Authority: IC 13-14-8; IC 13-18-3

Affected: IC 13-18-4

Sec. 8.7. The final bioconcentration factor (BCFf) standardized to reflect the value for fresh fish tissue having a lipid content of nine and six-tenths percent (9.6%) shall be determined as follows in order of preference:

1. (1) Measured, steady-state bioconcentration factors from standardized laboratory tests shall be recorded as BCFm. If more than a single value is available, the BCFm shall be equal to the geometric mean of the reported values.
2. (2) If bioconcentration factors are available from other laboratory tests, the BCFm will be the projected steady-state BCF as extrapolated from the test data.

3. (3) If measured bioconcentration factors (BCFm) are not available from laboratory studies, a calculated bioconcentration factor (BCFc) will be determined by the following equation: log BCF_c = 0.847 log Kow - 0.628

   1. (A) If a measured Kow is not available for the chemical of interest the Kow may be calculated according to standard references and used in the regression equation in this subdivision.
   2. (B) If a Kow cannot be calculated, BCFc may be estimated on a case-by-case basis using other regression equations or correlations as appropriate.

4. (4) The final bioconcentration factor (BCFf) will be obtained by normalization to nine and six-tenths percent (9.6%) lipids as follows:

   1. (A) For measured bioconcentration factors:

      Where:	BCFm	=	measured bioconcentration factor
      	L	=	percent lipid content of fish used in the test

   2. (B) For bioconcentration factors calculated from Kow:

      Where:	BCFc	=	calculated bioconcentration factor from log Kow or other regression equations
      	4.8	=	average percent lipid for test fish used to develop the regression equation in subdivision (3)

5. (5) The commissioner shall direct the evaluation of the final bioconcentration factor (BCFf) calculated above to determine if a trophic level adjustment is warranted.

(Water Pollution Control Division; 327 IAC 2-1-8.7; filed Feb 1, 1990, 4:30 p.m.: 13 IR 1039; readopted filed Oct 18, 2024, 1:57 p.m.: 20241113-IR-327230810RFA)