Lakhasly

adverse effects on sediment-dwelling organisms are unlikely or would be expected only infrequently; in contrast, adverse biological effects are more likely to occur when the total trace metal concentration is above the SEL, PEC, or ERM (Long et al. 1995; MacDonald et al. 1996; Pataki and Cahi 1999).

adverse effects on sediment-dwelling organisms are unlikely or would be expected only infrequently; in contrast, adverse biological effects are more likely to occur when the total trace metal concentration is above the SEL, PEC, or ERM (Long et al. 1995; MacDonald et al. 1996; Pataki and Cahi 1999). According to the LEL–SEL SQGs, all sediment samples have exceeded the LEL for total Cu, Ni, Pb, and Cr concentrations. However, they did not exceed the SEL levels. When com- pared with the TEC-PEC SQGs, total Cu, Ni, Pb, and Cr concentrations were all above the TEC in 100% of samples. Moreover, the ERL–ERM SQGs indicated that 100% of sam- ples exceeded the ERL level for total Ni concentration. These assessment results generally gave a conclusion that trace metals like Cu, Ni, Pb, and Cr should be of special concern. For these trace metals, the consideration of bioavailability will become important in future research. This is because total concentrations are often poor predictors of the risk posed by trace metals in sediments (Simpson and Batley 2016). However, further chemical fractionation can provide valuable information about the mobility, bioavailability, and related eco-toxicity of these trace metals in the sediments.