Phytotoxicity and plant uptake of fuel oil hydrocarbons

The phytotoxicity and phytoavailability of hydrocarbons (HC) were studied in soils artificially contaminated with fuel oil. The presence of HC in the soil inhibited seed germination and reduced plant growth. The germination and development or cultivated plants varied with the chemical structure of HC, the WC concentration in soil, and the plant species. The LC50 values for germination after 8 d in the presence of a fuel oil varied from 0.3 to 4% (oil/soil, w/w) for lettuce (Lactuca sativa L.), barley (Hordeum vulgare L.) clover (Trifolium repens L.), and maize (Zea mays L.) and from 4 to 9% for bean (Phaseolus vulgaris L.), wheat (Triticum aestivum L.), and sunflower (Helianthus annuus L.). Light aromatics and naphtas were the most phytotoxic HC. The inhibition of plant growth increased with HC concentration but was not linearly proportional to the loading rate. Reduction in aerial biomass was >80% for wheat and bean at a concentration of 0.3% and <30% for maize at 1.2%. No saturated nor aromatic fuel oil HC was defected by gas-chromatography in the stems and leaves of maize grown during 110 d on 1.2% oil-contaminated soil, indicating that no uptake of HC from soils occurred.