The effect of crude oil on growth of the weed (Paspalum scrobiculatum L.) – phytoremediation potential of the plant

Abstract

The use of grasses for phytoremediation of crude oil polluted soils especially in the tropics is a new area of study with a lot of potentials. The effect of different levels (0.00, 2.50, 5.00, 7.50, 10.00, 12.50 and 15.00%) of crude oil contamination on the growth of Paspalum scrobiculatum, a common weed in Nigeria was investigated. The weed is found growing luxuriantly in crude oil contaminated sites in Delta State, Nigeria. 3, 6 and 9 plants per pot of standing crops of the test plant were used for the study. The results show that the plant has potential for phytoremediation as it grew successfully in the different levels or concentrations of crude oil contamination. The different levels of crude oil contamination caused significant reduction in the growth of the plant using plant height, fresh weight and leaf area. The effect increased with increasing levels of contamination (e.g. there was reduction in the leaf area
from 68.47 cm2 in control to 34.07 cm2 in 15.00% level of contamination). The contamination did not cause significant reduction in the dry weights of the plant in 3 plants per pot and 6 plants per pot treatments but only in the 9 plants per pot treatment where the control recorded significantly higher dry
weight than all other treatment. The weed can be used for the restoration of crude oil contaminated soils as it showed great potentials by being able to withstand the high levels of crude oil contamination. It was observed that crude oil contamination did not affect biomass production of the test plant using dry weight basis and plant density improved the performance of the plant in the contaminated soils.

Key words: Phytoremediation, Paspalum scrobiculatum, crude oil contamination, phytotoxicity, biomass