EROD activity, chromosomal damage, and oxidative stress in response to contaminants exposure in tree swallow (Tachycineta bicolor) nestlings from Great Lakes Areas of Concern

Abstract

Tree swallow, Tachycineta bicolor, nestlings were collected from 60 sites in the Great Lakes, which included multiple sites within 27 Areas of Concern (AOCs) and six sites not listed as AOCs from 2010 to 2014. Nestlings, approximately 12 days-of-age, were evaluated for ethoxyresorufin-O-dealkylase (EROD) activity, chromosomal damage, and six measures of oxidative stress. Data on each of these biomarkers were divided into four equal numbered groups from the highest to lowest values and the groups were compared to contaminant concentrations using multivariate analysis. Contaminant concentrations, from the same nestlings, included polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs), and 17 elements. Alkylated polycyclic aromatic hydrocarbons (aPAHs) and parent PAHs (pPAHs) were measured in pooled nestling dietary samples. Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and pesticides were measured in sibling eggs. Concentrations of aPAHs, pPAHs, chlordane, dieldrin, heptachlor, and PCBs, in that order, were the major contributors to the significant differences between the lowest and highest EROD activities; PFCs, PBDEs, the remaining pesticides, and all elements were of secondary importance. The four categories of chromosomal damage did not separate out well based on the contaminants measured. Concentrations of aPAHs, pPAHs, heptachlor, PCBs, chlordane, and dieldrin were the major contributors to the significant differences between the lowest and highest activities of two oxidative stress measures, total sulfhydryl (TSH) activity and protein bound sulfhydryl (PBSH) activity. The four categories of thiobarbituric acid reacting substances (TBARS), oxidized glutathione (GSSG), reduced glutathione (GSH), and the ratio of GSSG/GSH did not separate well based on the contaminants measured.

Legacy and Contaminants of Emerging Concern in Tree Swallows Along an Agricultural to Industrial Gradient: Maumee River, Ohio

“…Bishop et al (2016) found a positive association between PAHs and EROD induction in double‐crested cormorants ( Phalacrocorax auritus ) nesting in Hamilton Harbor, Ontario, Canada; and Smits et al (2000) found induction of EROD activity at 2 sites that had high sediment PAH levels. At approximately 70 sites across the Great Lakes, Custer et al (2017b) found that the largest contributor to the difference between the high and low EROD groups were PAHs (22.7%), with total PCBs only contributing 8.2% to the differences. Total PCBs were higher at the sites lower in the drainage compared to the upper sites, as were the PAHs, so elevated EROD activity was most likely a result of both PAH and PCB exposure.…”

“…After nestlings were euthanized by decapitation, tissues collected for biomarker response assessments were snap‐frozen at −196 °C in a dry nitrogen shipper before being stored at −80 °C. See in‐depth methods in Custer et al (2017b, 2019). All samples were collected under applicable federal (MB123047‐0), state (17‐33), and local (012716, 012717) permits.…”

“…Tree swallows ( Tachycineta bicolor ) have been used extensively over the past 20 yr to study exposure and effects of contaminants (Custer 2011), providing a large amount of exposure information on many of these newer chemical classes (Custer et al 2016, 2017a). In addition, population‐level endpoints, biomarkers, and physiological response assays have been developed (Custer et al 2017b, 2018, 2019). Tree swallows offer many advantages over other avian species that have traditionally been used: 1) their food habits (aerial stage of benthic aquatic insects) closely reflect sediment contamination; 2) feeding range (<1 km), which is indicative of local rather than regional contamination; 3) nesting substrate (artificial nest boxes), which encourages nesting where data are needed; 4) widespread geographic distribution; and 5) tolerance of human activity.…”

Embryonic effects of an environmentally relevant PCB mixture in the domestic chicken

“…Polychlorinated biphenyls (PCBs) persist in the environment, bioaccumulate and biomagnify in wildlife, and are a human health risk (Van den Berg et al 2005;Golden and Kimbrough 2009;Bloom et al 2014;Fernandez-Gonzalez et al 2015;Warenik-Bany et al 2016;Batt et al 2017;Clatterbuck et al 2018). Exposure of wild birds has been documented for many years, with measurable chemical residues in field bird eggs as well as reports of impacts on endocrine function (Klaas and Swineford 1976;Thiel et al 1988;Powell et al 1997Powell et al , 1998McNabb and Fox 2003;Madden and Skinner 2016;Custer et al 2016Custer et al , 2017. It has been difficult to relate exposure and effects in wild birds because many species are migratory, often with different seasonal exposures to environmental contaminants.…”

In Memoriam: Thomas W. Custer 1945-2018

“…He investigated an eclectic mix of contaminants including PCBs, dioxins and furans, and trace metals such as mercury and lead, but he was more recently delving into the effects of many of the newer contaminants, such as the brominated flame retardants, perfluorinated chemicals and pharmaceuticals and personal care products. A recent bioindicator paper shows how Tom was always making successful collaborations that moved science forward, with research covering 7-8 years of science on the Great Lakes Restoration Initiative (GLRI) (Custer et al 2017). The results of a recent paper (Custer et al 1999) that DDE, not PCBs, was the primary driver in decreased reproductive success in Double-crested Cormorants (Phalacrocorax auritus), challenged a number of previous findings.…”