Accumulation of hydrocarbons and some heavy metal contents on sediments and plants from crude oil polluted mangrove ecosystem in Okrika, Nigeria

Composite soil sediments samples were randomly collected from three polluted sites in Okrika local Government Area of Rivers State. Old Isakka (01), Imonitanbie (1M) and AgiahiAma (AA). The samples were investigated to examine the effects of crude oil pollution and heavy metals status of soil sediments and plant tissue samples from mangrove ecosystems.The soil sediments were collected at a distance of 0, 20, 40 meters and a control sample taken from distance of 140 meters away from the polluted sites near the river with a spade from each of the locations. Six samples were taken from each location (four soil sediments and two plant samples) totaling twelve sediments and six plant samples. The samples were analyzed for: Total hydrocarbon contents (THC), and heavy metals (Pb, Cd and Zn) using conventional methods of analysis. Result revealed a significant (P1M>AA, the pollution decreased with increase in distance. The three locations were highly polluted with hydrocarbon thus posing a threat to aquatic organisms and human that consume the sea food. THC exceeded the alert and intervention limit for sensitive and less sensitive soils. Significant (P1M>AA. Value of zinc was significantly higher in control than polluted. The order of increase was 01>1M>AA. Both Zinc and Pb were below the permissible limit. There was a significant (P