Polychlorinated biphenyl sorption and availability in field-contaminated sediments

Area of Science:

• Environmental Chemistry
• Marine Biology
• Ecotoxicology

Background:

• Polychlorinated biphenyls (PCBs) are persistent organic pollutants found in sediments.
• Understanding PCB distribution among sediment, water, and biota is crucial for risk assessment.

Purpose of the Study:

• To review and compare traditional and new models for PCB distribution.
• To evaluate the accuracy of PCB concentration predictions in different environmental compartments.

Main Methods:

• Analysis of PCB distribution in seven freshwater and marine sediments.
• Comparison of predicted versus measured PCB concentrations using various models.
• Investigation of PCB sorption to sediment organic matter and black carbon (BC).

Main Results:

• Traditional models overestimate PCB concentrations in water and lipids by factors of 8 and 33, respectively.
• Models using measured free aqueous phase concentrations or desorbed PCB mass fraction provide better predictions.
• Distinguishing sorption to amorphous organic matter and black carbon improves solid-phase concentration-based predictions.
• Black carbon sorption appears linear for a wide range of PCB concentrations.

Conclusions:

• Newer models offer improved accuracy for predicting PCB distribution in aquatic ecosystems.
• Accounting for specific sediment properties like black carbon enhances predictive power.
• These findings aid in more precise environmental risk assessments for PCB contamination.