Abstract

Burrow pit effluent collected from a waste dump site in the Niger Delta area of Nigeria was subjected to sublethal test using periwinkle (Tympanotonus fuscatus linne). This was to ascertain if the heavy metals and organic constituents in the burrow pit effluent bioaccumulated in the tissues of the organisms. The test was conducted using the Organization for Economic Cooperation and Development (OECD) protocol #218 in a sediment medium with varying concentrations of the test effluent. Low bioaccumulation potentials were observed for the metals in the tissues of the organisms. The determination of sixteen polycyclic aromatic hydrocarbons (PAHs) revealed only three components at relatively low concentrations in the tissues of the organisms at test termination of 28 days for test effluents concentrations (3.125, 12.5 and 50%). Concentrations for benzo [b] fluoranthene were (0.0017 – 0.0039 ppm), phenanthrene, (0.0021 – 0.0049 ppm) and pyrene, (0.0035 - 0.0081 ppm). However, the concentration of PAHs in the tissues of the organisms at test initiation was <0.0001 ppm. There was significant (p < 0.05) difference in the PAHs concentrations in the organisms exposed to the test effluent and the controls. This could lead to adverse ecological imbalance on a variety of aquatic species including bottom dwelling organisms inhabiting such environment if the release of untreated effluent is not controlled in the Niger Delta area of Nigeria.

Key words: Periwinkle (Tympanotonus fuscatus linne), sediment toxicity, effluent, sublethal toxicity (Bioaccumulation).