Assessment of continuous biodegradation of commercial PCB formulations

Partition of metallic and organochlorinated pollutants and monoorthosubstituted PCB pattern in the trophic web from different areas of the river Seine

The partition of metals and organochlorines was studied along the trophic web at two different pollution level areas of the river Seine. The metal results along the trophic web were: (1) High concentration processes by the sediment (Kb from 0.7 x 10(2) to 32 x 10(2) according to metal). (2) Bioconcentration processes by the plants from the water and the sediment for all metals (Kb from 0.5 10(3) to 13.2 x 10(3)); (3) The mussel (benthic and fossorial) exhibited the highest metal levels; (4) the bream (benthic and detritivorous) had higher metal levels than the roach and the perch. No biomagnification was shown for the metals along the trophic web. The organochlorine results were: (1) High concentration in the sediment with Kb-values about 10(3). (2) A relationship between lipid and PCB levels in plants. (3) No rise in organochlorines along the trophic web at the slightly polluted areas. (4) Occurrence of organochlorine biomagnification in the highly polluted area. For the PCB pattern: (1) The profiles are similar in plants and the water. (2) Sediment and animals exhibited a rise in the more chlorinated congeners accompanied by an impoverishment of the less chlorinated and monoorthosubstituted ones with rising position in the trophic web.

Biodegradability of pesticides in water by microbes in activated sludge, soil and sediment

A relatively simple, aerobic and anaerobic biodegradation test method for pesticides is proposed. The method consists of the inoculation of the test substance to a substrate of non-acclimated microbes in activated sludge, field soil and river sediment in a stirred flask. This method was applied to the evaluation for biodegradability of twelve pesticides. The biodegradation rate constants obtained showed a parabolic correlation with the 1-octanol-water partition coefficients of the pesticides and a linear one with their alkaline hydrolysis rate constants. Therefore, the biodegradability of pesticides can be predicted by these two parameters.