[Speciation and Ecological Risk of Heavy Metals in Surface Sediments from Jiulong River]

Speciation characteristics of fifteen heavy metals in seventeen surface sediments from Jiulong River was analyzed using the modified BCR protocol and dilute HNO₃ method, respectively. The results of the modified BCR protocol showed that most of the elements (Fe, Ni, V, Tl, Ba, Sb, Ga, Cr and Sr) existed mainly in residual fractions, and extractable fraction was dominant for Mn (83.8%), followed by Cd, Pb, Zn, Co and Cu (80.0%, 75.5%, 74.3%, 70.8% and 57.7%). The results of dilute HNO₃ method showed that the proportions of the dilute HNO₃-extractable fractions of Pb, Mn, Cd, Co, Zn and Cu were higher (70.4%, 65.4%, 58.7%, 48.4%, 44.5% and 45.5%). The assessment results of RSP (ratio of secondary phase to primary phase) indicated that Pb, Mn, Cd, Co, Zn and Cu in surface sediments of Jiulong River had higher ecological risks. Both extraction methods had merits and demerits respectively. In general, the dilute HNO₃ method is enough to analyze the bioavailability and ecological risk of heavy metals in sediments.