Phenanthrene kinetics in blue crab from dietary sources

The disposition of many PAHs have been intensively studied.^1–3 However, many questions need to be examined on the fate of low-level PAH assimilation. Included among these are models of bioaccumulation and transport. In this study sexually mature male and female blue crabs (Callinectes sapidus) were administered known doses of ¹⁴C-phenanthrene by gavage. Accumulation from the gut and elimination from the whole body were determined for single and multiple dose studies. The data were applied to models describing absorption site kinetics and fluctuations in body burden.^3–7 For both sexes absorption and elimination follow first-order kinetics. Elimination of phenanthrene in male crabs declines as a single first-order rate process while in the female crabs a biexponential pattern indicates two phases of elimination, not a two-compartment pharmacokinetic model.⁸ No storage of phenanthrene should occur except for recent exposures. However, a stepwise accumulation of metabolites occurs with successive dosing.     

Heavy metal stress induced hyperglycemia in blue swimmer crab, Portunus pelagicus

The study was to find out the effect of cadmium and mercury on levels of hemolymph glucose, crustacean hyperglycemic hormone (CHH) and hepatopancreas glycogen in the blue swimmer crab Portunus pelagicus. The experiments were performed in both intact and eyestalk ablated crabs. Quantification of CHH was done by the indirect ELISA with the aid of primary anti-Carcinus maenas-CHH antibody. Higher glucose concentration was observed on exposure to 8×10^-6 of cadmium ((825.6±5.42) μg/mL) and 6×10^-6 of mercury ((90.5±6.25) μg/mL) after 48 h and 24 h respectively. Higher level of hemolymph glucose was observed in eyestalk intact crabs on exposure to cadmium and mercury than eyestalk ablated crabs. Decrease in the levels of CHH was observed in both eyestalk intact and ablated crabs on heavy metal exposure. Decline of the hepatopancreas glycogen level was also witnessed with the exposure to heavy metal, which validated its utilization in the production of glucose. Thus this study brings to light, the variations in hemolymph glucose, CHH and hepatopancreas glycogen on heavy metal stress. These carbohydrate metabolites can be used as biomarkers in assessing heavy metal contamination in water bodies.     

UHPLC-LTQ-Orbitrap-MS非定向筛查贝类中氮杂螺环酸毒素及其代谢产物

为了分析复杂贝类和微藻中的氮杂螺环酸毒素（AZAs）及其代谢产物,建立一种基于超高效液相色谱-线性离子阱/静电场轨道阱组合式高分辨质谱（UHPLC-LTQ-Orbitrap-MS）联用技术的非定向筛查分析方法。采用Full MS/dd MS²、PRM和Target-SIM/dd MS²三种质谱鉴定模式,整合多种数据采集挖掘策略,通过研究多种AZAs在不同基质样品中的质谱裂解规律及特征碎片离子丰度,实现AZAs及其衍生物的快速筛查检测和精准鉴别。结果表明：PRM模式能有效排除AZAs同分异构体的干扰,获得更高的专属性,适用于目标代谢物筛查;应用Full MS/dd MS²和PRM结合的方式,根据AZAs裂解途径及多种AZAs代谢产物裂解规律,在贝类中共鉴别出20种AZAs系列化合物,其中包括初步推测了3种新型AZAs代谢产物的结构。应用本方法还发现AZA9、AZA10、AZA19等代谢物均随代谢过程持续升高,是AZA2在贝类代谢过程中的末端产物。该方法能够为复杂基质中的AZAs系列毒素及其衍生常规检测与精准鉴别提供参考,可应用于解析AZAs毒素在贝类体内的代谢转化机制研究。     

Metabolism of tributyltin oxide by crabs, oysters and fish

Bis(tributyltin) oxide (TBTO) is widely used as an antifouling agent in various antifouling paints. Thus, some marinas have TBTO concentrations as high as 2 μg/liter.¹ These concentrations can be toxic to zooplankton.² The objectives of the present study were to determine the ability of a number of marine animals, including crabs, oysters and fish, to metabolize TBTO. Earlier work showed that extracts of rat liver were able to metabolize TBTO to a variety of metabolites, e.g. β-hydroxybutyldibutylin.³ The role of the cytochrome P-450 dependent mixed-function oxygenase system in oxidizing TBTO in marine animals was also of interest. Both in vivo (uptake of ¹⁴C-TBTO from food or water) and in vitro studies demonstrated that all the animals were able to metabolize TBTO. The oysters metabolized TBTO at a much slower rate than the other animals. The mixed-function oxygenase system from hepatic tissues of the various animals was able to metabolize TBTO by forming a number of hydroxylated metabolites.     

Seasonal variability of leaf litter removal by crabs in a Kandelia candel mangrove forest in Jiulongjiang Estuary, China

The seasonal variability of leaf litter removal by crabs was observed from May 2006 to April 2007 in a Kandelia candel mangrove forest in Jiulongjiang Estuary, China. Daily average quantities of leaf fall ranged 0.85–3.86 gDW m⁻² d⁻¹, with high values in May, August, October and November. The whole-year's leaf fall was 6.48 t ha⁻¹ yr⁻¹ (1.81 gDW m⁻² d⁻¹). The standing stock of leaf litter on the forest floor was 7.78 gDW m⁻² averaged from the whole year's data, with the lowest value in December (1.23 gDW m⁻²) and the highest in April (16.18 gDW m⁻²). Annually averaged removal (consumption on mangrove floor + burial in burrows) rate of leaf litter by crabs was 0.59 gDW m⁻² d⁻¹. High seasonal variability was observed in the removal rates of leaf litter by crabs. Removal rates in the winter months (December, January and February) were 0.07–0.09 gDW m⁻² d⁻¹, much lower than those in other months with values of 0.59–1.18 gDW m⁻² d⁻¹. Annually averaged percentage of leaf fall removed by crabs was 33%, with the highest values in September (reached 76%) and the lowest values in winter months. Of leaf litter removed by crabs, a large proportion was buried by crabs, and only 12% was consumed by crabs on the forest floor. Leaf litter removal rate, consumption rate on the forest floor, percentages of leaf fall and standing stock removed on the forest floor were significantly positively correlated with air temperature, indicating that leaf removal ability by crabs was higher in warm months than in cold months.     

A non-destructive assessment of the exposure of crabs to PAH using ELISA analyses of their urine and haemolymph

Urine and haemolymph can be repeatedly sampled from crabs with no (or limited) damage to the organism. Their analysis offers a measure of the animals' exposure to biologically available contaminants. Shore crabs (Carcinus maenas) were exposed to the PAHs phenanthrene and pyrene at concentrations ranging from 20 to 200 microg l(-1). After 48 h, urine and haemolymph samples were taken and analysed using ELISA and UV-fluorescence spectrophotometry. High correlations were recorded between the two sets of results from the urine analyses (r2 = 0.83 for phenanthrene and r2 = 0.88 for pyrene). Contaminant concentrations were much lower in haemolymph than in the urine. Analyses of urine taken from crabs collected from clean and contaminated sites confirm the suitability of these analyses for environmentally exposed organisms. Again, a good correlation was recorded between the ELISA and spectrofluorimetric analysis (r2 = 0.83). In this instance, difficulties were experienced with haemolymph analyses owing to a lack of sensitivity.     

Fate modeling of nonylphenol ethoxylates and their metabolites in the Dutch Scheldt and Rhine estuaries: validation with new field data

The environmental behavior of nonylphenol ethoxylates (A₉PEO) in the Rhine and Scheldt estuaries (The Netherlands) was investigated using a hydrodynamic advection-dispersion fate model (ECoS 3). The model was validated with the results of field studies, in which A₉PEO as well as the metabolites nonylphenoxy ethoxy acetic acids (A₉PEC) and nonylphenol (NP) were analyzed in sediment, water and suspended particulate material (SPM) samples using LC–MS methods. Maximum actual concentrations observed in surface sediments were 620, 560 and 1100 ng g⁻¹ d.w. for A₉PEO, A₉PEC and NP, respectively. In the dissolved phase, maximum observed concentrations amounted to 1100 ng L⁻¹ (A₉PEO), 6500 ng L⁻¹ (A₉PEC) and 960 ng L⁻¹ (NP). Clear spatial trends were observed for dissolved A₉PEO and metabolites in the Scheldt estuary, with decreasing concentrations going downstream. This concentration decrease was steeper than for conservatively behaving compounds. This trend was not visible in the Rhine estuary. The fate model was applied to A₉PEO and metabolites in both estuaries. Transport of chemicals in the water column was considered as a longitudinal one-dimensional process through a number of estuary segments. For the Rhine estuary, to cope with the stratification observed, a model structure was chosen consisting of two water layers above each other, between which exchange was possible. Sedimentation/erosion processes were included in the model. A biodegradation scheme was incorporated, and rates were adjusted to fit the calculated concentration profiles with the actual profiles of both A₉PEO and its metabolites. In this way, field biodegradation rates for A₉PEO, A₉PEC and NP could be derived, which were in agreement with values from literature. The measured dissolved concentration profiles as well as salinity and concentrations of SPM could be described successfully by the model. The concentrations calculated in SPM and sediment were of the same order of magnitude as the actual concentrations. In the Rhine estuary, additional sources of A₉PEO had to be included to account for the relatively high concentrations in the middle of the estuary. The fate model for the Scheldt estuary could be slightly improved by using salinity-dependent biodegradation rates. A sensitivity analysis of the model showed that in the Scheldt estuary, the environmental process with the strongest influence on the dissolved concentration profiles of A₉PEO and metabolites is biodegradation. In the Rhine estuary, the water residence time is too short for significant biodegradation to occur, and in this estuary the dissolved concentration profiles were mainly influenced by the additional A₉PEO sources.     

Diversity and abundance of mangrove fiddle crabs, genus Uca (Decapoda, Ocypodidae) at a mangrove in Kema, North Sulawesi, Indonesia

Mangrove ecosystems are sites with high biodiversity of benthic fauna, and fiddler crabs (genus Uca) are common benthic fauna in mangroves. The North Sulawesi in Indonesia has a good condition of mangrove while the information of the fiddler crabs is still limited. Manual samplings were conducted in wet, dry and transient seasons at a mangrove in Kema, North Sulawesi to investigate the species composition, density and distribution pattern of fiddler crabs. A total of 168 individuals, subjected to eight species of genus Uca crabs were collected at the mangrove, with U. triangularis having the highest abundance and U. annulipes having the lowest abundance. The densities of fiddle crabs were 27.56 ind./m², 32.89 ind./m² and 14.22 ind./m² at the seaward, middle and landward zones, respectively, and the density was higher in dry and wet seasons than in transient season.     

Basin-scale distribution of NH<Subscript>4</Subscript><Superscript>+</Superscript> and NO<Subscript>2</Subscript><Superscript>−</Superscript> in the Pacific Ocean

We used more than 25,000 nutrient samples to elucidate for the first time basin-scale distributions and seasonal changes of surface ammonium (NH₄ ⁺) and nitrite (NO₂ ^?) concentrations in the Pacific Ocean. The highest NH₄ ⁺, NO₂ ^?, and nitrate (NO₃ ^?) concentrations were observed north of 40°N, in the coastal upwelling region off the coast of Mexico, and in the Tasman Sea. NH₄ ⁺ concentrations were elevated during May–October in the western subarctic North Pacific, May–December in the eastern subarctic North Pacific, and June–September in the subtropical South Pacific. NO₂ ^? concentrations were highest in winter in both hemispheres. The seasonal cycle of NH₄ ⁺ was synchronous with NO₂ ^?, NO₃ ^?, and satellite chlorophyll a concentrations in the western subtropical South Pacific, whereas it was synchronous with chlorophyll-a but out of phase with NO₂ ^? and NO₃ ^? in the subarctic regions.     

Ciguatera: the detection of neurotoxins in carnivorous reef fish from the coast of Cameroon,West Africa

This work examined 64 large, carnivorous reef fish from the coastal waters of Cameroon for toxicity commonly associated with an incidence of ciguatera fish poisoning. The samples were also subjected to m-DNA analyses to confirm their taxonomic identification. The analyses showed that a subgroup of fish locally referred to as groupers are actually in the snapper family (Lutjanus spp.). Extracts from 22 barracuda Sphyraena barracuda and 42 snapper Lutjanus spp. samples were prepared and examined for the presence of ciguatera-like toxins. Sodium-channel activation was assessed by a sodium-channel-specific bioassay using mouse neuroblastoma (N2a) cells. Extracts were also subjected to chemical analysis via liquid chromatography/mass spectrometry (LC/MS) to compare the mass of peaks of interest to the molecular weights of fish toxins previously described. Two barracuda and one snapper tested positive for a sodium-channel activator, i.e. presumptive ciguatoxin, in the N2a assay. LC/MS analyses showed that only these three samples contained high-intensity peaks, with masses of 1 222 amu and 1 279 amu. These results represent the first analytical report indicating the presence of sodium-channel-specific neurotoxins in fish from along the coast of West Africa. Given the importance of such marine carnivores to the nutrition and socio-economy of the coastal populace, education and disease management appear to be warranted.     

Food preferences of mangrove crabs related to leaf nitrogen compounds in the Segara Anakan Lagoon,Java, Indonesia

The large amounts of leaf litter produced by tropical mangrove forests serve as a major food source for the benthic fauna. The reasons for the preferential consumption of mangrove leaves by crabs are unclear as yet. We investigated the diet, food preferences and consumption rates of 8 dominant grapsoid crab species (Perisesarma spp., Episesarma spp., Metopograpsus latifrons, and Metaplax elegans) in mangroves of Segara Anakan, Java, Indonesia, by means of stomach-content analysis and feeding experiments. Leaves from the five most abundant mangrove tree species (Aegiceras corniculatum, Avicennia alba, Ceriops decandra, Rhizophora apiculata, and Sonneratia caseolaris) were analyzed for organic carbon, total nitrogen, δ¹³C, δ¹⁵N and amino acids and hexosamines. This study is the first that investigated crab food preferences related to the nitrogen compound composition of leaves.Our results show that Episesarma spp. and Perisesarma spp. are omnivorous crabs which mainly feed on detritus, mangrove litter and bark, and on a small amount of roots, algae and animal matter whereas M. elegans is a detritus feeder. In feeding experiments with green, yellow and brown leaves Perisesarma spp. and E. singaporense had the highest consumption rates for brown leaves of R. apiculata and S. caseolaris, and for green leaves of A. alba. Preferred leaves were characterized by a high amount and/or freshness of nitrogenous compounds and their biochemical composition was significantly different from that of disliked leaves (all leaves of A. corniculatum and C. decandra, green and yellow leaves of R. apiculata and S. caseolaris). The presence of the hexosamine galactosamine found only in brown leaves indicates that bacteria contribute to the amount of bioavailable nitrogen compounds. We infer that the nitrogen compound composition rather than the C/N ratio alone is a determinant for bioavailability of mangrove leaves and hence may partly explain the crabs' food preferences.     

Equilibrium and structural studies of silicon(IV) and aluminium(III) in aqueous solution. II. Formation constants for the monosilicate ions SiO(OH)3− and SiO2(OH)22−. A precision study at 25°C in a simplified seawater medium

The hydrolysis of silicic acid, Si(OH)₄, was studied in a simplified seawater medium (0.6 M Na(Cl)) at 25°C. The measurements were performed as potentiometric titrations (hydrogen electrode) in which OH^? was generated coulometrically. The total concentration of Si(OH)₄, B, and log[H⁺] were varied within the limits 0.00075 ? B ? 0.008 M and 2.5 ? -log[H⁺] ? 11.7, respectively. Within these ranges the formation of SiO(OH)₃^? and SiO₂(OH)₂^2? with formation constants log β_?11(Si(OH)₄ ? SiO(OH)₃^? + H⁺) = ?9.472 ±0.002 and log β_?21(Si(OH)₄ ? SiO₂(OH)₂^2? + 2H⁺) = ?22.07 ± 0.01 was established. With B > 0.003 M polysilicate complexes are formed, however, with $\text{-}\text{log[H}{}^{\mathrm{+}}\text{] ? 10.7}$ their formation does not significantly affect the evaluated formation constants. Data were analyzed with the least squares computer program LETAGROPVRID.     

Characterization of hydrocarbons in a subsurface oil-rich layer in the Sargasso Sea

The hydrocarbon composition of seawater samples collected within a subsurface oil-rich layer in the southwest North Atlantic Ocean (Sargasso Sea) during February–March, 1978, has been examined in detail. Chromatograms generated through gas chromatographs/mass spectrometry (GC/MS) analyses of saturated and aromatic hydrocarbons are characterized by a narrow unresolved envelope (UCM or unresolved complex mixture) containing isoprenoids as major resolved peaks, suggesting a petroleum source which has undergone moderate biodegradative weathering. Distributions of terpanes, steranes and polycyclic aromatic hydrocarbons corroborate the inferred fossil origin. Stable carbon isotopic compositions (δ¹³C) suggest that the source of these hydrocarbons is enriched in ¹³C in comparison with most petroleums. The results support the previous suggestions (Harvey et al., 1979) that this layer is part of a massive submarine oil seep originating somewhere on the Venezuelan shelf, although its origin cannot be attributed to seepage of a specific oil formation.     

Environmental tolerances of the beach-hopper Orchestia gammarellus (Pallas) (Crustacea:Amphipoda)

Orchestia gammarellus (Pallas) will tolerate temperatures from 0°C to c. 30°C but dies in < 1 h at 35°C. Both small and large animals survive > 96 h in water (aerated) between 1 and 60%(.) salinity. In distilled water and 100%(.) brine death occurred after 8–24 h. In fully saline water, pH reduction to c. 3·3 is tolerated. Highly alkaline (pH 11–13) conditions in low salinity media are rapidly fatal. Ammonium concentrations (in fully saline water) some five orders of magnitude higher than normal for seawater are tolerated, reflecting the enhanced ammonium concentration encountered in rotting weed beds. Cl⁻ ion concentration equivalent to that in normal seawater will not support O. gammarellus in the absence of Na⁺ ions. High NO₃⁻ concentrations (> 100 mg NO₃⁻ litre⁻¹) are fatal in < 24 h. A large range of NaCl concentrations is tolerated (one to two orders of magnitude dilution) by immersed animals. Animals will live longer in air, however, when fed low Na⁺ food than when immersed in seawater diluted to an equivalent ion strength. Ca²⁺ and K⁺ ions cannot substitute for Na⁺. Orchestia gammarellus will, however, tolerate wide variations in the ratio of Na⁺:K⁺ ions (i.e to a shift from 30:1 to 0·3.1) in hypo-osmotic media. At 10°C it will survive c. 5 h of anoxia. It will penetrate into strongly reducing conditions (− 318 mV) even with access to better oxygenated conditions. In nature, behavioural avoidance probably ensures that O. gammarellus does not encounter many of these parameters at acutely limiting values. That this species is so tolerant, however, bears on the evolutionary adaptability of talitrid amphipods to non-marine conditions. Desiccation sensitivity and Na⁺ ion dependency are the species' most important barriers to life on land.     

Hydrocarbon geochemistry of the Puget Sound region—III. Polycyclic aromatic hydrocarbons in sediments

Polycyclic aromatic hydrocarbon (PAH) distributions and sources are characterized in 96 sediment samples from 24 ²¹⁰Pb-dated cores collected at locations in the greater Puget Sound. The highest PAH concentrations are found within a few kilometers of several sources including industrial facilities in northern Puget Sound, urban areas in central Puget Sound, and river systems draining coal-bearing strata. Regional patterns of combustion-derived PAH in surficial sediments indicate little atmospheric or waterborne exchange of PAH between different regions of the Sound. Significant subsurface maxima in combustion-derived PAH concentrations (²¹⁰Pb dated at the 1950s) occur only in sediment cores collected near urban centers. Perylene apparently derives from erosion of a terrestrial source with little or no evidence of in situ production at depth in sediment cores. Coal fragments are carriers of a characteristic suite of alkylated phenanthrene, chrysene, and picene derivatives concentrated near river mouths in central and southern Puget Sound.     

Population ecology of fiddler crab, Uca lactea annulipes (Decapoda: Ocypodidae) in Sirik mangrove estuary,Iran

Fiddler crabs are known as the most conspicuous bioturbating animals in mangrove forest, which by their burrowing activities promote nutrient cycling in ecosystems. Mangroves, crabs and bacteria are connected in the form of positive feedback loop, whereby an increase in the activity of any participant will tend to increase the activity of all others as well. Population structure, growth, mortality, recruitment, biomass and production of fiddler crabs as dominant species of deposit-feeder crabs have been investigated from May 2005 to March 2006 in the Sirik mangrove estuary in the eastern part of Strait of Hormuz. Ten 1 m² squares of the substrate were randomly sampled during low tide. There was a significant change in organic content in the sampling area during study period. The sex ratio was significantly deviated from 1:1 ratio in large sizes, where males were dominated year around. Fiddler crabs showed seasonal growth pattern during a year, which the maximum growth was observed during autumn and early summer and ceased during winter by low temperature. Growth parameters were estimated by Appeldoorn's method and fitted with seasonalized von Bertalanffy growth models. The Kimura likelihood ratio test revealed significant differences in the overall growth curves between males and females, originated from the differences in k$k$ and L_∞$L_{\mathrm{\infty }}$ between sexes. Males were found to exhibit higher growth rate and larger size than females, this could be attributed to the higher investment of energy for reproduction in females. Reproduction was restricted to spring and early summer, while recruitment occurs at the end of summer. Total annual production of males and females was 37.90 and 10.05 g dry weight/10 m² respectively and major production took place during early summer. Because of impact of temperature on the activity of fiddler crabs in subtropical regions, density of crabs has significant positive correlation with temperature (P < 0.01), while growth rate shows significant negative correlation with organic matter of sediment (P < 0.05). In conclusion these crabs showed lower mortality and production rate with the seasonal growth and recruitment in comparison with tropical species.     

Intertidal mangrove boundary zones as nursery grounds for the mud crab Scylla serrata

The demand for mud crab Scylla serrata (Forsskål 1775) in the global market has increased, hence there is growing momentum to farm the species in Africa. Aquaculture production in Kenya and elsewhere in East Africa currently relies on juvenile seeds sourced from the wild. Wild-seed collection calls for management of the juvenile crab industry founded on knowledge of the species’ ecology, so as to achieve a sustainable seed supply and recruitment to the capture fishery. This study investigated the tidal, diurnal and seasonal occurrence of juvenile crabs in three habitats (intertidal-flat boundary zones, inside the mangroves, and in channels) in small creeks (Mida, Kilifi and Mtwapa) and Gazi Bay, on the coast of Kenya. Sampling was done with scoop nets and seining at receding tides and via burrow searches at low spring tides (day and night). Juveniles in the mangrove/intertidal-flat boundary zone were found sheltered under mangrove leaves or debris, or in shallow burrows during low spring tides, whereas at receding tides they could be seen moving out with the tide or searching for sheltering substrate or burrows. Catch per unit effort at high-abundance sites varied between 59 and 68 crabs fisher^?1 day^?1. More juvenile crabs, sized 10–80 mm internal carapace width (ICW), occurred at night during the receding tide. Net-seining was effective in the collection of juvenile mud crabs <30 mm ICW, whereas burrow sampling was effective for gathering larger crabs. However, collection of juveniles by seining reduced the quality of the crabs caught due to frequent loss of chelipeds, as compared with retrieving individual crabs by searching burrows. Some juveniles collected in the intertidal-flat boundary-zone habitat were either in the process of moulting or had just moulted, indicating the significance of this habitat for mud crabs at this physically delicate life stage.     

Protein expression from zooplankton communities in a metal contaminated NW mediterranean coastal ecosystem

Bidimensional and monodimensional polyacrylamide gel electrophoresis were used to study protein expression from zooplankton collected in thirteen stations of Toulon Bay (NW Mediterranean). In this ecosystem, Little Bay showed higher trace metal concentrations (13.5–23.8 nM for Cu, 0.73–1.24 nM for Pb, 27.8–58.7 nM for Zn) than Large Bay (Cu 2.2–15.6 nM; Pb 0.19–0.78 nM; Zn 9.0–38.8 nM). Trace metals positively correlated (p < 0.05) with expression of four zooplankton proteins (MW in kDa/pI: 25.0/5.6; 48.8/4.1; 38.2/4.4; 38.3/5.8) and with biomass of Oithona nana, predominant copepod in Little Bay. Sequencing by LC–MS/MS putatively provided zooplankton identity of these proteins: they were cytoskeleton actin, except one protein that was the chaperone calreticulin. We suggest that actin and calreticulin could be regarded as zooplankton markers of metal stress and be involved in a possible tolerance of O. nana to contamination, contributing to its development in a marine perturbed ecosystem.     

The fate of polyaromatic hydrocarbons in an intertidal sediment exposure system: Bioavailability to macoma inquinata (mollusca: Pelecypoda) and abarenicola pacifica (annelida: Polychaeta)

Macoma inquinata, a detritus feeding clam, was exposed for 60 days to coarse-grained, and Abarenicola pacifica, a burrowing polychaete, to fine-grained, sediment. Each sediment contained ¹⁴-C-labelled phenanthrene, chrysene or benzo(a)pyrene. Over 70% of the chrysene and benzo(a)pyrene, but only 8% of the phenanthrene, remained in the coarse sediment during the exposure. Essentially all of the chrysene and benzo(a)pyrene and 70% of the phenanthrene remained in the fine sediment. The concentrations of chrysene and benzo(a)pyrene in the clams rose steadily, reaching levels 11·6 and 5·2 times as high as those in the sediment. The tissue phenanthrene concentration rose for 3 days, then fell to one-eighth of the initial concentration. The concentrations of each of the aromatic hydrocarbons in Abarenicola tissue increased for 2 weeks to four to six times the sediment levels. The tissue concentration of chrysene remained constant thereafter, but the levels of phenanthrene and benzo(a)pyrene fell to three-quarters of their peak values. No intermediate degradation products of any of the hydrocarbons were identified in extracts of sediment from either exposure system, or in solvent extracts of tissue or of tissue digestates.Significant ¹⁴C-activity, associated with non-solvent extractable compounds, remained in tissue digestates of individuals of both species exposed to phenanthrene.     

The reliability of analytical data for tributyltin (TBT) in sea water and its implications on water quality criteria

To investigate the reliability of analytical data for tributyltin (TBT) in sea water, split water samples were distributed to ten laboratories in six countries. The sub-surface samples comprised: (i) an offshore (0·5 km) water sample, (ii) the same sample but spiked with an undisclosed quantity of TBT standard compound (175 ng TBT⁺ liter⁻¹), and (iii) a sample taken from a yacht marina. The seven acceptable data sets were in good agreement for the spiked sample (178 ± 26 ng TBT⁺ liter⁻¹) but showed a greater variation in concentrations reported for the yacht marina sample (366 ± 93 ng TBT⁺ liter⁻¹). Atomic absorption and gas chromatographic-flame photometric detection techniques produced results of similar accuracy and precision. Samples acidified with 1 ml of 10% (v/v) acetic acid appeared stable for more than 2 weeks when stored refrigerated and in darkness. Analyses of the offshore seawater sample revealed TBT contamination (9 ± 7 ng TBT⁺ liter⁻¹) indicating dispersion of the compound to the shelf waters off Monaco. The spread in values reported by the laboratories demonstrates inherent difficulties in obtaining good precision below approximately 20 ng TBT⁺ liter⁻¹. This observation is discussed with respect to the setting and enforcing of water quality standards.