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Comparatively limited knowledge is known about the accumulation processes of tributyltin (TBT) and triphenyltin (TPT) in fish and aquatic plant in the freshwater environment, which has hindered a full understanding of their bioaccumulation potential and ecological risks. In the present study, sorption of TBT and TPT on dead biota of both carp and C. demersum from water via the batch equilibrium technique as well as uptake of them on live biota of both carp and C. demersum from water at a static and a dynamic kinetics tests were investigated, respectively. Both TBT and TPT exhibit a high affinity in carps and C. demersum. And C. demersum has a faster metabolism either for TBT or TPT than carp. The apparent uptake values (C bio  = 1904-8831 μg/kg) or bioconcentration factor (BCF = 3333-44000 L/kg) were one or two orders of magnitude higher than that of estimated by a simple sorption (405-472 μg/kg) or lipid model (74.5-149.6 μg/kg) for carp, indicating the uptake of TBT and TPT did not only depend on lipids but also oxygen ligands or macromolecules such as amino acids and proteins of the living organism. In contrast, the apparent C bio values (149.1-926.4 μg/kg) of both TBT and TPT were lower than that of estimated by sorption model (1341-1902 μg/kg) for C. demersum, which were due to the rapid metabolic rate of them, especially for TBT. But no relation was observed between TBT and TPT concentrations and lipid contents in C. demersum., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Muscle and liver tissues of nine fish species were analyzed to assess butyltin and phenyltin contamination. The samples were collected from three basins located in the Southern Baltic Sea coastal zone that each represent different potential for organotin pollution. Maximum total concentrations of butyltin compounds (BTs) in the fish muscles and livers were 715 and 1132ng Sn g(-1) d.w., respectively, whereas triphenyltin (TPhT) was not detected. In the muscle samples, the predominant compound in the sum of butyltins was tributyltin (TBT), while in the liver samples, tributyltin degradation products were found in the majority. The results demonstrate that 6-7years after the implementation of the total ban on harmful organotin use in antifouling paints, butyltins remain present in fishes from the Polish coast of the Baltic Sea. According to the HELCOM recommendation, eight samples exceeded the good environmental status boundary for tributyltin in seafood., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In the present study, the antioxidant response and acetylcholinesterase (AChE) activity were measured in Chinese rare minnow larvae (Gobiocypris rarus) after exposure to tributyltin (TBT) (0, 100, 400 and 800 ngL(-1)) for 7 days, as well as the expression of a series of genes, including cr, aptase and prl genes involved in the ion-regulatory process and igfbp3 and gh related to growth rate. Results shows that oxidative stress was generated in fish exposed to TBT, as evidenced by elevated malondialdehyde levels and the inhibition of antioxidant parameters. The activity of acetylcholinesterase (AChE) was also inhibited in fish under higher TBT stress. Moreover, genes involved in ion regulation and growth were affected, based on the regulated transcription of the cr, atpase, gh, prl and igfbp3 genes in the treated groups. The observed effects of TBT upon antioxidant responses and altered expression of genes provides insight into the use of these molecular biomarkers in evaluating mechanisms of TBT toxicity in fish.

We investigated the temporal trend in contamination of butyltin compounds (BTs) along the Korean coast using imposex and tributyltin (TBT) burden in gastropods (Thais clavigera) as a biomonitor. Thais clavigera were collected from 26 locations with different shipping activities between 2004 and 2009 after restrictions on TBT-based antifouling paints were imposed in Korea. In the present study, imposex indices and TBT tissue concentrations significantly decreased over time from 2004 to 2009, confirming the effectiveness of TBT regulation. However, imposex in 2009 samples was still found. Significantly high imposex indices and TBT tissue residues were found in large ports containing commercial and ferry services compared with small ports and background areas. Imposex indices in background areas had decreased to zero, suggesting recovery from imposex caused by BT contamination. These results suggest that recovery from TBT contamination occurs faster in areas with very low maritime activities than areas with high maritime activities.

Occurrence and distribution of 6 organotin compounds including butyltin and phenyltin species were detected in Thais clavigera which were collected from 9 coastal areas sites around Xiamen Coast, by pentylized derivatization, GC-FPD. Results indicated that all Thais clavigera samples were contaminated with organotin compounds. The concentrations in Thais clavigera soft bodies varied from 0.3 to 70.6 ng x g(-1) with a mean value of 28.8 ng x g(-1) for butyltin compounds, and from nd to 18.8 ng x g(-1) with a mean value of 7.9 ng x g(-1) for phenyltin compounds, respectively. MBT and TPhT were high levels in butyltin compounds and phentyltin compounds, respectively. In addition, butyltin compounds were the dominant contaminates in all samples with high percentage from 74.3% to 96.8%. There was a significant correlation between TBT and TPhT (R2=0.7109, p<0.01). This result showed that both TBT and TPhT came from antifouling paints for ships or for mariculture nets. Compared with those data reported from the other regions around southeast coast of China, present study reveals that contaminated level of organotin compounds in Thais clavigera are relatively lower in Xiamen Coast. But it is higher than those in 2002.

Surface sediment samples were analyzed for organotins namely tributyltin (TBT), dibutyltin and monobutyltin from six areas located in the Gulf of Cádiz (14 stations), Spain. The total butyltin ranged between undetected and 1,580 ng Sn g(-1). TBT generally prevailed in most of the samples, suggesting fresh inputs of butyltin compounds and/or less degradation of TBT. The observed levels of butyltins at several sites are much higher than that required to induce toxic effect on marine organisms, suggesting that these sediments are polluted with butyltin compounds. The clam Ruditapes philippinarum was used for studying bioaccumulation of butyltins by exposing them to contaminated sediments from the Gulf of Cádiz over a period of 28 days under laboratory conditions. Biota-sediment accumulation factor (BSAF) ranged from 0.44 to 3.99.

The isolate, Pesudoalteromonas sp. TBT1, could grow to overcome the toxicity of tributyltin chloride (TBTCl) up to 30 microM in the absence of Cl(-) in the medium until the cells reached an exponential phase of growth. The viability, however, was reduced after the cells reached a stationary phase. The degradation products, such as dibutyltin (DBT) and monobutyltin (MBT), were not detected in the growth medium, indicating that the isolate has no ability to degrade TBT into less toxic DBT and MBT. Up to about 10(7.5) TBT molecules were adsorbed by a single cell. The observation of morphological changes with an electron microscope showed that the cell surface became wrinkled after exposure to the lethal concentration of 10 mM TBTCl. These results indicate that the resistance of the isolate toward the toxicity of TBTCl is not related to the unique cell surface, which seems to play an important role in preventing the diffusion of TBTCl into the cytoplasm.

We examined the effects of tributyltin (TBT) on aerobic and anaerobic energy metabolism of pen shell (Atrina pectinata japonica). We exposed pen shells to TBT at nominal concentrations of 0 (control) and 1.0microg/l for 72h under aerobic condition. At the end of the exposure, half of the pen shells in each treatment were wrapped in plastic wrap to simulate exposure to hypoxia and held at 25 degrees C for another 12h. The concentrations of the products of energy metabolism, namely lactate, pyruvate, fumarate and succinate, in adductor muscle were measured. The exposure to TBT under aerobic condition significantly elevated lactate, pyruvate and fumarate concentrations (p<0.001). After subsequent exposure to anaerobic condition, the mean concentration of succinate in the TBT treatment group was 64% of that in the control group, but there were no significant differences. Our results suggest that the energy metabolism of pen shell is disrupted by exposure to TBT.

Concentrations and composition of butyltin (BT) and phenyltin (PT) compounds were compared in tissues of mussels Mytilus edulis and clams Mya arenaria collected from the Mersey Estuary. Tributyltin (TBT) concentrations were consistently highest in digestive gland and low in muscular tissues such as siphons (Mya) and adductor muscle (Mytilus). Lowest concentrations were found in the periostracum surrounding the siphons of Mya. Ratios of monobutyltin (MBT), dibutyltin (DBT) and TBT to total BT content of Mytilus tissues were in the ranges 25-34%, 21-28% and 44-51%, respectively. Much higher proportions of TBT:total BT were characteristic of Mya (>80% in the digestive gland, remaining tissue and gonad) implying that slow degradation rates account for the relatively high levels of TBT in this species. TPT was the only phenyltin compound detected (albeit at relatively low levels), and, like TBT, was present in highest concentrations in the digestive gland of clams--suggesting an important dietary component in the accumulation of OTs in these bivalves.

Biofilm, fish, oyster, mussel, clam, surface seawater, suspended particulate matter (SPM), and sediment samples were collected from marine and/or estuarine waters of the west coast of India. These samples were analysed for butyltin derivatives such as dibutyltin (DBT) and tributyltin (TBT). The concentrations DBT plus TBT varied between 2.4 and 8.3, 163 and 363 ng/l, 5 and 2853 ng/g dry wt in the SPM, seawater and sediment samples, respectively, of the Marmugao harbour. The values of DBT plus TBT ranged between 0.60 and 29, 123 and 242 ng/l and 1.4 and 65 ng/g dry wt in SPM, water and sediment samples, respectively, collected from the Mandovi estuary. In the Dona Paula Bay the DBT plus TBT varied from 10 to 89 ng/l in surface seawater, and TBT from 10 to 513 ng/g in biofilm samples. For the coastal sediment samples the concentration of DBT plus TBT ranged between 36 and 133 ng/g dry wt of sediment. For the animal samples the DBT plus TBT ranged between 58 and 825 ng/g dry wt of the tissue. Mussel tissues contained the highest amount of DBT plus TBT (825 ng/g dry wt tissue), whereas highest TBT concentration was recorded in the oyster (732 ng/g dry wt). TBT was generally the most abundant butyltin compound in most of the samples suggesting fresh inputs and/or less degradation of TBT. A wide range of the observed butyltin concentrations suggests the presence of localized areas of contamination. Leaching of tributyltin-containing antifouling paints from the ocean going ships, fishing and recreational boats, barges, and the inputs of TBT from the Goa shipyard and dry dock facility situated in the harbour are the probable sources of the DBT and TBT in the samples of the west coast of India. Higher levels of TBT were observed in biofilm relative to that in the surrounding seawater. When fed on TBT contaminated biofilm of the diatom Navicula subinflata, butyltin concentrations in the clam Paphia malabarica increased over the period of feeding suggesting the importance of biofilm in the transfer of butyltins to higher group of organisms.

The effects of tributyltin (TBT) on the seagrass Ruppia maritima were studied in two growth experiments. Plants were sampled at stations in Odense Fjord and Lunkebugten, Denmark, and replanted in reference sediment without TBT, reference sediment spiked with TBT, and in impacted sediment sampled in the highly TBT contaminated (7-57 microg kg (-1) dw) Odense Fjord. Plant performance was studied at weekly intervals for 3-4 weeks, by measuring net photosynthetic activity, respiration, relative growth rate (RGR) and number of leaves. Net photosynthetic activity in plants from spiked and impacted sediment was reduced by up to 60% relative to reference plants. Respiration both increased and decreased in response to TBT exposure, while RGR was generally lower in plants from contaminated sediments (reduced by 8-25%). The effects of spiked and impacted sediment differed between the experiments, which could be partly explained by the bioavailability of TBT in the two treatments, but also by adaptation of the plants from Odense Fjord to TBT. Measurements of enhanced TBT concentrations in the sediments in Odense Fjord suggest an impact of TBT on R. maritima is possible under in situ conditions.

Imposex in the gastropod Hinia reticulata, a bioindicator for tributyltin (TBT) contamination, was investigated in locations at different distances from the Oporto harbour-dredged material discharge site. The degree of imposex found was inversely related to the distance to the discharge site, the highest imposex frequency being found closest to the discharge area. However, the levels of imposex found were low when compared with those reported for H. reticulata populations from moderately TBT-contaminated areas. Despite detectable levels of dibutyltin (DBT) and monobutyltin (MBT) in snail tissues (total butyltins ranging from 84 to 410 ng/g Sn dry wt.), TBT was below detection limit in all snail samples collected in open sea.

Background: Organotins have been used world-wide as antifoulants in ship paints. Repeatedly, severe effects on aquatic species have resulted. The use of organotins for this purpose was ruled out, and dumping of contaminated harbor sludge into the sea was prohibited. Land-based dumping is seen as an alternative., Objective: This study investigates sorption, uptake and translocation of tributyltin (TBT) to willow trees in order to evaluate phytoremediation as treatment option. The study considers the influence of pH on the plant uptake of organotins. EXPERIMENTAL SET-UP: Chemicals investigated were the weak base tributyltin chloride (TBTCl) and the neutral tributyltin hydride (TBTH). Organotins were extracted from solution and plant material with toluene, and analyzed as tin by AAS with graphite oven. The pH in solution varied from pH 4 to pH 7. The sorption to living and dead roots, stems and leaves was measured in shaking experiments. The uptake into intact trees was measured at nominal levels of 1 and 10 mg TBT/l for TBTH and TBTCl at low and high pH., Results: The sorption to roots and leaves dropped for dead tissue, but did not vary much with pH. The sorption to stems increased for dead stems and with pH. The solubility of TBTCl in water was below 10 mg/l and lowest at pH 4. Concentrations of TBTCl and TBTH in solutions with trees dropped rapidly to low values. Highest TBT contents in trees were found in roots and lower stems. The concentrations followed the concentrations in solution. The pH had only a small effect on the plant uptake of TBTCl, and no effect on the uptake of TBTH. No effective translocation to higher stems or leaves was found., Discussion: An ion trap mechanism that accumulates the weak base TBTCl in the xylem sap of plants and leads to upward translocation could not be detected. Neither TBTCl at low or high pH, nor the neutral lipophilic chemical TBTH, were translocated effectively to leaves. The TBT+ cation sorbed strongly to plant tissue. The exact mechanism for the strong sorption of the cation is unknown, but similar effects have been observed for algae, liposomes and isolated biomembranes., Conclusions: Both the uptake of the neutral TBTH and the uptake of the neutral molecule form of TBTCl into willows was as is to be expected from theory. The cation TBT+ showed an unexpected behavior which has been observed before. No ion trap occurs, and the phytoextraction of TBT is not feasible., Outlook: Planting trees, or other appropriate vegetation, could have a beneficial remediation effect by aeration of the TBT-contaminated soil or sludge. In a follow-up paper, the toxicity of TBT to willow trees will be described.

Nassarius kraussianus populations in the Durban and Richards Bay harbours (along the eastern seaboard of southern Africa) and in the Knysna lagoon (southern Cape coast) showed imposex development, confirming bioavailability of tributyltin (TBT) in these waterways. Incidence of imposex (which ranged from 29% to 100%) and relative penis length of females (RPL; which ranged from 1.3% to 55.2%) were markedly variable among populations from different sites in each waterway, indicative of localised effects of TBT contamination. Shell length of the snails was apparently not correlated with contamination level, as assessed from imposex measurements. While population imposex features are easy to determine and often provide a sensitive biomarker of TBT exposure, the discussion outlines reservations when extrapolating these to general ecological situations. Additionally, this study represents the first published report on the topic for sub-Saharan, African harbours, some of which seem remarkably less affected than suggested for other world regions.

In previous studies, it was shown that waterborne Hg(II), Cd(II), and Mn(II) enter nerves innervating water-exposed sensory organs of fish and are transported to the brain by axonal transport. However, it is not known if organometals, such as tributyltin (TBT), can reach the brain of fish via the same route. In this work, we exposed rainbow trout (Oncorhynchus mykiss) to waterborne [113Sn]-TBT (4.2 kBq/L). Three fish were sampled after a 2-week exposure, and three others were sampled after a 2-week depuration period. Another group of four fish received an intravenous injection of [113Sn]-TBT and were sampled after 2 and 14 d. Distribution of the radiolabel was visualized and quantified by quantitative whole-body autoradiography. The brain accumulated a significant amount of 113Sn, with hot spots being found in parts receiving sensory nerves from water-exposed sensory organs, such as eminentia granulares (lateral lines organs). Labeling of the brain was also seen for i.v.-injected fish, indicating that the blood-brain barrier is not impervious to TBT or its metabolites. Nevertheless, the distribution of radioactivity in the brain was much more uniform, with no evident hot spot. Though the transfer [water --> gills --> blood stream --> blood-brain barrier --> brain] may account for a certain proportion of the radiolabel accumulation in fish brain, exposure to [113Sn]-TBT via water resulted in higher accumulation in some areas of the brain, of which the specific location strongly suggests that it was taken up in different water-exposed sensory nerve terminals and transported directly to the brain by axonal transport, as the parent compound or as a metabolite. The resulting local enhancement of the accumulation of butyltins might jeopardize the integrity of nervous system. Further work is needed to assess the toxicological significance of this process.

In archived samples from the German Environmental Specimen Bank, organotin compounds including tributyltin (TBT) and triphenyltin (TPT) as well as their degradation products were quantified. Biota samples from North Sea and Baltic Sea areas were analyzed by gas chromatography/atomic emission detection-coupling after extraction and Grignard or ethylborate derivatization. TBT and TPT were detected in nearly all samples. A decrease of TPT contamination was observed in bladder wrack, common mussels, and eelpout muscle tissues in the period 1985-1999. In this period, TPT concentrations in North Sea mussels decreased from 98 to 7 ng/g (as organotin cation concentration in wet tissue). Concentrations of TBT remained relatively constant with 17 +/- 3 ng/g for mussels from a site with nearby marine traffic and 8 +/- 2 ng/g for a more remote area. The results reflect that TBT is still used as a biocide in antifouling paints whereas the use of TPT as a co-toxicant in such preparations had been ceased in the 1980s. The fact that the use of TBT in antifouling paints was banned in 1991 for small boats within the European Community seems not to have resulted in a decrease of TBT levels in marine biota.

Accumulation of tributyltin (TBT) was determined in liver of olive flounder exposed to TBT (3.65, 36.5, 365, 3,650, and 7,300 ng Sn/L) for 10 or 30 days, followed by 60 days depuration. Effect of TBT on hepatic cytochrome P450 content was also measured in liver of olive flounder. TBT was highly accumulated in liver of fish during the 10- to 30-day exposures, and hepatic cytochrome P450 content decreased with increasing TBT concentration. Hepatic cytochrome P450 contents were affected in olive flounder exposed to even environmentally relevant TBT concentrations, such as 3.65 ng Sn/L. In addition, the liver TBT levels demonstrated strong negative correlation to the hepatic cytochrome P450 content. The effects started to appear from 20 ng Sn/g dry weight of TBT in liver. Tributyltin concentrations and hepatic cytochrome P450 were also determined in feral fine-spotted flounder. The relationship between other organic pollutants known as cytochrome P450 inducers (e.g., polychlorinated biphenyls) as well as TBT and hepatic cytochrome P450 in the feral fish implied that TBT even at ppt level could impose antagonistic effects on hepatic cytochrome P450 induction.

The effect of the concentration of tributyltin (TBT) in feed on the dietary bioaccumulation of tributyltin chloride (TBTCl) was studied in an 8-week uptake experiment and a 4-week elimination experiment using red sea bream (Pagrus major). The biomagnification factor (BMF) and the assimilation efficiency (AE) decreased from 0.30 to 0.15 and from 13% to 5.9%, respectively, as the TBT concentration in feed increased from 1.3 to 20 microg/g. The elimination rate constant (k(2)) was independent of the TBT concentration in the fish. Laboratory measurements of the BMF and AE of TBTCl underestimate actual field values if highly contaminated feed is used. Judging from the BMF and AE, the risk of the bioaccumulation of TBTCl through the food chain might be smaller than that of polychlorinated biphenyls., (Copyright 2002 Elsevier Science Ltd.)

Aquatic pollution resulting from extensive usage of organotin compounds has been of great concern due to their deleterious effects in nontarget organisms. However, organotin contamination in deep-sea ecosystems has been rarely studied. The presentwork attempted to determine butyltin and phenyltin compounds in deep-sea fish collected between 1000 and 1800 m depth in the NW Mediterranean. The concentration of tributyltin (TBT) and its degradation products, mono- (MBT) and dibutyltin (DBT), aswell astriphenyltin (TPT),and mono- anddiphenyltin (MPT, DPT) was determined in different tissues (liver, gills, digestive tube, and muscle) of several fish species. Total butyltin residues were up to 175 ng/g wet wt, and they were comparable to levels found in coastal fish collected along the Catalan coast. In contrast, deep-sea fish contained much higher levels of phenyltins (up to 1700 ng/g wet wt), and particularly TPT (up to 1430 ng/g wet wt), than previously reported concentrations in shallow-water organisms. The obtained results confirm the long-range transport of organotin compounds to the deep-sea environment, and the subsequent exposure of fish inhabiting nonpoint source areas. The use of TPT in agriculture or as an antifouling agent, its transport to the deep-sea environment associated to particulate matter, and its nonbiodegradable nature in the food chain may account for the high residue levels detected in deep-sea organisms.

This study assesses the relative importance of water and sediments as vectors of TBT uptake in the sediment-dwelling suspension feeder, Ruditapes decussatus. Accumulation of TBT was determined in R. decussatus exposed for 60 days to moderately high but environmentally realistic levels of TBT in water (100 ng Snl(-1)) and sediments (0.8 microg Sn g(-1) dw), separately or in combination, using constant-flow systems. The results indicate that this species accumulates TBT predominantly from water. Although some accumulation from sediments does occur, the processing of large amounts of water needed to sustain the filter-feeding habits of this species is a prime determinant of TBT uptake. The route of exposures reflected in tissue distributions of TBT in R. decussatus. However, gills are the most important site for accumulation of TBT from water, irrespective of whether contaminated sediments are present or not.

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.

Nucella lapillus imposex (superimposition of male characters onto prosobranch females) and organotin body burden were surveyed in the Portuguese coast in 1997 and 2000. Time comparisons of the available data on Nucella lapillus imposex in the Portuguese coast indicate a global increase of TBT pollution in recent years, revealing the inefficacy of the 1993 legislation that bans the use of TBT paints on small boats (<25 m). The absence or scarcity of the species inside harbours, which are the most polluted sites in Portugal, is probably a consequence of extinction due to female sterilisation by TBT.

A newly developed toxicity test organism, the Chinese rare minnow ( Gobiocypris rarus), which has similar merits to some common experimental fishes and could become a standardized test species for China, was used in a short-term study with emphasis on accumulation in fish muscles and cytological effects of sublethal concentrations of tri-n-butyltin chloride (TBT). The 1-year-old fish were exposed for 1 or 2 weeks to a concentration range of 50 to 5,000 ng TBT/L in static systems. Hepatosomatic Index (HSI) and Gonad Somatic Index (GSI) sensitively showed the adverse effects of TBT to the fish. Compared with the nominal TBT concentrations in water phase, 459-(5,000 ng TBT/L, 1 week) to 4,065- (50 ng TBT/L, 2 weeks)-fold higher concentrations of butyltin species were detected in the corresponding exposure fish muscle. Contaminations of TBT in muscle tissue increased with both the exposure levels and exposure time. The cellular pathological effects in the liver were studied. These included vacuoles with increasing number and size, swelling of mitochondria, abnormal nuclei, and decreases of rough endoplasmic reticulum cisternaes. The results confirmed that the Chinese rare minnow ( G. rarus) could be utilized as a useful species to evaluate water toxicity in the laboratory.

Fifty four sediment samples and three pooled samples of whole three-spined stickleback (Gasterosteus aculleatus) collected from four marinas located along the south-western coast of the Gulf of Gdańsk, Baltic Sea, Poland, were examined for butyltins (BTs) i.e., tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT), to understand the degree of pollution and distribution pattern. Total butyltin concentrations in sediments from the marina of the city of Gdynia ranged between 130 and 20,000 ng Sn/g dry wt. with a mean value of 2,900 ng Sn/g. In sediments collected from the marinas located in the area of the Brave Vistula River Channel BT concentrations ranged between 10 to 15,000 ng Sn/g drywt. with a mean values between 500 and 5,500 ng Sn/g, and the innermost sites of each of four marinas were the most polluted. The mean BT concentrations in three-spined stickleback were between 1,500 and 3,100 ng Sn/g wetwt. and the values followed mean concentrations noted in sediments from the corresponding marina. The pleasure yachts are identified as the main source of BT pollution of sediment and fish. Tributyltin was a major form of BTs present in sediments (between 24 and 43%) and in three-spined stickleback (between 54 and 70%), suggesting a very recent use of marine paints containing TBT in pleasure yachts. Evidently at the Polish coast of the Baltic Sea TBT was continuously used in 1997 in marine paints for boats less then 25 m long.

The muricid Thais distinguenda (ca. 1,300 individuals) was collected from a pristine island in the Andaman Sea and tagged prior to translocation to an area of intense shipping activities. A minimum of 50 tagged individuals were recaptured 1, 2, 3, 5, 6, 7, 8 and 12 months after transplantation. The animals were separated into small (< or = 25 mm) and big (>25 mm) specimens based on total shell length and both incidence of imposex and body burden of butyltin (BT) were determined. After 3 months 16.7% of the small size and none of the big size class had developed imposex. After 5 months the incidence of imposex in the big and small size classes increased steadily with time reaching 86.4 and 80%, respectively after 1 year. Time after transplantation was significantly correlated with the incidence of imposex for the big size class (Spearman Rs=1; P=0.008); RPLI (Spearman Rs=1; P=0.008) and VDSI (Spearman Rs=1; P=0.008); and the small size class: incidence of imposex (Spearman Rs=1; P=0.006); RPLI (Spearman Rs=1; P=0.006) and VDSI (Spearman Rs=1: P=0.007). The development of imposex was not significantly related to body size after five months (chi square P<0.001). The body burden of tributyltin was not significantly different between the two size classes (paired t-test ) but the smaller animals had significantly higher concentrations of both dibutyltin (DBT; P<0.005) and monobutyltin (MBT; P<0.001). The use of transplantation experiments in addition to imposex surveys and analysis of body burden of tributyltin (TBT) can enhance the interpretation of the results and understanding of the time scale involved with the development of imposex.

The removal of tributyltin (TBT) from artificial wastewater by dead and live cells of four microalgal species, Chlorella miniata, C. sorokiniana, Scenedesmus dimorphus and S. platydiscus was investigated. Dead cells were generally more efficient in removing TBT during three days exposure. More than 90% and 85% TBT were removed by dead cells of Scenedesmus and Chlorella, respectively. Although the removal percentages of live microalgae were smaller, TBT was continuously absorbed and degraded, and TBT removal percentages similar to respective dead cells were achieved at the end of 14 days treatment. Degradation products, DBT and MBT, were recorded mainly inside the cells, and intracellular MBT concentrations were significantly higher than DBT. In terms of TBT removal, Scenedesmus cells were more effective than Chlorella, probably due to larger cell sizes and biomass. However, TBT specific uptake and degradation by Chlorella was higher than in Scenedesmus. The highest specific TBT uptake values, as well as the highest degradation, were recorded in C. miniata, a Hong Kong isolate.

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.

Transplanted common whelk (Buccinum undatum) (Mollusca, Gastropoda) accumulated fairly high levels of organotins (tributyltin (TBT) and triphenyltin (TPT)) during exposure in three harbours with different TBT contamination. This did not though lead to an increase in imposex frequency in the adult females studied. Simulating harbour dredging in an experiment using suspended sediment from one of the harbours only resulted in a low concentration of TBT in the tissues of the common whelk and subsequently no changes in the occurrence and degree of imposex. The common whelk seemed to receive the main part of TBT from the water column and the limited bioaccumulation in the experiment indicates that desorption of TBT from the suspended sediment was slow. After TBT has been totally banned, dredging of contaminated sediments will cause increased exposure of the biota to TBT. Due to slow desorption the increase may however, be slight and temporary to pelagic and epibenthic species unless the settled particles are resuspended.

While inorganic forms of tin are of relatively low toxicity towards microorganisms, the more lipid-soluble organotins can be highly toxic. Generally, trisubstituted (R3SnX) organotins are more toxic than di- (R2SnX2) and monosubstituted (RSnX3) compounds; the anion (X) apparently having little influence on toxicity. However, many microorganisms exhibit resistance to organotins, a phenomenon of relevance to the environmental cycling of organotins and also to novel biological methods of treatment. Organotin degradation can involve the sequential removal of organic moieties to yield less toxic derivatives, e.g. debutylation of tributyltin compounds to di- and monobutylins. Such degradation is known to take place in bacteria, algae and fungi, and this provides one route for detoxification. In addition, microorganisms are capable of accumulating tributyltin compounds, and this is another mechanism of removal from solution. The high lipid solubility of organotins ensures cell penetration and association with intracellular sites, while cell wall components also play an important role. Of the fungal wall components, melanin pigments are capable of TBT binding, and the addition of melanin to growing cultures can remove toxicity; melanised strains are also more sensitive than albino strains of the same species. To date, little attention has been paid to the biotechnological exploitation of these interactions for the degradation of tributyltin or its removal from solution. This paper describes some interactions of microorganisms (bacteria, cyanobacteria, microalgae, and fungi) with tributyltin compounds, with particular reference to toxicity, bioaccumulation and detoxification. Such processes should receive due consideration in any environmental management programme.

Specimens of the gastropod Nucella lapillus were transplanted from their natural habitat to sites affected by tributyltin (TBT) pollution to diverse degrees; individuals were held in cages that also included mussels as food. Subsamples were taken from the cages and the natural site at different time intervals (1, 2 and 5 months) to compare growth, imposex (a set of sexual anomalies caused by TBT) and butyltin concentrations accumulated in female tissues. Individuals in cages experienced negligible mortality and considerable growth. In addition, while the Relative Penis Size Index (RPSI, an index of imposex) remained consistent in the natural site through the experiment, it increased markedly at the implant sites; the same applies to the butyltin residues. These results are discussed to conclude that cage transplanting of N. lapillus is a suitable technique that can quickly (i.e. 1 month) detect differences in the level of TBT contamination among sites; however, extrapolation of experimental results to the field seems to require a longer exposure time (at least 5 months). Finally, the use of such an approach is deemed helpful to interpret the relationship between N. lapillus population dynamics and TBT pollution.

Field studies on imposex and organotin (butyltin and phenyltin) contamination in the Japanese molluscs (the rock shell, Thais clavigera, and the Pacific oyster, Crassostrea gigas) were conducted along the coast of both the Seto Inland Sea and the Sanriku region, Japan, during February-March 1996. The percentage occurrence of imposex in the rock shell, Thais clavigera, was still 100% at all sites surveyed (22 and seven sites in the Seto Inland Sea and the Sanriku regions, respectively). Observed values of the Relative Penis Length (RPL) index (%), defined as the ratio of mean penis length in females to that in males, exceeded 50 at many sites. Sterile individuals whose oviducts were blocked by vas deferens formation were also extensively observed. Tissue concentrations of organotin compounds in the rock shell and the Pacific oyster were higher than those from other areas of Japan. The degree of imposex (RPL index) was correlated with the sum of TBT and TPT concentrations in tissue of the rock shell. Less recovery from imposex in the rock shell and less amelioration of TBT pollution were observed, suggesting that organotin use in antifouling paints has still continued for vessels larger than 25 m in length and that it has influenced imposex symptoms in the rock shell.

Concentrations of butyltin compounds (BTs) were determined in various body tissues of common cormorants (Phalacrocorax carbo) collected from the Lake Biwa, Japan. Elevated concentrations of butyltins were detected in the feathers of cormorants. Among other organs and tissues, butyltin levels were also higher in the kidney (290+/-150 ng/g) and liver (270+/-260 ng/g), ranging from 115 to 544 ng/g and 142 to 1007 ng/g (wet wt basis), respectively. The accumulation of BTs in cormorant bodies was in the order of MBT>DBT>TBT and their organ specific burdens were in the order of muscle>/=feathers>skin>liver>rest of the tissues and organs. The higher levels of BTs residues in feather suggested the excretion of about one fourth of their body burden during a complete molting cycle, which has been a natural detoxification mechanism in these birds. Based on the whole body concentrations of BTs in cormorants (42-160 ng/g wet wt) and fish (10-55 ng/g wet wt) biomagnification factors were assessed to be in the range of 1.1-4.1. To our knowledge, this is the first fundamental study to substantially indicate the contamination and kinetics of BTs in wild birds.

Tributyltin (TBT) and its breakdown products, mono-(MBT) and dibutyltin (DBT) were determined in bottlenose dolphin (Tursiops truncatus), bluefin tuna (Thunnus thynnus thynnus) and blue shark (Prionace glauca) collected from the Italian coast of the Mediterranean Sea in 1992-1993. Concentrations of total butyltin (BTs) in the liver of dolphin (1,200-2,200 ng/g wet wt) were an order of magnitude higher than in the blubber (48-320 ng/g wet wt). TBT was the predominant butyltin species in the blubber while DBT accounted for an higher proportion in the liver of dolphins. Butyltin concentrations in bluefin tuna were lower than those in dolphins, with TBT highest in the muscle and DBT in the liver. Concentrations of BTs in blue sharks were lower than those in dolphin and tuna, with kidney having the highest concentrations. TBT was the predominant form of butyltin derivatives in all the tissues of shark. Accumulation of butyltin compounds in liver/kidney seems to be associated with the presence of proteins such as glutathione.