ENVIRONMENTAL EFFECTS, PHYTOTOXICITY AND BREAKDOWN OF TAR OIL FROM IMPREGNATED TREE STAKES

This study was aimed at evaluating environmental effects of tar oil-impregnated tree stakes using simple and efficient biotests to determine the ecological impacts during tar oil breakdown in the stake and surrounding soil.

– Benzo[a]pyrene (BaP), a carcinogenic compound of the polycyclic aromatic hydrocarbons (PAHs) in tar oil, comprised between 0.05% and 0.2% of the overall PAH concentration in the impregnated tree stakes.

– Kinetic analysis of the dynamics of PAH breakdown in the tar oil impregnated tree stakes over the years using Dixon plots showed 50% PAH breakdown (“Ki”) ca. every 3 years.

– Germination of cress seeds in the orchard soil around tar oil impregnated tree stakes was inhibited or retarded.

– Soil respiration, as an indication of soil microbial activity, was inhibited both in situ close to tar oil impregnated tree stakes and in soil mixed with chippings even from 20-year-old tar oil impregnated tree stakes.

Seed germination and soil respiration proved a sensible indicator of the phytotoxicity and ecotoxicity of tar oil impregnated tree stakes in fruit orchards.

VIII International Symposium on Canopy, Rootstocks and Environmental Physiology in Orchard Systems

J. Lepsis, M.M. Blanke

Malus domestica Borkh., carcinogenic, contamination, creosote, decontamination, eco-toxicity, PAH, polycyclic, aromatic hydrocarbons, pollution, resource conservation, soil, soil respiration, sustainable production

https://doi.org/10.17660/ActaHortic.2007.732.98