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Effects of chronic toxicity on threshold food concentrations

Conference ·
OSTI ID:372513
;  [1]
  1. Georgia Inst. of Tech., Atlanta, GA (United States). School of Biology
Food shortage and toxicant stress have been proposed separately as structuring factors for zooplankton communities. How these factors interact to affect zooplankton remains poorly understood. The amount of food ingested by filter feeders depends upon food concentration, and a threshold concentration exists below which population growth is zero. A standard 2-d population growth test was used to determine whether toxicant stress altered the food threshold of the freshwater rotifer Brachionus calyciflorus. Threshold toxicant concentrations resulting in zero population growth rate and the NOEC were also compared at starving and abundant food conditions. Nutritional requirements were related to toxic exposure. For example, the threshold concentration of sodium pentachlorophenate (PCP) was 1.5 times lower at low food concentrations (0.3 million Nannochloris cells per milliliter) than at high food concentrations (3 million cells/ml). These results indicate that both factors must be considered in the validation of standard toxicity tests and their extrapolation to field conditions for ecologically meaningful predictions of toxicity.
OSTI ID:
372513
Report Number(s):
CONF-9511137--; ISBN 1-880611-03-1
Country of Publication:
United States
Language:
English