Effects of crude oil treatment on the morphology and performance of water hyacinth (Eichhornia crassipes (Mart) Solms) in Niger-Delta region of Nigeria

Abstract

Many aquatic plants existing in the Niger Delta area of Nigeria are at the risk of extinction due to oil spill. The present study was aimed at investigating the effect of different concentrations of crude oil on the morphology and growth performance of the hydrophyte, Eichhornia crassipes present in coastal waters of Nigeria’s Niger Delta region, where crude oil exploitation as well as oil spill is high. The plant, E. crassipes was subjected to varying concentrations of crude oil treatments (1.25%, 2.5%, 5%, 7.5% and 10%). Each treatment was replicated three times. The performance was measured using various growth parameters which include height, number of leaves, leaf area, fresh weight and dry weight. The results showed that the control plant performed better than the treated plants with respect to all the morphological characters considered. The control plant of E. crassipes produced a height of 7.56±0.028 from an initial height of 6.02±0.028. Among the treated plants, 1.25% and 2.5% promoted height, leaf area, number of leaves, fresh and dry weight up to the 6^th week of growth while 7.5% and 10% decreased plant height up to the 4^th week. The E. crassipes treated with 7.5% and 10% crude oil concentrations died 6 weeks following the treatments. The ability of E. crassipes to tolerate the different levels of crude oil was authenticated in this study. However, the study showed that there is a limit of sustenance of petroleum hydrocarbons pollution for E. crassipes above which toxicity will apply.