title: Implementing a framework for integrating toxicokinetics into human health risk assessment for agrochemicals.
abstract: A strategic and comprehensive program in which toxicokinetic (TK) measurements are made for all agrochemicals undergoing toxicity testing (both new compounds and compounds already registered for use) is described. This approach provides the data to more accurately assess the toxicokinetics of agrochemicals and their metabolites in laboratory animals and humans. Having this knowledge provides the ability to conduct more insightful toxicity studies, refine and interpret exposure assessments and reduce uncertainty in risk assessments. By developing a better understanding of TK across species, including humans via in vitro metabolism studies, any differences across species in TK can be identified early and the most relevant species can be selected for toxicity tests. It also provides the ability to identify any non-linearities in TK as a function of dose, which in turn can be used to identify a kinetically derived maximum dose (KMD) and avoid dosing inappropriately outside of the kinetic linear range. Measuring TK in key life stages also helps to identify changes in ADME parameters from in utero to adults. A robust TK database can also be used to set internal concentration based "Reference Concentrations" and Biomonitoring Equivalents (BE), and support selection of Chemical Specific Adjustment Factors (CSAF). All of these factors support the reduction of uncertainty throughout the entire risk assessment process. This paper outlines how a TK research strategy can be integrated into new agrochemical toxicity testing programs, together with a proposed Framework for future use.
authors.affiliation: Dow AgroSciences LLC, Indianapolis, IN, USA. Electronic address: cterry@dow.com.
authors.forename: Claire
authors.initials: C
authors.lastname: Terry
authors.affiliation: Summit Toxicology, CO, USA.
authors.forename: Sean
authors.initials: S
authors.lastname: Hays
authors.affiliation: The Dow Chemical Company, Midland, MI, USA.
authors.forename: Alene T
authors.initials: AT
authors.lastname: McCoy
authors.affiliation: The Dow Chemical Company, Midland, MI, USA.
authors.forename: Lisa G
authors.initials: LG
authors.lastname: McFadden
authors.affiliation: Dow AgroSciences LLC, Indianapolis, IN, USA.
authors.forename: Manoj
authors.initials: M
authors.lastname: Aggarwal
authors.affiliation: Dow AgroSciences LLC, Indianapolis, IN, USA.
authors.forename: Reza J
authors.initials: RJ
authors.lastname: Rasoulpour
authors.affiliation: Dow AgroSciences LLC, Indianapolis, IN, USA.
authors.forename: Daland R
authors.initials: DR
authors.lastname: Juberg
mesh_terms: D016573:Agrochemicals / Q000493:pharmacokinetics* / Q000633:toxicity*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure / Q000032:analysis; D006801:Humans; D018570:Risk Assessment / Q000379:methods*; D066007:Toxicokinetics
chemical_list: D016573:Agrochemicals
keywords: Agrochemicals; Biomonitoring equivalents; Pesticides; Risk assessment; Toxicokinetics