Bioaccumulation of arsenic,chromium and lead in fish: constraints imposed by sediment geochemistry

Determining metal bioavailability is critical in assessing the necessity to remediate contaminated sediments. In the Halls Brook Holding Area Pond (HBHAP) sapropel, As (3000 mg/kg), and Cr (1400 mg/ kg), are sequestered by amorphous Fe(OH)₃ (Kd_As=560; Kf_Cr=59,0001/kg), while Pb solubility is limited by PbS_(am). Fillet As concentrations in detritivorous and omnivorous fish were similar in the HBHAP (1.19 mg/kg), and the adjacent unimpacted Phillips Pond (1.18 mg/kg). Cr and Pb in both HBHAP and Phillips Pond fish were below analytical detection limits, except for one (0.73 mg/kj Pb), in the HBHAP. The low sediment bioaccumulation factors for As, Cr, and Pb (6.5 × 10⁻⁴, < 1.1 × 10, and 1.8 × 10⁻⁶, respectively in HBHAP) suggest that the sediment acts to sequester metals, rendering them non-bioavailable due to precipitation of solids, and sorption to iron phases.