Invasive Species Compendium

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Abstract

Possibility of using Conocarpus lancifolius Engl. in remediation of some Iraqi soils polluted by crude oil.

Abstract

Iraq is one of the main oil producing countries in the world. Soil is sometimes exposing to pollution through the processes of production, piping, transporting, and refining of crude oil. Remediation of such polluted soils is not applying in the country yet. In this research, we suggested the use of new-introduced species Conocarpus lancifolius Engl. in soil phytoremediation. Two types of soil treated with five levels of crude oil pollution were the substrate in which forty seedlings were replanted. Experiment lasted 8 months during which plants were daily irrigated and observations were recorded. Results showed that plants could survive even under the highest pollution level (10%). Depression in growth parameters occurred largely by the addition of 2.5% oil, then it was little with increasing oil percent. Although sandy soil appeared more favorable than clayey one to C. lancifolius, pollution had more impact upon it that made the end growth in both polluted soils not far from each other. Pollution highly affected number of branches during hot months through its retarding from May until September. Unpolluted plants continued growing even though the absolute maximum temperature exceeded 48°C. The addition of 10% of crude oil resulted in declining of growth parameters at the end of experiment between 21%-62% depending on the specific property. Shoot weight was the most affected property by high pollution. From results, it was concluded that C. lancifolius could survive under certain levels of crude oil pollution in Iraqi soils. Further studies were recommended to investigate the capability of the species in degrading total petroleum hydrocarbons in rhizosphere.