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Measurement of zinc amelioration of cadmium toxicity in Chlorella pyrenoidosa using turbidostat culture
Author(s) -
Bennett William N.,
Brooks Arthur S.
Publication year - 1989
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.5620081006
Subject(s) - chlorella pyrenoidosa , cadmium , toxicity , zinc , population , zinc toxicity , biology , steady state (chemistry) , chemistry , ecotoxicology , zoology , toxicology , environmental chemistry , chlorella , algae , botany , medicine , environmental health , organic chemistry
The amelioration of cadmium toxicity by zinc was measured in terms of changes in the maximum specific growth rate (μ max ) of a Chlorella pyrenoidosa population using turbidostat culture. In this continuous culture system, μ max is a dependent variable that responds directly to toxic effects. At a sublethal cadmium concentration (2.05 μM Cd) in the medium, the population μ max was in steady state at 70% of control values. When zinc was added to the medium to a concentration of 4.08 μM Zn, μ max increased immediately to a rate of 2.2% of control μ max /generation for seven generations, reaching steady state at 90% of the control. Additional increases in zinc did not elicit further increases in μ max . Full recovery of μ max subsequently occurred after five generations in control medium. Mean cell size and percentage dry mass also changed during periods of toxicity and amelioration. Mechanisms of the amelioration process are discussed.