Chlorpyrifos (CPF) is a widely used broad-spectrum organophosphate insecticide. Following exposures, CPF and its more toxic oxon metabolite (CPFO) elicit neurotoxic effects by inhibiting the activity of the acetylcholinesterase enzyme (AChE), resulting in altered fitness and death at high doses. Following exposure, organisms bioactivate CPF to CPFO through the Cytochrome...
Pacific Northwest and California freshwater resources are key elements in the life history and ecology of Pacific salmon and steelhead listed as threatened or endangered under the Endangered Species Act. Risk to listed Pacific salmonid species can be assessed by evaluating the spatial and temporal co-occurrence of salmonid species at...
Volatile loss rates of pesticides from turfgrass were measured using the Backward-Time
Lagrangian Stochastic Dispersion model (Flesch et al., 1995). Solar radiation, ambient
temperature, surface temperature, relative humidity, wind direction, and wind speed were
monitored continuously. Growth regulator was applied to the turf plot several days before
pesticide application to...
The purpose of this work was to determine if environmentally-relevant
concentrations of chlorpyrifos and copper, two commonly detected chemicals in
Western surface waters, can negatively impact the biological health of salmonids.
Both compounds are highly neurotoxic to fish, but each with distinct biological target
sites and mechanisms of action. We...
Natural and synthetic estrogenic compounds detected in surface waters have
been linked to endocrine signaling disruption in several species. Endogenous
estrogen contributes to cartilage and bone deposition during development in
vertebrates, and is susceptible to perturbation from xenoestrogens. The goals of
this work were to develop a teleost model to...
Organophosphate insecticides may produce sublethal, adverse effects on salmonid
growth, reproduction, maturation, swimming, and feeding. Chlorpyrifos, an
organophosphate insecticide, was detected by the Oregon Department of Environmental
Quality in the Hood River and tributaries during March 1999 at levels exceeding state
water quality standards in the range of 0.011-0.482 μg/L....
Riparian zones of Pacific Northwest forests have high species diversity and
abundance and act as an important interface between the aquatic and terrestrial
ecosystems. In addition, riparian zones comprise a significant portion of the total buffer
zone established during commercial forest production to protect aquatic ecosystems from
adjacent management activities....
Aquatic insects are used extensively to evaluate water quality. Despite their
widespread use as indicator organisms, relatively little is known about the
organismal characteristics that determine sensitivity differences to individual and
multiple stressors. Insects have evolved several respiratory strategies that range
from breathing atmospheric air to utilizing dissolved oxygen in...