The potential application of sea cucumber (Holothuria leucospilota) as a bioindicator of heavy metals contamination: a case study from Chabahar Bay, Oman Sea, Iran

Biomonitoring is an interesting approach to evaluate the ecological risk of marine environmental pollutants. This study was carried out to investigate the application of sea cucumber (Holothuria leucospilota) in heavy metals bioaccumulation in Chabahar Bay, Oman Sea, Iran. The concentrations and ecological risks of heavy metals including Pb, Cd, Cr and Ni were determined in the sediments, water and various tissues of Holothuria leucospilota in four different locations in Chabahar Bay. The results showed that the bioaccumulation of the heavy metals in all studied sea cucumber's tissues, including respiratory tree, derm and gonad were 45.83, 39.65 and 43.18 mg/kg, respectively. The metal accumulation in the tissues of H. leucospilota was in the following descending order: Pb > Cr > Ni > Cd. However, a high potential ecological risk factor for Cd was observed in the region. The results reveals that due to high metal bioaccumulation, the respiratory tree of sea cucumbers is a suitable indicator of heavy metals, in particular Cd with bioaccumulation factor > 1, and can be used in biomonitoring studies in the region.