Polychlorinated biphenyl sorption and availability in field-contaminated sediments

Abstract

Traditional and new relationships of polychlorinated biphenyl (PCB) distribution among the solid phases, the free aqueous phase, and biolipids are comprehensively reviewed using seven well-characterized freshwater and marine sediments polluted with PCBs. The traditional relationship relating free aqueous concentration and biolipid concentration to sediment total organic carbon, compound octanol-water partitioning coefficient, and solid-phase contaminant concentration overestimates measured free aqueous concentrations and biolipid concentrations by mean factors of 8 and 33, respectively. By contrast, relationships based on measured free aqueous phase concentrations or the PCB mass fraction desorbed from sediment provide reasonable predictions of biolipid concentrations. Solid-phase concentration-based predictions perform better when sorption to amorphous organic matter and black carbon (BC) is distinguished. Contrary to previously published relationships, BC sorption appears to be linear for free aqueous PCB-congener concentrations in the picogram to microgram per liter range.

Figure 1

Comparison of measured aqueous PCB concentrations with those (a) estimated from K_OW values, the sediment f_OC and solid phase concentrations according to eq 1, and (b) estimated from solid phase concentrations, the sediment f_OC and f_BC and K_OW values according to eqs 5 and 6. Data represent Hunters Point sediment (⧫), Lake Hartwell sediment (○), Grasse River sediment (◻), Crab Orchard Lake sediment (•), Milwaukee River location 1 sediment (Δ), Milwaukee River location 2 sediment (×), and Niagara River sediment (+). The line is drawn to show a 1:1 relationship between estimated and measured data.

Figure 2

Comparison of measured biolipid PCB concentrations with those estimated from (a) K_OW values, the sediment f_OC, and solid phase concentrations according to eq 3; (b) solid phase concentrations, the sediment f_OC, and f_BC and K_OW values according to equations (5 − 7); (c) the contaminant mass fraction desorbed from sediment using a tenax extraction according to eq 4; and (d) actual measured free aqueous concentrations according to eq 2. Data represent Hunters Point sediment, Neanthes arenaceodentata (⧫) and Leptocheirus plumulosus (◊); Grasse River sediment, Lumbriculus variegatus (◻); Crab Orchard Lake sediment, Lumbriculus variegatus (•); Milwaukee River location 1 sediment, Lumbriculus variegatus (Δ); Milwaukee River location 2 sediment, Lumbriculus variegatus (×); and Niagara River sediment, Lumbriculus variegatus (+). The line is drawn to show a 1:1 relationship between estimated and measured data.

Figure 3

(a) Comparison of measured aqueous PCB concentrations with those estimated from solid phase concentrations, the sediment f_OC and f_BC and K_OW values according to eqs 5 and 9, using K_BC,lin and n = 1 instead of K_fr,BC and n = 0.7, and (10). Data represent Hunters Point sediment (⧫), Grasse River sediment (◻), Milwaukee River location 1 sediment (Δ), Milwaukee River location 2 sediment (×) and Niagara River sediment (+). (b) comparison of measured biolipid PCB concentrations with those estimated from solid phase concentrations, the sediment f_OC and f_BC and K_OW values according to eq 5, 9, using K_BC,lin and n = 1 instead of K_fr,BC and n = 0.7, and (10). Equation 2 was used to estimate biolipid concentrations from estimated aqueous concentrations in Figure 3a. Data represent Hunters Point sediment, Neanthes arenaceodentata (⧫) and Leptocheirus plumulosus (◊); Grasse River sediment, Lumbriculus variegatus (◻); Milwaukee River location 1 sediment, Lumbriculus variegatus (Δ); Milwaukee River location 2 sediment, Lumbriculus variegatus (×); and Niagara River sediment, Lumbriculus variegatus (+). The line is drawn to show a 1:1 relationship between estimated and measured data.