Toxicity of petroleum substances to microorganisms and plants

The paper discusses sources of petroleum substances in environment and threats caused by petroleum contamination of water and soil. The physicochemical and biological properties of petroleum substances have been determined along with their toxicity, particularly that of aromatic hydrocarbons, including the so-called BTEX group (benzene, toluene, ethyl benzene and xylenes) to microorganisms and plants. Much emphasis has been laid on the properties which shape toxicity. The effect (typically degrading one) on live organisms present in water and soil environment, including biological equilibrium of soil (abundance of microorganisms, enzymatic activity), has been discussed as well as the growth and development of plants growing on soil polluted with these substances. In addition, factors (soil or water properties and condition, C:N ratio, pH reaction, soil moisture, content of organic substance, fertilization, type and species of aquatic or land organisms) which influence the effect produced by petroleum substances on live organisms in environment have been mentioned.