Tributylin Research Articles

Antimicrobial Properties of Transition Metals Substituted Chitosan against Cobetia Marina

This research work offers the new organic compound which has potential to replace the use of tributylin (TBT) in antifouling application. All modified chitosan powders were synthesized using in-house powder processing techniques. Pure and modified chitosan were evaluated for fouling properties via antimicrobial activity test against Cobetia Marina (C. Marina). The results indicated that copper substituted chitosan (CS-Cu) showed the highest inhibition zone and lowest number of C. Marina survival. It can be implied that CS-Cu showed the best antimicrobial ability against C. Marina.

Effects of Organotin Alternative Antifoulants on Oyster Embryo

In September 2008, organotin (Ot) compounds were prohibited from being used worldwide. From 1997 onward in Japan, the production of paints containing TBT (tributylin) compounds was prohibited, and thus alternatives to Ot antifoulants have been used since then. It has been said that the decomposition characteristics of these materials are better than those of Ot compounds. The toxicity of alternative Ot antifoulants (e.g., diuron, irgarol 1051®, and Sea-Nine 211®) and Ot compounds (TBT and TPT (triphenyltin)), using oysters that inhabit a large area of Hiroshima Bay, were evaluated. The results showed that the toxicity of diuron and irgarol 1051 is very low, and the toxicity of Sea-Nine 211 is almost the same as that of TPT. Sea-Nine 211's effect was stronger on oysters than other shellfish, causing concern about the extent of Sea-Nine 211's impact on oyster development.

Temporal Trend of Butyltins in Seawater, Sediments, and Mussels from Busan Harbor of Korea Between 2002 and 2007: Tracking the Effectiveness of Tributylin Regulation

Butyltins were determined in seawater, sediments, and mussels (Mytilus edulis) collected from Busan Harbor, the largest commercial harbor in Korea, to assess the contamination status and the effectiveness of tributylin (TBT) restriction. TBT concentrations were found to be 7.6 +/- 8.3 ng Sn/L in seawater, 387 +/- 606 ng Sn/g dry weight (wt) in sediments, and 322 +/- 167 ng Sn/g dry wt in mussels, and are comparable to those in the largest harbors worldwide. TBT levels were highest at locations near shipyards and related facilities. Busan Harbor was characterized by the long-term history of butyltin contamination, based on the lowered TBT/DBT ratios in environmental matrices. The temporal trend of TBT levels decreased significantly in seawater and mussels from 2002 to 2007, probably as a consequence of the legislative action in Korea (MOE Regulation 154/2000). However, TBT in sediments did not show any trend, suggesting a long half-life for TBT, about 17 years, in sediments.

Increases in cytosolic calcium ion levels in human natural killer cells in response to butyltin exposure.

This study investigated whether exposures to butyltins (BTs), tributylin (TBT), and dibutyltin (DBT) were able to alter cytosolic calcium levels in human natural killer (NK) cells. Additionally, the effects of cytosolic calcium ion increases on the activation state of mitogen-activated protein kinases (MAPKs) in NK cells were also investigated. NK cells are an intital immune defense against the development of tumors or viral infections. TBT and DBT are widespread environmental contaminants, due to their various industrial applications. Both TBT and DBT have been shown to decrease the ability of NK cells to lyse tumor cells (lytic function). TBT has also been shown to activate MAPKs in NK cells. The results of this study indicated that TBT increased cytosolic calcium levels by as much as 100% after a 60-min exposure to 500 nM TBT, whereas DBT increased cytosolic calcium levels to a much smaller extent (and required higher concentrations). The results also indicated that increases in cytosolic calcium could activate MAPKs but only for a short period of time (5 min), whereas previous studies showed that activation of MAPKs by TBT last for at least 6 h. Thus, it appears that TBT-stimulated increases in cytosolic calcium might contribute to, but are not fully responsible for, TBT-induced activation of MAPKs.

Routes of TBT uptake in the clam Ruditapes decussatus. II. Food as vector of TBT uptake

Marine bivalves are exposed to contaminants via the aqueous phase, sediments and food. Nevertheless, the relative importance of these phases as uptake vectors of contaminants in these marine organisms has not been well studied. Phytoplankton concentrate contaminants from seawater and given their position at the base of most marine food webs, these algal cells may play critical roles in the transfer of contaminants to higher trophic levels. This study assesses the relative importance of microalgae as a vector of tributylin (TBT) uptake in the infaunal, suspension-feeding bivalve Ruditapes decussatus. Accumulation of TBT via the algal diet was determined by experimental exposure of R. decussatus to 14C-TBT labelled phytoplankton Isochrisis galbana, for a period up to 60 days. The digestive tract of these clams initially accumulates TBT preferentially from food. After a few weeks of exposure, internal remobilization results in a more widespread partitioning of TBT amongst tissues.

Organotin Levels in Seafood

Tolerable average residue levels (TARL) for tributylin (TBT) in seafood products were calculated based on the tolerable daily intake (TDI) of TBT and the seafood consumption of the average consumer in various countries. Data from the literature show that these TARLs in seafood are exceeded in one or more samples in nine of the 22 countries for which data were available, i.e. Canada, France, Italy, Japan, Korea, Poland, Taiwan, Thailand and USA. In Italy also the average TBT residue level in seafood exceeded the TARL with a factor of 2.5, while in Japan the average TBT residue level in seafood almost equaled the TARL for this country. For the majority of countries, however, no data on organotin levels in seafood were available. This study shows that there is a need for country-specific maximum residue limits (MRL) for TBT in seafood products and that TBT levels in seafood should be monitored more regularly.

The Occurrence of Dual-gender Imposex in Japanese Freshwater Crab.

Tributylin (TBT)-induced imposex phenomena have been reported only in mollusks. Our findings reveal that imposex is not a phenomenon exclusive to mollusks. The imposex phenomenon has been found to occur in a common Japanese freshwater crab, Geothelphusa dehaani, which inhabits TBT-uncontaminated mountain streams in Japan. In addition, the imposex of G. dehaani occurred not only in females but also in males (dual-gender imposex) : either female genital opening (gonopore) or a single ovary occured in male crabs. However, the definitive causal factors and mechanics relating to the occurrence of imposex are still unclear.

Survey of imposex in dogwhelks (Nucella lapillus) from North Sea coasts

Following a North Sea Task Force (NSTF) initiative in 1991, and funding from the Department of Environment (DOE), The Scottish Office Agriculture, Environment and Fisheries Department Marine Laboratory (SOAEFD), Aberdeen, was awarded a contract to assess the impact of tributyltin compounds in dogwhelks in all North Sea coastal waters. These waters were surveyed in 1991 and 1992 to evaluate the distribution and effects of tributylin (TBT) compounds on the common dogwhelk, Nucella lapillus. Wild and, where necessary, transplanted dogwhelks were analysed for imposex. Historical records indicate that Nucella lapillus was once present, on suitable substrates, around the whole of the North Sea coastline. Wild dogwhelks could be collected in all countries except Belgium and Germany, where the species is present only on Helgoland (in numbers too small to be sampled). All wild populations of dogwhelks showed imposex. Near sites of intense boating activity, all populations examined contained some sterile females. At all sites where transplants were recovered, the dogwhelks were affected by TBT. Prolonged survival of dogwhelks at any of these sites would not be expected, except perhaps at Torsminde in Denmark. All sites studied were categorized with reference to their potential for the maintenance of self-sustaining Nucella populations. All sites in the southern part of the North Sea (i.e. the coastlines of Belgium, The Netherlands, Germany and southern Denmark) were placed in Category C (reduced egg capsule production) or D (adult females expected to be sterile). In Norway, sites near large harbours had only sterile females in the population (Category D), whilst those further from harbours probably had reduced egg capsule production (Category C). In Sweden, all wild sites were affected but probably had no reduction in egg capsule production (Category B). In France and the UK, sites near large harbours or areas of small-boat activity probably had reduced egg capsule production (Category C). Sites further from sources of TBT contamination probably do not have reduced egg capsule production ( Category B). One site on the north east coast of Scotland shows effects consistent with an area distant from a source of TBT pollution (Category A). Copyright © 1999 Crown Copyright

Development of a supercritical fluid extraction procedure for tributyltin determination in sediments

The effect of extraction variables, such as extraction time, temperature and extraction agent composition ( X), in supercritical fluid extraction (SFE) and tributylin (TBT) from a spiked sediment, has been optimized by using a factorial-fractional experimental design. Under the optimum conditions ( T = 60°C, P = 35 MPa, X = 5.1 M methanol in CO 2, t = 30 min) the TBT extraction efficiency was 82% with a coefficient of variation (C.V.) of 9.2% ( n = 5). Furthermore, the analytical procedure was validated using a reference material (RM) certified for its TBT content and was successfully applied to the analysis of a Certified Reference Material (CRM). Furthermore, an intercomparison of the SFE with another extraction procedure based on atmospheric pressure liquid extraction (APE) for the TBT determination in sediments has been carried out. Although TBT recoveries were significantly higher in the SFE procedure, the precision of both methods was comparable, probably associated to similar steps in the extract treatment procedure (derivatization and clean up).

Butyltin distribution in a sediment core from Arcachon harbour (France)

The concentrations of butyltin compounds in water, intertidal sediments and in a sediment core have been measured in the harbour of Arcachon (France) in order to assess the effectiveness of government legislative actions on the use of tributylin (TBT) in marine antifouling paints. The results revealed the occurrence of an increasing TBT gradient from the bottom to the top of the core with a maximum at 15 cm depth, and a slight decrease within the upper 15 cm. It is shown that the TBT levels are still very high in this area and that this compound is not rapidly degraded in sediment as was previously assumed. This leads to the conclusion that even if the regulations have been respected, contamination from resuspended sediments is still likely.

The accumulation of organotins in adult and seed oysters from selected estuaries prior to the introduction of U.K. regulations governing the use of tributyltin-based antifouling paints

Between April and November, 1985, a study of the levels of organotins in adult and seed Crassostrea gigas grown in the southwest and southeast of England was carried out. This work corresponds with a similar study of organotin water levels (reported separately). The analytical procedure used was directly coupled high performance liquid chromatography-flame atomic absorption spectrometry. Individual adult oysters and groups of 20–40 seed oysters were taken for analysis on a monthly basis. The profiles of tributylin (TBT), dibutyltin (DBT) and monobutyltin (MBT) are discussed in relation to each other and levels found in the waters. In general, levels of all three organotin species were found to be higher in the seed oysters. Mean levels of TBT reached 3.1 μg g −1 in seed oysters from the Exe, Devon, in October, whereas mean levels of DBT and MBT reached 16.1 and 16.7 μg g −1 in Teign, Devon, seed oysters in October. Bioconcentration factors of ∼ 10000 were found, but seem to be greater when lower levels of TBT were present in the water, perhaps indicating a more ‘efficient’ removal from the water. The degree of shell thickening was calculated for all oysters submitted for analysis. The highest percentage of adult oysters with severely thickened shells was found at Tollesbury Fleet, where 61% of oysters showed shell thickness index values of six or less. Generally, two peaks in TBT levels in the oysters were observed, in the late spring and early summer: these seem to correlate with peak levels of TBT in the waters immediately preceding these times. A large proportion of the DBT and MBT found in the oysters seems to come from the metabolism of the TBT ingested. It is suggested that high sediment loadings may contribute to the severe deformation of oysters grown at Tollesbury Fleet, but only in the presence of TBT.

Inhibition of tributyltin mediated hemolysis by mercapto compounds

Hydrophobic tributyltin (TBT) compounds at concentrations greater than 10 microM caused hemolysis of human erythrocytes and formed structures in plasma membranes. The mercapto compounds, beta-mercaptoethanol (beta MER), 2,3-dimercaptopropanol (BAL), 2,3-dimercapto-1-propane sulfonate (DMPS), DL-dithiothreitol (DTT), and meso-2,3-dimercaptosuccinic acid (DMSA) were examined for their ability to inhibit TBT mediated hemolysis. The relative order of effectiveness for inhibition of TBT mediated hemolysis was BAL greater than DTT greater than DMSA greater than DMPS greater than beta MER. A four-fold excess of BAL over TBT prevented hemolysis for 4 hrs and addition of BAL 0.5 hr after TBT reduced the rate of hemolysis. The number of membrane associated TBT aggregates observed per cell profile decreased as the BAL concentration increased from 0 to 100 microM. However, the mean diameter of TBT aggregates nearly doubled in erythrocyte suspensions at 100 microM BAL. Reactions of dimercapto compounds with lipophilic TBT aggregates may depend on their relative lipid solubilities. Also, conversion of the weak Lewis acid, TBT, from a four to a five or six-coordinate tin adduct by the dimercapto Lewis bases used could also be a factor slowing hemolysis rates.