Biomedical subjects

Scott E Belanger

Publications and source records attributed to Scott E Belanger.

4 recordsLinked to original sources

PubMed2006

Interspecies correlation estimates predict protective environmental concentrations.

Environmental risk assessments often use multiple single species toxicity test results and species sensitivity distributions (SSDs) to derive a predicted no-effect concentration in the environment, typically the 5th percentile of the SSD, termed the HC5. The shape and location of the distribution are best known when populated with numerous toxicity values. To help overcome the cost of multiple toxicity tests, we explored the potential of the U.S. EPA's Interspecies Correlation Estimation (ICE) program to predict single species toxicity values from a single known toxicity value. ICE uses the initial toxicity estimate for one species to produce correlation toxicity values for multiple species, which can be used to develop SSD and HC5. To test this approach to deriving HC5, we generated toxicity values based on measured toxicity values for three surrogate species Pimephales promelas (Fathead minnow), Onchorynchus mykiss (Rainbow trout), and Daphnia magna (water flea). Algal taxa were not used due to the paucity of high quality algal-aquatic invertebrate and algal-fish correlations. The compounds used (dodecyl linear alkylbenzenesulfonate (LAS), nonylphenol, fenvalerate, atrazine, and copper) have multiple measured toxicity values and diverse modes of action and toxicities. Distribution parameters and HC5 values from the measured toxicity values were compared with ICE predicted distributions and HC5 values. While distributional parameters (scale and intercept) differed between measured and predicted distributions, in general, the ICE-based SSDs had HC5 values that were within an order of magnitude of the measured HC5 values. Examination of species placements within the SSDs indicated that the most sensitive species were coldwater species (e.g., salmonids and Gammarus pseudolimnaeus). These results raise the potential of using quantitative structure activity models to estimate HC5s.

Animals↗

PubMed2005

Utility of stable isotopes ((13)C and (15)N) to demonstrate comparability between natural and experimental streams for environmental risk assessment.

Environmental safety of contaminants sometimes requires testing at the ecosystem level. Model ecosystems can serve as a surrogate to receiving waters for the assessor. Tools to verify that model ecosystems are good surrogates for natural receiving water systems have been based on structural attributes such as taxa lists. While examining taxa lists can be useful within a geography, they are less informative when comparing across different topographical and climatic regions. This paper illustrates an alternative approach that uses natural abundance ratios of nitrogen and carbon. Comparisons were made between the Procter and Gamble Co. (P and G) Experimental Stream Facility (ESF) and the East Fork Little Miami River (EFLMR). We also conducted stable isotopes releases of nitrogen ((15)NH(4)Cl) in the ESF and EFLMR. Results from the nitrogen releases for the ESF and EFLMR were compared to each other and to stable isotope releases conducted in 9 streams as part of the Lotic Intersite Nitrogen eXperiment (LINX). Preliminary evaluations of nitrogen uptake show that the uptake rate of ammonium for the P and G experimental streams (0.019 m(-1)) is similar to uptake rates in natural streams of similar flow and fits the regression of uptake length and discharge for the LINX streams. Nutrient flow data obtained in this study in most cases verified model (SISTM) predictions.

Carbon↗

PubMed2005

Comprehensive assessment of aquatic community responses to a new anionic surfactant, high-solubility alkyl sulfate.

High-solubility alkyl sulfate (HSAS) is a new anionic surfactant for use in consumer product applications that provides enhanced water solubility and improved water hardness tolerance. A comprehensive model stream ecosystem investigation was conducted to assess ecological and toxicological effects of HSAS on stream invertebrates. Model streams were dosed with HSAS for a period of 56 days following 56 days of colonization in a single-pass, flow-through system. Exposures were control and 9.1, 24.1, 64.0, 165.8, and 426.5 microg/L based on specific analytical detection methods. Benthic abundance on gravel substrates, drift, and insect emergence were assessed. Several taxonomically unrelated taxa were found sensitive to HSAS and formed the basis of toxicological conclusions. Abundance or biomass of a limpet (Ferrissea), a bivalve (Corbicula), flatworms (Turbellaria), and a mayfly (Stenonema) was reduced at concentrations ranging from 165.8 to 426.5 microg/L. Principal response curve analysis, a constrained form of principal components analysis, demonstrated consistency with univariate analyses and identified similar populations as being sensitive to HSAS. Comparison with historical studies from the same testing site, streams, and experimental design, but with structurally related alkyl sulfate and alkyl ethoxysulfate anionic surfactants, revealed several similar trends in response profiles at the population level for both tolerant and sensitive species. Based on the comprehensive nature of the study, strength of data trends, and demonstrated sensitivity of the aquatic communities contained in the experimental system, the no-observed-effect concentration for HSAS was concluded to be 64.0 microg/L. An application factor of 1 is justified for deriving a predicted no-effect concentration) for HSAS in aquatic systems.

Animals↗

PubMed2004

Responses of periphyton and invertebrates to a tetradecyl-pentadecyl sulfate mixture in stream mesocosms.

Alkyl sulfates (AS) are anionic surfactants widely used in household and personal cleansing applications. Aquatic toxicity of AS under laboratory conditions indicated effects at relatively low concentrations (50-230 microg/L) for some sensitive species. A comprehensive stream mesocosm study of an AS mixture composed of tetra- (C14) and pentadecyl (C15) chain lengths was conducted to better understand effects on microbial and macroinvertebrate populations and communities. A 56-d exposure of AS was performed at concentrations ranging from 57 to 419 microg/L (analytically confirmed exposures) and was accompanied by detailed investigations of periphyton community function (autotrophy, heterotrophy, and metabolism of test chemical), periphyton structure (algal population and community dynamics based on taxonomic identity), and invertebrate structure (benthic abundance, drift, and insect emergence patterns based on taxonomic identity). A no-observed-effect-concentration (NOEC) of 222 microg/L was concluded for several individual algal and invertebrate species based on univariate statistical analyses. An apparent energetic subsidy from C14-15AS at the highest concentrations of 222 to 419 microg/L was observed and tied to changes in microbial community processing of AS when added at these high concentrations. A multivariate analysis based on principal response curves (PRC) indicated that communities in streams exposed to 222 to 419 microg/L were significantly different from the controls leading to an overall (multivariate and univariate) conclusion that 106 microg/L was the ecosystem NOEC. Exposure to AS in the environment has been demonstrated to be in the range of 5 to 21 microg/L in 100% wastewater treatment plant effluent. Potential environmental effects are at least 5 to 20 times above worst-case environmental exposures; therefore, C14-15AS does not pose a risk to the aquatic environment due to normal use patterns.

Animals↗