Details

Autor(en) / Beteiligte

• Deardorff, Angela D
• Stark, John D

Titel

Population-level toxicity of the insecticide, spinosad and the nonylphenol polyethoxylate, R-11, to the cladoceran species Ceriodaphnia dubia Richard

Ist Teil von

• Journal of environmental science and health. Part B, Pesticides, food contaminants, and agricultural wastes, 2011-01, Vol.46 (4), p.336-340

Ort / Verlag

Philadelphia, PA: Taylor & Francis Group

Erscheinungsjahr

2011

Quelle

Taylor & Francis

Beschreibungen/Notizen

• The effects of the natural insecticide, spinosad, and the agricultural adjuvant, R-11, were evaluated on populations of the water flea, Ceriodaphnia dubia after chronic 8-day exposures. The number of individuals used to start the chronic exposure studies (founders) and the number of offspring/surviving female were significantly reduced after exposure to spinosad concentrations ⩾ 2.5 μg/L. The final number of individuals was significantly reduced after exposure to spinosad concentrations ⩾ 1.0 μg/L. Population growth rate was significantly reduced after exposure to spinosad concentrations ⩾ 1 μg/L. Extinction occurred (defined as negative population growth rate) after exposure to spinosad concentrations of 10 μg/L. Therefore, negative effects were observed in C. dubia after exposure to spinosad at a concentration near the chronic expected environmental concentration (EEC) of 2.3 μg/L. R-11 was much less toxic to C. dubia than spinosad. The number of founders was not significantly reduced until C. dubia were exposed to 12,000 μg/L. The number of offspring/surviving female, final number of individuals, and population growth rate were significantly reduced after exposure to R-11 concentrations ⩾ 5,000 μg/L. Extinction occurred after exposure to R-11 concentrations of 12,000 μg/L which was above the EEC of 790 μg/L. These results indicate that spinosad and R-11 both have lethal and sublethal effects on C. dubia. However, spinosad appears to affect C. dubia at or near the EEC while R-11 does not negatively affect this species until concentrations are much higher than the EEC.