Effects of temperature on type approval testing of ballast water treatment systems.

To limit the risk associated with invasion of habitats by exogenous species, the International Convention for the Control and Management of the Ships' Ballast Water and Sediments was adopted in February 2004 and may soon enter into force. The International Maritime Organization (IMO) has produced guidelines to assess the efficacy and reliability of Ballast Water Treatment Systems (BWTS), but no guidance on how to take temperature into account during test cycles has been provided yet. Temperature is one of the main factors influencing the distribution and ecology of organisms along latitudes. Its increase results in higher grazing, growth, and reproduction rates of zooplankton. Under dark conditions, phytoplankton loss is also increased due to faster natural decay as well as enhanced top down control from zooplankton. Increased temperatures also improve the efficacy of chemical treatment, whereas the decay rates of disinfectants and their byproducts are potentially accelerated. The IMO guidelines for the type approval of BWTS should be amended to include recommendations on how to take temperature into account. Failing to ensure comparability and reliability between tests may pose a threat to the environment and may create problems for those attempting to apply BWTS. We propose to use a fixed Q10 value and a temperature of reference to adjust the retention time in ballast water tanks during testing.

Multiple experimental approaches of immunotoxic effects of mercury chloride in the blue mussel, Mytilus edulis, through in vivo, in tubo and in vitro exposures.

Biological impairments due to mercury discharge into the environment are now an issue of global concern. From the three forms of mercury found in aquatic ecosystems, the immunotoxic effects of mercury chloride were examined in the model animal, the blue mussel. In order to investigate the toxic potency of this chemical, three exposure regimes were carried out: chronic exposure of groups of individuals, a new protocol "in tubo" designed for sub-acute exposures of individuals, and acute exposures of target cells. Chronic exposure revealed significant immunotoxic effects after 7 days at 10(-6)M, while acute exposures showed significant inhibition of phagocytosis at 10(-4)M and 10(-3)M. In sub-acute exposures both circulating haemocytes and haemocyte mortality increased at 10(-4)M and 10(-3)M while phagocytosis and the clearance rate drew hormetic toxic effects on healthy individuals. These results suggest the use of the "in tubo" design for bivalve toxicological individual studies.

Flow cytometric measurement of the clearance rate in the blue mussel Mytilus edulis and the development of a new individual exposure system for aquatic immunotoxicological studies.

Animals in poor health condition are not relevant biological models. The current study focused on the use of the clearance rate of Mytilus edulis to assess the gross physiological condition of individuals maintained in stressful experimental conditions. This approach was developed in a new, highly controlled experimental exposure device designed to investigate individual responses in aquatic ecotoxicological studies. Both clearance rate values and immune parameters analysis indicated that the health condition of mussels kept in 50ml tubes for 24h or 48h was not altered compared to controls, while most parameters were depressed after 72h. Moreover, this study confirms the relevance of flow cytometric for the measurement of clearance rate compared to techniques utilizing microscopy. Current results prompted us to perform further 24h chemical exposure using this "in tubo" device.

A multiparametric approach for monitoring immunotoxic responses in mussels from contaminated sites in Western Mediterranea.

As a part of the multidisciplinary program Biological Effects of Environmental Pollution in Marine Coastal Ecosystems of the European Commission, this study aimed to validate immunological alterations as biomarkers of exposure to chemical contamination in polluted areas of Western Mediterranea. The status of the immune system has been assessed in mussels (Mytilus galloprovincialis) by measuring several immunopathological and immunocompetence parameters. Alterations of total hemocyte counts, lysosomal stability, and phagocytosis were among the most reliable effects observed in polluted sites and suggested immunosuppressive conditions in contaminated mussels. An immunotoxicological index was calculated from the set of individual data. By providing a single value per sampling station to score immunological alterations in mussels, this novel approach allowed recognition of a gradient of perturbation correlated to pollution intensity in two of the three sites monitored. Processing a set of biological parameters by this method was found to increase the ecotoxicological relevance of such multiparametric studies for the assessment of chemical contamination in coastal waters.