Variation in the shell of the dog-whelk, Nucella lapillus (L.) from Sullom Voe and other parts of the Shetland islands

In most parts of southwestern Europe the shape of dog-whelk shells varies in a predictable manner with the exposure of the shore on which the animals are living. As the same relationship also applies on shores near Mongstad in Norway, it was thought that it might be true in Sullom Voe (Shetland) which is at about the same latitude. In fact the relationship only holds for some west coast samples. Exposed shores are indeed colonised by the short squat form expected of such places but the more elongated form, usually associated with very sheltered shores, is also found on all but the really exposed sites: there is accordingly very little difference in the shape of dog-whelk shells on Shetland shores. The species is consequently of little or no use in the assessment of exposure.     

Risk assessment of TBT in the Japanese short-neck clam (Ruditapes philippinarum) of Tokyo Bay using a chemical fate model

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.     

Contamination of organotin compounds and imposex in molluscs from Vancouver,Canada

Gastropods and bivalves were collected at 15 sites at Vancouver and Victoria, Canada between 24 May and 7 June, 1999, to establish tissue concentrations of butyltin and phenyltin compounds, to record imposex symptoms in gastropods, and to assess the present status of organotin contamination around Vancouver. No neogastropods (such as Nucella lima) were found around Vancouver. Neogastropod populations could have been extirpated by severe TBT contamination in Vancouver, as relatively high concentrations of TBT were detected in tissues of Mytilus trossulus from Vancouver, and the neogastropods distributed in Vancouver might be sensitive to TBT. Recovery from imposex, however, was observed in neogastropod populations from three sites at Victoria and Mission Point. TBT contamination has continued around Vancouver, arising from continuous use of TBT in antifouling paints for vessels larger than 25 m in length; however, TBT has decreased around Victoria and Mission Point. Different patterns of TBT accumulation in tissue were observed among the bivalve species from Vancouver. The highest TBT concentration detected in Tresus capax suggested some possible adverse effects. TBT was the most predominant butyltin component in almost all bivalve specimens surveyed, suggesting a low rate of TBT metabolism. Phenyltin compounds were not detected in any molluscan specimens in this study.     

Geographical distribution and age composition of Euphausia superba larvae (Crustacea：Euphausiacea) in the South Shetland Islands region and southern Scotia Sea in relation to environmental conditions

Spatial distribution patterns of the different life stages of Euphausia superba in the region of the South Shet- land Islands and southern Scotia Sea （Antarctica） were assessed based on scientific survey data collected in lanuary and February of 2010. Adults, eggs, nauplii, metanauplii, calyptopis I-Ill, and furcilia I-II were found in the investigation. The abundance of larvae averaged 1 172.8 ind./mz, with calyptopis I and II as the dominant stages. Habitat occupancy patterns varied among Euphausia superba at different stages, and three sub-regions were identified by cluster analysis. The degree of larval development increased from west to east. Larvae were not observed north of the South Shetland Islands. Calyptopis I was predominant in the water between Elephant Island and the South Orkney Islands, which featured no thermocline. Older stages, including calyptopis II and III and furcilia I and II, were common in north and northeast of the South Orkney Islands, which were characterized by high temperature and high chlorophyll concentration. Distri- bution and abundance of the early life stages of E. superba were associated with specific environmental con- ditions. According to Biota-Environment matching （BIOENV）, the distributions of E. superba larvae were correlated with a combination of temperature at the surface and 200 m, and 0-100 m integrated chlorophyll a concentration.     

Bioavailability and effects of sediment-bound TBT in deposit-feeding clams, Scrobicularia plana

Concentrations of tributyltin (TBT), dibutyltin (DBT), inorganic and total tin have been measured in water, sediments and deposit feeding clams, Scrobicularia plana, from 25 estuarine locations in England and Wales, in order to compare the bioavailability of different forms of the element. Abnormally high tin values in Scrobicularia from harbours and areas of high boating activity testify to the high bioaccumulation potential of organotins, notably TBT derived from anti-fouling paints, relative to inorganic tin.Infaunal deposit-feeding bivalves consistently contain higher concentrations of TBT than other benthic organisms indicating that sediments may be an important route for uptake. Significant correlations between sediment TBT values and residues in clams such as S. plana (r = 0·81, p < 0·001) support this hypothesis. Direct evidence of the bioaccumulation of sediment-bound TBT is provided from laboratory experiments in which Scrobicularia were exposed to TBT in water and in sediments, either separately or in combination. The results of these experiments clearly demonstrate a predominantly particulate component for TBT uptake in clams.The kinetics of TBT accumulation and elimination were studied in Scrobicularia exposed to sediments containing 0·3 and 1·0 μg/g TBT (as tin). Equilibrium concentrations in tissue are approached after 40 days.Sediments containing 10 μg/g TBT are acutely toxic to S. plana, although such concentrations are only likely to occur close to dockyards and large marinas. Preliminary laboratory and field observations suggest however, that clam populations could be affected at TBT concentrations in sediments of 0·3 μg/g and possibly lower.     

Reductions in TBT concentrations in UK estuaries following legislation in 1986 and 1987

In 1986 the Government of the United Kingdom (UK) introduced legislation to control the sale of tribytltin (TBT)-based paints. From 1986 to 1989 monitoring was undertaken, whereby samples of water, sediment, oysters (Crassostrea gigas) and mussels (Mytilus edulis) were collected from six estuaries and water samples from five marinas/harbours, and analysed for TBT. In 1989 the concentrations of TBT in water, oysters and mussels were generally only one-third to one-quarter of those observed in 1986. The most marked decrease in concentrations of TBT in oysters and mussels occurred in 1987–1988, following the 1987 ban on the use of TBT-based paints on small boats and mariculture equipment. As the concentrations of TBT in oyster tissues had decreased there has been improvement in oyster growth in terms of both meat production and growth of thin (i.e. normally shaped) shells. Oysters with a normal shell shape can now be grown in five of the six estuaries which were monitored. In contrast to the reduction in concentrations of TBT noted in water and bivalves, changes in concentrations of TBT in sediments showed no clear trend from 1986 to 1989.     

TBT contamination of an artisanal subsistence fishery in Suva harbour,Fiji

The intertidal zone around the Suva Peninsula, Fiji, supports separate finfish and invertebrate subsistence fisheries. This important source of fresh marine food for many low-income families around metropolitan Suva is under threat from foreshore reclamation projects and from anthropogenic biochemical pollution. Damage to or loss of this invertebrate intertidal fishery would remove a significant area where urban dwellers can pursue this traditional (non-cash) means of seafood acquisition. In 1996, Suva Peninsula was considered for the development of a marina, hotel, aquarium, roads, walls, and other structures. There is also increasing evidence of a serious anthropogenic TBT (tributyltin) pollution threat to the local invertebrate fishery. Although this substance is well known to have ecologically deleterious effects, its use is unregulated in Fiji. The inputs are likely to be large commercial vessels, and in particular the shipyards around the west side of Suva Harbour, where TBT antifouling coatings are both applied and removed, the old paint debris being allowed to wash into the harbour. Inputs from small boats are probably less important as there are relatively few (<150 boats) but uses of TBT, as a wood treatment chemical, for example, may lead to other inputs (but these have not been investigated). Samples of Anadara antiquata and Gafarium tumidum contained high levels of TBT ranging from <50 ng TBT gm⁻¹ to 240 ng TBT gm⁻¹. Samples of the edible bivalve G. tumidum taken from the Lami Dump intertidal zone had accumulated 10,500 ng TBT gm⁻¹. The values of TBT in Suva Harbour and Laucala Bay sediments have reached levels that are among the highest in the world and indicate that these sediments are functioning as geochemical sinks for this toxic organotin substance.     

Butyltins in marine waters of The Netherlands in 1988 and 1989; Concentrations and effects

Specific effects of tributyltin (TBT) on Crassostrea gigas—valve thickening, and Nucella lapillus—imposex, were measured on local populations, relatively clean unaffected species from England were transferred to the Netherlands and exposed during six weeks to ambient TBT concentrations. Near marinas 50% of the exposed species were sterile after six weeks. In general, no dissolved butyltins were detected in the Rhine and Scheldt estuaries. In 1988 TBT concentrations in marinas ranged from 120 to 4000 ng litre⁻¹. In sediments (fraction <60 μm) and suspended particulate matter TBT concentrations reached up to 1200 ng g⁻¹. TBT concentrations in mussel tissue ranged from <1 to 2300 ng g⁻¹ based on a dry weight. In 1989 concentrations of dissolved TBT ranged from <0·1 to 7200 ng litre⁻¹. In 1989 a seasonal study in the marina of Colijnsplaat showed that dissolved butyltins increased from April to the end of May due to the launching of freshly painted boats, and decreased afterwards.     

Tributyl tin levels for sea water,sediment, and selected marine species in coastal Northland and Auckland,New Zealand

Water and sediment samples were collected from the Waitemata Harbour, Opua Inlet, and Tutukaka Harbour, and analysed for tributyl tin (TBT) using a hydride generation atomic absorption method. Specimens of oysters (Crassostrea gigas, Saccostrea glomerata, Ostrea heffordi) and oyster borer, Lepsiella scobina, were collected from the Tamaki Estuary and surrounding areas. These specimens were analysed for TBT using graphite furnace atomic absorption, and the oyster shell valves were examined for thickening. Concentrations of TBT in the water column were as high as 0.32 μg TBT‐Sn H. Marina sediments contained up to 0.240 μg TBT‐Sn g^‐1. Shell thickening was found to occur in C. gigas where its incidence was correlated with the TBT body burden. Concentrations up to 2.24 μg TBT‐Sn gr^‐1 (on a dry weight basis) were observed for C. gigas. This survey provides evidence for the toxic influence of TBT on non‐target organisms in New Zealand.     

Chronic toxicity of tributyltin on development and reproduction of the hermaphroditic snail Physa fontinalis: Influence of population density

Tributyltin (TBT) is toxic to aquatic organisms and occurs widely in sediments and surface waters of American and European rivers and lakes. This study investigated TBT effects on development and population growth rate (r) of the common, hermaphroditic European freshwater snail Physa fontinalis. Egg ropes of similar age (1-3 days old) were exposed to a control (solvent only) and nominal concentrations of 0.01, 1.0 and 10 microg TBT l(-1) in triplicate. Hatching and mortality were recorded during 0-40 days of exposure. At day 40, 18 juveniles were randomly selected from each concentration (i.e., six from each test vessel) and individually exposed to the same concentration of TBT in 50 ml beakers. A cohort of 20 juveniles was allowed to continue developing in the original test vessels, so that individual and grouped results could be compared. Mortality and reproduction were recorded at 48-h intervals throughout the study period (110 days). Abnormal embryonic development was observed at 1 and 10 microg TBT l(-1). Although 50% of eggs hatched at 10 microg TBT l(-1), all these hatchlings failed to survive. Survivorship of hatchlings was significantly reduced by TBT at 1 microgl(-1). In general, there was a delay in egg production in isolated snails when compared with the grouped snails. Survival, fecundity and population growth rate (r) were reduced in both individual and grouped P. fontinalis at 1.0 microg TBT l(-1). Only a decline in r was observed in snails exposed individually to 0.01 microg TBT l(-1).     

Exploring the use of caged Nucella lapillus to monitor changes to TBT hotspot areas: a trial in the River Tyne estuary (UK)

Caged dogwhelks (Nucella lapillus) and mussels (Mytilus edulis) were placed in situ at sites along the River Tyne (UK) in order to investigate the potential for monitoring any change in tributyltin (TBT) mediated effects. After 6 months the development of imposex was investigated in the dogwhelks and concentrations of TBT were determined in the whole tissues of both species. Sites within the estuary showed a high degree of imposex, whilst those at sites North and South of the estuary mouth exhibited significantly lower induction. Concentrations of TBT measured in the dogwhelk and mussel tissues showed the same pattern. The success of the caging technique, occurrence of imposex at other UK sites and the need for further monitoring at TBT impacted locations in the light of current international controls on the use of TBT-based antifouling paints on sea-going vessels are discussed.     

Effects of tributyltin (TBT) exposure on the reproduction and embryonic development of the bivalve Scrobicularia plana

Field and laboratory work was carried out during the summers of 1990 and 1991 on bivalves Scrobicularia plana from sites moderately-affected and relatively-unaffected by tributyltin (TBT) contamination (i.e. a mean concentration in clam tissues of 0.4 and 0.02 μg Sn g⁻¹ dry wt, respectively). Standard cultures after artificial fertilizations with broodstock of either site did not result in dissimilar survival of embryos nor in larvae of different quality at the time of hatching. Static 48 h toxicity tests on S. plana embryos showed that an EC₅₀ of less than the nominal 250 ng Sn litre⁻¹ (a range of 178–198 ng Sn litre⁻¹, as analysed) can be set for TBT independently of the origin of broodstock. The results are discussed in relation to the reported disappearance of S. plana throughout northern Europe and the simultaneous presence of toxic levels of butyltin. It is concluded that TBT has probably reduced the recruitment into some UK clam populations by preventing the successful development of a significant proportion of their embryos.     

The distribution of phytoplankton size and major influencing factors in the surface waters near the northern end of the Antarctic Peninsula

The waters near the Antarctic Peninsula have always been a study hot spot because of their variable and unique oceanographic conditions.To determine the distribution and possible influencing factors on phytoplankton size and abundance near the Antarctic Peninsula,a large-scale survey was conducted during the austral summer of2018.Samples were collected in 27 stations located in the Drake Passage(DP),South Shetland Islands(SSI),and South Orkney Islands(SOI).Phytoplankton communities were described using chlorophyll a(Chl a),flow cytometry and light microscopy to cover a size range from pico-to microphytoplankton.Nanophytoplankton,especially small nanophytoplankton(2-6 μm) with abundance ranging from 0.66 ×10~3 cells/mL to 8.46 ×10~3 cells/mL,was predominant throughout the study area.Among different regions,there was an obvious size shift.The proportion of picophytoplankton near the Elephant Island(EI) and DP was higher than other regions,and larger cells were found mainly in east of SOI.The distribution of phytoplankton abundance detected by flow cytometry was not completely consistent with Chl a concentrations due to the contribution of larger cells to Chl a.Possible influencing factors on the phytoplankton size distribution were discussed.The properties of water masses such as temperature and salinity can influence the phytoplankton size distribution.Correlation analysis revealed that only picophytoplankton is significantly correlated with salinity.Light and Fe availability might affect phytoplankton abundance and size distribution especially near the waters of SSI and EI in this study.It was also speculated that the abundance of cryptophytes is possibly related to ice melting.     

Uptake and transformation of C-labelled tributyltin chloride by the dog-whelk, nucella lapillus: Importance of absorption from the diet

The importance of the diet as a source of tributyltin (TBT) in Nucella lapillus was studied using [¹⁴C]tributyltin chloride. In N. lapillus provided with prelabelled mussels, Mytilus edulis, in labelled water (mean 20·5 ng/litre TBT) the rate of accumulation of total ¹⁴C was 2–3 times that in unfed animals. Owing to its degradation in the tissues of both fed and unfed animals, concentrations of [¹⁴C]TBT tended to reach a plateau after only 28 days. However, total concentrations of ¹⁴C were still increasing after 49 days. Under experimental conditions (15°C, ample food, no disturbance) the diet accounted for about 50% of the body burden of TBT in N. lapillus after 49 days exposure: concentration factors (dry tissue/water) for [¹⁴C]TBT in both male and female N. lapillus were similar at about 60 000 in fed and 30 000 in unfed animals. It is concluded that the diet may contribute less than half of the body burden of TBT found in natural populations subjected to life-long exposure.     

Sea-to-air flux of contaminants via bubbles bursting. An experimental approach for tributyltin

Although seawater concentration of tributyltin (TBT) should decrease when the direct inputs from ship hulls will cease after the incoming world ban of organotin-based antifouling paints in 2003 or later, the TBT environmental issue will still be present for decades as contaminated sediments in shallow waters will be acting as a long-lasting reservoir for TBT and its degradation products. The lost of TBT to the atmosphere by volatilization has already been proposed as a part of its molecular motion through the aquatic environment but most recent calculated values of water-to-air rate of exchange of TBT (from 20 to 510 nmol m⁻² year⁻¹) do not take into account the potential contribution of aerosols ejection to the atmosphere upon bubbles bursting, an important process for pollutants transport in the marine environment. In this work, an experimental approach to measure the seawater-to-air flux of TBT mediated by bubbles bursting is described, and the influence of phytoplankton cells and dissolved organic matter from exudates and culture weathering on flux rates was assessed. The results demonstrate that TBT can be transferred from water to air via the ejection of droplets from bubbles bursting and that cell density strongly affected the transfer. Under a bubbling regime, the water-to-air flux (pmol TBT cm⁻² min⁻¹ level) is estimated up to 1000-fold the flux measured for the molecular diffusion and volatilization under static quiescent conditions. The surface microlayer acted as a transient boundary between the water column and the atmosphere where the dynamic of TBT accumulation has the same trend as the dynamic of TBT ejection. This physical transfer mechanism might be of high significance in nearshore environments, harbors, and shallow channels where clouds of bubbles generated in the wake of large ships play an important role for the atmosphere/seawater chemical exchanges.     

三丁基锡对褐菖鮋精巢性激素受体表达的影响

三丁基锡(Tributyltin,TBT)能够影响鱼类生殖功能,而有关TBT对鱼类生殖细胞发育至关重要的雄激素和雌激素受体的影响还未见报道。本实验以海洋经济鱼类褐菖鲉(Sebastiscus marmoratus)为对象,研究环境水平TBT(1,10和100ng/L)对精巢雄激素和雌激素受体表达的影响。结果表明,TBT暴露能够抑制褐菖鲉精巢发育和精巢雌激素受体蛋白的水平,并且发现雌激素受体主要定位于精巢精小叶腔间隙。小叶腔间隙的雌激素受体蛋白水平降低可能影响支持细胞和间隙细胞的正常功能,从而影响精巢的正常发育。TBT暴露对雄激素受体的表达并没有显著的影响。该结果为全面了解TBT产生鱼类生殖毒性效应、途径和机制提供了新的重要的资料。     

The effects of the ‘Braer’ oil spill, Shetland Isles, Scotland, on P4501A in fanned Atlantic salmon (Salmo salar) and the common dab (Limanda limanda)

This paper describes the response of two fish species, the Atlantic salmon (Salmo salar) and the common dab (Limanda limanda) to the oil spilled from the Braer tanker which grounded on the southern tip of Shetland, Scotland, on 5 January 1993. Both the immediate sublethal effects and the long-term response to the oil which accumulated in sediments around the Shetland Isles, Scotland, are examined. The primary response measured was the induction of detoxification enzymes and the relationship of the levels or activities of these enzymes to the concentration and distribution of aromatic hydrocarbons measured in sediments, water and fish. The results show that, immediately following the spill, there was a marked induction of Cytochrome P4501A enzymes in salmon, indicative of exposure to bioavailable aromatics. In dab there was evidence of induction at some sites in January 1993 immediately following the spill but, subsequently, no induction has been observed in fish caught in the vicinity of Shetland despite the very high concentrations of oil measured in sediments at some locations. This would indicate that the polyaromatic hydrocarbons in these sediments are unlikely to be directly bioavailable to fish. The effect of the oil spill on hepatic pathology in dab was investigated and shows that pathology predictive of neoplasia, such as basophilic foci and vacuolation, were observed in fish from the most contaminated sites in 1994 but not in 1993. The incidence of this pathology appeared to correlate with the degree of contamination at the sites, but additional studies are required to establish whether this was a consequence of the initial impact and exposure from waterborne oil at the time of the spill or whether it was due to the continued exposure to oil from the sediments.     

Comparison of organotin accumulation in the masu salmon Oncorhynchus masou accompanying migratory histories

In order to examine the accumulation pattern of organotin compounds (OTs) accompanying the migration pattern in diadromous fish, tributyltin (TBT) and triphenyltin (TPT) compounds and their derivatives were determined in the liver, muscle, gill, and ovary tissues of both sea-run and freshwater-resident masu salmon, which are of the same species, Oncorhynchus masou. Their migratory histories were estimated using strontium (Sr) and calcium (Ca) analysis in the otolith. A significant difference in the mean Sr:Ca ratio from the core to the edge of the otolith was found between sea-run and freshwater-resident masu salmon. The TBT concentration in the liver was significantly higher than that in the other tissues in both sea-run and freshwater-resident fishes. In sea-run masu salmon, the TBT concentrations in all tissues except for the ovary were significantly higher than in those of freshwater-resident individuals. In the sea-run type, the percentage of TBT was higher than that of the freshwater-resident type. The TPT concentration in the liver of the sea-run type was also significantly higher than that in the other tissues, while that in the gill of the freshwater-resident type was significantly higher than that in the other tissues except for the ovary. The TPT concentrations found in the liver and muscle of the sea-run type were significantly higher than those in the freshwater-resident type, whereas the values of the gill in the sea-run type were significantly lower than those in the freshwater-resident fish examined. The percentage of TPT in the sea-run type was higher than that of the freshwater-resident type. These results suggest that the sea-run O. masou has a higher ecological risk of TBT and TPT exposure than the freshwater-residents during their life history.     

Environmental drivers of phytoplankton crops and taxonomic composition in northeastern Antarctic Peninsula adjacent sea area

The ecosystem of the sea region adjacent to the Antarctic Peninsula is undergoing remarkable physical and biological changes, in the context of global warming. However, understanding of the dynamics of phytoplankton taxonomic composition in this marginal ice zone remains unclear. In this study, seawater samples collected from 36 stations in the northeastern Antarctic Peninsula were analyzed for nutrients and phytoplankton pigments.Combining with CHEMTAX analysis, remote sensing data, and physico...     

The effect of tributyltin upon steroid titres in the female dogwhelk, Nucella lapillus, and the development of imposex

Exposure of female Nucella lapillus to tributyltin (TBT) in seawater at a concentration of 40 ng Sn/litre led to accumulation of TBT in the tissues, and an increase in penis length compared to control animals. Investigation of the steroid concentrations by radioimmunoassay revealed a significant increase in testosterone after 28 days exposure to TBT. No significant effect was noted upon the amounts of progesterone or estradiol-17β. When testosterone was injected into female N. lapillus in the absence of TBT, penis length was found to increase significantly. These observation suggest that there may be an association between the change in testosterone titre in response to exposure to TBT and the development of imposex in the dogwhelk.