Project

Ecotoxicological aspects of rational application of chemicals in response to oil spills to reduce environmental damage

This project focuses on ecotoxicological effects of untreated oil, dispersed oil, and the dispersants alone on the stress responses and survival of pelagic plankton species and on benthic organisms.

Oil spilled in the marine environment can pose serious toxicological threats to marine and coastal ecosystems. Depending on the spill characteristics, several response actions can be taken to limit the negative spill effects. One of these is the use of chemical dispersants, which reduces the risk of oil slicks landing on coasts and oiling of birds and marine mammals. Less visible disadvantages are acute increases in exposure of pelagic organisms to dissolved contaminants, and possibly increased sedimentation of complexes of dispersed oil with suspended particles and plankton to the ocean floor, thus threatening benthic species.

This project focuses on ecotoxicological effects of untreated oil, dispersed oil, and the dispersants alone on the stress responses and survival of pelagic plankton species and on benthic organisms. In vitro experiments will be conducted to elucidate the toxic potencies and mechanisms of (dispersed) oil. In vivo experiments with representative marine species will be performed to elucidate the effects on whole organisms, including repopulation and recovery. Passive samplers and biomarkers will be used both to investigate toxic potency as well as to evaluate these as monitoring tools.

Figure 1: Dispersant, oil, exposure water, and extracts of passive samplers in exposure water (A), pore water (B) and sediments (C) will be tested in vitro for toxic potency. In vivo tests with marine organisms will produce a Species Sensitivity Distribution (SSD) and Potentially Affected Fractions (PAFs). Recovery of populations and repopulation of contaminated locations will be studied in mesocosms. Biomarkers and passive samplers will be evaluated as monitoring options. Algal stress responses and the increased sedimentation of marine snow will play a central role throughout the project.
Figure 1: Dispersant, oil, exposure water, and extracts of passive samplers in exposure water (A), pore water (B) and sediments (C) will be tested in vitro for toxic potency. In vivo tests with marine organisms will produce a Species Sensitivity Distribution (SSD) and Potentially Affected Fractions (PAFs). Recovery of populations and repopulation of contaminated locations will be studied in mesocosms. Biomarkers and passive samplers will be evaluated as monitoring options. Algal stress responses and the increased sedimentation of marine snow will play a central role throughout the project.

The enhanced sedimentation of oil in the presence of particles and plankton has not received adequate attention yet. After the Deepwater Horizon oil spill in the Gulf of Mexico in 2010, a thick layer of oiled sediment was found at 800 m depth. This layer contained many phytoplankton and zooplankton species which only occur at the ocean surface. Therefore, influence of particulate matter will be included in the experiments as well.

The research will be performed in collaboration with three other PhD projects, studying biodegradation, modelling the fate of oil under different conditions, and developing a location specific decision support tool.

Collaboration

The research will be performed in collaboration with three other PhD projects, studying biodegradation (WUR – Environmental Technology), modelling the fate of oil under different conditions (NHL Leeuwarden), and developing a location specific decision support tool (WUR – Toxicology).