Heavy metal pollution assessment in coastal sediments and bioaccumulation on seagrass (Enhalus acoroides) of Palau

Heavy metals in coastal sediments and seagrass (Enhalus acoroides) were studied to assess the pollution level and to understand the bioaccumulation of metals on different organs. The mean of metal concentrations in sediments were in the following order: Cr > Ni > As>Zn > Cu > Co > Pb > Cd > Hg. The results of principal component analysis indicate that Cr, Ni, Cu, Zn, As and Hg are derived from natural sources but Cd and Pb seems to be of anthropogenic sources. Cr, Ni, Cu, Zn, Cd and Pb in the coastal sediments were at low ecological risk level. As and Hg presented the highest ecological risk among all metals. The mean concentrations of Cr, Ni, Cu, Zn, Cd, and Hg were higher in leaves of E. acoroides than in roots. Significant correlations (p < 0.05) for Cr, Ni, Cu, Zn, and Pb in between sediments and in E. acoroides both leaves and roots. High bioconcentration factor (BCF) were calculated for Zn, Cd, and Hg.

Automated summary

The study showed that heavy metals in coastal sediments and seagrass mainly come from natural sources, with As and Hg posing the highest ecological risk. The concentrations of Cr, Ni, Cu, Zn, Cd, and Hg were higher in leaves of E. acoroides than in roots, and Zn, Cd, and Hg had high bioconcentration factors.