Evaluation the potentiality of Rhizophora mucronata for pollutants remediation on the Red Sea Coast, Egypt

Abstract

Abstract Rhizophora mucronata was assessed as a biological tool for remediation and reduction of heavy metals mobility in sediments in Safaga and Hamata, the Red Sea Coast. It is an important region for tourism and nature reserves; however, this area suffers from various anthropogenic contaminants. Investigation of metal behavior in mangrove plants and sediments is important for clarifying the ability of mangroves to reduce sediments contamination through bioaccumulation, phytostabilization or phytoextraction. Sediments of Safaga site showed higher significant concentrations of all studied heavy metals. Heavy metal contents in sediments were significantly lower in case of elder plants than younger ones as well as in rhizosphere samples than non-rhizosphere ones. The order of remediation efficiency was Mo > Ni > Mn ≥ Co > Al > Cu > Zn ≥ Cr > Fe > V, where the highest % were 99.25, 58.97, 42.64, 42.48, 41.91, 39.47, 37.93, 37.01, 36.89, and 29.44, respectively. R. mucronata parts were more significantly contaminated in Safaga site with Co, Cr, Cu, Mo and Zn, meanwhile they were more significantly contaminated in Hamata site with Al, Fe, Mn, Ni and V. The elder plants accumulated higher concentrations than younger ones and contents of heavy metals in plant samples followed the order of root > aerial roots > shoot. Bioconcentration factor (BCF) values representing the accumulation efficiency of R. mucronata was Ni > Mo > Zn > Cu > Cr > Co > Mn ≥ Al > V > Fe, where their highest values were 17.74, 7.89, 3.95, 3.84, 2.66, 1.91, 1.67, 1.66, 1.6, 1.18, respectively. BCF values exceeded one for all metals and values of translocation factor (TF) were less than unity in all cases, thus Rhizophora mucronata can be considered as a good phytostabilizer of ten studied heavy metals able to reduce their mobility through accumulation by roots, thereby reducing off-site contamination.