Heavy Metal Concnetrations in Sediment and Periwinkle -Tympanotonus fuscastus in the Different Ecological Zones of Bonny River System, Niger Delta, Nigeria

ABSTRACT

Studies of total hydrocarbon concentrations (THC) and heavy metals was conducted at the Bonny /New Calabar River in order to determine the level of these contaminants (from municipal and industrial sources) on sediment and important biological organism in the environment in September 2000 for wet and January 2001 for dry seasons. The study area is within the eastern arm of the Niger Delta located between longitude 40 25" to 40 40" N and latitude 70 25" to 70 15" E. In the 3 ecological areas studied, the distribution of THC was found to be higher in dry season (411.53 ± 118.77 mg/l than wet (400 ± 375.50 mg/l). Similarly differences were found in the heavy metals distribution in the river system. The magnitude was in the decreasing order of Zn > Cu > Pb > V>Cd>Cr>Cd respectively. This pattern was consistent for all the ecological zones. Bioaccumulation studies also showed that the Tympanotonus fuscatus tissue had more THC and metal contaminants than the sediment. Although the heavy metal values obtained were less than the regulatory standards, the continued accumulation of the contaminants is a cause for concern. THC in both sediment and tissue are high enough to affect the quality of the organism for human consumption.

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