Comparative Assessment of Total Hydrocarbon Content and Bioaccumulation of Heavy Metals in Sarotherodon Melanotheron at Atlas Cove Area and Okobaba of Lagos Lagoon

Industrial waste discharge has increased the hazard of water pollution. The total hydrocarbon content and bioaccumulation of heavy metals in Sarotherodon melanotheron at Atlas cove area and at Okobaba end of Lagoon Lagos were assessed between November, 2014 and January, 2015. The physicochemical parameters were determined according to APHA-AWWA-WEF and heavy metals in the fish species were determined using Atomic Absorption Spectrometer. The total hydrocarbon content (THC) in the fish samples were analysed by using Soxhlet extraction gravimetric methods. The heavy metal values evaluated are Fe, Cr, Pb, Ni and Cu. The concentration of Iron (Fe) in Sarotherodon melanotheron was 72.72 ± 125.95mg/kg, Chromium (Cr)- 10.29 ± 4.61mg/kg; Lead (Pb)- 1.08 ± 0.23mg/kg; Nickel (Ni)- 0.39 ± 0.26mg/kg; and Copper (Cu)- 0.20 ± 0.26mg/kg at Atlas cove area while at Okobaba the concentration were;Fe- 115.98±87,Cr-5.25±1.02,Pb-2.04±1.50,Ni-0.78±0.08,and Cu is 0.36±0.15mg/kg. The levels of accumulation of all the heavy metals in Sarotherodon melanotheron were above the WHO permissible limits. The concentration of n- alkanes in Sarotherodon melanotheron at Atlas cove was 164.69 ± 97.04μg/g, polycyclic aromatic hydrocarbon (PAH) was 73.58 ± 72.48μg/g, and total petroleum hydrocarbon was 526.67 ± 214.34μg/g. The average intake of polycyclic aromatic hydrocarbon through fish consumption at Atlas cove area was estimated to be 5039.94 ± 49.2mg/kg; body weight/day. The mean concentration of nalkanes hydrocarbon in Sarotherodon melanotheron at Okobaba was 152.62±54.11μg/g, the Polycyclic Aromatic Hydrocarbon (PAH) was 74.4±50.30 μg/g.The carcinogenic high molecular weight polycyclic aromatic hydrocarbons (HMW-PAH) were of higher concentrations than the lower molecular weight polycyclic aromatic hydrocarbon (LMW-PAH). Therefore, Atlas cove area is more exposed to carcinogenic health risks associated with the consumption of the studied fish than Okobaba end of Lagos Lagoon. This indicates significant carcinogenic health risks associated with the consumption of black jaw Tilapia fish caught from the study areas.

Keywords:

total hydrocarbon content , Heavy metals , Sarotherodon melanotheron , Lagoon ,