ABSTRACT
Concentration of PAH in bivalves (Arca senilis) and human health risks due to consumption was examined in samples collected from southern Nigeria and analysed using gas chromatography. Mean PAH concentration (ngkg-1) ranged from 12.0⯱â¯5.0-5500.0⯱â¯1000 with a significant difference (pâ¯<â¯0.001) while total PAH ranged from 3000.0-16,000.0. Concentrations (ngkg-1) of PAH4 varied from 250 to 15268.0 while concentrations of PAH8 ranged from 542.0 to 15620.7 with significant difference (pâ¯<â¯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-1) 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 <10-6. 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⯵g kg-1) for PAH4. The margin of exposures were above the 10,000 critical limit proposed by EFSA while incremental life cancer risk (ILCR) value (10-5 - 10-9) 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 (Arca senilis) in southern Nigeria generally have minimal health risk concern via consumption but regular monitoring is required to detect changes.
ABSTRACT
Internationally publicized impacts upon human health associated with potentially harmful element (PHE) exposure have been reported amongst internally displaced populations (IDPs) in Mitrovica, Kosovo, following the Kosovan War. Particular concern has surrounded the exposure to Pb indicated by the presence of highly elevated concentrations of Pb in blood and hair samples. This study utilizes a physiologically-based in-vitro extraction method to assess the bioaccessibility of PHEs in surface soils and metallurgical waste in Mitrovica and assesses the potential daily intake of soil-bound PHEs. Maximum As (210mgkg(-1)), Cd (38mgkg(-1)), Cu (410mgkg(-1)), Pb (18790mgkg(-1)) and Zn (8500mgkg(-1)) concentrations in surface soils (0-10cm) are elevated above guideline values. Samples with high PHE concentrations (e.g. As >1000mgkg(-1); Pb >1500mgkg(-1)) exhibit a wide range of bioaccessibilities (5.40 - 92.20% in the gastric (G) phase and 10.00 - 55.80% in the gastric-intestinal (G-I) phase). Samples associated with lower bioaccessibilities typically contain a number of XRD-identifiable primary and secondary mineral phases, particularly As- and Pb-bearing arsenian pyrite, beudantite, galena and cerrusite. Quantification of the potential human exposure risk associated with the ingestion of soil-associated PHEs indicates that on average, 0.01µg Cd kg(-1) BW d(-1), 0.16µg Cu kg(-1) BW d(--1), 0.12µg As kg(-1) BW d(-1), 7.81µg Pb kg(-1) BW d(-1), and 2.68µg Zn kg(-1) BW d(-1) could be bioaccessible following ingestion of PHE-rich soils in the Mitrovica region, with Pb, and to a lesser extent As, indicating the likely possibility of local populations exceeding the recommended tolerable daily intake. Lead present within surface soils of the area could indeed have contributed to the human Pb burden due to the high bioaccessibility of Pb present within these soils (13.40 - 92.20% in the gastric phase). Data for Pb levels in scalp hair (≤120µgg(-1)) and blood (≥650µgdL(-1); WHO, 2004) for children that have lived within IDP camps in Mitrovica indicate significant Pb uptake has indeed taken place. The highly bioaccessible nature of soil-associated PHEs in this study highlights the need for appropriate environmental management approaches that limit the exposure of local populations to these contaminated soils.
