重质原油和轻质原油水溶性组分对紫贻贝(Mytilus edulis)毒理效应的研究

近年来,海洋石油开采与运输泄漏、石油及产品离岸排放等事故逐年增多,对近海海域生态环境产生了巨大破坏。为探究重质原油和轻质原油对紫贻贝(Mytilus edulis)毒理效应,测定了不同浓度重质原油和轻质原油暴露下紫贻贝鳃和外套膜中过氧化氢酶(CAT)和超氧化物歧化酶(SOD)的活性及体内石油烃的含量变化。结果显示,石油污染暴露下,紫贻贝腮和外套膜中CAT和SOD活性变化明显,与暴露浓度和暴露时间有关。CAT活性在轻质原油组随着浓度的增大,呈现下降趋势,且随着暴露时间的延长呈现先下降后上升趋势;在重质原油暴露组,随着浓度的增大,呈现先上升后下降趋势,且随着暴露时间的延长呈现先下降后上升趋势。SOD活性在轻质原油与重质原油暴露组,随着浓度的增大,呈现下降趋势,且随着暴露时间的延长呈现上升趋势并存在一定的剂量-效应关系。重质原油和轻质原油暴露168 h后紫贻贝体内总石油烃含量呈线性递增,生物富集系数(BCF)随着暴露浓度的增加不断减小并最终趋于平稳。结果表明,以紫贻贝腮和外套膜中SOD和CAT活性作为石油烃污染的生物标志物具有一定应用前景,紫贻贝对原油溶液中石油烃的生物富集作用可用来判断污染原油的来源和性质。     

Bioconcentration of Cd and Ni in various tissues of two marine bivalves living in different habitats and exposed to heavily polluted seawater

Two marine bivalves, Mytilus galloprovincialis and Callista chione, were exposed to various concentrations of cadmium and nickel (0.5, 1.0, 2.5 and 20 ppm), for 20 days, plus 10 days’ depuration period, in a laboratory experiment. Animals from each experimental condition were dissected and the bioaccumulation and distribution of Cd and Ni were determined in their gills, mantles and remaining bodies. The concentrations of Fe and Zn were also measured. Heavy metal tolerance, bioconcentration and distribution of heavy metals in tissues were considerably different in M. galloprovincialis and C. chione: (i) both animals were tolerant to Ni pollution, even at the highest concentration used; (ii) C. chione was more tolerant to Cd; (iii) M. galloprovincialis was a better Cd and Ni accumulator, with the exception of the highest Cd concentration tested, where C. chione accumulated more Cd; (iv) Fe and Zn levels were much more affected in M. galloprovincialis; (v) in general, accumulation and distribution of Ni and Cd in the tissues were metal-, species- and time of exposure- dependent; (vi) significant amounts of heavy metals remained in the tissues after 10 days’ depuration. Our results support a hypothesis for a two competing processes mechanism for metal accumulation and detoxification.     

Processing of antifouling paint particles by Mytilus edulis

Particles of spent antifouling paint collected from a marine boatyard were ground and subsequently administered to the filter-feeding bivalve, Mytilus edulis, maintained in static aquaria. Concentrations of Cu and Zn were measured in seawater throughout a 16 h feeding phase and a 24 h depuration phase, in rejected and egested particles collected during the respective phases, and in the organisms themselves at the end of the experiments. Concentrations and distributions of Cu and Zn in processed particles indicated that M. edulis was able to ingest paint particles, regardless of whether nutritionally viable silt was present, and no mechanism of particle discrimination was evident. Enrichment of Cu and Zn in the visceral mass of individuals and in the aqueous phase during depuration supported these assertions, although elevated concentrations in other compartments of the organism (e.g. shell, gill) suggested that biotic and abiotic uptake of aqueous metal was also important.     

Preliminary investigation of sensitive biomarkers of trace metal pollution in mussel (Mytilus galloprovincialis) from Izmir Bay (Turkey)

The aim of this study was to identify possible relationships between biochemical- superoxide dismutase (SOD), glutathione peroxidase (GPx), thiobarbituric acid reactive substances (TBARS) of mussels (Mytilus galloprovincialis) and chemical (Hg, Cd, Pb, Cr, Cu, Zn, Mn and Fe) contaminants from relatively clean area (Middle Bay) and heavily polluted area (Inner Bay) of the Izmir Bay. Sampling of mussels was performed in the beginning of May 2004. Mussel digestive glands have been used for biochemical assays. Trace metal content was determined by atomic absorption spectrophotometer using standard procedures. Metal contents in mussels collected at polluted site increased compared to the middle part of the bay. While there was a positive correlation between metals and SOD enzyme activity, there was a negative correlation between metals and GPx enzyme activity. An increase was observed in SOD enzyme activity and a decrease of GPx enzyme activity at the inner part of the bay.     

Chromium in intertidal sediments of the Clyde,UK: potential for remobilisation and bioaccumulation

Detailed surveys of intertidal sediments have been performed along the north and south shores of the Inner Clyde estuary, UK. Surface sediment data reveal significant spatial variation in Cr content and an association with major sediment characteristics and location within the estuary. Depth variation for Cr and other heavy metals cannot be explained by variation in major geochemical controls such as grain size and organic matter and highlights the impact of historical contamination on sediment quality. These elevated levels at depth may still have environmental impact through redox-reactivity, in association with iron and manganese. Sequential extraction of sediments and pore water analysis of Cr(VI) and Cr(III) provide detailed information on release potential from the sediments. The implication of Cr mobility for biota in the estuary has been assessed by the analysis of a common marine bivalve, Mytilus edulis (Blue Mussel) and a burrowing polychaete, Nereis diversicolor (rag worm) from a number of survey sites. Bioconcentration factors for Mytilus indicate that the weakly held portion of sediment Cr is available for uptake and in the case of Nereis, bioaccumulation appears to be inhibited by sediment organic matter.     

The Use of Mytilus Galloprovincialis Acetylcholinesterase and Glutathione S-Transferases Activities as Biomarkers of Environmental Contamination Along the Northwest Portuguese Coast

With the aim of using Mytilus galloprovincialis acetylcholinesterase (AChE) and glutathione S-transferases (GST) activities as biomarkers of environmental contamination in risk assessment studies along the northwest Portuguese coast, the objective of this study was to provide background information related to: (1) baseline values of these enzymatic activities both in reference and contaminated areas and their responsiveness as indicators of exposure to environmental contaminants; (2) the importance of seasonal variations of such biomarkers in M. galloprovincialis along this area. For this, the activity of these enzymes was seasonally determined in mussels collected from four sites, including a reference and three stations with different contamination sources along the referred area. Statistically significant differences on both enzymatic activities were found among the four sampling stations, at the four sampling periods. In comparison to the reference station, lower AChE and higher GST activity values were found in mussels collected in stations potentially contaminated by pesticides and domestic/industrial effluents and in mussels collected in the vicinity of an oil refinery and an industrial/mercantile harbour, respectively. The results obtained in this work highlighted the potential suitability of these biomarkers to be used as components of environmental monitoring programs in risk assessment studies along the northwest Portuguese coast. Since a seasonal variation in both enzymatic activities was found, the possible implications of such variability in the use of these enzymes as environmental biomarkers are also discussed.     

全氟辛酸在紫贻贝体内的富集、分布与消除

以紫贻贝为受试生物,采用半静态暴露的方式,研究了全氟辛酸（PFOA）在紫贻贝体内的富集特征、器官分布与消除规律.结果表明,紫贻贝可快速富集PFOA,整贝在不同浓度PFOA暴露下,于4~6d达到平衡态,半衰期为0.34~0.44d（约8~10h）,生物富集系数（BCFs）为5.10~9.55mL/g.PFOA在紫贻贝鳃和内脏团中的富集作用大于外套膜、性腺和闭壳肌.紫贻贝中PFOA的含量在净化6~9d后趋于空白组水平,主要代谢途径可能为鳃的作用.紫贻贝对PFOA的富集作用与暴露浓度相关,浓度越低,吸收系数和生物富集系数越大.     

Immune modulation in the blue mussel Mytilus edulis exposed to North Sea produced water

The discharge of oil well produced water (PW) provides a constant source of contaminants to the marine environment including polycyclic aromatic hydrocarbons, alkylated phenols, metals and production chemicals. High concentrations of PW cause adverse effects to exposed biota, including reduced survival, growth and reproduction. Here we explore the effects of PW on immune function in the blue mussel, Mytilus edulis. Mussels were exposed for 21 days to sublethal PW concentrations (0.125-0.5%) and cellular parameters were measured. Cell viability, phagocytosis and cytotoxicity were inhibited after exposure to 0.25% and 0.5% PW, whilst the 0.125% PW treatment produced significant increases in these biomarker responses. This biphasic response was only observed after 7 days exposure; longer exposure periods led to a reduction in immune parameters. Results indicate that PW concentrations close to the discharge point cause modulation to cellular immunity. The implications for longer-term disease resistance are discussed.     

Assessment of the effect of environmental pollution in a marina on caged mussels using chemical and genotoxic analysis

An integrated approach using the contamination levels and DNA damage in mussels (Mytilus galloprovincialis) was applied in order to assess the chemical contamination in a marina (Eastern coastline of Aegean Sea). Mussels, which were harvested from a reference site (Foca), were transplanted into a marina situated along the coast of Izmir Bay. The transplanted mussels were collected at the 14th, 30th and 60th day of the experimental period. Polycyclic aromatic hydrocarbon (PAH) levels (27–51?ng?g^?1?wet?weight) detected in the mussels were similar to the levels detected in other coastal areas of the Mediterranean Sea. The marina’s sediment was found to be contaminated with PAHs (∑PAH?=?25?µg?g^?1) of pyrolytic origin and may become a source of pollution and a threat to the marine environment. In order to assess the DNA damage, the haemolymph and gill cells of the mussels were used for the comet analysis and considered as an indicator of exposure to genotoxic chemicals including 16 PAH compounds and metals. The highest levels of DNA damage expressed as %Tail-DNA (%T-DNA) were observed at the end of the experiment (21.5% T-DNA). The correlation analyses conducted between 2-, 3-, 4-ring PAHs in mussels and %T-DNA in haemolymph and gill cells showed a significant positive correlation. This investigation confirmed that transplanted mussel can be a useful tool to determine PAH contamination in marinas.     

Effects of estrogen exposure in mussels, Mytilus edulis, at different stages of gametogenesis

Mytilus edulis were exposed to 17β-estradiol (E2) and the synthetic estrogens ethinyl estradiol (EE2) and estradiol benzoate (EB) for 10 days. Two exposures were performed to determine their effect on vitellogenin (VTG) and estrogen receptor 2 (ER2) mRNA expression at different stages of the reproductive cycle. Significant natural variation was not observed in VTG mRNA expression, though ER2 mRNA expression displayed significantly lower values during January, February and July compared with other times of the year. A significant increase in VTG and ER2 mRNA expression was observed in mussels exposed to estrogens at the early stage of gametogenesis. In contrast, mature mussels displayed no statistically significant change in the VTG or ER2 mRNA expression. The data presented suggests that the reproductive physiology of molluscs, in terms of VTG and ER2 mRNA expression, may be susceptible to damage by environmental estrogens at certain points in their gametogenesis process.