coastal urbanisation exposes surrounding estuarine environments to urban-related contaminants such as polycyclic hydrocarbon (PAHs), polychlorobiphenyls (PCBs) and pesticide mixtures.
hydrophobic contaminants can adsorb on estuarine sediments. they can subsequently be released on a massive scale in theaquatic environment due to artificial or natural phenomena there by thre atening living organisms. the contamination of sediment is a significant ecoogical issue in the seine estuary,france. howver, few relevant methods have been develoed to assess sediment toxicity and its ecological impacts in a cost-effective way.
in this context, we aimed to assess sediment toxicity of nutural sediment from the seine estuary on the development of them the calanoid copepod eurytemora affinis using a perviously developed larval bioassay.
this assay invoves direct exposure of naupill to elutriates of sediments for six days.
sediment were collected along the seine estuary from six polluted sites and one reference site.
pollutants in this estuary included PAHs, PCBs and OCPs. nauplius survival was significantly more affected by exposure to all contaminated sediment elutriates, than by exposure to sediment from yville-sur-seine, where as nauplius growth was significantly reduced after exposure to contaminated sediment elutiates from four of the six contaminated sites.
we identifie two distinct site clusters, one including both sand-rich and the least polluted sediment and the orther includting both clay- and silt-rich, and the most polute sediment.
as expected, survival was significantly more impacted after exposure to elutriates from the second cluster than from the first.
this work enables assessment of the toxicity of natural sediment in the seine estuary and validation of the larval bioassay previously developed using sorbed sediment with model molecules.