Assessment of heavy metals pollution in surface sediments of a tidal creek in the Niger Delta, Nigeria

The present investigation was carried out to assess the heavy metals pollution in surface sediments of a tidal creek in the Niger Delta, Nigeria. Sediments obtained from Azuabie creek were examined for heavy metals viz., Cd, Cr, Pb and Zn pollution using the Okujagu creek as a control point. Three stations were established on the Azuabie creek while the control creek had one station. Sediments samples were collected in duplicates on a monthly basis for three months (October – December, 2015) and analyzed using atomic absorption spectrophotometry. Results show that Azuabie creek had higher metal concentrations compared to the control creek with mean metal values as follows Zn: 27.5 – 293.3 mg/kg; Cd: 0.0 – 0.6 mg/kg; Cr: 2.8 – 35.7 mg/kg and Pb:5.7 – 22.5 mg/kg. Zn levels in sediment had significant difference (p<0.05) between stations which occurred thus: St1 < St2 = St3 < St Control. The values of Contamination factor (CF) ranged from 0.00 – 3.1 indicating low to moderate level of sediment contamination. The values of the degree of contamination computed ranged from 1.28 at the control station to 5.98 at St.1 while the PLI values generally indicated “no pollution” except at St.3 where the values was slightly >1. Generally, EF and I_geo values were lowest at the control station compared to other stations. The study concluded there was low to moderate level of contamination indicating heavy metal input from anthropogenic origin was found in the study area.