[The behavior of polycyclic aromatic hydrocarbons in soil fertilized with sewage sludge-garbage compost. II. Laboratory studies]

The possible destruction in the soil of PAH present in sewage sludge-garbage composts in considerable amounts has been studied under various conditions. Sandy and loamy soil were mixed with the compost and kept in a climate chamber at 20 degrees C, 25 degrees C and 28 degrees C with 30% and 80% relative moisture. One part of the samples was illuminated the other kept in the dark. Control samples with and without compost were sterilized. PAH determinations, bacterial counts on Moutonagar and counts of the actinomycetes were carried out in regular intervals. No influence of temperature, moisture or light could be demonstrated under the experimental conditions. No difference in the behaviour of PAH concentrations in sterilized and nonsterilized soil samples during the periods of experiment, no increase or decrease of PAH were found. There was no correlation between bacterial counts and PAH concentrations. The laboratory experiments confirmed the results of the field investigations.