Article

Dynamic Exposure of Organisms and Passive Samplers to Hydrophobic Chemicals

CABE, University of Geneva, Sciences II, 30 Quai Ernest Ansermet, CH 1211, Geneva 4, Switzerland.
Environmental Science and Technology (Impact Factor: 5.48). 05/2009; 43(7):2206-15. DOI: 10.1021/es8029895
Source: PubMed

ABSTRACT An insight into the dynamic aspects of the accumulation process is essential for understanding bioaccumulation as well as effect studies of hydrophobic organic chemicals. This review presents an overview of kinetic studies with organisms (fish, bivalve, crustacean, insect, worm, algae, and protozoan) as well as passive samplers (solid and liquid phase microextraction, semipermeable membrane device, polymer sheet, solid-phase extraction, Chemcatcher, etc.) for the uptake of neutral nonpolar chemicals from the aqueous phase. Information about uptake rates, elimination rates, and 95% equilibration times was collected and analyzed with diffusion based models. The present literature review suggests that the surface to volume ratio appears to be a critical parameter for the uptake rate of the more hydrophobic chemicals both for samplers and organisms. In addition, as a very first approximation, the combination of the first-order kinetic model with the assumption that diffusion through the aqueous boundary layers is rate limiting, gives a reasonable description of the experimental kinetic data. In this way, the presented model might be used to estimate uptake and elimination rate constants of chemicals by organisms or passive samplers.

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Available from: Stephane Bayen, Feb 11, 2014
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    • "Many factors can affect sampling kinetics, such as the sampler geometry, hydrodynamic conditions around the sampler, temperature and fouling on the surfaces, as well as the distribution coefficient between the sampler and water (K SW ). Of these, K SW is considered one of the most important parameters in determining whether a sampler is suitable for evaluating the time-weighted average concentration, as the time required to attain equilibrium between the sampler and water increases with increasing K SW (Huckins et al., 1999; Stuer- Lauridsen, 2005; Mazzella et al., 2007; Bayen et al., 2009; Llorca et al., 2009). Most passive samplers can run in a time-integrative mode, without much modification, for compounds with a high K SW . "
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    ABSTRACT: Despite the great success of time-weighted average passive sampling of hydrophobic contaminants, such as PCBs and PAHs, the sampling of polar organic compounds still presents a challenge because the equilibrium between water and most sampling phases is attained in a relatively short time. In this study, we proposed a new time-integrative sampler using in situ solvent extraction (TISIS) for polar organic chemicals. The sampler was composed of a 15 cm poly(dimethylsiloxane) (PDMS) tubing, with an internal diameter of 0.5 mm and wall thickness of 0.5 mm, through which an extraction solvent (acetonitrile) was passed. Four polar organic contaminants, caffeine, atrazine, diuron and 17α-ethynylestradiol, were chosen for the evaluation of the performance of the sampler. Without the use of in situ solvent extraction, the PDMS tubing when exposed to a constant aqueous concentration of the four model compounds was able to linearly accumulate those compounds for less than 12 h and equilibrium between the PDMS tubing and water was attained in 2 d under our laboratory conditions. However, TISIS when exposed to a constant aqueous concentration was able to linearly accumulate all the model compounds without any exposure time limitation. The measured sampling rates at three different extraction flow rates (0.2, 0.5, 1.5 mL min(-1)) were similar, regardless of the chemicals, indicating that the overall mass transfer from aqueous solution to the extraction solvent was most likely dominated by partitioning to the PDMS tubing and the internal diffusion within PDMS. In addition, a pulsed exposure experiment confirmed that TISIS operated in a time-integrative mode when the environmental concentration was highly fluctuated.
    Chemosphere 11/2011; 86(2):190-7. DOI:10.1016/j.chemosphere.2011.10.011 · 3.50 Impact Factor
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    • "Passivsammler erfassen die chemische Aktivität der Substanzen bzw. die frei gelösten Stoffmengen im Umweltmedium (Bayen et al. 2009). Der verwendete Ansatz basiert auf der Desorption hydrophober organischer Schadstoffe (hydrophobic organic contaminant, HOC) aus Sediment und auf der Gleichgewichtseinstellung zwischen der Matrix , dem Porenwasser und dem Elastomer (Abb. "
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    ABSTRACT: Graduation date: 2010 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.
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