Diuron in Water: Functional Toxicity and Intracellular Detoxification Patterns of Active Concentrations Assayed in Tandem by a Yeast-Based Probe

A study on the acute and chronic effects of the herbicide diuron was carried out. The test, basing on a yeast cell probe, investigated the interference with cellular catabolism and possible self-detoxification capacity of Saccharomyces cerevisiae . Aerobic respiration was taken as the toxicological end-point. Percentage interference (%r) with cellular respiration was measured in water by increased dissolved O 2 concentration (ppm) after exposure to different doses. Interference was calculated through the comparison of respiratory activity of exposed and non-exposed cells. Short-term and long-term (6 and 24 h respectively) exposures were also considered. The test for short-term exposure gave positive %r values except that for 10 −6 M (11.11%, 11.76%, 13.33% and 0% for 10 −10 M, 10 −8 M, 10 −7 M and 10 −6 M respectively). In the case of long-term exposure the test showed positive %r values, but less effect than short-term exposure until 10 −8 M and much higher at 10 −6 M (7.41%, 8.82%, 11.76% and 6.06% for 10 −10 M, 10 −8 M, 10 −7 M and 10 −6 M respectively). The findings of aerobic respiration as toxicological end-point were in agreement with known mechanisms of toxicity and intracellular detoxification for both the doses and exposure times employed.