Effects of oil pollution on seed germination and seedling emergence toxicity

Oil spill represents the release of a liquid petroleum hydrocarbon (including its volatile fraction) into the environment, due to human activities like tankers, oil wells, off shore and terrestrial oil platforms. The goal of this paper was to identify potentially useful plant indicator species for ecological restoration and remediate of oil contaminated soils. The use of plant-based system to remediate contaminated soils has become an area of intense scientific study in recent years and it is apparent that plant which grow well in contaminated soils need to be identified and screened for use in phytoremediation technologies. Therefore, in this study the effect of crude oil on germination and seedling emergence of selected plant species was investigated. The objective was to determine if crude oil exerts detrimental effect to plants during early critical stages in their development. The detrimental effect growth was compared to the control after 14 days. Three grass species were tested: Festuca pratensis, Lolium perenne and Poa pratensis. We measured plant height, root length, and plant dry weight. Visual phyto-toxicity was also recorded in a laboratory experiment where seeds that germinated were photographed and morphological parts measured. In contaminated soil that was air-dried at 30 degrees C and volatile compounds lost during the preparation of treatments, the inhibition effect was insignificant. The results indicate that the volatile compounds exert a significant inhibition effect on seed germination and seedling emergence compared tocrude oil. A concentration of 8 mg oil/g soil determined a decrease of about 50% of the biomass and a concentration of 32 mg oil/g soil a decrease of seed germination rate to about 50% for Poa pratensis. In this case the range 64-128 mg oil/g soil is critical to determine the EC50. The soil analyses indicated a content of sand (46%), silt (46%), clay (8%), TN (0.91 +/- 0.12 mg/g dry soil), TP (0.26 +/- 0.08 mg/g dry soil), TK (6.81 +/- 0.56 (mg/g dry soil); and a higher pollution with Total Petroleum Hydrocarbons TPH (C10 - C40) (20 mg/g soil) at Tintea site.