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Fluorescence induction as a bioindicator of creosote toxicity in plants

Conference ·
OSTI ID:218466
;  [1];  [2]
  1. Univ. of Guelph, Ontario (Canada). Centre for Toxicology
  2. Univ. of Waterloo, Ontario (Canada). Dept. of Biology
The use of chlorophyll fluorescence induction as a photosynthetic bioindicator was evaluated as part of a study to assess the effects of polycyclic aromatic hydrocarbons (PAHs) on aquatic macrophytes. The wood preservative creosote was used as a mixed PAH source. Toxicity to aquatic plants was measured at the biomarker level using chlorophyll fluorescence induction and compared to effects at the population level in outdoor mesocosms. As well, the aquatic macrophytes Lemna gibba (G3) and Myriophyllum sp., and the green alga Selenastrum capricomutum were exposed to liquid creosote at nominal concentrations of 0.1 to 100 {micro}1/1 in static renewal 8-day toxicity bioassays. Plants were incubated in simulated solar radiation, which mimics the relative levels of UV in natural sunlight. Population-level endpoints (growth rate, cell numbers, chlorophyll content) were compared to results of the fluorescence induction assay. Growth rates of plants were significantly inhibited by creosote at concentrations above 3 {micro}l/l. However, inhibition of photosynthesis was detected by fluorescence induction at the lowest creosote concentration. Fluorescence induction assays of plants exposed to creosote in outdoor mesocosms also detected photosynthetic inhibition at lower creosote concentrations than growth assays, In addition, damage to the photosynthetic apparatus was detected by fluorescence induction after only a few hours of exposure to creosote. Chlorophyll fluorescence therefore appears to be a rapid and sensitive bioindicator for the toxicity of a PAH mixture. The fluorescence induction assay is also consistent with results from growth-based bioassays and is predictive of effects at population levels.
OSTI ID:
218466
Report Number(s):
CONF-9511137--; ISBN 1-880611-03-1
Country of Publication:
United States
Language:
English