Application of the SEM-AVS Concept in a Risk Assessment Context

Figure 4 represents the tiered approach that can be used to refine the risk assessment using the SEM-AVS concept.

No risk is identified when the total nickel concentration is smaller than the RWC PNEC. This PNEC for nickel can be derived using sediments high in bioavailability (see Fact Sheet 8).

If a risk is identified and historical AVS data are available for the receiving water or river/lake systems similar in characteristics these data can be used to calculate the PNEC AVS normalized using the available nickel bioavailability models.            

 
 Figure 4: Overview of tiered approach for assessing risks of nickel in sediments
on a bioavailable basis applicable for a local scenario

 

The risks for the local site can subsequently be calculated from the comparison between the PECTotal and the PNECAVS normalized, site specific (Equation 3).

 

 

The actual risk can be calculated using actual measured SEM-AVS concentrations for the site under investigation.

Total SEM site specific – AVSsite specific < 0 no risk

Total SEM site specific – AVSsite specific > potential risk

 In case SEM-AVS > 0 a further weight of analysis can be conducted (e.g., direct toxicity testing, macro-invertebrate analysis etc.).