Decadal re-evaluation of contaminant exposure and productivity of ospreys (Pandion haliaetus) nesting in Chesapeake Bay Regions of Concern

Abstract

The last large-scale ecotoxicological study of ospreys (Pandion haliaetus) in Chesapeake Bay was conducted in 2000-2001 and focused on U.S. EPA-designated Regions of Concern (ROCs; Baltimore Harbor/Patapsco, Anacostia/middle Potomac, and Elizabeth Rivers). In 2011-2012, ROCs were re-evaluated to determine spatial and temporal trends in productivity and contaminants. Concentrations of p,p'-DDE were low in eggs and below the threshold associated with eggshell thinning. Eggs from the Anacostia/middle Potomac Rivers had lower total PCB concentrations in 2011 than in 2000; however, concentrations remained unchanged in Baltimore Harbor. Polybrominated diphenyl ether flame retardants declined by 40%, and five alternative brominated flame retardants were detected at low levels. Osprey productivity was adequate to sustain local populations, and there was no relation between productivity and halogenated contaminants. Our findings document continued recovery of the osprey population, declining levels of many persistent halogenated compounds, and modest evidence of genetic damage in nestlings from industrialized regions.

Chesapeake Bay fish–osprey (Pandion haliaetus) food chain: Evaluation of contaminant exposure and genetic damage

“…Using the sample egg collection technique , after completion of a clutch (3 or more eggs), 1 fresh egg was randomly sampled from each study nest (Susquehanna River and flats, n = 10; Anacostia/middle Potomac, n = 13; James River, n = 12; Back River, n = 5; Poplar Island, n = 12). Eggs were transported to the USGS Patuxent Wildlife Research Center, cleaned, and weighed, and the length and width were measured to the nearest 0.01 mm . A 2.4‐mm hole was drilled into the blunt end of the egg (MultiPro ® 7.2V, model 770; Dremel ® ), and distilled water was injected into the air cell to return contaminant concentrations to that of a freshly laid egg .…”

“…Chemical analyses were conducted at the Virginia Institute of Marine Science based on previously described approaches . Briefly, egg contents were homogenized, lyophilized, and spiked with surrogate PCB standards (congeners 30, 65, and 204; Ultra Scientific, 13 C‐PCB‐126) and 2,3,4,4′,5,6‐hexabromodiphenyl ether (BDE‐166; Cambridge Isotope Laboratories).…”

“…Whole fish and osprey egg contents were analyzed for 129 PCB congeners, 44 Chemical analyses were conducted at the Virginia Institute of Marine Science based on previously described approaches [16,[26][27][28][29]. Briefly, egg contents were homogenized, lyophilized, and spiked with surrogate PCB standards .…”

“…Year was used as a blocking factor, because DNA damage assays from 2011 versus 2012 and 2013 were not comparable [16]. This analysis was conducted using the redundancy analysis function from the Vegan package in R [39,40].…”

“…Means with different capital letters are significantly different by Tukey's honest significant difference method of multiple comparisons (p < 0.05) or a generalized Wilcoxon nonparametric test followed by pairwise comparisons using a Bonferroni correction. b A subset of these data has been published previously [16]. c If nondetects were present in fewer than half of the samples, the Kaplan Meier method was used to estimate the extremes of the mean.…”