Soil/Air Partitioning of Semivolatile Organic Compounds. 1. Method Development and Influence of Physical−Chemical Properties

Abstract

Soil is the primary sink of semivolatile organic compounds (SOCs) in the terrestrial environment, while the atmosphere is the primary vector of these substances to humans via the agricultural food chain. Hence, the exchange of SOCs between soil and air is of paramount importance to their environmental fate and potential risk to humans. In this paper, a method is developed to determine soil/air partition coefficients (KSA) of SOCs. On the basis of the solid-phase fugacity meter developed for plants, the method was initially tested using a soil contaminated in the laboratory with chlorinated benzenes, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. A systematic validation exercise demonstrated that the method is not subject to a wide range of potential artifacts. It was then shown that KSA in moist soil (relative humidity = 100%) is independent of the water content of the soil. The method was then extended to the measurement of KSA in the original soil, which contained background levels of ...