title: Probabilistic ecological hazard assessment: evaluating pharmaceutical effects on aquatic higher plants as an example.
abstract: The practicality of a probabilistic ecological hazard assessment (PEHA) methodology using intraspecies endpoint sensitivity distributions (IESDs) and chemical toxicity distributions (CTDs) was evaluated on data sets of pharmaceutical toxicity to aquatic macrophytes. A PEHA does not use an exposure distribution but rather uses a point estimate, which is useful for applications with sufficient effects data but lacking in comprehensive exposure data or when a criterion concentration is desired. The probability of finding an effect measure or potency value below a threshold can be calculated from the effects distribution. PEHA analyses using CTDs for both EC(10) and EC(25)Lemna gibba toxicity values indicated a <1% probability of encountering an antibiotic with toxicity below 1 microg/L. IESDs for microcosm mixture studies with eight pharmaceuticals (8PM) and four tetracyclines showed that the probability was nearly 20% for Myriophyllum sibiricum and 13% for L. gibba (8PM data). Hazard quotients calculated from the 1% and 5% distribution thresholds indicated potential risk only in certain cases.
authors.affiliation: Centre for Toxicology and Department of Environmental Biology, University of Guelph, Guelph, Ont., Canada N1G 2W1. rbrain01@uoguelph.ca
authors.forename: Richard A
authors.initials: RA
authors.lastname: Brain
authors.forename: Hans
authors.initials: H
authors.lastname: Sanderson
authors.forename: Paul K
authors.initials: PK
authors.lastname: Sibley
authors.forename: Keith R
authors.initials: KR
authors.lastname: Solomon
mesh_terms: D000900:Anti-Bacterial Agents / Q000633:toxicity*; D029064:Araceae / Q000187:drug effects* / Q000254:growth & development; D001681:Biological Assay / Q000592:standards; D017753:Ecosystem; D019684:Magnoliopsida / Q000187:drug effects* / Q000254:growth & development; D015233:Models, Statistical; D018570:Risk Assessment / Q000379:methods; D018675:Toxicity Tests
chemical_list: D000900:Anti-Bacterial Agents