title: Quantitative structure - photodegradation relationships of polybrominated diphenyl ethers, phenoxyphenols and selected organochlorines.
abstract: Among other developments, the technological revolution has lead to introduction of new chemicals to better serve in instruments and materials. The consequences of the extensive increase in use of new chemicals can be detected in the environment world wide, i.e. in wildlife and humans. To ensure this problem to be minimised in the future, new chemicals need to be subjected to predictive assessments before commercialised. To facilitate screening, qualitative structure-activity relationships, quantitative structure-activity relationships may be applied to describe reactivity of chemicals. Physico-chemical properties of chemicals such as partition coefficients and half-lives for the various environmental compartments are essential input data in multimedia environmental fate models. In this study we examine how structural characteristics can quantitatively describe laboratory determined photolytic half-lives of halogenated compounds of different classes, such as polybrominated diphenyl ethers (PBDEs), hydroxylated brominated diphenyl ethers (OH-PBDEs), and other organohalogens. A total of 30 chemicals with experimentally measured half-lives are used. Results reveal that the most important descriptors for describing the half-lives of the brominated compounds are the energy gap (GAP-1) between HOMO-1 and LUMO, the lowest partial charge on a halogen atom (Qhal-), topological polar surface area (TPSA), the atom with highest radical superdelocalizability (Rad-super+) and LUMO density (LUMO+).
authors.affiliation: NILU, Polar Environmental Centre, NO-9296 Tromsø, Norway. esh@nilu.no
authors.forename: Eldbjørg Sofie
authors.initials: ES
authors.lastname: Heimstad
authors.forename: Patricia Moreira
authors.initials: PM
authors.lastname: Bastos
authors.forename: Johan
authors.initials: J
authors.lastname: Eriksson
authors.forename: Ke
authors.initials: K
authors.lastname: Bergman
authors.forename: Mikael
authors.initials: M
authors.lastname: Harju
mesh_terms: D004785:Environmental Pollutants / Q000737:chemistry / Q000378:metabolism*; D052918:Environmental Restoration and Remediation; D006207:Half-Life; D055768:Halogenated Diphenyl Ethers / Q000737:chemistry / Q000378:metabolism*; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry / Q000378:metabolism*; D008956:Models, Chemical; D010636:Phenols / Q000737:chemistry / Q000378:metabolism*; D010782:Photolysis; D025341:Principal Component Analysis; D021281:Quantitative Structure-Activity Relationship
chemical_list: D004785:Environmental Pollutants; D055768:Halogenated Diphenyl Ethers; D006843:Hydrocarbons, Chlorinated; D010636:Phenols