Time-course evaluation of ROS-mediated toxicity in mussels, Mytilus galloprovincialis, during a field translocation experiment

Harbours can be considered as model environments for developing and validating field monitoring procedures and to investigate mechanistic relationships between different biological responses. In this study several biomarkers were investigated in marine mussels caged for 4 weeks (June-July 2001) into an industrialized harbour of NW Italy. Organisms were collected at different time-intervals to better characterize the sensitivity, temporal variations and interactions of analysed responses. Besides single antioxidants the total oxyradical scavenging capacity (TOSC) assay was used to analyse the capability of the whole antioxidant system to neutralize specific forms of radicals: these data were further integrated by measurement of DNA integrity, oxidized bases and the impairment of lysosomal membrane stability in haemocytes. Results showed a biphasic trend for single antioxidants and TOSC, with an increase during the first 2 weeks of exposure to the polluted site followed by a progressive decrease up to a severe depletion in the final part of the experiment.     

Trace metal uptake by the Chinese mitten crab Eriocheir sinensis: the role of osmoregulation

Changes in salinity affect the bioavailability and consequent uptake of trace metals by euryhaline invertebrates. In many cases, salinity-related effects on metal uptake can be explained by changes in chemical speciation but salinity may also influence uptake indirectly through its action on osmoregulatory mechanisms. Specifically, it can be hypothesised that trace metal uptake may be reduced at salinities approaching the isosmotic point of a species because, at this point, there is reduced activity of ionic exchange pumps. The present study tested this hypothesis using the Chinese mitten crab, Eriocheir sinensis, a hyper-hypoosmoregulator with an isosmotic point around 33 per thousand. Crabs were exposed to radio-labelled cadmium and zinc at 23, 33 and 43 per thousand for 4 days. To eradicate speciation effects, crabs were exposed to the same concentration of the radio-labelled free metal ion (estimated using MineQL computer software) at each salinity. Haemolymph samples were taken daily and radio-labelled metal concentrations were estimated from radioactivity counts and used to provide relative measures of metal uptake. Neither cadmium nor zinc uptake was lowest at the isosmotic point. The uptake of cadmium increased significantly with increase in salinity, while the uptake of zinc showed no significant change with increased salinity. Thus changes in trace metal uptake rates in E. sinensis do not appear to be controlled only by changes in free metal ion concentrations. The different effects of salinity change on the uptake of cadmium and zinc (in the absence of free metal ion change) also indicate that physiological responses to osmotic change alone do not control metal uptake rates for this species.     

Vancouver workshop: overview and synthesis

Investigators from the six PICES member nations conducted a May, 1999 interdisciplinary research assessment of Vancouver Harbour, BC, Canada. Sediment contaminants were analyzed at several sites along an assumed pollution gradient extending eastward into the harbour from the relatively less-impacted Howe Sound area (located outside and seaward, to the west). Subsets of a few representative benthic biota (English sole for general contaminants; specific mollusks for TBT) at the sampling sites were concurrently assessed for specific tissue contaminants. Measurements of biotic response to contaminants-across a wide spectrum of biological and ecosystem organization, and ranging from selected biomarkers and tissue responses, to observations at the organism and community level-were likewise conducted. Parameters examined included: P-450 expression, EROD induction and histopathologic assessment of toxicopathic liver lesions in English sole; prevalence and frequency of imposex in neogastropods; perturbations in benthic community responses to pollutants; tissue assays of various bivalve shellfish species for PSP. Results affirmed a consistent east-to-west trend in declining contaminant-associated effects, across a range of biological assessments, thus providing strong evidence that these effects are pollution-related. Specific findings revealed a significant distortion of benthic community structure along the pollution gradient, as well as biomarker evidence of histological and biochemical stress in English sole from central and inner harbour sites. Although the study reaffirms prior assumptions that various species of neogastropods have been extirpated from the harbour, most likely from the antifoulant uses of tributyltin, some of the adverse impacts from TBT may be declining. Also noted were strong biochemical inferences that sediments in the relatively "uncontaminated" Howe Sound, may well contain significant P450-inducing pollutants which were not included as analytes in the design of this limited and preliminary assessment. During the brief sampling period, PSP contamination did not appear to be a significant issue for the harbour.     

胜利原油和Corexit 9527分散剂对海洋围隔实验生态系中浮游动物的影响

本文分析了Corexit 9527分散剂和中国胜利原油对海洋实验生态系中浮游动物群落的影响,得出的主要结论是:1.单独的Corexit 9527对草食性桡足类的生长发育稍有抑制作用,但种群可得恢复和发展,对肉食性桡足类及其他各类浮游动物没有影响;2.Corexit 9527和原油的混合物对所有类别浮游动物均有极大的抑制作用,它导致种群的迅速缩小且无法得以恢复。     

重金属及沉积物对实验海洋生态系中浮游动物的影响

应用濒海陆基水池中8个围隔生冬系实验袋研究污染物对浮游动物的影响,结果表明:低浓度Cd,Cu,Pb,Zn,Hg的混合物对草食性桡足类的生长发育有一定的抑制作用,当浓度增到高值,抑制作用更为强烈.低浓度沉积物对草食性桡足类的生长发育同样具有一定的抑制作用,当浓度增到高值,抑制作用也更为明显,两类污染物均在不同程度上改变了生态系的结构,肉食性桡足类对污染物的反应并不明显,但幼形类住囊虫(Oikipleura sp.)对低,高浓度混合重金属则较为敏感,而对低、高浓度的沉积物却没有表现出明显的反应迹象.     

基底中的澳大利亚微玻陨石：测定铁锰结壳生长速率的一种新方法

Glass(1967)在深海岩心中发现的微玻陨石，根据其地层位置和地理产状，已经被用于将玻陨石和微玻陨石建立起一个成因上的联系，这一点已被其化学性质进一步证实．澳大利亚微玻陨石分布区与布容／松山地磁倒转范围明显有关，由于澳大利亚撞击事件只是瞬时过程，表示的是瞬间的地质记录，所以微玻陨石用于沉积物再生的标志。     

The impact of oestrogenic and androgenic contamination on marine organisms in the United Kingdom--summary of the EDMAR programme. Endocrine Disruption in the Marine Environment

This paper summarises results of the EDMAR programme which is investigating oestrogenic and androgenic endocrine disruption in UK coastal waters. Most of the data concern fish. Four species (flounder, viviparous blenny and two sand gobies) are experiencing feminisation in industrialised estuaries. In males this includes vitellogenin (VTG) synthesis, ovotestis induction and/or feminised sexual characteristics. Although reproductive success may be impaired in some cases, implications for fish populations are still unclear. Suspected causative contaminants include natural oestrogenic substances and synthetic oestrogen mimics. The majority of the oestrogenic activity is adsorbed to sediments, and routes of exposure may include benthic food chain transfer. Some natural androgenic substances are also being discharged to estuaries, but their activity appears low.     

Assemblages of animals around urban structures: testing hypotheses of patterns in sediments under boat-mooring pontoons

Assemblages of animals in soft-sediments were studied in relation to pontoons for mooring private boats in two estuaries near Sydney, Australia. Based on previously observed patterns around other types of artificial structures, it was predicted that assemblages of animals under pontoons would be different from those in similar areas away from pontoons. Hypotheses about overall differences in average abundance and composition between sites with and without pontoons were tested, as were hypotheses about variable differences among and within estuaries. Analyses revealed that there were fewer crustaceans under pontoons in one estuary. The most conspicuous patterns related to pontoons were, however, differences in variability among sites with pontoons compared to sites without pontoons. Differences in spatial variability were found for the overall multivariate structure using Bray-Curtis dissimilarities and for abundances of most major taxa. Total abundance was approximately 60 times more variable among sites without pontoons and number of taxa were seven times more variable among sites with pontoons. Such patterns indicate that impacts of pontoons occur at some sites but not at others. This may be explained by intrinsic differences among sites or by differences in practices for maintenance. Predictions from these two contrasting models need to be tested in order to achieve efficient management of this type of structure.     

Biotransference and biomagnification of selenium copper,cadmium, zinc,arsenic and lead in a temperate seagrass ecosystem from Lake Macquarie Estuary,NSW, Australia

In this study the biotransference of selenium copper, cadmium, zinc, arsenic and lead was measured in a contaminated seagrass ecosystem in Lake Macquarie, NSW, Australia, to determine if biomagnification of these trace metals is occurring and if they reach concentrations that pose a threat to the resident organisms or human consumers. Selenium was found to biomagnify, exceeding maximum permitted concentrations for human consumption within carnivorous fish tissue, the highest trophic level examined. Selenium concentrations measured within carnivorous fish were also above those shown to elicit sub-lethal effects in freshwater fish. As comparisons are made to selenium concentrations known to effect freshwater fish, inferences must be made with caution. There was no evidence of copper, cadmium, zinc or lead biomagnification within the food web examined. Copper, cadmium, zinc and lead concentrations were below concentrations shown to elicit adverse responses in biota. Copper concentrations within crustaceans M. bennettae and P. palagicus were found to exceed maximum permitted concentrations for human consumption. It is likely that copper concentrations within these species were accumulated due to the essential nature of this trace metal for many species of molluscs and crustaceans. Arsenic showed some evidence of biomagnification. Total arsenic concentrations are similar to those found in other uncontaminated marine ecosystems, thus arsenic concentrations are unlikely to cause adverse effects to aquatic organisms. Inorganic arsenic concentrations are below maximum permitted concentrations for human consumption.