Evaluation of Heavy Metals and Total Hydrocarbon Contents in Crassostrea Spp (Oysters) from Qua Iboe River, Ibeno LGA

This study evaluates the level of heavy metals and total hydrocarbon content in Crassostrea spp. (oysters) at Qua Iboe River, Ibeno LGA. Heavy metals analysis was carried out using the Atomic absorption spectrophotometer (AAS) while the total hydrocarbon content (THC) was determined with Gas chromatography fitted with flame ionization detector (GC-FID). The oysters were selected randomly at three sample study areas analyzed for heavy metal and THC. The results for lead, copper, cadmium and nickel analysis showed that the mean metal concentration at site A were as follows: Pb (1.014 ± 0.011 mg/kg), Cu (0.067 ± 0.089 mg/kg), Ni (0.029 ± 0.006 mg/kg), Cd (0.001±0.001 mg/kg); site B - Pb (1.033 ± 0.003 mg/kg), Ni (1.027 ± 0.010 mg/kg), Cu (0.045 ± 0.010 mg/kg), Cd (0.003 ± 0.002 mg/kg) and site C (control) – Ni (1.025 ± 0.002 mg/kg), Pb (0.01 ± 0.001 mg/kg), Cu (0.001 ± 0.001 mg/kg), Cd was below detection limit (BDL). The total hydrocarbon content at site A was (141244.0±6801.3 mg/kg), site B (172130.4±25703.1 mg/kg) and site C (1894.7±94.3 mg/kg). Health risk was estimated to assess the total hazard quotient (THQ) of heavy metals at the study sites. The estimated daily intake of heavy metals at the study sites were: site A Pb (2.589mg/kg), Cd (0.003 mg/kg), Cu (0.171 mg/kg) and Ni (0.072 mg/kg). THQ at site A of Pb was 2.7795, Cd (0.0096), Cu (0.0174) and Ni (0.0005), site B Pb (2.8316) was the highest followed by Ni (0.4927), Cu (0.01167) and Cd (0.0288) and site C (control) Ni (0.4917) was the highest followed by Pb (0.0027) and Cu (0.0003). The THQ results from site C were below 1 and as such the oysters were safe for consumption. The total hazard quotient for sites A and B, for Cu Cd and Ni were less than 1 and Pb greater than 1, implying that the oysters from sites A and B were not safe and will pose an appreciable hazard to humans for the metal pollutants. Statistically, there was no significant difference because the P0.05-value was greater than alpha (p>0.05).