title: Critical tissue residue approach linking accumulated metals in aquatic insects to population and community-level effects.
abstract: Whole body Zn concentrations in individuals (n = 825) from three aquatic insect taxa (mayflies Rhithrogena spp. and Drunella spp. and the caddisfly Arctopsyche grandis) were used to predict effects on populations and communities (n = 149 samples). Both mayflies accumulated significantly more Zn than the caddisfly. The presence/absence of Drunella spp. most reliably distinguished sites with low and high Zn concentrations; however, population densities of mayflies were more sensitive to increases in accumulated Zn. Critical tissue residues (634 μg/g Zn for Drunella spp. and 267 μg/g Zn for Rhithrogena spp.) caused a 20% reduction in maximum (90th quantile) mayfly densities. These critical tissue residues were associated with exposure to 7.0 and 3.9 μg/L dissolved Zn for Drunella spp. and Rhithrogena spp., respectively. A threshold in a measure of taxonomic completeness (observed/expected) was observed at 5.4 μg/L dissolved Zn. Dissolved Zn concentrations associated with critical tissue residues in mayflies were also associated with adverse effects in the aquatic community as a whole. These effects on populations and communities occurred at Zn concentrations below the U.S. EPA hardness-adjusted continuous chronic criterion.
authors.affiliation: Fort Collins Science Center, U.S. Geological Survey, Fort Collins, Colorado 80526, USA. tschmidt@usgs.gov
authors.forename: Travis S
authors.initials: TS
authors.lastname: Schmidt
authors.forename: William H
authors.initials: WH
authors.lastname: Clements
authors.forename: Robert E
authors.initials: RE
authors.lastname: Zuellig
authors.forename: Katharine A
authors.initials: KA
authors.lastname: Mitchell
authors.forename: Stanley E
authors.initials: SE
authors.lastname: Church
authors.forename: Richard B
authors.initials: RB
authors.lastname: Wanty
authors.forename: Carma A
authors.initials: CA
authors.lastname: San Juan
authors.forename: Monique
authors.initials: M
authors.lastname: Adams
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Lamothe
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000378:metabolism*; D016001:Confidence Intervals; D004784:Environmental Monitoring / Q000379:methods*; D007313:Insecta / Q000378:metabolism*; D016014:Linear Models; D016015:Logistic Models; D008670:Metals / Q000378:metabolism*; D009928:Organ Specificity; D011157:Population Dynamics; D014481:United States
chemical_list: D008670:Metals