A critical body residue approach for predicting persistent bioaccumulative toxicant effects on reproduction and population dynamics of meiobenthic copepods

TitleA critical body residue approach for predicting persistent bioaccumulative toxicant effects on reproduction and population dynamics of meiobenthic copepods
Publication TypeJournal Article
Year of Publication2012
AuthorsChandler, GT, Ferguson, PL, Klauber, WW, Washburn, KM
JournalEnvironmental Toxicology & Chemistry
Volume31
Issue5
Start Page1076
Pagination1076 - 1082
Date Published01/2012
Abstract

Critical body residues (CBRs) are the measured tissue toxicant concentrations yielding a median dose-response on a dry-weight or lipid-normalized basis. They facilitate management decisions for species protection using tissue analysis. Population CBR is the mean dose yielding 50% population suppression and was predicted here in Amphiascus tenuiremis for fipronil sulfide (FS) using lifetables and the Leslie matrix. Microplate bioassays (ASTM E-2317-14) produced biomass sufficient for dry mass and lipid-normalized CBR estimates of reproduction (fertility) and population growth suppression. Significant FS toxic effects were delayed naupliar development (at ≥0.10μgL -1), delayed copepodite development (at 0.85μgL -1), decreased reproductive success (at ≥ 0.39μgL -1), and decreased offspring production (at 0.85μgL -1). A reproductive median effective concentration (EC50) of 0.16μgL -1 (95% CI: 0.12-0.21μgL -1) corresponded to an adult all-sex CBR and lipid-normalized CBR of 0.38pg FS·μg -1 dry weight (95% CI: 0.27-0.52pg FS·μg -1) or 2.8pg FS·μg -1 lipid (95% CI: 2.2-3.6pg FS·μg -1), respectively. Copepod log bioconcentration factor (BCF)=4.11±0.2. Leslie matrix projections regressed against internal dose predicted fewer than five gravid females in a population by the third generation at 0.39 and 0.85μg FS·L -1 (i.e., 9.6-10.2μg FS·μg -1 lipid), and 50% population suppression at a CBR of 1.6pg FS·μg -1 lipid. This more integrative population CBR as a management tool would fall 1.75 times below the CBR for the single most sensitive endpoint-fertility rate. © 2012 SETAC.

DOI10.1002/etc.1766
Short TitleEnvironmental Toxicology & Chemistry