Comparison of laboratory-derived biomagnification factors for hexachlorobenzene in common carp conducted under 9 test conditions.

Nine dietary exposure bioaccumulation fish tests with hexachlorobenzene (HCB) were conducted with common carp to explore how differences in test conditions (different test foods and feeding rates) influenced the lipid-corrected, growth-corrected kinetic biomagnification factor (BMFkgL ) value (BMFkgL  = BMFkg  × lipid content of test food/lipid content of test fish). The BMFkgL values for HCB differed by approximately a factor of 5 among the tests. The average, median, 95% confidence interval, and coefficient of variation of the BMFkgL values were 0.925, 0.998, 0.578 to 1.27, and 49%, respectively. The BMFkgL value differed markedly between tests conducted using test food with lipid contents of approximately 5 and 15%. Different feeding rates (2 or 3% of body weight/d) had comparatively little effect on the BMFkgL of HCB. The present study revealed that the lipid content of test fish was correlated with the growth-corrected kinetic BMF (BMFkg ) value of HCB but the lipid content of test food was poorly correlated with BMFkg . This lack of correlation might explain the large variations of the BMFkgL values observed. The value of the BMFkg normalized to a fish with a 5% lipid content (defined as the 5% lipid-normalized BMFkg in the present study) did not differ markedly between tests conducted using test food with different lipid contents (5-15%). It is therefore useful to report the 5% lipid-normalized BMFkg as well as the BMFkgL when dietary exposure tests are conducted. Environ Toxicol Chem 2018;37:1032-1039.