Phytoremediation of crude oil-contaminated soil using Cynodon dactylon (L.) pers

Abstract

Contamination of soil with petroleum hydrocarbons (PHCs) has become a serious problem in Upper Assam, India. For rehabilitation of oil-contaminated sites, phytoremediation represents a promising technology whereby plants are used to enhance biodegradation processes in soil. The aim of this experiment was to evaluate the efficiency of a native species Cynodon dactylon (L.) Pers. that could be effective in phytoremediation of petroleum hydrocarbon-contaminated soil. Experiments were conducted in net house to determine the tolerance of this species to crude oil-contaminated soil samples with application of two fertilizer levels. Plants were monitored for 180 days to analyze the reduction of petroleum hydrocarbon concentration if any in soil. In the presence of contaminants, plant biomass and height were reduced up to 33.8 % and 21.9 % respectively. As for fertilization, the lower fertilizer level led to higher biomass production. The root growth was reduced under the effects of petroleum hydrocarbon concentration in soil. C. dactylon was found to tolerate crude oil contamination in a concentration of 7.5 % (w/w). The estimation of total oil and grease in soil of the tested plants revealed that C. dactylon could decrease crude oil up to 46.7 % in low fertilizer level (200N, 100P, 100K) and 38.2 % in high fertilizer level (240N, 120P, 120K) in comparison to 11.5 % in low fertilizer level and 10 % in high fertilizer level in control pots without plants. The present investigation reveals that C. dactylon can serve as a low-cost alternative for removal of hydrocarbon contaminants from soil.