Bioaccumulation of Polycyclic Aromatic Hydrocarbon (PAH) in a bivalve (- blood cockles) and health risk assessment.

Concentration of PAH in bivalves () and human health risks due to consumption was examined in samples collected from southern Nigeria and analysed using gas chromatography. Mean PAH concentration (ngkg) ranged from 12.0 ± 5.0-5500.0 ± 1000 with a significant difference (p < 0.001) while total PAH ranged from 3000.0-16,000.0. Concentrations (ngkg) of PAH4 varied from 250 to 15268.0 while concentrations of PAH8 ranged from 542.0 to 15620.7 with significant difference (p < 0.001). Diagnostic ratios for PAH source distinction suggested mixture of petrogenic and pyrogenic sources. Dietary daily intake-DDI (ng/kg/day) of individual PAHs ranged from 1.04 to 9.86 while DDI for PAH4 and PAH8 were 340.8 and 379.8 respectively. Carcinogenic potencies (ngkg) varied from 0.012 to 900.0 for individual PAH while carcinogenic toxic equivalent (TEQs) values were 1916.2, 572.49 and 1914.4 for total PAH, PAH4 and PAH8 respectively. The Excess cancer risk (ECR) for individual PAHs, PAH4 and PAH8 were all <10. DDI and ECR values obtained were below USEPA threshold concentration/limits indicating minimal health risk concerns while PAH4 and PAH8 concentrations were also below the EU regulatory limits (30 μg kg) for PAH4. The margin of exposures were above the 10,000 critical limit proposed by EFSA while incremental life cancer risk (ILCR) value (10 - 10) also suggests low potential health risk for consumers of the sea food. The screening value (SV) was 0.095 but lower than observed TEQs values indicating potential health concerns. The study concluded that consumers of bivalves ( in southern Nigeria generally have minimal health risk concern via consumption but regular monitoring is required to detect changes.