QSAR/QSPR and Multicomponent Joint Toxic Effect Modeling of Organic Pollutants at Aqueous-Solid Phase Interfaces

Abstract

Information about environmental chemodynamics of organic pollutants is a basic need in environmental planning, restoration, and engineering management. Sorption/desorption, an important chemodynamic behavior of various pollutants, can greatly influence the mobility and bioavailability of these compounds in different environmental compartments. Accordingly, aqueous-solid phase interfaces are significant in determining: (1) the route and rates by which organic pollutants can transfer to and from these interfaces, (2) the ultimate behavior and fate of pollutants, and (3) their toxicity, genotoxicity, and bioavailability to microorganisms.

When the rates of sorption or desorption processes are known, environmental fate modeling can provide an educated estimate and prediction on the accessibility and bioavailability of a target pollutant to a specific transport mechanism in the environment. Hence, the present chapter is an attempt to assess fate (i.e., in terms of pollutant mobility using predictive sorption or desorption coefficients) as well as effects (i.e., in terms of bioavailability) of various pollutants and to correlate these observations for development of predictive relationships.

In order to fulfill this general objective in the present chapter, the following interdisciplinary approaches are covered: (1) an overview of some physical and chemical properties of organic pollutants in complex mixtures which can affect their sorption/desorption chemodynamics, (2) a discussion of the fundamentals of both quantitative structure-activity and structure-property relationships (QSARs and QSPRs, respectively), with special emphasis on using molecular connectivity indices as useful properties to predict pollutant mobility and bioavailability, and (3) a review of the multicomponent (i.e., multipollutant) joint toxic/genotoxic effect models (i.e., additivity, synergism, antagonism) to predict the bioavailable fraction and action of organic pollutants at aqueous-solid phase interfaces.

The applicability of using these interdisciplinary approaches, which include incorporation of various physical and chemical properties of the pollutants, QSARs/QSPRs and multicomponent joint action modeling are discussed and evaluated using a group of toxic and carcinogenic pollutants, i.e., polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs).