The testing of model plant Raphanus sativus germination and phytomass production on oil-composts

Abstract

In industrialized society, large amounts of oily sediments from contaminated sites as well asoily sludge from industrial processes need to be treated in sustainable way. Nowadaysbiological treatment is becoming more important. The purpose of biotreatment is to decreasethe concentration of organic pollutants (e.g. oil) in soil or compost by mineralizing hazardouschemicals into harmless compounds such as carbon dioxide or some other gas or inorganicsubstance, water, and cell material. Whereas hydrocarbons are generally well degradable,some organic compounds (e.g. PAH) are less degradable; and some (heavy metals) can not bedegraded. However, resistant compounds can be transformed through sorption, methylation,and complexation, and change in valence state, which affect mobility and bioavailability. Theuse of oil-compost depends on legislative limits, and response of vegetation. Oil-content mayhave a negative effect on plant root system even in low concentrations. Heavy metals mayinhibit the growth, but in the other hand, the plants are also known in uptaking heavy metalsand other contaminants, known as phytoremediation. This may create a situation, wherevegetation cover acts as additional treatment system for matured oil-composts. The objectiveof this study was to examine the effect of hydrocarbon residues in different substances(compost and soil mixtures) on soil model plants (Raphanus sativus) germination andphytomass production. The germination study demonstrated that the plants germination andbiomass production was highly dependent on compost decomposition degree, nutrient contentand biological properties of soil. On less matured compost, the germination and growth wassuppressed. The phytomass production experiment showed that plants in oil compost haddecreased height, taproot mass and above ground phytomass. The application of complexmineral fertilizers increased the volume of abovementioned parameters.