
piluliferum found in close proximity of aquaculture facilities is a suitable organism for monitoring nitrogen loading from fish aquaculture
facilities, through the analysis of δ15N.
Fisheries Science 04/2012; 76(1):147-153. · 0.94 Impact Factor
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ABSTRACT: The dominant coastal bivalve in Vietnam, hard clams Meretrix spp., collected from the South Key Economic Zone (SKEZ), the Mekong River Delta, and the Central Coastal Zone (CCZ) were
analyzed for 21 trace elements. Comparison of the results from the three regions indicated that levels of most of the trace
elements, especially As, Mo, Sn, and Pb, were highest in the samples collected from the CCZ, whereas most of the trace elements
were found to be present at relatively low levels in samples from the SKEZ. The high concentrations of these trace elements
in the CCZ, a sparsely populated region with less human activity than the other two regions, were believed to have originated
from industrial waste produced in a shipyard. Although the trace element concentrations in the bivalves were within safe levels
for human-consumption criteria reported by the United State Food and Drug Administration and the European Commission, estimation
of cancer risk based on As concentration indicates that the hard clams from the CCZ pose a high risk to consumers. Thus, the
industrial waste produced in the less densely populated region might increase the health risk to consumers via the contamination
of bivalves commonly used as food.
KeywordsHealth risk-
Meretrix
-Shipyard waste-Trace element-Vietnam
Fisheries Science 04/2012; 76(4):677-686. · 0.94 Impact Factor
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ABSTRACT: We performed stable carbon and nitrogen-guided analyses of biomagnification profiles of arsenic (As) species, including total As, lipid-soluble As, eight water-soluble As compounds (arsenobetaine (AB), arsenocholine (AC), tetramethylarsonium ion (TETRA), trimethylarsine oxide (TMAO), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), arsenate (As[V]), and arsenite (As[III])), and non-extracted As in a tropical mangrove ecosystem in the Ba Ria Vung Tau, South Vietnam. Arsenobetaine was the predominant As species (65-96% of water-soluble As). Simple linear regression slopes of log-transformed concentrations of total As, As fractions or individual As compounds on stable nitrogen isotopic ratio (δ15N) values are regarded as indices of biomagnification. In this ecosystem, lipid-soluble As (slope, 0.130) and AB (slope, 0.108) were significantly biomagnified through the food web; total As and other water-soluble As compounds were not. To our knowledge, this is one of the first reports on biomagnification profiles of As compounds from a tropical mangrove ecosystem.
Marine pollution bulletin 04/2011; 63(5-12):124-34. · 2.63 Impact Factor
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ABSTRACT: Organisms collected from a coastal ecosystem in Japan were analyzed for concentrations of 205 polychlorinated biphenyls (PCBs) congeners; analyses were guided by delta(13)C and delta(15)N measurements. The regression slopes of log PCB concentration on delta(15)N value are regarded as indices of biomagnification in food webs. The slope (wet weight basis) of SigmaPCBs was +0.104; the slope (lipid weight basis) was close to zero. Lipid content increased from 0.06% in a primary producer to 8.32% in the highest trophic level consumer. Hence, biomagnification of SigmaPCBs (wet weight basis) can be attributed to increase of lipid content through the food web. For most of the congeners, the slopes (wet weight basis) exceeded those (lipid weight basis) by ca. 0.10. Slopes increased with increasing PCB chlorination levels between chlorine numbers 1-6; slopes decreased at higher chlorination levels. This decrease is likely caused by a decrease in membrane permeability with increasing molecular weight.
Marine pollution bulletin 09/2009; 58(11):1615-23. · 2.63 Impact Factor
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ABSTRACT: Bivalves, crabs, fishes, seawater, and sediment collected from the inner part of Tokyo Bay, Japan, were measured for 20 polybrominated diphenyl ether (PBDE) and 5 polychlorinated biphenyl (PCB) congeners. To determine the trophic levels of the organisms, carbon and nitrogen stable isotope ratios (delta(13)C and delta(15)N) were also measured. Bioconcentration factors of PBDE and PCB congeners increased as the octanol-water partition coefficient (K(ow)) rose to log K(ow)=7, above which they decreased again. Biomagnification of PCBs and several PBDE congeners (BDE47, 99, 100, 153 and 154) up the trophic ladder was confirmed by a positive correlation between their concentrations and delta(15)N. Other PBDE congeners showed a negative or no correlation, suggesting their biotransformation through metabolism. The more hydrophobic congeners of both PBDEs (Br=2-6) and PCBs (Cl=6-9) were biomagnified more. It thus appears that PBDEs are less biomagnified than PCBs.
Marine pollution bulletin 05/2009; 58(8):1217-24. · 2.63 Impact Factor
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ABSTRACT: Biomagnification profiles of polycyclic aromatic hydrocarbons (PAHs), alkylphenols, and polychlorinated biphenyls (PCBs) from the innermost part of Tokyo Bay, Japan were analyzed using stable carbon (delta(13)C) and nitrogen (delta(15)N) isotope ratios as guides to trophic web structure. delta(15)N analysis indicated that all species of mollusks tested were primary consumers, while decapods and fish were secondary consumers. Higher concentrations of PCBs occurred in decapods and fish than in mollusks. In contrast, concentrations of PAHs and alkylphenols were lower in decapods and fish than in mollusks. Unlike PCBs, whose concentrations largely increased with increasing delta(15)N (i.e. increasing trophic level), all PAHs and alkylphenols analyzed followed a reverse trend. Molecular weights of PAHs are lower than those of PCBs, therefore low membrane permeability caused by large molecular size is an unlikely factor in the "biodilution" of PAHs. Organisms at higher trophic levels may rapidly metabolize PAHs or they may assimilate less of them.
Marine pollution bulletin 04/2009; 58(5):663-71. · 2.63 Impact Factor
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ABSTRACT: The measurement of organotins in the various biotas of coastal food webs with stable nitrogen isotope ratios (delta(15)N), which increase 3.4 per thousand per trophic level, can provide a biomagnification profile of organotins through food web. In this study, various biological samples were collected from three localities in Western Japan between 2002 and 2003 for analyses. Tributyltin (TBT) and triphenyltin (TPT) were still detected with a maximum of 99.5 and 8.7 ng wet weight g(-1), respectively. Unlike TBT, significant biomagnification of TPT through the food web (expressed by delta(15)N) was found in all three localities. The log transformed octanol-water partition coefficient (log K(ow)) of TPT of 2.11-3.43 was overlapped by, but was slightly lower than, that of TBT of 3.70-4.70. Thus, this study demonstrates that although these chemicals have a log K(ow) lower than 5, at least TPT undergoes significant biomagnification through the food web.
Chemosphere 11/2008; 73(11):1749-56. · 3.21 Impact Factor
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ABSTRACT: The present study elucidated the biomagnification profiles of persistent organic pollutants (POPs) through a tropical aquatic food web of Vietnam based on trophic characterization using stable nitrogen analysis. Various biological samples collected from the main stream of the Mekong Delta were provided for the analysis for both POPs, and stable nitrogen and carbon isotope ratios. Of the POPs analyzed, dichlorodiphenyltrichloroethane and its metabolites (DDTs) were the predominant contaminants with concentrations ranging from 0.058 to 12 ng/g wet weight, followed by polychlorinated biphenyls (PCBs) at 0.017-8.9 ng/g, chlordane compounds (CHLs) at 0.0043-0.76 ng/g, tris-4-chlorophenyl methane (TCPMe) at N.D.-0.26 ng/g, hexachlorocyclohexane isomers (HCHs) at N.D.-0.20 ng/g and hexachlorobenzene (HCB) at 0.0021-0.096 ng/g. Significant positive increases of concentrations in DDTs, CHLs, and TCPMe against the stable nitrogen ratio (delta(15)N) were detected, while, concentrations of HCHs and HCB showed no significant increase. The slopes of the regression equations between the log-transformed concentrations of these POPs and delta(15)N were used as indices of biomagnification. The slopes of the POPs for which positive biomagnification was detected ranged from 0.149 to 0.177 on a wet weight basis. The slopes of DDTs and CHLs were less than those reported for a marine food web of the Arctic Ocean, indicating that less biomagnification had occurred in the tropical food web. Of the isomers of CHLs, unlike the studies of the Arctic Ocean, oxychlordane did not undergo significant biomagnification through the food web of the Mekong Delta. This difference is considered to be due to a lack of marine mammals, which might metabolize cis- and trans-chlordane to oxychlordane, in the Mekong Delta ecosystem. The biomagnification profile of TCPMe is reported for the first time in the present study.
Chemosphere 06/2008; 72(1):104-14. · 3.21 Impact Factor
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ABSTRACT: In the present study, we report the concentrations of 21 trace elements (V, Cr, Mn, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Hg, Tl, Pb, and Bi), as well as the results of the analysis of stable carbon and nitrogen isotopes, of the various biota that make up the food web in the main stream of the Mekong Delta near Can Tho, South Vietnam. A significant trophic level-dependent increase was found in concentrations of Se, Rb, and Hg with increasing delta(15)N, indicating that an overall biomagnification of these elements occurred. However, the increase of Hg concentration per trophic level was lower than in previous studies. In contrast, the concentration of Mn showed an opposite trend in the food web of the Mekong Delta. In addition to these overall trends, the present study revealed that the biomagnification profiles of trace metals differ between crustaceans and fishes; concentrations of Mn, Cu, Zn, As, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, and Pb were significantly higher in crustaceans, whereas fishes showed higher concentrations of Cr, Rb, and Hg (trophic level determined by delta(15)N). The differences in the biomagnification profile between the major taxa might be attributed to differences in metal accumulation and in detoxification abilities such as possessing a metal-binding protein, e.g., metallothionein (MT).
Archives of Environmental Contamination and Toxicology 05/2008; 54(3):504-15. · 1.93 Impact Factor
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ABSTRACT: Accumulation profiles of 22 trace elements in abdominal muscle, abdominal exoskeleton and the hepatopancreas of the giant river prawn Macrobrachium rosenbergii were analyzed. The giant river prawn is an indigenous freshwater species from South Vietnam, and is cultured commercially and fished in the wild. Samples were collected from Ho Chi Minh City and the surrounding area (SKEZ, South Key Economic Zone), and from the Mekong River Delta between 2003 and 2005. Highest accumulations of essential (Cu, Se and Mo) and toxic (As, Ag, Cd and Hg) elements were observed in hepatopancreatic tissue, except for Mn, Sr, Sn, Ba and V in the exoskeleton and Rb and Cs in muscle tissue. Spatial differences showed concentrations of Cs and Pb in muscle and Sr in exoskeletons from the SKEZ were higher than those from the Mekong River Delta. The opposite trend was observed for Cr, Se and Sb in muscle, Mo, Sb and Tl in exoskeleton, and Se, Hg, Mo, Cd, Sb, Tl and Bi in the hepatopancreas. These differences in trace element concentrations in prawns likely reflect differences in industrialization and human activities between the two regions of South Vietnam.
Fisheries Science 01/2008; 74(1):109 - 119. · 0.94 Impact Factor
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ABSTRACT: Hatched juveniles of Caprella danilevskii (Crustacea: Amphipoda) were exposed to one of two concentrations of tributyltin (TBT) (1.1 and 10.7 ng TBTL(-1)) for 49 d at 20 degrees C. These concentrations are near or below ambient levels in seawater. In both treatments and control, the survival rate was 100% at maturation, and >85% at the end of the experiments. Females reached maturation at 20 (median) to 21.5d at instar VII, and repeated spawning 4-5 times during the experiment. The total number of juveniles per female decreased significantly from 39.5 in the control to 24.5 and 17.5 in 1.1 ng L(-1) and 10.7 ng L(-1) treatments, respectively. An earlier study reported that as the TBT concentration in seawater increased from a 0-10 ng L(-1) regime to a 10-20 ng L(-1) regime, the number of stations where Caprella spp. could be collected decreased along the coast of the Seto Inland Sea, of Japan. Thus, the present study indicates the possibility that the extremely low concentration of TBT measured in Japanese waters after 2000 lead to a reduction in reproductive success of Caprella spp.
Marine Pollution Bulletin 01/2008; 57(6-12):515-23. · 2.50 Impact Factor
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ABSTRACT: The goal of the present study was to examine the specific bioaccumulation of 22 trace elements in muscle, exoskeleton and hepatopancreas of black tiger shrimp Penaeus monodon from the Mekong River Delta (MRD), and the South Key Economic Zone (SKEZ), South Vietnam. The general tendency in most trace element concentrations among different tissues were hepatopancreas>exoskeleton>muscle. Comparisons of trace element levels in tissues between the two regions showed that concentrations of Se in muscle and As in all three tissues were higher in SKEZ; whereas in MRD, the higher concentrations of most elements such as Mn, Cu, Cd, Ba, Hg, were observed in tissues. These geographical variations in trace element levels may reflect the differences in human activities between the two regions of South Vietnam. The target hazard quotient (THQ) values for trace elements (<1) indicate that local residents are not exposed to potential health risks via the consumption of shrimp.
Marine Pollution Bulletin 01/2008; 57(6-12):858-66. · 2.50 Impact Factor
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ABSTRACT: Restrictions on the use of tributyltin (TBT) in aquaculture and on boats in coastal regions, except for ocean-going vessels, have been in place in Japan since 1990 due to the strong toxic effects of TBT on marine organisms. However, TBT pollution along the Japanese coasts has been reported after this legislation was enacted. In order to elucidate the present status of contamination by butyltin (BT) compounds, we measured the levels of BTs [monobutyltin (MBT), dibutyltin (DBT) and TBT] in seawater and Caprella spp. samples obtained from the western part of Seto Inland Sea, Uwa Sea and Uranouchi Bay in western Japan during March to September, 2001. Butyltins were detected in more than 90% of the seawater samples (n = 59), with average concentrations of 8.2+/-9.2 (SD) ng MBT L(-1), 3.3+/-3.0 ng DBT L(-1) and 9.0+/-7.0 ng TBT L(-1). Among 41 stations situated on coastal lines, a sufficient number of Caprella organisms for chemical analysis could be collected from only 16 stations. The butyltin concentrations in seawater and Caprella samples from Uwa Sea and Uranouchi Bay, in which the dominant industry in both waters is aquaculture, showed significantly higher than or no significant differences from those samples from the western part of Seto Inland Sea, a major heavy-industry area in Japan. As the TBT concentration in seawater increased, the number of Caprella organisms collected decreased. The mean TBT concentration among the seawater samples was above the estimated lowest observable effect concentration (LOEC) that reduces the survival rate of Caprella danilevskii. Thus, the present study indicates that TBT is still a potential ecological hazard to the survival of marine invertebrates inhabiting coasts along western Japan, even 11 years after the partial ban on TBT usage was implemented.
Marine Pollution Bulletin 02/2005; 51(8-12):940-9. · 2.50 Impact Factor
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ABSTRACT: 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.
Journal of the Marine Biological Association of the UK 09/2004; 84(05):911 - 918. · 1.00 Impact Factor
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ABSTRACT: The concentrations of butyltins along the Japanese coastline were investigated from 1997 to 1999, 7 to 9 years after implementation of legislation limiting the use of tributyltin (TBT) in Japan. Seawater was sampled at 0.5 m depth, and Caprella spp. were collected from Sargassum spp. and aquaculture facilities from 18 areas within four broad areas along the coastline of Japan, i.e., the Pacific coast of northern Japan, the coast along the Sea of Japan, Tokyo Bay and adjacent areas, and western Japan. Butyltins (MBT, DBT and TBT) were detected in 32 of the 63 seawater samples with average concentrations of 4.6 ng MBT/l, 4.5 ng DBT/l and 6.8 ng TBT/l, respectively. Butyltin concentrations in seawater from western Japan indicate "hot spots" even in unpopulated areas. Butyltins (MBT, DBT and TBT) were detected in all samples of Caprella spp., varying from 2.3 ng BTs /g wet wt in C. penantis R-type from Tobishima Island in the Sea of Japan to 464 ng BTs /g wet wt in C. decipiens Mayer from Amakusa, western Kyushu. The BT concentrations in Caprella spp. form western Japan were significantly higher than those from other areas, including Tokyo Bay and adjacent areas, where large scale industry and international ports are located. These results indicate that butyltin contamination still remains even in unpopulated areas after the regulation on TBT usage, and that the regulation governing TBT usage since 1990 has not been effective enough to concede recovery of shallow water ecosystems around Japan.
Marine Environmental Research 07/2004; 57(5):397-414. · 2.28 Impact Factor
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ABSTRACT: Tests for the acute toxicity of tributyltin (TBT) were conducted on amphipod crustaceans collected from Otsuchi Bay, Japan. Five species of caprellids and three species of gammarids, which belong to a closely related ecological niche, were used for the exposure experiments at seven test concentrations (0, 0.001, 0.01, 0.1, 1, 10 and 100 microg TBTCl/l) for 48 h at 20 degrees C. The 48-h LC50 values of the caprellids were 1.2-6.6 microg TBTCl/l, and these were significantly lower than those of the gammarids (17.8-23.1 microg TBTCl/l). This suggests that caprellids are more sensitive to TBT than gammarids. Furthermore, the proportions of TBT and its derivatives, dibutyltin (DBT) and monobutyltin (MBT), were measured in the amphipods collected from Otsuchi Bay. In the caprellids, TBT was the predominant compound, accounting for 72% of the total butyltin which reflected the butyltin ratio in seawater, while in the gammarids, TBT's breakdown products (DBT and MBT) predominated, accounting for 75% of the total butyltin. This difference suggests that caprellids may have lower metabolic capacity to degrade TBT than gammarids. Therefore, the difference in sensitivity to TBT among the amphipods is thought to be related to the species-specific capacity to metabolize TBT.
Marine Pollution Bulletin 02/2002; 44(1):16-24. · 2.50 Impact Factor
