Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:3:p18
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 3 (pt 18/21)
Character Range: 1392139–1394981

of species to be protected.
These methods are critically assessed below.

3.2.8         Using biomagnification algorithms
There are three slightly different biomagnification algorithms. The main difference between them is whether ingestion of soil is considered (the US EPA and Canadian methods) or not (the Dutch method).

The US EPA methodology (US EPA 1996), which accounts for soil ingestion, calculates the secondary poisoning SQG (SQGsp) by:

               (equation 14)

where SQGsp is the soil quality guideline that accounts for secondary poisoning and is expressed in mg/kg, the toxicity reference value is expressed in mg contaminant/kg prey tissue, FIR is food intake rate (kg food [dry weight]/ kg body weight [wet weight] /day), Ps is the proportion of the diet that is soil (%) and BAFij is the bioaccumulation factor for contaminant 'i' by species 'j' (unitless).

The Canadian methodology (CCME 2006) is based on daily intake models similar to derivation of maximum human daily uptake models. The Canadian methodology takes into account direct soil ingestion and bioaccumulation through the food chain.

SQGs are thereby calculated using the following equation:

   (equation 15)

where SQG2C refers to the soil quality guideline for soil and food ingestion for the secondary consumer (mg/kg dry weight soil), DTED2C is the daily threshold effects dose for the secondary consumer (mg/kg body weight-day), BW2C is the body weight of the species used in the DTED2C (kg), SIR2C is the soil ingestion rate for the species used in the DTED2C (kg dry weight soil/day), BF is the bioavailability factor (unitless), FIR2C is the food ingestion rate for the species used in the DTED2C (kg dw food/day) and BAF2 is the bioaccumulation factor (unitless) (CCME 2006).

The Dutch methodology developed by Van der Plassche (1994) or Romijn et al. (1991) does not account for soil ingestion and calculates the SQG by:

     (equation 16)

where SQGsp is the soil quality guideline that accounts for secondary poisoning expressed in mg/kg, NOEC predator is the NOEC for a predator expressed as mg contaminant/kg prey tissue, BCFprey is the bioconcentration factor of the contaminant for a prey species expressed as a ratio of concentration in the prey and in the soil. If the BCFprey is unknown, the BCF was predicted based on the log Kow of the contaminant using QSARs.

The above methods were not adopted in the Australian and NZ WQGs because of 'the lack of relevant data' and as there is 'no formal and specific guidance on how to take information on bioaccumulation into account when deriving water quality guidelines' (ANZECC & ARMCANZ 2000). Food web approaches were not advocated because they are 'very complex and require extensive data sets, which are not available for the majority of contaminants' (ANZECC & ARMCANZ 2000). These