[Kinetics of distribution of specific contaminants in an aqueous environment]

The study was carried out for establishing the distribution of benzo(a)pyrene, fluoroanthene, methylene chloride, chloroform and carbon tetrachloride under model conditions, simulating the environment of river water moderately contaminated and distilled water. The experiments were carried out for safe concentrations and concentrations 2-5 times greater at two temperatures: about 20 degrees C and 4 degrees C, and after adaptation of microorganisms to the presence of the analysed substances. In the light of the obtained results the kinetic parameters were established of the degradation process: rate constant and degradation half-times. The process developed in accordance with the kinetic equation of 1st order and depended on the model, group of determined compounds, initial concentration, temperature and microflora adaptation to the presence of the studied substances. Of the studied contaminants the degradation of polycyclic aromatic hydrocarbons-benzo(a)pyrene and fluoroanthene, progressed at the highest rate. The higher rate of degradation in river water than in distilled water suggests that microorganisms present in natural waters participated in the degradation od the determined compounds. This process was slowed down by temperature fall to about 4 degrees C. When the microflora had been adapted to the presence of chlorinated methane derivatives the process of degradation was as rule slower than in the situation of their direct addition to the experimental model adaptation was shown to have no effect on the kinetics of polycyclic hydrocarbon degradation.