What is the Biogenic Interference Calculation (BIC) Index?

Modified on: Tue, 18 Apr, 2023 at 2:57 PM

The Biogenic Interference Calculation Index (BIC) is an approach that has been adopted across Canada as an additional line of evidence towards delineation of petroleum hydrocarbons (PHCs) in organic soils and compost.  

It is a mathematical tool for identifying false exceedences of applicable soil guidelines for PHCs, due to the presence of biogenic organic compounds.

The tool was developed by Dr. Francine Kelly-Hooper.

Additional information on the calculation development can be found here.

The BIC Index is calculated using the following equation: 

BIC=([PHC F2])/([PHC F2]+[PHC F3b]) × 100


F2 indicates the quantifiable petroleum hydrocarbons in the C10-C16 range


F3b indicates the F3 sub-fraction range of C22-C34.  

(Sub-fraction F3a range is C16-C22).

Interpretation of the BIC:
Samples with a BIC <10% indicates potentially false exceedances of the F3 guideline (i.e. biogenic interference);
Samples with a BIC ≥10% indicates potentially true exceedances of F3 guideline (i.e. petroleum impact).

BIC Limitations

For an accurate conclusion on the source of quantified hydrocarbons, skilled evaluation of the associated chromatograms is still required, so like many semi-quantitative mathematical models applied to analytical testing, this approach is not intended to be an “answer to all”. 

This model is intended to be applied to light petroleum products with a hydrocarbon range that includes the F2 fraction (i.e. gasolines, diesels / fuel oils, condensates or crudes). 

This model cannot be applied to heavy petroleum distillates such as asphalt, bitumen, motor/lubricating or hydraulic oils.

This service is available at the St. John's and Calgary Environmental laboratory facilities.

The calculation test code F3FIDEB-SC should be added to: F24FIDEN-S

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