PhD conferral Foppe Smedes
Aula, Vrije Universiteit Amsterdam
Passive sampling: effective sensing of environmental quality
prof. dr. J. de Boer & prof. P. Mayer, copromotor dr. K. Booij & dr. B. Vrana
Amsterdam Institute of Molecular and Life Sciences
The environment is contaminated with poorly water-soluble (hydrophobic) substances, such as PCBs, hexachlorobenzene, DDT and brominated flame retardants, which accumulate in organisms and eventually humans. This accumulation differs greatly for various environmental compartments such as water, sediment, fish, etc., which have different binding properties in time and space. In addition, concentrations in fish are strongly influenced by the type of fish and biological factors such as lipid content, growth rate, trophic level, food supply and food chain, etc. Consequently, measured concentrations for these hydrophobic substance are not comparable.
Passive sampling – placing a sheet of silicone (or other polymer) in the environment – essentially adds a compartment to the environment with constant uptake properties. The silicone absorbs hydrophobic substances because of their million times or more greater solubility therein compared to water. The solubility in silicone does not differ much from that in fat, and results from passive sampling can accurately be converted to a fat-based concentration. This thesis describes the techniques and calibration of passive sampling in different environmental compartments. Passive sampling was subsequently used to investigate how bioaccumulation in fish of different trophic levels relates to lipid-equivalent concentrations in the water phase.
This lipid-based concentration assessed by passive sampling varies less than that assessed in fish lipid, which is strongly influenced by the above-mentioned biological factors. Passive sampling is therefore a stable method to investigate whether levels of poorly water-soluble substances in surface waters meet EU quality criteria, with the additional benefit of sparing the lives of a significant number of fish.