Deposit‐feeding marine clams (Macoma nasuta) were exposed for 119 d to three sediment types that varied in total organic carbon (TOC) from 0.8 to 2.5%. Sediments were spiked with equal concentrations of 13 polychlorinated biphenyl congeners and hexachlorobenzene. Tissue residues were measured, and steady‐state bioaccumulation factors (BAFs), the corresponding lipid, and TOC‐normalized biota sediment accumulation factors (BSAFs) were determined. The BSAFs were less variable than were the BAFs with the exception of compounds with log Kow > 7. Many of the BSAFs exceeded 1.7, which is a calculated maximum value based on partitioning alone. Although BSAFs varied with sediment type and compound, the use of a BSAF of 4 as a screening level for neutral organic compounds in assessing dredge materials is supported by the present study.