Chlorpyrifos (CPF) is moderately persistent in soils. In our study, microcalorimetry was introduced for the first time to explore the acute toxic effect of CPF on a Pseudomonas strain in sterilized soil. Firstly, it was determined by microcalorimetry that P. putida failed to degrade CPF. Then the acute toxicity of increasing concentrations of CPF to P. putida was determined by its temporal effects on metabolism and counts of colony forming units. Results revealed that the increase of CPF concentration could induce a decrease of the growth rate constant (k) and the total thermal effect (Q T), representing an inhibiting action on P. putida. In addition, the colony forming units (CFU) for P. putida were counted. Results showed that the number of P. putida decreased with increasing CPF dose after 18 h of incubation in sterilized soil. Interestingly, the trend of the number of CFU was similar to the growth rate constant k, whereas the trend became irregular after 36 h of incubation. This indicated that P. putida resisted and also expresses high metabolic activity during the exponential growth phase of 18 h; thereafter the microorganisms showed a certain adaptation, even declining in number and activity.
|Number of pages||7|
|Journal||Archives of Environmental Contamination and Toxicology|
|Publication status||Published - Apr 1 2010|
ASJC Scopus subject areas
- Health, Toxicology and Mutagenesis