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Doug Hardesty

Doug is a Biological Science Lab Technician at the Columbia Environmental Research Center.

Education and Certifications

  • B.S. Fisheries and Wildlife, University of Missouri-Columbia, 1988

Science and Products

Filter Total Items: 17

Survival and growth of freshwater pulmonate and nonpulmonate snails in 28-day exposures to copper, ammonia, and pentachlorophenol

We performed toxicity tests with two species of pulmonate snails (Lymnaea stagnalis and Physa gyrina) and four taxa of nonpulmonate snails in the family Hydrobiidae (Pyrgulopsis robusta,Taylorconcha serpenticola, Fluminicola sp., and Fontigens aldrichi). Snails were maintained in static-renewal or recirculating culture systems with adults removed periodically to isolate cohorts of offspring for to
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Ecosystems, Contaminant Biology, Environmental Health Program, Columbia Environmental Research Center

Acute and chronic toxicity of sodium sulfate to four freshwater organisms in water-only exposures

The acute and chronic toxicity of sulfate (tested as sodium sulfate) was determined in diluted well water (hardness of 100 mg/L and pH 8.2) with a cladoceran (Ceriodaphnia dubia; 2-d and 7-d exposures), a midge (Chironomus dilutus; 4-d and 41-d exposures), a unionid mussel (pink mucket, Lampsilis abrupta; 4-d and 28-d exposures), and a fish (fathead minnow, Pimephales promelas; 4-d and 34-d exposu
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Ecosystems, Columbia Environmental Research Center

Chronic sensitivity of white sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss) to cadmium, copper, lead, or zinc in laboratory water-only exposures

Chronic toxicity of cadmium, copper, lead, or zinc to white sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss) was evaluated in water-only exposures started with newly hatched larvae or approximately 1-mo-old juveniles. The 20% effect concentration (EC20) for cadmium from the sturgeon tests was higher than the EC20 from the trout tests, whereas the EC20 for copper, lead, or
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Ecosystems, Contaminant Biology, Environmental Health Program, Columbia Environmental Research Center

Use of lethal short-term chlorine exposures to limit release of non-native freshwater organisms

Fish hatcheries and other types of aquatic facilities are potential sources for the introduction of nonnative species of fish or aquatic invertebrates into watersheds. Chlorine has been suggested for use to kill organisms that might be released from the effluent of a facility. While acute LC50s (concentrations lethal to 50% of organisms exposed for up to 96 h) for chlorine are available for some s
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Ecosystems, Columbia Environmental Research Center

Contaminants in stream sediments from seven United States metropolitan areas: part II—sediment toxicity to the amphipod <i>Hyalella azteca</i> and the midge <i>Chironomus dilutus</i>

Relationships between sediment toxicity and sediment chemistry were evaluated for 98 samples collected from seven metropolitan study areas across the United States. Sediment-toxicity tests were conducted with the amphipod Hyalella azteca (28 day exposures) and with the midge Chironomus dilutus (10 day exposures). Overall, 33 % of the samples were toxic to amphipods and 12 % of the samples were to
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Ecosystems, Columbia Environmental Research Center

Toxicity of carbon nanotubes to freshwater aquatic invertebrates

Carbon nanotubes (CNTs) are hydrophobic in nature and thus tend to accumulate in sediments if released into aquatic environments. As part of our overall effort to examine the toxicity of carbon-based nanomaterials to sediment-dwelling invertebrates, we have evaluated the toxicity of different types of CNTs in 14-d water-only exposures to an amphipod (Hyalella azteca), a midge (Chironomus dilutus),
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Ecosystems, Columbia Environmental Research Center

An evaluation of the influence of substrate on the response of juvenile freshwater mussels (fatmucket, Lampsilis siliquoidea) in acute water exposures to ammonia

Acute 96-h ammonia toxicity to three-month-old juvenile mussels (Lampsilis siliquoidea) was evaluated in four treatments (water-only, water-only with feeding, water and soil, and water and sand) using an exposure unit designed to maintain consistent pH and ammonia concentrations in overlying water and in pore water surrounding the substrates. Median effect concentrations (EC50s) for total ammonia
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Ecosystems, Contaminant Biology, Environmental Health Program, Columbia Environmental Research Center

Sensitivity of early life stages of freshwater mussels (Unionidae) to acute and chronic toxicity of lead, cadmium, and zinc in water

Toxicity of lead, cadmium, or zinc to early life stages of freshwater mussels (fatmucket, Lampsilis siliquoidea; Neosho mucket, L. rafinesqueana) was evaluated in 48‐h exposures with mussel larvae (glochidia), in 96‐h exposures with newly transformed (5‐d‐old) and two‐ or six‐month‐old juvenile mussels, or in 28‐d exposures with two‐ or four‐month‐old mussels in reconstituted soft water. The 24‐h
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Ecosystems, Contaminant Biology, Environmental Health Program, Columbia Environmental Research Center

Acute toxicity of copper, ammonia, and chlorine to glochidia and juveniles of freshwater mussels (Unionidae)

The objective of the present study was to determine acute toxicity of copper, ammonia, or chlorine to larval (glochidia) and juvenile mussels using the recently published American Society for Testing and Materials (ASTM) Standard guide for conducting laboratory toxicity tests with freshwater mussels. Toxicity tests were conducted with glochidia (24- to 48-h exposures) and juveniles (96-h exposures
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Ecosystems, Columbia Environmental Research Center

Chronic toxicity of copper and ammonia to juvenile freshwater mussels (Unionidae)

The objectives of the present study were to develop methods for conducting chronic toxicity tests with juvenile mussels under flow-through conditions and to determine the chronic toxicity of copper and ammonia to juvenile mussels using these methods. In two feeding tests, two-month-old fatmucket (Lampsilis siliquoidea) and rainbow mussel (Villosa iris) were fed various live algae or nonviable alga
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Ecosystems, Columbia Environmental Research Center

Assessing contaminant sensitivity of endangered and threatened aquatic species: Part III. Effluent toxicity tests

Toxicity tests using standard effluent test procedures described by the U.S. Environmental Protection Agency were conducted with Ceriodaphnia dubia, fathead minnows (Pimephales promelas), and seven threatened and endangered (listed) fish species from four families: (1) Acipenseridae: shortnose sturgeon (Acipenser brevirostrum); (2) Catostomidae; razorback sucker (Xyrauchen texanus); (3) Cyprinidae
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Ecosystems, Columbia Environmental Research Center

Assessing contaminant sensitivity of endangered and threatened aquatic species: Part I. Acute toxicity of five chemicals

Assessment of contaminant impacts to federally identified endangered, threatened and candidate, and state-identified endangered species (collectively referred to as "listed" species) requires understanding of a species' sensitivities to particular chemicals. The most direct approach would be to determine the sensitivity of a listed species to a particular contaminant or perturbation. An indirect a
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Ecosystems, Columbia Environmental Research Center

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