title: Case Study Part 1: How to calculate appropriate deterministic long-term toxicity to exposure ratios (TERs) for birds and mammals.
abstract: In the European Union, first-tier assessment of the long-term risk to birds and mammals from pesticides is based on calculation of a deterministic long-term toxicity/exposure ratio (TER(lt)). The ratio is developed from generic herbivores and insectivores and applied to all species. This paper describes two case studies that implement proposed improvements to the way long-term risk is assessed. These refined methods require calculation of a TER for each of five identified phases of reproduction (phase-specific TERs) and use of adjusted No Observed Effect Levels (NOELs) to incorporate variation in species sensitivity to pesticides. They also involve progressive refinement of the exposure estimate so that it applies to particular species, rather than generic indicators, and relates spraying date to onset of reproduction. The effect of using these new methods on the assessment of risk is described. Each refinement did not necessarily alter the calculated TER value in a way that was either predictable or consistent across both case studies. However, use of adjusted NOELs always reduced TERs, and relating spraying date to onset of reproduction increased most phase-specific TERs. The case studies suggested that the current first-tier TER(lt )assessment may underestimate risk in some circumstances and that phase-specific assessments can help identify appropriate risk-reduction measures. The way in which deterministic phase-specific assessments can currently be implemented to enhance first-tier assessment is outlined.
authors.affiliation: Centre for Ecology and Hydrology, Monks Wood, Cambridgeshire, UK. rfs@ceh.ac.uk
authors.forename: R F
authors.initials: RF
authors.lastname: Shore
authors.forename: D R
authors.initials: DR
authors.lastname: Crocker
authors.forename: H R
authors.initials: HR
authors.lastname: Akcakaya
authors.forename: R S
authors.initials: RS
authors.lastname: Bennett
authors.forename: P F
authors.initials: PF
authors.lastname: Chapman
authors.forename: M
authors.initials: M
authors.lastname: Clook
authors.forename: M
authors.initials: M
authors.lastname: Crane
authors.forename: I C
authors.initials: IC
authors.lastname: Dewhurst
authors.forename: P J
authors.initials: PJ
authors.lastname: Edwards
authors.forename: A
authors.initials: A
authors.lastname: Fairbrother
authors.forename: S
authors.initials: S
authors.lastname: Ferson
authors.forename: D
authors.initials: D
authors.lastname: Fischer
authors.forename: A D M
authors.initials: AD
authors.lastname: Hart
authors.forename: M
authors.initials: M
authors.lastname: Holmes
authors.forename: M J
authors.initials: MJ
authors.lastname: Hooper
authors.forename: M
authors.initials: M
authors.lastname: Lavine
authors.forename: A
authors.initials: A
authors.lastname: Leopold
authors.forename: R
authors.initials: R
authors.lastname: Luttik
authors.forename: P
authors.initials: P
authors.lastname: Mineau
authors.forename: D R J
authors.initials: DR
authors.lastname: Moore
authors.forename: S R
authors.initials: SR
authors.lastname: Mortenson
authors.forename: D G
authors.initials: DG
authors.lastname: Noble
authors.forename: R J
authors.initials: RJ
authors.lastname: O'Connor
authors.forename: W
authors.initials: W
authors.lastname: Roelofs
authors.forename: R M
authors.initials: RM
authors.lastname: Sibly
authors.forename: G C
authors.initials: GC
authors.lastname: Smith
authors.forename: M
authors.initials: M
authors.lastname: Spendiff
authors.forename: T A
authors.initials: TA
authors.lastname: Springer
authors.forename: H M
authors.initials: HM
authors.lastname: Thompson
authors.forename: C
authors.initials: C
authors.lastname: Topping
mesh_terms: D000818:Animals; D001717:Birds; D018556:Crops, Agricultural; D002523:Edible Grain; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000633:toxicity*; D008322:Mammals; D019055:No-Observed-Adverse-Effect Level; D010575:Pesticides / Q000633:toxicity*; D006109:Poaceae; D012098:Reproduction / Q000187:drug effects*; D018570:Risk Assessment / Q000379:methods; D013995:Time
chemical_list: D004785:Environmental Pollutants; D010575:Pesticides