Bioaccumulation Of Tributyltin Research Articles

Marine Pollutant Tributyltin Affects DNA Methylation and Fitness of Banded Murex (Hexaplex trunculus) Populations

Banded murex, Hexaplex trunculus, is a marine gastropod whose reproductive fitness can be severely affected by very low concentrations of antifouling compound tributyltin (TBT). TBT has strong xenoandrogen impacts on snails, causing the development of imposex (e.g., the superimposition of male sexual characteristic in females), thereby affecting the fitness of entire populations. TBT is also known as a DNA-demethylating agent and an obesogenic factor. The aim of this study was to unravel the interactions between TBT bioaccumulation, phenotypic responses, and epigenetic and genetic endpoints in native populations of H. trunculus. Seven populations inhabiting environments along the pollution gradient were sampled in the coastal eastern Adriatic. These included sites of intense marine traffic and boat maintenance activity and sites with low anthropogenic impact. Populations inhabiting intermediately and highly polluted sites exhibited higher TBT burdens, higher incidences of imposex, and higher wet masses of snails than populations in lowly polluted sites. Other morphometric traits and cellular biomarker responses did not show clear differentiation among populations in relation to marine traffic/pollution intensity. An analysis of methylation sensitive amplification polymorphism (MSAP) revealed environmentally driven population differentiation and higher epigenetics than genetic within-population diversity. Moreover, decreases in genome-wide DNA methylation coincided with the imposex level and snail mass, suggesting an epigenetic background of the animal phenotypic response.

Effects of tributyltin on gonad and brood pouch development of male pregnant lined seahorse (Hippocampus erectus) at environmentally relevant concentrations

The male pregnancy of seahorses is unique, but their reproductive response to environmental disturbances has not yet been clarified. Tributyltin (TBT) is known to have an endocrine disrupting effect on the reproductive system of coastal marine organisms. This study evaluated the potential effects of exposure to environmentally relevant concentrations of TBT on the development of gonads and brood pouch of the lined seahorse (Hippocampus erectus). Physiological, histological, and transcriptional analyses were conducted, and results showed that high levels of TBT bioaccumulation occurred in male and female seahorses. TBT led to ovarian follicular atresia and apoptosis with the elevation of androgen levels, accompanied by the induction of genes associated with lysosomes and autophagosomes. Comparative transcriptional analyses revealed the likely inhibition of spermatogenesis via the suppression of cyclic AMP and androgen synthesis. Notably, the transcriptional profiles showed that TBT potentially affects the immune system, angiogenesis, and embryo nourishment of the brood pouch, which indicates that it has negative effects on the male reproductive system of seahorses. In summary, this study reveals that environmental levels of TBT potentially affect the reproductive efficiency of seahorses, and may ultimately lead to a reduction in their populations in coastal environments.

Bioaccumulation of TBT and Its Cellular Toxic Effects on the Freshwater Prawn Macrobrachium rosenbergii.

To test the toxic effects of tributyltin (TBT), Macrobrachium rosenbergii were exposed to three concentrations of TBT viz. 10ng/L, 100ng/L and 1000ng/L for 90days. The bioaccumulation of TBT level varied in hepatopancreas based upon dose dependent manner. Histopathological results revealed the reduction in basement membrane thickness, disruption of the hepatopancreatic tubules and abnormal lumen in hepatopancreas of TBT treated prawns. The ultrastructure of the control prawn showed normal architecture of cellular organelles with prominent nuclei in hepatocytes. On the other hand, many vacuoles, irregular arrangements of microvilli, swollen mitochondria, distorted rough endoplasmic reticulum cisternaes and abnormal nucleus were seen in the TBT treated group. Further, the biochemical and vitellogenin content were altered remarkably due to TBT exposure. It directly indicated that TBT had conspicuously inhibited the vitellogenesis. Therefore, it was inferred that the administration of TBT has considerably affected the hepatopancreatic functions in M. rosenbergii.

STUDI HISTOPATOLOGI GONAD GASTROPODA LAUT (THAIS TUBEROSA DAN MONODONTA LABIO) YANG MENGALAMI IMPOSEKS AKIBAT TERPAPAR TRIBUTYLTIN (TBT)

Tributyltin (TBT) is an organotin compound used as antifouling material for ship or boat paints to preventattachment of marine biota on the wall of ships or boats. The most dangerous effect of TBT bioaccumulation onmarine organisms, particularly gastropods, is the failure on the reproduction system, such as the occurrence ofimposex symptoms. The main purposes of this study are to know the histopathology of gonads by species Thaistuberosa and Monodonta labio that has been exposed to imposeks the compound tributyltin (TBT). The samplingof Thais tuberosa and Monodonta labio was conducted at 2 sites: Manado Port and Tateli Coastal Waters. Thehistopathology test was conducted in the Central Diagnostic Laboratory of Anatomic Pathology, Manado, withHaematoxylin-Eosin (HE) technique. The result showed that histopatology gonads marine gastropods type Thaistuberosa and Monodonta labio there has been a change in the tissues showing the imposex character, ifcompared with tissues of normal individuals of male and female, but in these changes tissues not cause damagecaused by a compound tributyltin (TBT).Keywords : Histopatology of gonad, Gastropods, Imposex, Tributyltin

Tributyltin bioaccumulation and toxic effects in freshwater gastropods Pomacea canaliculata after a chronic exposure: field and laboratory studies.

Freshwater samples and gastropod mollusks (Pomacea canaliculata) were collected at 5 sampling stations located along the lower Río de la Plata basin, Argentina, to assess the extent of tributyltin (TBT) contamination. Determined data revealed the presence of TBT and some of its breakdown products (dibutyltin: DBT, and monobutyltin: MBT) in all freshwater samples and also in soft tissues of P. canaliculata gastropods. Chronic bioassays (6 months) were performed using female gastropods that had been reared under laboratory conditions and exposed to a similar TBT concentration than the value determined in freshwater samples (1 µg L-1). The aims of this study were to evaluate the extent of TBT accumulation, the tissue distribution, and the effects on selected biomarkers (activity of superoxide dismutasa: SOD, activity of catalase: CAT, levels of total glutathione: t-GSH, lipid peroxidation, and activity of acetylcholinesterase: AChE). Gonads presented the highest accumulation, followed by the cephalopedal region, albumin gland, and finally hepatopancreas. Both metabolites, DBT and MBT, were also found. All exposed female animals presented development of a penis reflecting the potential of TBT as an endocrine disrupting chemical for this gastropod species. Results on the selected biomarkers confirmed additional adverse effects induced by TBT. An increase in CAT activity and changes in t-GSH levels are indicative of alterations on the cellular redox status. The inhibition of AChE could reflect signs of neurotoxicity. Altogether, these results reveal a negative impact on the health of this gastropod population.

Disruptions in aromatase expression in the brain, reproductive behavior, and secondary sexual characteristics in male guppies (Poecilia reticulata) induced by tributyltin

Although bioaccumulation of tributyltin (TBT) in fish has been confirmed, information on possible effects of TBT on reproductive system of fish is still relatively scarce, particularly at environmentally relevant levels. To evaluate the adverse effects and intrinsic toxicological properties of TBT in male fish, we studied aromatase gene expression in the brain, sex steroid contents, primary and secondary sexual characteristics, and reproductive behavior in male guppies (Poecilia reticulata) exposed to tributyltin chloride at the nominal concentrations of 5, 50, and 500ng/L for 28 days in a semi-static exposure system. Radioimmunoassay demonstrated that treatment with 50ng/L TBT caused an increase in systemic levels of testosterone of male guppies. Gonopodial index, which showed a positive correlation with testosterone levels, was elevated in the 5ng/L and 50ng/L TBT treated groups. Real-time PCR revealed that TBT exposure had inhibiting effects on expression of two isoforms of guppy aromatase in the brain, and these changes at the molecular levels were associated with a disturbance of reproductive behavior of the individuals, as measured by decreases in frequencies of posturing, sigmoid display, and chase activities when males were paired with females. This study provides the first evidence that TBT can cause abnormalities of secondary sexual characteristics in teleosts and that suppression of reproductive behavior in teleosts by TBT is due to its endocrine–disrupting action as an aromatase inhibitor targeting the nervous system.

Bioaccumulation of Tributyltin by Blue Crabs

This study evaluated the bioaccumulation of tributyltin (TBT) by the blue crab (Callinectes sapidus). Animals were fed with contaminated food containing 30 µg g-1 of TBT expressed as Sn. The analytes were determined in the gills, hepatopancreas and muscle. Acid digestion was used in the total Sn determination, and a solid-phase extraction technique was used for the selective determination of TBT. Limits of detection of 44.6 and 4.46 ng g-1 were found for HG-ICP OES (hydride generation-inductively coupled plasma optical emission spectroscopy) and ICP-MS (ICP-mass spectrometry), respectively. The results for non-contaminated animals were below 50 ng g-1, while the animals subjected to the contaminated food showed higher tissue concentrations of Sn (until 6229 ng g-1) and TBT (until 3357 ng g-1) related to the number of exposure days. According to the results, Sn is bioaccumulated by the blue crab in higher concentrations in the hepatopancreas. For most of these animals, the results suggest that Sn is bioaccumulated as TBT.

Bioaccumulation of tributyltin and its impact on spermatogenesis in mud crab Scylla serrata (Forskal)

The effects of tributyltin (TBT) on the spermatogenesis of mud crab Scylla serrata were studied. TBT-exposed crabs exhibited a decrease in the gonadosomatic Index and the hepatosomatic Index compared to the crabs in the control group. Bioaccumulation of the TBT levels also varied in different tissues. The treated crabs showed variation in the weight of the testes with respect to TBT concentrations. Histological results clearly indicated that the control crabs showed spermatophores and granular substances were seen filling up the lumen of the seminiferous tubules. The testes of the experimental crabs illustrated that disruption in the seminiferous tubule membrane architecture, arrangement of spermatophores, granular substance, vacuolation, and reduction in the number of epithelial cells of the membrane were apparent in the seminiferous tubules. Biochemical constituents such as protein and glycogen contents also decreased in experimental crabs. Thus, TBT had significantly retarded the reproductive activity and substantially reduced the biochemical constituents ultimately led to impairment of spermatogenesis in the mud crab S. serrata.

Organotin accumulation in oysters and rock shells under field conditions

This study characterises the accumulation of organotin in oysters (Crassostrea gigas) and rock shells (Thais clavigera and Thais rufotincta) under different field conditions. The bioaccumulation of tributyltin and triphenyltin in oysters and rock shells was less efficient during the winter, when higher levels of tributyltin pollution were not reflected in rock shell concentrations. The accumulations of tributyltin and triphenyltin were higher in T. clavigera than in T. rufotincta, while less difference between the two species was observed during the winter. A negative correlation was found between the ratio of tributyltin/total butyltin and tributyltin content in oysters and rock shells, suggesting that the metabolic rate of tributyltin is burden-dependent in these organisms, and that bioaccumulation factors are reduced by a high tributyltin burden. In addition, persistent accumulation of triphenyltin has a high probability of food chain magnification. These observations provide insights for future study of organotin pollution and suggest considerations for monitoring these species as bioindicators.

Comparison of Toxicity and Bioaccumulation of Tributyltin in Hyalella azteca and Five Other Freshwater Invertebrates

Abstract This study evaluates the suitability of using Hyalella azteca as a predictor of the risk that tributyltin (TBT) poses to freshwater invertebrates by comparing the toxicity and bioaccumulation of TBT in H. azteca to five species: Hexagenia limbata, Physella gyrina, Tubifex tubifex, Chironomus riparius and Daphnia magna. Young from each species were added to aquaria containing sediment spiked with TBT concentrations of 0,28.6, 258 and 1900 ng Sn/g dry weight. Chironomus riparius data could not be quantified reliably due to poor control survival. Bioaccumulation of TBT in the five remaining species was similar at sediment concentrations of 258 ng Sn/g, and the bioaccumulation relationships of P. gyrina and H. azteca were virtually identical. No toxicity was evident in any test species at body concentrations of 1100 to 1800 ng Sn/g. Body concentrations of 4000 to 6000 ng Sn/g were associated with significant (p < 0.05) mortality in H. limbata, P. gyrina, T. tubifex and D. magna, but not in H. azteca. However, bioaccumulation of TBT in H. azteca was comparable and can be used in predicting the effects of environmental TBT concentrations on these four species of freshwater invertebrates.

A Tribute to Richard A. Vollenweider (1922-2007)

Abstract This study evaluates the suitability of using Hyalella azteca as a predictor of the risk that tributyltin (TBT) poses to freshwater invertebrates by comparing the toxicity and bioaccumulation of TBT in H. azteca to five species: Hexagenia limbata, Physella gyrina, Tubifex tubifex, Chironomus riparius and Daphnia magna. Young from each species were added to aquaria containing sediment spiked with TBT concentrations of 0, 28.6, 258 and 1900 ng Sn/g dry weight. Chironomus riparius data could not be quantified reliably due to poor control survival. Bioaccumulation of TBT in the five remaining species was similar at sediment concentrations of 258 ng Sn/g, and the bioaccumulation relationships of P. gyrina and H. azteca were virtually identical. No toxicity was evident in any test species at body concentrations of 1100 to 1800 ng Sn/g. Body concentrations of 4000 to 6000 ng Sn/g were associated with significant (p < 0.05) mortality in H. limbata, P. gyrina, T. tubifex and D. magna, but not in H. azteca. However, bioaccumulation of TBT in H. azteca was comparable and can be used in predicting the effects of environmental TBT concentrations on these four species of freshwater invertebrates.

Toxicity and bioaccumulation of tributyltin in Hyalella azteca from freshwater harbour sediments in the Great Lakes Basin, Canada

This study was designed to evaluate the risk that tributyltin (TBT) levels in harbour sediments pose to the freshwater invertebrate Hyalella azteca and to rank TBT as an environmental concern compared with inorganic metal species. Four-week toxicity tests and 2-week bioaccumulation tests were conducted with sediments collected from five harbours historically contaminated with TBT: Montreal, Kingston, Toronto, Hamilton, and Port Weller. While there was no observable effect of TBT on survival or growth of H. azteca, bioaccumulation of TBT exceeded levels expected to cause chronic toxicity in some sediments from Kingston, Montreal, and Port Weller. There was a positive relationship between TBT in H. azteca and TBT in sediments (r2 = 0.72), although TBT in field sediments was less bioavailable than in laboratory-spiked sediments. Body concentrations of arsenic, cadmium, chromium, cobalt, lead, manganese, nickel, and thallium were well below levels expected to cause toxicity in H. azteca. However, overlying water concentrations of copper and zinc approached or exceeded levels of concern in Toronto, Hamilton, and Port Weller sediments. This research suggests that levels of TBT in harbour sediments may cause chronic toxicity to H. azteca and freshwater invertebrate species of similar sensitivity and that copper and zinc also pose a risk at these sites.

Toxicity and bioaccumulation of tributyltin and triphenyltin on oysters and rock shells collected from Taiwan maricuture area

The present study was undertaken to evaluate the toxicity of tributyltin (TBT) on oysters ( Crassostrea gigas) and bioaccumulation of TBT and triphenyltin (TPhT) on oysters and rock shells ( Thais clavigera) from mariculture areas of Taiwan. When treated with concentrations of 0.08, 0.40, 2.00, 10.00 and 50.00 μg TBT/L, the 48-, 72-, 96- and 120-h LC50s of oysters were 44.6, 18.4, 17.9 and 14.3 μg TBT/L, respectively. In the bioaccumulation experiments, oysters and rock shells were exposed to various concentrations of organotins, i.e. A: control, B: 0.40 μg TBT/L, C: 0.40 μg TPhT/L, and D: 0.20 μg TBT/L + 0.20 μg TPhT/L. In general, TPhT was faster accumulated than TBT in both oysters and rock shells and oysters had a higher elimination capability than rock shells. Additionally, greater bioaccumulation and elimination rates had been observed in female oysters than males. To rock shells, the bioaccumulation rate of organotins in imposex females was greater than males and females.

Accumulation of tributyltin in Hyalella azteca as an indicator of chronic toxicity: Survival, growth, and reproduction

The chronic toxicity of tributyltin (TBT) was examined by exposing two successive generations of the freshwater amphipod, Hyalella azteca, to sediments spiked with TBT. Survival was the most sensitive measure of effect, with lethal concentration resulting in 50% mortality (LC50) values on a water and body concentration basis ranging from 76 to 145 ng Sn/L and 2,790 to 4,300 ng Sn/g, respectively. Individual growth of amphipods was not negatively affected by TBT, and although reproduction might be more sensitive than survival, the data were too variable to use on a routine basis. There were no detectable TBT-induced differences in the response between first- and second-generation animals. The relationship between toxicity and bioaccumulation of TBT in H. azteca was determined and can be used as a tool to predict the toxicity of TBT in environmental samples. Body concentrations exceeding 2,000 ng Sn/g in H. azteca exposed to field-collected samples would indicate that chronic toxicity due to TBT is likely occurring in amphipod populations at those sites.

Microcosm tributyltin bioaccumulation and multibiomarker assessment in the blue mussel Mytilus edulis.

Blue mussels, Mytilus edulis, were exposed to two different concentrations of tributyltin (TBT) in seawater, 1,000 ng Sn/L (C1 experiment) and 10 ng Sn/L (C2 experiment), for 4 d, in order to evaluate the bioaccumulation of TBT by mussels Mytilus edulis in microcosms and to test the ability of a multimarkers analysis to determine the effects of TBT on the biochemical parameters in mussels. Tissue burdens of Mytilus edulis were 204 +/- 7 and 2,120 +/- 4 ng Sn/g TBT after the 4-d tests for the C2 and C1 experiments, respectively. Analyses of dissected organs and/or tissues demonstrated that TBT accumulated to the greatest extent in gills in the C1 experiment and in the digestive gland in the C2 experiment. Bioconcentration factors (BCFs) were 12,100 +/- 300 and 2,000 +/- 10 for mussels exposed in the C2 and C1 experiments, respectively. The four biomarkers used in this work were acetylcholinesterase (AChE), glutathione S-transferase (GST), catalase (CAT) activities, and thiobarbituric acid-reactive substances (TBARS) contents. No significant changes were observed in the measured enzyme activities or in TBARS concentration after the 4-d TBT exposure.

Sea-nine antifoulant: an environmentally acceptable alternative to organotin antifoulants

This article reviews previously reported data on the performance, environmental fate, and environmental modeling of Sea-Nine™ 211 antifoulant 2 Sea-Nine is a trademark of the Rohm and Haas Company, Philadelphia, PA. 2 (4,5-dichloro-2- n-octyl-4-isothiazolin-3-one). Since organotins are an industry standard, the environmental fate and environmental modeling results of tributyltin (TBT) are compared to those of the Sea-Nine antifoulant for reference. Laboratory and field tests results have shown Sea-Nine antifoulant to be highly effective. Five years of commercial use has confirmed this. Sea-Nine antifoulant and TBT were compared in an environmental risk assessment to predict their effects on the environment. Sea-Nine antifoulant was degraded rapidly in the environment by microorganisms. Its half-life in aerobic and anaerobic microcosm studies was less than 1 h. TBT degraded slowly under aerobic and anaerobic conditions with half-lives ranging from 6 to 9 months. The degradation products of Sea-Nine antifoulant were ring-opened compounds with greatly reduced toxicity. TBT degraded to dibutyltin species, which were still toxic and persistent in the environment. Bioaccumulation studies in fish showed essentially no bioaccumulation of the Sea-Nine biocide. The bioaccumulation of TBT was significant, with bioconcentration factors as high as 10 000. The Sea-Nine antifoulant showed no chronic or reproductive toxicity to marine species, while TBT showed a wide range of effects on growth, development, and reproduction at levels as low as 2 parts per trillion (ppt). Computer modeling using the Exposure Analysis Modeling System (EXAMS) predicted maximum concentrations of Sea-Nine biocide of up to 10 ppt, far below the maximum acceptable environmental concentration (MAEC) of 630 ppt. The maximum predicted concentrations of TBT were as high as 345 ppt, far above the UK Environmental Standard in seawater of 2 ppt.

A review of organotin regulatory strategies, pending actions, related costs and benefits

Achieving consensus on equitable and effective national and global regulation(s) for the use of organotins as biocides in antifouling boat bottom paints has proven to be very complex and difficult for a variety of reasons as discussed in this paper. There appears to be broad agreement among stakeholders about the effectiveness of tributyltin (TBT) in antifouling paints. A draft Assembly Resolution prepared by the Marine Environmental Protection Committee (MEPC) of the International Maritime Organization (IMO) to propose a global ban on the use of organotins in antifouling paints was approved by the IMO at its 21st regular session (November 1999). In approving the Resolution, the Assembly agreed that a legally binding instrument (global convention--an international treaty) be developed by the Marine Environmental Protection Committee that should ensure by 1 January 2003, a ban on the application of tributyltin (TBT)-based antifouling paints; and 1 January 2008 as the last date for having TBT-based antifouling paint on a vessel. The Assembly also agreed that a diplomatic conference be held in 2001 to consider adoption of the international legal instrument. Monitoring, policing, enforcement, fines and record-keeping are yet to be defined. In addition, the MEPC has also proposed that IMO promotes the use of environmentally-safe anti-fouling technologies to replace TBT. Existing national regulations in the US and Europe have: (1) restricted the use of TBT in antifouling boat bottom paints by vessel size (less than 25 m in length), thus eliminating TBT from the smaller and recreational vessels that exist in shallow coastal waters where the impacted oysters species grow; (2) restricted the release rates of TBT from co-polymer paints; and (3) eliminated the use of free TBT in paints. The present movement toward a global ban suggests that the above regulatory approach has not been sufficient in some countries. Advocates of the ban cite international findings of: (1) higher levels of TBT in surface waters of ports and open waters; (2) imposex still occurring and affecting a larger number of snail species; (3) TBT bioaccumulation in selected fisheries; and (4) the availability of 'comparable' alternatives (to TBT) with less environmental impact. The global ban has been absent of a policy debate on the: (1) lack of 'acceptable and approved' alternatives in many nations; (2) appreciation of market forces in nations without TBT regulations; (3) full consideration of the economic benefits from the use of TBT; (4) 'acceptance' of environmental impacts in marinas, ports and harbors; and (5) realization of the 'real' time period required by ships for antifoulant protection (is 5-7 years necessary or desirable?). Estimates of fuel savings range from $500 million to one billion. In assessing the environmental impact from TBT, there are two sources: the shipyard painting vessels and the painted vessel itself. Today vessels can be painted with regulated or banned antifouling materials by boatyards in a country that does not have TBT regulations and subsequently travel in international and regulated national waters and thus bringing the impact back to the country which was trying to prevent it. Worse, local and national regulations for TBT have proven to be the antithesis of the popular environmental cliché--'Think Globally and Act Locally.' Legislative policies enacted by 'regulated' countries to regulate the use of TBT to protect (their) local marine resources have subsequently had far reaching environmental and economic impacts which have in essence transferred TBT contamination to those countries least able to deal with it. Market forces are selective for cheap labor and cheap environments. 'Unregulated' countries have unknowingly accepted the environmental and human health risks to gain the economic benefits from painting TBT on ships. (ABSTRACT TRUNCATED)

Bioaccumulation and toxicity of tributyltin to a burrowing heart urchin and an amphipod in spiked, silty marine sediments.

The presence of tributyltin (TBT) in silty sediments is regarded as a long-term threat to marine and estuarine environments due to its persistence. The bioaccumulation kinetics and toxicity of TBT in the deposit-feeding heart urchin Echinocardium cordatum was studied in silty sediment spiked with TBT and equilibrated prior to the 28-d exposure. An additional 10-d acute toxicity test was carried out with the burrowing amphipod Corophium volutator in the same sediment. Because E. cordatum has a low lipid content and apparently high elimination and metabolic rates, only a moderate degree of TBT bioaccumulation was observed, with biota-sediment accumulation factors (BASFs) of 0.09 to 0.21 (dry weight basis) and biota accumulation factors (BAFs) of 180 to 843 (wet weight basis). The lethal body residue in E. cordatum (soft tissue and skeleton) was 0.8 to 3.4 nmol TBT+ /g wet weight which, considering the differences in lipid content, is comparable to data on other taxonomic groups. For E. cordatum and C. volutator, the LC50s for pore water (222 and 329 ng Sn/L) were also close to reported values for aquatic and benthic organisms. The TBT concentrations in the pore water of the silty sediment were much lower than might be expected from the octanol-water partition coefficient. The measured sediment-water partitioning coefficient Kp was 8,700 L/kg dry weight. Consequently, toxicity was observed at a relatively high TBT concentration in the bulk sediment with LC50s for E. cordatum and C. volutator of 1,594 and 2,185 ng Sn/g dry weight, respectively. The results show that TBT is highly toxic to the benthic species investigated and sorption in the silty sediment strongly reduced the bioavailability of the compound.

Occurrence of butyltin compounds in water and mussel samples collected in an oil port

The aim of the present study was to follow the seasonal variations of butyltin compounds in water and mussels under natural conditions in the Genoa oil port. To this purpose, water and organisms were collected in the same location within the port, at two-monthly intervals, between 1997 and 1998. The extraction of organotin compounds was performed both on unfiltered and filtered seawater to determine partitioning between the dissolved and the particulate phases. Moreover the extraction was carried out on the whole body, gills and digestive glands of mussels to analyze the distribution in marine organism tissues. The determinations were carried out using a HPLC-hydride generation-ICP/AES system. The results revealed the presence of tributyltin, dibutyltin and monobutyltin in all matrices, showing variations during the sampling period. In particular, in oil port waters, butyltin compounds were predominantly in the dissolved phase. Moreover, comparing butyltin trends in water and in mussel tissues, the best correlation was found in gill distributions, in this tissue a higher tributyltin bioaccumulation factor was observed.

Effects of tributyltin chloride on marine bivalve mussels

Using marine bivalve mussels Mytidus edulis and Aequipecten irradians as the biological indicators, the chronic (60 days) bioaccumulation tests were conducted to evaluate the effect of tributyltin (TBT) on bivalve mussels. TBT and its degraded products—Dibutyltin and Monobutyltin—were determined in mussels and seawater. Bioconcentration Factor (BCF) increased exponentially with decreasing concentration of TBT, BCFs were much higher than predicted values by Kow. Some physiological effects of TBT on the shell length, width, whole body weight and Condition Index were measured and used as indicating indices on the contamination of TBT to bivalve mussels. Some pathological effects at cellular level were observed under the electron-microscope, the mitochondria of test M. edulis's liver swelled and disrupted, so the mechanism of toxicity was suggested. Based on the results of the bioaccumulation test the risk evaluation for humans was made. The results of bioaccumulation of TBT by algae revealed that accumulation through the food chain was very important.