Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:3:p2
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 3 (pt 2/9)
Character Range: 1155168–1158067

environment as adverse (for further information refer to Section 2.4, Schedule B5b). Thus, rather than having a single numerical limit for a contaminant, different soils will have different limits. The EIL derivation methodology generates, wherever possible, soil-specific EILs. However, in developing this ERA framework, it was not possible to derive soil-specific EILs for all contaminants so the EILs for some contaminants are soil-specific while for others they are generic.

In addition, most of the available toxicity data for contaminants in soil was obtained in laboratories where the contaminant is added to the soil immediately prior to commencing the test. However, it is known that some contaminants become less bioavailable in the field and over time (they age). Thus, laboratory-based experiments may overestimate toxicity in the field.

Also, laboratory experiments that use soils spiked with soluble metal salts overestimate toxicity compared to equivalent field soils, due to a lack of leaching of soluble salts that affect metal sorption. These factors have been addressed in recent EU risk assessments for metals in soils using 'ageing/leaching' factors.

Therefore, whenever ageing/leaching factors were available, they were used to correct the laboratory-based toxicity data (see Schedule B5c).

Where sufficient data permitted, EILs were derived for sites with fresh (<2 years) and aged (≥2 years) contamination. For the contaminants with generic EILs, there is a single value for each combination of land use and age of the contamination. For the contaminants with soil-specific EILs, a suite of values was derived (based on the soil physicochemical properties that control the toxicity) for each combination of land use and age of contamination.

Soil-specific physicochemical properties and ageing are two characteristics that would have been considered in Level 2 ERAs in the previous Measure (NEPC 1999).

By deriving EILs that account for soil-specific properties and ageing, the first ERA component is, in effect, a combination of Level 1 and Level 2 of the previous ERA framework (NEPM 1999). In summary, the framework for conducting ERAs has been simplified and now consists of two levels: a Preliminary ERA and a Definitive ERA (see Figure 1).

A summary of the EILs for eight chemicals (arsenic, copper, chromium (III), DDT, lead, naphthalene, nickel and zinc) is provided in Appendix 1. More details on the methodology and the data used in the derivation of these EILs can be found in Schedules B5b and B5c.

Figure 1. The framework for conducting ecological risk assessments
It is important to note that the EILs only apply to soil down to a depth of two metres[1] below the current soil surface, which corresponds to the root zone and habitation zone of many species.

The tiered ERA approach used in this guideline permits:
    * identification of the ecological