Toxic concentrations in fish early life stages peak at a critical moment

Abstract

During the development of an embryo into a juvenile, the physiology and behavior of a fish change greatly, affecting exposure to and uptake of environmental pollutants. Based on experimental data with sole (Solea solea), an existing bioaccumulation model was adapted and validated to calculate the development of concentrations of persistent organic pollutants in the tissue of developing fish. Simulation revealed that toxic tissue concentrations of pollutants with log octanol-water partition ratio (K(OW)) > 5 peak at the moment when the larvae become free-feeding, when the lipid reserves are depleted. This may explain the delayed effects observed in fish early-life-stage experiments with exposed eggs. In the field, eggs can be exposed through maternal transfer to adult pollutant tissue concentrations, which will increase in the larva to peak tissue concentrations, exceeding those of the adult fish. The results demonstrate the risk of underestimating the effects of lipophilic persistent organic pollutants with log K(OW) > 5 in short-term, early-life-stage fish tests and underscore the importance of maternal transfer as an exposure route in the field situation.

Differential sensitivity in embryonic stages of the zebrafish (Danio rerio): The role of toxicokinetics for stage-specific susceptibility for azinphos-methyl lethal effects

“…Görge and Nagel (1990) demonstrated for lindane that eggs showed a lower uptake than later larval stages. A study by Foekema et al (2012) demonstrated that fish eggs had a lower uptake and excretion of PCBs compared to newly hatched larvae. Given the presence of the chorion (hatching does not occur before 48 hpf) the slower uptake may be related to the presence of the PVS and its function as a diffusion boundary layer.…”

Early life exposure to PCB126 results in delayed mortality and growth impairment in the zebrafish larvae

“…The onset of delayed mortality coincided with the transition from yolk-sac to the free-feeding larval stage, the moment when the yolk lipids become depleted. The associated release of lipid-stored organic substances leads to a high peak in the internal exposure concentrations (Foekema et al, 2012).…”

Mesocosm validation of the marine No Effect Concentration of dissolved copper derived from a species sensitivity distribution

“…The mesocosms were installed with about 20 cm of natural sandy sediment that was collected from the coastal North Sea and a 150 cm deep water column of natural seawater collected from the Oosterschelde, a relatively pristine tidal bay in direct connection with the North Sea, often used as a reference site in marine ecotoxicological studies in the Netherlands (e.g. Kuiper et al, 2007;Foekema et al, 2008Foekema et al, , 2012. Concentrations of selected metals measured in the batch of water used for this study were 0.2 μg Cd/L, 1.26 μg Ni/L, 0.5 μg Pb/L, 59 μg Zn/L and 1.1 μg Cu/L.…”