Sediments have a crucial role in biogeochemical cycling and represent a variety of habitats and favorable conditions for a large biodiversity, often supporting the base of aquatic food chains. Over the past decades, sediments have been recognized as the largest global repository of nutrients, metals, and organic micropollutants, decreasing the bioavallability of dissolved contaminants. However, sediments can also act as a source of pollution and impact the health of aquatic ecosystems, either altering the communities living in contact with this compartment or through dredging or flooding. Moreover, the dynamic nature of sediments, with erosion and fluvial processes as critical drivers, and the expected intensification of such processes with climate change make this complex environmental compartment an essential and increasingly important part of evaluating the ecological integrity of aquatic ecosystems.
Sediments are assessed as part of monitoring programs of the ecological quality of water bodies or in specific contaminated areas. Assessments on sediments are also foreseen for the registration of chemicals (e.g. pre-marketing authorizations for pesticides}. In all cases such assessments are based on ecotoxicological data. Sediment toxicity tests have been used in many countries including the US, Canada, Australia and many European countries since the 90s. Standard protocols are available from international agencies but, ideally species of regional importance should be used for increased relevance.
The ecotqx lab at IER has successfully established several test organisms for surface waters, including standard organisms such as Daphnia magna and Dania rerio, and other species more relevant for regional assessment such as Daphnia tumholtzi and Ceriodaphnia comuta. However, until now, no tests for sediment assessment has been established.
The present proposal addresses this gap and proposes to train personnel from the ecotox lab at IER so that the sediment compartment can be effectively considered and studied in Vietnam in addition to surface waters.
With this overall goal, the specific objectives of the project are twofold:
– To provide training to the incoming researcher from the ecotox lab at IER during the visit at EPFL in specific tools for assessing the quality of sediments, including specific toxicity tests relevant for Vietnam and approaches for sediment sampling and pre-treatment, and extraction techniques for quantification of priority contaminants for this environmental compartment.
– To start a collaboration between the partner laboratories, promoting knowledge transfer and mutual exchange of experiences between the two countries in sediment quality and risk assessment and in the other areas in which the Ecotox Centre works (e.g. ecotoxicology of emerging contaminants: terrestrial ecotoxicology).
Dr. Maria del Carmen Casado Martinez
M.Sc. Le Than Kiet Bui