Heavy metal detection in shellfish from an area in front of Selaata

Abstract

The bivalves, Spondylus gaederopus, highly sold in the Lebanese local market, were harvested from Selaata in North Lebanon, and tested for their contamination by four heavy metals, mercury (Hg), lead (Pb), cadmium (Cd) and chromium (Cr). Studies were carried out in order to assess the risk, these bivalves may cause to human health. The region of Selaata hosts a large number of industrial, as well as, residential activities. Samples were also harvested from Al-Barbara, 11.5 km south of Selaata, and analyzed for their heavy metal contamination. This region was considered a control area due to the absence of industrial activity. The relationship between heavy metal content and the bivalve weight was also investigated. A negative correlation between the weight and the amount of heavy metal, ie Hg, Pb and Cr, concentrated in tissues was detected in shellfish harvested from Selaata. Cadmium however, did not show any significant relationship to the weight of the organisms. Shellfish collected from Al-Barbara did not show a significant correlation between the weight and the amount of the four heavy metals tested. In addition, the result of the analysis showed no significant difference in the means of heavy metal contamination in shellfish between the two regions. In Selaata, the mean levels of heavy metal concentration in shellfish tissues were 0.123, 0.509, 0.457 and 1.113 mg/kg for Hg, Pb, Cd and Cr respectively. On the other hand, Hg, Pb, Cd and Cr content in shellfish from Al-Barbara was 0.081, 0.282, 1.254 and 0.685 mg/kg respectively. The average content of heavy metals in shellfish harvested from Selaata was below the standard limit of the FAO/WHO. For the shellfish collected from Al-Barbara, the mean heavy metal content was within the permissible limit of FAO/WHO for all metals tested except for Cd. High Cd levels found in shellfish tissues might be due to the influence of marine constructions in Al-Barbara fishing port, In conclusion, the mean heavy metal content in shellfish was detected below the permissible limit in both regions except for Cd in organisms harvested from Al-Barbara, which require further investigation to determine if there is any risk on human health.