Pesticides are ubiquitous, with more than one billion tons of pesticide products used in the United States annually. These compounds are characterized by their toxic effects to the target organism; however, pesticides are also well known for their deleterious effects to non-target species. Because pesticides have ecological and human health effects, it is important to
investigate their prevalence in the environment, as well as their bioavailability and toxicity.
Passive sampling devices (PSD) are commonly used to evaluate contaminants, including pesticides, found in water, air and soil. The PSD used for this research is an aquatic sampler that sequesters freely dissolved non-polar and semi-polar contaminants by diffusion into and adsorption to a lipid-free polyethylene membrane tubing (LFT). Thus, PSD can act reasonably as a biological surrogate, mimicking non-dietary bioavailability. Additionally, PSD extracts are proposed to be amenable to investigate toxicity of biologically available environmental mixtures utilizing the embryonic zebrafish (Danio rerio) model.
To investigate this potential application, experiments were performed to evaluate the toxicity of non-deployed blank PSD extracts and
non-deployed extracts spiked with individual pesticides or pesticide mixtures. For this proof of concept study, embryonic zebrafish were static waterborne exposed before the initiation of
organogenesis. Two time points were monitored for mortality and alterations in development. The blank extracts did not result in any adverse developmental effects, relative to non-exposed
controls. Embryos exposed to a comprehensive fourteen compound pesticide mixture extract produced an increase in adverse developmental responses as concentration increased. Experiments investigating the toxicity of individual compounds and partial pesticide mixtures were also performed. These preliminary studies indicate that the coupling of PSD extracts and in vivo toxicological assessments is realistic.