Assessment of Cu and Zn pollution in surface sediments of Song Cau – Thai Nguyen city

Abstract

The level of heavy metals pollution on the aquatic environment depends not only on the total metal concentration but also on the fractions of heavy metals in the sediments. In this study, the level of contamination of Cu and Zn in surface sediments of Cau river - Thai Nguyen city has been analyzed and assessed by the total metal concentration and the fractions of these metals. Surface sediment samples were collected at 08 locations, the results showed that, according to QCVN 2012, the Cu concentration didn’t exceed the pollution limit and the Zn concentration of 03 sampling locations (S1, S6, and S7) exceeded the pollution limit. The geological accumulation index of Cu is Igeo -Cu < 0 and that of Zn is about 1 < Igeo-Zn < 2 or copper is not polluted and zinc is moderately polluted. The enrichment factors of Cu are in the range of 5 < EF < 20 while Zn has an EF > 20 or the enrichment capacity of Zn is high and Cu is insignificant. The %RAC value of Cu is in the range of 10 < %RAC < 30 and for Zn %RAC < 10 that means the risk assessment code of Zn is low and that of Cu is moderate. Both of the individual contamination factors of Cu and Zn are low (ICF < 1).