ABSTRACT
Per- and polyfluoroalkyl substances (PFAS) in the environment pose persistent and complex threats to human and wildlife health. Around the world, PFAS point sources such as military bases expose thousands of populations of wildlife and game species, with potentially far-reaching implications for population and ecosystem health. But few studies shed light on the extent to which PFAS permeate food webs, particularly ecologically and taxonomically diverse communities of primary and secondary consumers. Here we conducted >2000 assays to measure tissue-concentrations of 17 PFAS in 23 species of mammals and migratory birds at Holloman Air Force Base (AFB), New Mexico, USA, where wastewater catchment lakes form biodiverse oases. PFAS concentrations were among the highest reported in animal tissues, and high levels have persisted for at least three decades. Twenty of 23 species sampled at Holloman AFB were heavily contaminated, representing middle trophic levels and wetland to desert microhabitats, implicating pathways for PFAS uptake: ingestion of surface water, sediments, and soil; foraging on aquatic invertebrates and plants; and preying upon birds or mammals. The hazardous long carbon-chain form, perfluorooctanosulfonic acid (PFOS), was most abundant, with liver concentrations averaging >10,000 ng/g wet weight (ww) in birds and mammals, respectively, and reaching as high 97,000 ng/g ww in a 1994 specimen. Perfluorohexanesulfonic acid (PFHxS) averaged thousands of ng/g ww in the livers of aquatic birds and littoral-zone house mice, but one order of magnitude lower in the livers of upland desert rodent species. Piscivores and upland desert songbirds were relatively uncontaminated. At control sites, PFAS levels were strikingly lower on average and different in composition. In sum, legacy PFAS at this desert oasis have permeated local aquatic and terrestrial food webs across decades, severely contaminating populations of resident and migrant animals, and exposing people via game meat consumption and outdoor recreation.
Subject(s)
Birds , Environmental Monitoring , Fluorocarbons , Animals , New Mexico , Fluorocarbons/analysis , Humans , Birds/metabolism , Mammals , Environmental Pollutants/analysis , Food Chain , Desert Climate , Environmental ExposureABSTRACT
OBJECTIVE: Hybrid zones are geographic regions where genetically distinct taxa interbreed, resulting in offspring of mixed ancestry. California Scrub-Jays (Aphelocoma californica) and Woodhouse's Scrub-Jays (A. woodhouseii) come into secondary contact and hybridize in western Nevada. Although previous work investigated divergence and gene flow between these species using a handful of microsatellite markers, the hybrid zone has not been studied using genome-scale markers, providing an opportunity to assess genome-wide introgression, test for a genetic basis for ecomorphological traits, and compare these estimates to those derived from microsatellites. RESULTS: Using variant sites flanking ultraconserved elements (UCEs), we performed population assignment and quantified hybrid ancestry for 16 individuals across the zone of secondary contact. Our study included 2468 SNPs distributed throughout the genome, allowing discrimination of genetic affinities of hybrid individuals that were similar to estimates from microsatellites. We show a relationship between bill and wing length and the genetic composition of individuals that was not found in prior work using microsatellites, suggesting a genetic basis for these traits. Our analyses demonstrate the utility of UCEs for the analysis of hybrid zones and provide a basis for future studies to identify the genomic architecture of speciation and phenotypic differences between these incipient species.
