Factors Influencing the Soil–Air Partitioning and the Strength of Soils as a Secondary Source of Polychlorinated Biphenyls to the Atmosphere

• Published in: Environmental science & technology 2011-06, Vol.45 (11), p.4785-4792
• Main Authors: Cabrerizo, Ana, Dachs, Jordi, Moeckel, Claudia, Ojeda, María-José, Caballero, Gemma, Barceló, Damià, Jones, Kevin C
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; Applied sciences; Atmosphere; Atmospheric pollution; Biological and physicochemical properties of pollutants. Interaction in the soil; Correlation analysis; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Processes; Exact sciences and technology; PCB; Pollutants; Pollutants physicochemistry study: properties, effects, reactions, transport and distribution; Pollution; Pollution, environment geology; Polychlorinated biphenyls; Polychlorinated Biphenyls - analysis; Soil - chemistry; Soil and sediments pollution; Soil Pollutants - analysis; Soils; Spain; Temperature; United Kingdom
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es200400e

Soils are a major reservoir of persistent organic pollutants, and soil–air partitioning and exchange are key processes controlling the atmospheric concentrations and regional fate of pollutants. Here, we report and discuss the concentrations of polychlorinated biphenyls (PCBs) in soils, their measured fugacities in soil, the soil–air partition coefficients (K SA) and soil–air fugacity gradients in rural background areas of N-NE Spain and N-NW England. Four sampling campaigns were carried out to assess seasonal and daily variability and differences between sampling sites. K SA values were significantly dependent on soil temperature and soil organic matter quantity, and to a minor extent organic matter type. All the PCB congeners in the soil are close to equilibrium with the atmosphere at rural Ebro sites, but soil fugacities tend to be higher than ambient air fugacities in early and late summer, consistent with the influence of temperature on soil–air partitioning. Therefore, during warm periods, soils increment their strength as secondary sources to the atmosphere. The mixture of PCBs found in the atmosphere is clearly strongly influenced by the mixture of PCBs which escape from soil, with significant correlations between them (R 2 ranging between 0.35 and 0.74 and p-level