Uptake and concentration of heavy metals in dominant mangrove species from Hainan Island, South China

By investigating three dominant mangrove species, namelyAegiceras corniculatum,Kandelia candel,Ceriops tagaland their rhizosediment in Mangrove wetlands in Hainan Island, this research analyzed absorption, concentration and distribution of heavy metals (Cr, Cu, Zn, As, Cd and Pb) in mangroves. The results found that the concentration of specific heavy metal differs in the different mangrove organs (leaf, stem and root). The content of heavy metals concentrated greatly in roots, but less in leaves and stems. The study also revealed that concentration capacity was weak in all three mangrove species (BCF0.02-0.91), with their organ ranking BCFroot > BCFstem > BCFleaf. Among three mangrove species, the transfer factors of leaves and stems inCeriops tagalwere highest, indicating a great distribution capability for heavy metals, followed byKandelia candel. Transfer factors inAegiceras corniculatumwere the weakest. This ranking was opposite to bioconcentration factors of roots. This study can further reflect bioavailability of heavy metals in sediments, which provides scientific evidence on ecosystem protection and management in mangrove wetlands.

Automated summary

The concentration of heavy metals in different organs of mangroves varies, with roots containing the most. The three mangrove species showed weak concentration capacity, withCeriops tagalbeing the best at distributing heavy metals. This study provides insight into the bioavailability of heavy metals in sediments for ecosystem protection in mangrove wetlands.