Preliminary assessment of cadmium mobility in surface sediments of a tropical estuary

Abstract

Cadmium is a toxic metal often found with a strong enrichment factor in coastal sediments. The sequential extraction procedure proposed by the BCR (Community Bureau of Reference) was applied for partitioning of Cd in tropical estuary sediments. The method showed satisfactory recoveries. The repartition of Cd in different phases of sediment was controlled by the residual phase (50.32 to 67.45 %). However, the exchangeable and acid soluble fraction (F1) was in general found to be the second most abundant fraction in the surface sediments (11.14 to 15.24 %), indicating that an important portion of Cd could be remobilized, thus becoming available to aquatic biota. Cd also showed different distribution patterns in the sediment phases due to the heterogeneity of the sediments, as well as the physical and chemical conditions along with the different sources of Cd in the bays. The risk assessment code investigation showed a medium risk of Cd in the estuary.

KEY WORDS: Cadmium, Mobility, Sediment toxicity, Sequential extraction

Bull. Chem. Soc. Ethiop. 2014, 28(2), 245-254. 

DOI: http://dx.doi.org/10.4314/bcse.v28i2.8