Accumulation of Heavy Metals in Sediments and Tissues of Rhizopora Apiculata, Sonneratia Alba and Avicennia Sp. In Alinsaog River, Zambales, Central Luzon, Philippines

Abstract

Phytoaccumulative capacity for heavy metals (Zn, Ni, Fe, Mn and Cr) of mangrove species (Rhizophora apiculata, Avicennia sp. Sonneratia alba) was evaluated on sediments collected along the riparian zone of mining-impacted river. Ni, Fe, Mn and Cr exceeded the probable effect level suggesting their potential adverse effects to aquatic organisms and ecosystem. Metal concentration in the sediments was in decreasing order of Fe>Cr>Ni>Mn>Zn. The potential for metal accumulation which was assessed using bioconcentration factor (BCF) and translocation factor was found to vary depending on metals, mangrove species and plant tissues. The tested metals highly accumulated in the roots except for Mn with higher uptake in the leaves. Highest BCF was recorded on Zn (0.7) in Avicennia sp. while metals with high mean level in sediments (4,244.1mg/kg Ni, 137,049.4mg/kg Fe and 13,985.9mg/kg dry weight Cr) registered lower BCF. Variations in metal uptake of the same species could be due to differences in metal bioavailability and sediment characteristics. Limited translocation of Cr in all species, Ni on S. alba, Fe in R. apiculata and Avicennia sp. suggests that they can potentially be used for remediation of Ni-Cr-Fe laden sediments particularly for phytostabilization. Enhancement of metal uptake by mangroves through increasing metal bioavailability should be explored in future studies.