Bridging environmental mixtures and toxic effects

Abstract

BRIDGES is a bioanalytical tool that combines passive sampling with the embryonic zebrafish developmental toxicity bioassay to provide a quantitative measure of the toxicity of bioavailable complex mixtures. Passive sampling devices (PSDs), which sequester and concentrate bioavailable organic contaminants from the environment, were deployed in the Willamette and Columbia Rivers within and outside of the Portland Harbor Superfund site in Portland, Oregon. Six sampling events were conducted in the summer and fall of 2009 and 2010. PSD extracts were analyzed for polycyclic aromatic hydrocarbon (PAH) compounds and screened for 1201 chemicals of concern using deconvolution reporting software. The developmental toxicity of the extracts was analyzed using the embryonic zebrafish bioassay. BRIDGES provided site-specific, temporally resolved information about environmental contaminant mixtures and their toxicity. Multivariate modeling approaches were applied to paired chemical and toxic effects data sets to help unravel chemistry-toxicity associations. Modeling demonstrated a significant correlation between PAH concentrations and the toxicity of the samples and identified a subset of PAH analytes that were the most highly correlated with observed toxicity. Although this research highlights the complexity of discerning specific bioactive compounds in complex mixtures, it demonstrates methods for associating toxic effects with chemical characteristics of environmental samples.

Sustainable exposure prevention through innovative detection and remediation technologies from the NIEHS Superfund Research Program

“…Passive sampling methods have also been used to predict PAH concentrations in crayfish -a simple model that could be adapted to predict risks of eating other shellfish in contaminated environments (Table 1F) (9). For other studies, researchers use a large quantity of PE not only for chemical analysis, but also for toxicity testing with an embryotic zebrafish developmental toxicity bioassay (10). This way, the PSD application facilitates detection of both the fraction of contamination present and the overall toxicity of the contamination as well.…”

Using passive samplers to assess bioavailability, toxicity, and reactivity of hydrophobic organic chemicals (HOCs)

“…Recent studies have devised methods for using GC × GC retention times for the calculation of numerous environmentally relevant properties such as aqueous solubilities, vapor pressures and K OW . [36][37][38] In this work we developed similar methods for evaluating polyethylene-water (K PEW ) and the phospholipid membrane-water (K PLW ) partition coefficients from GC × GC retention times, which can be used to calculate the corresponding concentration of a chemical in the lipids of an exposed organism, for any given concentration in the passive sampler. The advantages of using chromatography for evaluating partition coefficients is that we can apply this method without needing to identify all the mixture components.…”

“…37 Furthermore, other studies compared the Bligh and Dyer method against other lipid extraction methods (Sohxlet extractions of freeze dried tissue with 10:7 acetone:hexane 38 or acetone extraction of homogenized wet tissue 39 ) and found that the lipid content results could vary by as much as factor of 3. The difference was dependent on the type of tissue (e.g., less than 10% difference for fat fish, but factors of 2-3 more lipids were extracted with Bligh and Dyer versus Soxhlet extraction for lean fish, for polar and nonpolar lipids alike).…”

“…To test this hypothesis, we selected a set of sediments that contained both PAHs and UCMs in various proportions. We note that thus far, numerous studies have proposed the idea that UCM hydrocarbons present in sediments could contribute to cumulative toxicity, 14,38 but very few studies have attempted to test these compounds at levels, and as part of mixtures, that mimic those found in the environment. 21 The passive dosing procedures developed and implemented in this study offer an opportunity to study not only acute effects (as was done in this work) but also long term chronic effects of diverse sets of HOCs and their mixtures.…”

“…This is an improvement over the sampling rate model 23 , which was not able to fit the uptake profiles of all three chemicals. The best fit boundary layers deduced from the finite bath uptake experiments showed a weak dependency on molecular weight ( Figure S4 38 . If we eliminate the deviating points from Figure S4, the R 2 goes up to 0.80, without a significant change in the fit coefficients (δ ≈ MW -0.47±0.06 ).…”