Environmental modification of the photosynthetic response of lake plankton to surfactants and significance to a laboratory field comparison
Lewis, M.A.; Hamm, B.G.
Water Research 20(12): 1575-1582
1986
ISSN/ISBN: 0043-1354 DOI: 10.1016/0043-1354(86)90123-5
Accession: 005368989
The toxic effects of nine surfactants on the short-term photosynthetic activity of lake plankton and factors affecting the response were investigated in multiple monthly studies conducted during May-October. The impact of the detergent chemicals on photosynthesis differed with the mean 3 h EC50 values ranging from 0.6 to 28.7 mg l-1. The photosynthetic response to the same surfactant varied as much as 80.times., attributed in part to monthly changes in water temperature (range = 17-28.degree. C) and to seasonal differences in phytoplankton composition. Overall, the test chemicals were less toxic during periods of lower water temperature, diatom dominance and low algal density. The in situ photosynthesis results were compared to those from standard algal laboratory toxicity tests to assess the environmental relevance of a laboratory data base. These 96 h tests were conducted with the same surfactants but monitored growth effects on three cultured algae. Based on this comparison, the laboratory effect concentrations were typically either similar to or lower than those in the field. Key considerations in this laboratory-field comparison were the environmental modification of the photosynthetic response, the surfactant type, and the differential sensitivities of the cultured laboratory algae.