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Organotin compounds (OTCs) such as tributyltin (TBT) and triphenyltin (TPT), which are contaminating many coastal areas, are known to induce imposex in female gastropods. Hence, imposex induction in the Rock Shell Thais clavigera from 2003 to 2010 and OTC concentrations in the water, sediments, T. clavigera and in their prey were investigated from 2004 to 2006 at Iso (reference site) and Akobaru (polluted site) in Kagoshima Bay, Japan. Almost all female Rock Shells at Akobaru had imposex induction, but none at Iso. Higher concentrations of TBT and TPT in sediments (123 ng g-1 dry weight for TBT and 6.4 ng g−1 for TPT), Rock Shell (97 ∼ 182 ng g−1 for TBT and less than detection limit for TPT) and their prey (2.7 ∼ 289 ng g−1 for TBT and 1.8 ∼ 4.1 ng g−1 for TPT) were detected at Akobaru as compared to Iso. However, TBT and TPT in the water at Akobaru were less than 3.6 ng l−1 and less than 0.2 ng l−1, respectively. These results suggested that prey organisms were the main sources of organotin compounds in Rock Shells, while the source of these compounds in prey organisms was possibly the sediments or suspended particles. [ABSTRACT FROM PUBLISHER]

An ecological risk assessment of tributyltin (TBT) in Ise Bay was conducted using the margin of exposure (MOE) method. The assessment endpoint was defined to protect the survival, growth and reproduction of marine organisms. Sources of TBT in this study were assumed to be commercial vessels in harbors and navigation routes. Concentrations of TBT in Ise Bay were estimated using a three-dimensional hydrodynamic model, an ecosystem model and a chemical fate model. Estimated MOEs for marine organisms for 1990 and 2008 were approximately 0.1–2.0 and over 100 respectively, indicating a declining temporal trend in the probability of adverse effects. The chemical fate model predicts a much longer persistence of TBT in sediments than in the water column. Therefore, it is necessary to monitor the harmful effects of TBT on benthic organisms. [Copyright &y& Elsevier]

The measurement of organotins in the various biotas of coastal food webs with stable nitrogen isotope ratios (δ 15N), which increase 3.4‰ 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 8.7ngwet weightg−1, respectively. Unlike TBT, significant biomagnification of TPT through the food web (expressed by δ 15N) 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. [Copyright &y& Elsevier]

We analyzed the fate of organotins in seawater and sediments from Tokyo Bay, Japan, by gas chromatography/inductively coupled plasma mass spectrometry. We also measured the toxicity of methylated butyltins by in vitro bioassays, the retinoid X receptor (RXR) activation method, and the marine luminescent bacterium Vibrio fischeri. Concentrations of tributyltin (TBT) and tributylmonomethyltin (TBMMT) in seawater were 0.0636 to 0.419 and 0.0050 to 0.108 ng Sn/L and in sediment were 7.51 to 17.8 and 3.67 to 6.87 ng Sn/wet weight g, respectively. Methylated butyltins did not activate RXR and were not toxic to bacteria. Tributylmonomethyltin in seawater would elute from sediment since TBMMT-to-TBT ratios showed a positive correlation (r² = 0.858) between sediment and deep seawater. Both methylation and debutylation of TBT seem to be major routes of decomposition of TBT in sediment. Methylation of TBT would not only cause subsequent volatilization but also decrease the toxicity of TBT species in the marine environment. [ABSTRACT FROM AUTHOR]

The spatial and temporal behaviours of the organotin compounds (OTCs) (butyl- and phenyltin) were investigated in the Manko and Okukubi protected estuarine ecosystems on Okinawa Island, Japan from February to October 2006. Butyltin compounds (BTCs) were frequently detected in all seasons, while phenyltin (PhTs) were found in winter and early spring. In Manko estuary, the total mean concentrations of BTCs and PhTs were 22.78 ± 30.85, (mean ± SD, n = 53) and 0.08 ± 0.27 ng(Sn) L-1, respectively. In Okukubi estuary, BTCs and PhTs were 12.58 ± 23.96 and 0.47 ± 1.67 (n = 55) ng(Sn) L-1, respectively. The Manko sediments can be classified as lightly contaminated, while the Okukubi sediments were uncontaminated with tributyltin (TBT). The mean levels of TBT shown in Manko estuary exceeded the threshold level and represent an ecotoxicological risk to sensitive aquatic life. Generally, the present study reports the occurrence and continuous input of OTCs in the protected estuaries, even 16 years after legal restriction of TBT usage in coastal waters was implemented by the Japanese Environmental Authorities. [ABSTRACT FROM AUTHOR]

Abstract: A risk assessment of Tributyltin (TBT) in Tokyo Bay was conducted using the Margin of Exposure (MOE) method at the species level using the Japanese short-neck clam, Ruditapes philippinarum. The assessment endpoint was defined to protect R. philippinarum in Tokyo Bay from TBT (growth effects). A No Observed Effect Concentration (NOEC) for this species with respect to growth reduction induced by TBT was estimated from experimental results published in the scientific literature. Sources of TBT in this study were assumed to be commercial vessels in harbors and navigation routes. Concentrations of TBT in Tokyo Bay were estimated using a three-dimensional hydrodynamic model, an ecosystem model and a chemical fate model. MOEs for this species were estimated for the years 1990, 2000, and 2007. Estimated MOEs for R. philippinarum for 1990, 2000, and 2007 were approximately 1–3, 10, and 100, respectively, indicating a declining temporal trend in the probability of adverse growth effects. A simplified software package called RAMTB was developed by incorporating the chemical fate model and the databases of seasonal flow fields and distributions of organic substances (phytoplankton and detritus) in Tokyo Bay, simulated by the hydrodynamic and ecological model, respectively. [Copyright &y& Elsevier]

The state of imposex in Neptunea arthritica from seven sites along the coast of Hokkaido, Japan was examined in 2002 based on the criteria: (i) relative penis size index (RPSI); (ii) imposex frequency; (iii) stage frequency distribution of imposex in adult and immature whelks; and (iv) sex ratio. RPSI differed from site to site, although values from all sites were low (0.186-5.294). In particular, the RPSI values for four sites were very low (<1.0). In sites where immature whelks were also collected, the frequency of imposex was considerably lower in immature (7.7%-55.6%) than in adult whelks (50%-95.2%) except at one site. The imposex stage frequency distribution also differed among sites, and the trend in the adult whelks corresponded with their RPSI value. Female whelks showing severe imposex (Stage 3 and 3+) were restricted to large individuals. [ABSTRACT FROM AUTHOR]

The concentrations of butyltins along the Japanese coastline were investigated from 1997 to 1999, 7 to 9 years after implemantion 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. [Copyright &y& Elsevier]

p,p ′ -DDE [1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene; DDE] and tributyltin (TBT) are ubiquitous in the environment and in Japan were shown to bioaccumulate in marine products. Thus these chemicals serve as a source of contaminant in the mammalian food chain. Fetuses and neonates through maternal ingestion may be exposed to DDE and TBT. Therefore, the effects of concurrent exposure to DDE and TBT were investigated in male Wistar rat offspring of dams ingesting these two contaminants. In this study, TBT suppressed the growth and delayed eye opening. However, both growth retardation and delayed eye opening produced by TBT failed to occur in the presence of DDE. Unexpectedly, the prostate weight of male rat offspring was significantly reduced with the administration of TBT but restored in the presence of DDE. These results indicate that TBT and DDE affected the development of male rat offspring following maternal exposure, and simultaneous administration of DDE prevented some of the observed effects of TBT, especially of an antagonistic nature, through a mechanism, still to be determined. [ABSTRACT FROM AUTHOR]