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Effects of terbutryn on aufwuchs and Lumbriculus variegatus in artificial indoor streams
Author(s) -
Brust Kristin,
Licht Oliver,
Hultsch Veit,
Jungmann Dirk,
Nagel Roland
Publication year - 2001
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620200919
Subject(s) - microcosm , periphyton , environmental chemistry , population , aquatic ecosystem , chemistry , river ecosystem , streams , ecology , biology , ecosystem , biomass (ecology) , sociology , demography , computer network , computer science
The effects of the herbicide terbutryn on a simple lotic food web were investigated during a 72‐d exposure period in five artificial indoor streams in a greenhouse. The model compound terbutryn, an s ‐triazine and an inhibitor of photosynthesis, was applied once in each stream at nominal concentrations of 0.6, 6, 60, or 600 μg/L. Terbutryn concentrations in the water were analyzed by gas chromatography/mass spectrometry, and an overall time to 50% dissipation (DT50) of 28 d was calculated. The development of aufwuchs and the population growth and development of the oligochaete Lumbriculus variegatus were investigated. We determined that terbutryn was toxic to L. variegatus at 23.7 mg/L (96‐h median lethal concentration [LC50]) and 16.5 mg/L (96‐h median effective concentration [EC50]) in static acute toxicity tests. Terbutryn decreased aufwuchs production at 0.6 μg/L in the experimental streams. Population growth of L. variegatus was decreased by 50% at 6 μg/L. The effect of terbutryn on the aufwuchs was a direct effect of decreases in the periphyton. However, the effects on L. variegatus were an indirect effect of terbutryn as a consequence of decrease in the aufwuchs food source and occurred at three‐orders‐of‐magnitude‐lower concentrations of terbutryn than the acute toxicity effects. Our study demonstrates the utility of indoor lotic microcosm studies for evaluating both direct and indirect effects of contaminants on aquatic ecosystems.