The accessibility and chemical activity of polycyclic aromatic hydrocarbons in soil

Abstract: This thesis proposes the use of two concepts: accessibility and chemical activity. Accessibility describes the mass quantity of PAHs that is or can become available within a given time span and under given conditions. Chemical activity quantifies the energetic state of the PAHs that determines the potential for spontaneous physicochemical processes, such as diffusion and partitioning. Chemical activity is closely related to fugacity and freely dissolved concentrations. Accessibility and chemical activity jointly govern the physicochemical part of what is known as bioavailability. Five (I-V) accompanying papers are discussed and elaborated. Paper I, is a general account of the two concepts as useful and measurable. Paper II describes a method to measure the chemical activity of PAHs in soil. Paper III is a case study; the accessibility and chemical activity of some PAHs found in a former industrial site soil were measured. Paper IV makes progress in the methodology of calibrating equilibrium sampling devices. Paper V is another case study, concerning PAHs in a highway roadside soil.