Bioaccumulation and toxicity of lipophilic chemical in algae, crustaceans and fish

Lipophilic Organic Chemicals, LOC's constitute an important group of concern pollutants. LOC´s may bioconcentrate and even bioaccumulate via food webs (mostly in terrestrial systems). The compounds may be toxic not only to directly exposed populations of organisms but also cause indirect poisoning of man and other predators at the top of the food chain. While well studied with respect to toxicity and accumulation in fish, surprisingly little information has hitherto been available for other types of organisms, and the sorptive behaviour in surface waters, where algae may constitute a significant particulate phase, is generally not known. Information on sorption is important, nevertheless, not only for assessing the exposure of aquatic organisms to bioavailable toxicants, but also for the purpose of assessing the general chemical fate of LOC's. Sedimentation mediated by sinking algae is here an important transport process moving the LOC's from the water column to the sediments which may act as an ultimate sink and concern compartment since with no or slow biodegradation under the prevailing anaerobic conditions, lrge LOC concentrations may build up in time. The project aimed at contributing to fill the knowledge gabs on ecotoxicity to other organisms than fish, and further to investigate in detail the mechanisms involved in sorption and toxicity to phytoplankton algae including looking at the basic dose concept. According to current practice in aquatic ecotoxicology, concentration (total or dissolved) is used as a dose surrogate., while the real dose defining toxic exposure may either be the sorbed or bioaccumulated amount per unit of biomass or be the bioavailable concentration in partitioning equilibrium with this internal dose or biomass burden.