Relative sensitivity of Chironomus tentans instars to various toxicants
- Environmental Protection Agency, Duluth, MN (United States). Environmental Research Lab.
- Science Applications International Corp., Duluth, MN (United States)
During the recent efforts by the US Environmental Protection Agency to standardize the sediment toxicity test methods, the authors conducted experiments to evaluate the influence of instar on the sensitivity of C. tentans to seven toxicants with varying modes of action. These experiments consisted of water only 96 h acute toxicity tests using C. tentans larvae that were 4-d, 6-d, 8-d, 10-d, and 12-d post-hatch. These ages covered the first, second, third, and fourth instar stages. Toxicants used were copper, nickel, zinc, potassium chloride, diazinon, a surfactant, and ammonia. Each acute test was also conducted using larvae cultured on two different amounts of the same Tetrafin{reg_sign} food. For the type of toxicant, differences in the sensitivity were observed with respect to the age of the animals for the two feeding levels. However, the overall age-specific difference was variable for the type of toxicant. For most of the toxicants, the LC50s varied by 50% or less among the ages tested for either feeding level while the older animals were more sensitive to the surfactant tested yet for potassium chloride the fourth instar was the least sensitive. The trends observed will be discussed. Additional information on identifying the instar and useful measurements will be discussed.
- OSTI ID:
- 49548
- Report Number(s):
- CONF-9410273-; TRN: IM9523%%371
- Resource Relation:
- Conference: 15. annual meeting of the Society of Environmental Toxicology and Chemistry (SETAC), Denver, CO (United States), 30 Oct - 3 Nov 1994; Other Information: PBD: 1994; Related Information: Is Part Of Society of Environmental Toxicology and Chemistry 15th annual meeting: Abstract book. Ecological risk: Science, policy, law, and perception; PB: 286 p.
- Country of Publication:
- United States
- Language:
- English
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