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.     

The impact of tributyltin from large vessels on dogwhelk (Nucella lapillus) populations around Scottish oil ports

Surveys of imposex in dogwhelk (Nucella lapillus) populations around oil terminals in Sullom Voe (Shetland) and Scapa Flow (Orkney) have confirmed that the effects of tributyltin (TBT) released from large vessels in coastal waters can be recognised. The impact of large vessels can be separated from the effects of other inputs of TBT in the areas studied. The intensity of the effects was greater in Shetland than in Orkney, reflecting the higher exposure to TBT resulting from the greater volume of traffic using the Shetland terminal, and the more restricted water exchange in that area. A large proportion of the female dogwhelks in Sullom Voe were unable to reproduce. Females in Scapa Flow were still able to reproduce, except for a small proportion close to two fish farm sites where TBT net-treatments were used prior to 1987.     

Sex-different effects of tributyltin on brain aromatase,estrogen receptor and retinoid X receptor gene expression in rockfish (Sebastiscus marmoratus)

Since the brain plays important roles in reproduction, the brain aromatase (Cyp19b), estrogen receptor (ER), retinoid X receptor (RXR) α and peroxisome proliferator-activated receptor γ were examined in rockfish after TBT exposure (1, 10, and 100 ng L⁻¹). The results showed that the Cyp19b expression was elevated in the male rockfish, while no effect was produced in the females. Inconsistently, serum testosterone and 17β-estradiol showed no change in the males, while an increase of testosterone and a decrease of 17β-estradiol were observed in the females. TBT affected the ER expression in the males depending on the concentrations, however, no change was observed in the females. In addition, TBT elevated the RXRα expression in the males but produced an opposite effect in the females. In conclusion, TBT might have had sex-different effects on the brain Cyp19b, ER and RXR expression in rockfish, indicating a complex endocrine disrupting effect of TBT.     

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.     

Effects of organic toxicants on the anoxic energy metabolism of the mussel Mytilus edulis

The anoxic rates of heat dissipation by mussels (Mytilus edulis) were enhanced after exposure to pentachlorophenol (PCP) and tributyltin (TBT), both known uncouplers of oxidative phosphorylation. The degree of metabolic activation under anoxia was dependent upon the amount of toxicant accumulated in the tissues, but the concentration-response relationship was different to that under aerobic conditions. Biochemical measurements indicated that the anaerobic metabolic pathways were significantly disturbed by PCP and TBT. There was a decline in succinate, an increase in the fumarate: succinate ratio, and an increase in the accumulation of lactate, indicating a shift from succinate to lactate anaerobic pathways. A consequence of organic toxicant exposure was a reduction in anoxic survival time of mussels.     

Mechanisms of imposex induction in the mud snail, Ilyanassa obsoleta: TBT as a neurotoxin and aromatase inhibitor

The occurrence of imposex, imposition of male sex characteristics on female snails, has been extensively documented throughout the world. Tributyltin (TBT) and other organotins have been causally linked to imposex induction at levels as low as 2 ng/l. There are several proposed mechanisms of action. First, TBT has been shown to be neurotoxic and to accumulate in snail ganglia. Peptide hormones control sexual differentiation in gastropods, and one hypothesis is that TBT acts as a neurotoxin to abnormally release the peptide hormone Penis Morphogenic Factor (PMF). However, PMF has not been characterized to date. The neuropeptide APGWamide significantly induces imposex in the mud snail, Ilyanassa obsoleta, at 10⁻¹⁶ moles sub-cutaneous (SQ) injection over 2 weeks, and could be the PMF in this species. A second hypothesis is that TBT inhibits aromatase activity leading to increased testosterone levels and decreased estradiol. In vitro studies with snail digestive gland microsomes showed that TBT-dosed snails not exhibiting imposex had a 52% reduction in aromatase activity. Although the role of vertebrate sex steroids is not known in gastropods, it is possible that the combination of changes in peptide and steroid hormones may lead to imposex induction at extremely low doses of TBT.     

Different crab species influence feeding of the snail Nucella lapillus through trait‐mediated indirect interactions

Indirect interactions are among the many important factors that influence the community structure of the rocky intertidal zone. Trait‐mediated indirect interactions, in which the presence of a predator or competitor can influence the relationship between two other species, have emerged as vital for understanding community dynamics. This study examined the effect of different crab species on the feeding habits of an intertidal snail, Nucella lapillus. Crab species were defined as being sympatric predatory (Carcinus maenas and Cancer irroratus), sympatric non‐predatory (Uca pugnax and Pagurus longicarpus), or allopatric predatory (Mithrax sculptus and Percnon gibbesi). Nucella lapillus were potentially exposed to risk cues from each of the crab species. Crabs were kept in perforated boxes, which allowed any chemical cues to be emitted but prevented direct contact. Nucella lapillus had significantly lower feeding rates in the presence of sympatric predatory crab species than N. lapillus exposed to either sympatric non‐predatory crabs or allopatric predatory crabs. There was no difference in feeding rate between N. lapillus exposed to the sympatric non‐predatory crabs and to the allopatric predatory crabs. Nucella lapillus in the presence of sympatric predatory crabs had a feeding rate of only 0.07 barnacles per snail per day, whereas N. lapillus housed with non‐predatory crabs and allopatric predatory crabs had rates of 0.11 and 0.12, respectively, suggesting that N. lapillus alter their behavior in response to chemical risk cues from local predators. These results suggest that the ability to detect and respond to risk cues is a selectively evolved trait.     

Specific accumulation of organotin compounds in tissues of the rock shell,Thais clavigera

Concentrations of organotin compounds (butyltins and phenyltins) were determined in gonad, accessory sex organs, penis, digestive gland, kidney, radula with sac, oesophagus with crop, stomach, hypobranchial gland, rectum, mantle, osphradium, ctenidium, heart, salivary gland, head ganglia and muscle of imposex-exhibiting female and male rock shells (Thais clavigera), by gas chromatography with flame photometric detection (GC-FPD). Different tissue distributions were observed between butyltin and phenyltin compounds. More than 1000 ng TBT/g wet wt. were observed in ovary, digestive gland, kidney, heart, ctenidium, osphradium, stomach, head ganglia and penis, of both imposex-exhibiting females and males. More than 1000 ng TPT/g wet wt. were found in almost all tissues of both sexes. Approximately one-third or more of total TBT was accumulated in the digestive glands of both females and males, respectively. Meanwhile, approximately 40–50% and one-half of total TPT accumulated in the digestive glands of females and males, respectively.     

Comparison of organotin accumulation on the white-spotted charr Salvelinus leucomaenis between sea-run and freshwater-resident types

To examine the accumulation pattern of organotin compounds (OTs) in relation to the migration of diadromous fish, tributyltin (TBT) and triphenyltin (TPT) compounds and their derivatives were determined in the muscle tissue of both sea-run (anadromous) and freshwater-resident (nonanadromous) types of the white-spotted charr Salvelinus leucomaenis. There were generally no significant correlations between the TBT and TPT accumulation and various biological characteristics such as the total length (TL), body weight (BW), age and sex in S. leucomaenis. It is noteworthy that the TBT and TPT concentrations in sea-run white-spotted charr were significantly higher than in freshwater-resident individuals, although they are intraspecies. These results suggest that the sea-run S. leucomaenis has a higher ecological risk of TBT and TPT exposure than the freshwater-residents during their life history.     

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.     

Acute toxicity of heavy metals, tributyltin, ammonia and polycyclic aromatic hydrocarbons to benthic amphipodgrandidierella japonica

Benthic amphipod,Grandidierella japonica widely inhabits the Korean coastal waters and is developed as a standard test species for sediment toxicity tests. We exposedG . japonica to various pollutants including 4 kinds of inorganic metals (Ag, Cd, Cu and Hg), tributyltin [TBT], ammonia and 7 polycyclic aromatic hydrocarbon (PAH) compounds (acenaphthene, chrysene, fluoranthene, fluorene, naphthalene, phenanthrene and pyrene) to estimate the no observed effect concentration (NOEC) and the median lethal concentration (LC50) of each pollutant during the 96-hour acute exposure. Among all tested pollutants, TBT was most toxic toG. japonica, and Hg was most toxic among inorganic metals. The toxicity of pyrene toG. japonica was greatest among PAH compounds, followed by fluoranthene, phenanathrene, acenaphthene, fluorene and naphthalene. The toxicity of PAH compounds was closely related to their physico-chemical characteristics such as K_ow and water solubility.G. japonica responded adequately to pollutant concentrations and exposure durations, and the sensitivity ofG. japonica to various inorganic and organic pollutants was generally comparable to other amphipods used as standard test species in ecotoxicological studies, indicating this species can be applied in the assessment of environments polluted by various harmful substances.     

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.     

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.     

Dumpton syndrome reduces the tributyltin (TBT) sterilising effect on Nucella lapillus (L.) by limiting the development of the imposed vas deferens

TBT induces imposex and sterilisation in female Nucella lapillus. Interestingly, there are populations where individuals (both males and imposexed females) may suffer from a genetic aberration [Dumpton Syndrome (DS)] which results in the development of no penis (i.e. aphally). This anomaly confers a so far unexplained protection against TBT. Six populations with contrasting DS frequency were sampled; the imposex stage in females and the mean calibre of every vas deferens (VDC) were assessed. While the sex ratio in the 600 specimens examined was close to 1, aphally was more frequent in females than in males (31 and 7%, respectively). VDC was significantly higher in normal than in aphallic (DS) specimens, independently of sex and/or site. It is concluded that the vas deferens imposed by TBT onto DS females is less prone to develop thick enough so as to interfere with normal egg laying.     

东太平洋赤道海域茎柔鱼(Dosidicus gigas)的体型月间变化及环境效应

为了掌握茎柔鱼体型生长变化及其与栖息环境因子的效应关系, 2017年2—4月和6—8月,在东太平洋赤道海域逐月随机采集了3 628尾茎柔鱼样本,进行体质量、胴长的月间变化分析和胴长与海表温、叶绿素a浓度的效应关系研究。结果显示,雌性个体胴长分布范围为163—468mm,体质量分布范围为123—3034g;雄性个体胴长分布范围为171—475mm,体质量分布范围为145—2 681 g。不同月份之间,雌性、雄性个体的胴长和体质量均存在显著性差异,雌雄性个体胴长、体质量均以2月份的最大, 6—8月份的较小。然而,每个月份雌性、雄性个体的胴长分布均为单峰值区间分布。体质量-胴长幂函数关系显示,2—4月份雌雄性个体多倾向于匀速生长、体征较差,6—8月份个体则以负异速生长为主、体征较为良好。雌性、雄性个体胴长与采样海域海表温、采样纬度呈显著的正效应关系,采样海域叶绿素a浓度对雌性胴长产生正效应影响。研究表明,东太平洋赤道海域茎柔鱼体型的月间差异性显著,体型变化与采样海域海表温、采样纬度关系密切,并且雌性体型与海域叶绿素a浓度呈正效应关系。     

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.     

Tributyltin compounds in mussels,oysters and sediments of Chinhae Bay,Korea

To study the historical and current status of the environmental levels of organotin compounds in Chinhae Bay in southeast Korea, mussels (Mytilus edulis galloprovincialis), oysters (Crassostrea gigas) and sediment cores were analysed for tributyltin (TBT) compounds. TBT concentrations were higher in oysters (mean: 0.25 μg TBT-Sn/g dry wt) than in mussels (mean: 0.20 μg TBT-Sn/g dry wt). The major sources of TBT are in the inner bay, and the highest TBT concentrations of 0.50 μg TBT-Sn/g (mussels) and 0.74 μg TBT-Sn/g (oysters) were observed at the site adjacent to the port. Concentrations of TBT decreased sharply with distance from the inner bay toward the outer bay and there was little TBT in the outer bay. A significant correlation was observed between this distance and the tissue TBT content of oysters and mussels. The concentration and percentages of TBT in sediment cores decreased with depth as a result of debutylation. Half-lives of TBT and dibutyltin (DBT) in sediments were 6.9 and 11.6 y, respectively. The TBT concentrations in mussels were higher than those in sediments by a factor of 4–7.     

Reproductive endocrine function in female atlantic croaker exposed to pollutants

To examine whether xenobiotics impair teleost reproduction by altering reproductive endocrine function, steroid hormone secretion and ovarian growth were investigated in female Atlantic croaker (Micropogonias undulatus) after chronic oral administration with sublethal doses of three classes of reproductive toxins (lead, benzo[a]pyrene and Aroclor 1254). All the sublethal treatments significantly impaired ovarian growth as assessed by the gonadosomatic index. Reduced ovarian growth was accompanied by a significant decline in circulating 17β-estradiol levels in fish exposed to lead and benzo[a]pyrene. All three toxicants significantly decreased plasma testosterone levels. However, the steroidogenic capacity of ovarian tissue in vitro was not altered by xenobiotic exposure. The data suggest that the decreased ovarian growth in croaker after pollutant exposure may be a consequence of the decline in plasma 17β-estradiol levels. Further, this decrease in circulating levels of gonadal steroids does not appear to be caused by a direct effect of the chemicals on ovarian steroid synthesis.     

Fecundity in the marine spiny lobster Jasus verreauxi (H. Milne Edwards) (Crustacea: Decapoda: Palinuridae)

Fecundity in Jasus verreauxi (H. Milne Edwards, 1851) has been studied by a detailed investigation of (a) the total weight of eggs carried by female specimens, (b) the average number of eggs per 1 g sample, and (c) the total number of eggs carried by females. In mid October 1966, 217 females “in berry” (that is, carrying external eggs) were examined and measured at Spirits Bay, New Zealand. The fecundity study is based on the results obtained from 21 selected specimens, with carapace lengths from 15.5 cm to 23.5 cm.

A direct relation was found between the total weight of eggs carried and increase in carapace length. The total weight of eggs carried varied from about 51 g to 238 g for carapace lengths of 15.5 cm to 23.5 cm. No correlation was shown between the average number of eggs per 1 g sample and increase in carapace length. Considerable variation was noted in the number of eggs per 1 g sample, which ranged from a low count of 6,453 eggs to a high count of 8,341 eggs. The total number of eggs carried by female J. verreauxi was found to be related to an increase in carapace length. Furthermore, increase in fecundity per relative carapace length increase was noted to be greater in smaller specimens than in larger specimens. The total number of eggs carried ranged from about 385,000 for a carapace length of 15.5 cm to 1,940,000 for a carapace length of 23.5 cm.

Fecundity, as measured by the total weight of eggs carried and the total number of eggs produced, was found to be much higher in J. verreauxi than in several Jasus species previously studied by other workers.     

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.