Pacific EcoRisk

Fairfield, CA, United States

Pacific EcoRisk

Fairfield, CA, United States
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Hwang H.-M.,University of California at Davis | Carr R.S.,Texas A&M University-Corpus Christi | Cherr G.N.,University of California at Davis | Green P.G.,University of California at Davis | And 9 more authors.
Science of the Total Environment | Year: 2013

The objective of this study was to evaluate the efficacy of integrating a traditional sediment quality triad approach with selected sublethal chronic indicators in resident species in assessing sediment quality in four salt marshes in northern California, USA. These included the highly contaminated (Stege Marsh) and relatively clean (China Camp) marshes in San Francisco Bay and two reference marshes in Tomales Bay. Toxicity potential of contaminants and benthic macroinvertebrate survey showed significant differences between contaminated and reference marshes. Sublethal responses (e.g., apoptotic DNA fragmentation, lipid accumulation, and glycogen depletion) in livers of longjaw mudsucker (Gillichthys mirabilis) and embryo abnormality in lined shore crab (Pachygrapsus crassipes) also clearly distinguished contaminated and reference marshes, while other responses (e.g., cytochrome P450, metallothionein) did not. This study demonstrates that additional chronic sublethal responses in resident species under field exposure conditions can be readily combined with sediment quality triads for an expanded multiple lines of evidence approach. This confirmatory step may be warranted in environments like salt marshes in which natural variables may affect interpretation of toxicity test data. Qualitative and quantitative integration of the portfolio of responses in resident species and traditional approach can support a more comprehensive and informative sediment quality assessment in salt marshes and possibly other habitat types as well. © 2013 .

Clark S.L.,Pacific EcoRisk | Ogle R.S.,Pacific EcoRisk | Gantner A.,Pacific EcoRisk | Hall L.W.,University of Maryland College Park | And 6 more authors.
Environmental Toxicology and Chemistry | Year: 2015

Hyalella azteca are epibenthic invertebrates that are widely used for toxicity studies. They are reported to be more sensitive to pyrethroid insecticides than most other test species, which has prompted considerable use of this species in toxicity testing of ambient surface waters where the presence of pyrethroids is suspected. However, resident H. azteca have been found in some ambient water bodies reported to contain surface water and/or sediment pyrethroid concentrations that are toxic to laboratory reared H. azteca. This observation suggests differences in the sensitivities of laboratory reared and field populations of H. azteca to pyrethroids. The goal of the present study was to determine the sensitivities of laboratory reared and field populations of H. azteca to the pyrethroids bifenthrin and cypermethrin. Specimens of H. azteca were collected from resident populations at field sites that are subject to varied land-use activities as well as from laboratory populations. These organisms were exposed to bifenthrin- or cypermethrin-spiked water in 96-h water-only toxicity tests. The resulting data demonstrated that: 1) field-collected populations in urban and agricultural settings can be >2 orders of magnitude less sensitive to the pyrethroids than laboratory reared organisms; 2) field-collected organisms varied in their sensitivity (possibly based on land-use activities), with organisms collected from undeveloped sites exhibiting sensitivities similar to laboratory reared organisms; and 3) the sensitivity of field-collected "tolerant" organisms increased in subsequent generations reared under laboratory conditions. Potential mechanisms for these differences are discussed. © 2015 SETAC.

Harbourt C.M.,Waterborne Environmental Inc. | Goodwin G.E.,Waterborne Environmental Inc. | Clark S.L.,Pacific EcoRisk | Gantner D.,Pacific EcoRisk | And 5 more authors.
ACS Symposium Series | Year: 2014

A multi-site, spatio-temporal transect study on the Lower American River was conducted to systematically investigate the influence of agricultural and urban landcover, river flows and rainfall events on the concentration of pyrethroids. The majority of the flow in this section of the river throughout the year is controlled discharge from Folsom Dam. Local storm drains, small ephemeral channels and an extensive network of organized storm drain collection and pump stations discharge excess rainfall from surrounding urban and suburban environments into the Lower American River channel. Rainfall event-driven sampling was carried out during the 2011-2012 and 2012-2013 rainy seasons for eight pyrethroids. Results indicate that rainfall-runoff events are the driving perturbations behind the infrequent and highly variable pyrethroid movement into the Lower American River. A variety of factors contribute to environmental complexity. However, rainfall is the only true driver, while other land cover complexities, stormwater detention systems, and hard surfaces contribute to the variability in local rainfall-runoff contribution to river flows. © 2014 American Chemical Society.

Arnold W.R.,Aquatic Ecological Risk Assessment | Cotsifas J.S.,Pacific EcoRisk | Ogle R.S.,Pacific EcoRisk | DePalma S.G.S.,University of Waterloo | Smith D.S.,Wilfrid Laurier University
Environmental Toxicology and Chemistry | Year: 2010

The copper sensitivity of four saltwater invertebrates (the mussel Mytilus galloprovincialis, the oyster Crassostrea virginica, the sand dollar Dendraster excentricus, and the sea urchin Strongylocentrotus purpuratus) was determined experimentally using chronic-estimator embryo-larval test procedures. The effect of sample dissolved organic matter (DOM) content on Cu bioavailability was determined for these species using commonly prescribed test procedures. Comparisons were made among these test results and test results reported previously for two other invertebrate species: the mussel Mytilus edulis and the copepod Eurytemora affinis. All six species exhibited a direct and significant relationship between the sample dissolved organic carbon (DOC; a surrogate measure of DOM) and either the dissolved Cu median lethal concentration (LC50) values or median effect concentration (EC50) values. This relationship is significant even when the DOM has different quality as evidenced by molecular fluorescence spectroscopy. Once normalized for the effects of DOM, the Cu sensitivity of these species from least to most sensitive were E. affinis < D. excitricus < C. virginica ≈ S. purpuratus ≈ M. edulis ≈ M. galloprovincialis. This ranking of species sensitivity differs from the saltwater species sensitivity distribution proposed in 2003 by the U.S. Environmental Protection Agency. These results support the need to account for factors that modify Cu bioavailability in future saltwater Cu criteria development efforts. More specifically, Cu saltwater species sensitivity distribution data will need to be normalized by factors affecting Cu bioavailability to assure that accurate and protective criteria are subsequently developed for saltwater species and their uses. © 2009 SETAC.

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