Section 327IAC2-1-8.7. Determination of bioconcentration factor

  7. The final bioconcentration factor (BCF_f) 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) Measured, steady-state bioconcentration factors from standardized laboratory tests shall be recorded as BCF_m. If more than a single value is available, the BCF_m shall be equal to the geometric mean of the reported values.

(2) If bioconcentration factors are available from other laboratory tests, the BCF_m will be the projected steady-state BCF as extrapolated from the test data.

(3) If measured bioconcentration factors (BCF_m) are not available from laboratory studies, a calculated bioconcentration factor (BCF_c) will be determined by the following equation:

log BCF_c = 0.847 log Kow - 0.628

(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.

(B) If a Kow cannot be calculated, BCF_c may be estimated on a case-by-case basis using other regression equations or correlations as appropriate.

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

(A) For measured bioconcentration factors:

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

(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) The commissioner shall direct the evaluation of the final bioconcentration factor (BCF_f) 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)