Abstract:
Ecological risk assessment and early warning of surface sediments in Liaodong Bay were conducted by a geoaccumulation index (Igeo), a potential ecological risk index (RI) and an ecological risk warning model (IER) based on the concentrations of a range of heavy metals (As, Cd, Cu, Hg, Pb and Zn) from August 2012 to August 2014. The Igeo results showed that the regional sediments were practically uncontaminated (Igeo<0). The sequence of different elements' Igeo was As>Cu>Zn>Pb>Cd>Hg in both 2012 and 2013, while it changed to As>Zn>Cu>Pb>Hg>Cd in 2014. The contaminated areas were mainly distributed in the northern estuaries of Liaodong Bay and near Huludao. The average potential ecological risk indexes for single heavy metals (Eri) were less than 40, and the potential toxicity response index (RI) from 2012 to 2014 was less than 150, which was in the low risk category. Approximately 5.6% of the sampling sites were classified in the second ecological risk level (O
eR SUB>≤1.0) in 2012, which indicated an ecological risk warning, while the remaining 94.4% were in the “no ecological risk warning” category. No ecological risks were documented in 2013 and 2014. The RI calculations indicate that there are potential ecological risks from As, Cd and Hg in Liaodong Bay. The numerical values from IER calculations for surface sediments of Liaodong Bay show that there will most likely be negative impacts on the environment from As, Cd and Zn.