Contaminant concentrations and biomarker response in great blue heron eggs from 10 colonies on the upper Mississippi River, USA

Abstract

Abstract-In 1993, great blue heron (Ardea herodias; GBH) eggs were collected from 10 colonies on the upper Mississippi River (UMR). They were then artificially incubated until pipping and analyzed for mercury, selenium, and organochlorines. Livers of embryos were analyzed for hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity and four measures of oxidative stress. Brains were measured for asymmetry and blood was measured for the coefficient of variation of DNA (DNA CV). Organochlorine concentrations were generally low (geometric mean DDE ϭ 1.3 g/g wet weight; polychlorinated biphenyl [PCB] ϭ 3.0 g/g; 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD] ϭ 11.5 pg/g). Eggshell thickness was negatively correlated with DDE concentrations. Mercury (geometric mean ϭ 0.8 g/g dry weight) and selenium (3.1 g/g dry weight) concentrations in GBH eggs were within background levels. EROD activity was not correlated with total PCBs, TCDD, or toxic equivalents (TEQs), based on the relative contribution of individual PCB congeners, dibenzodioxins (PCDDs), and dibenzofurans (PCDFs) to total calculated TEQs. Three of the four measures of oxidative stress were correlated with mercury concentrations. Twenty of 43 (47%) embryo brains were asymmetrical and the embryos with asymmetrical brains had higher EROD concentrations in the liver and higher DNA CV in the blood than embryos with symmetrical brains.

Oxidative stress response of Forster's terns (Sterna forsteri) and Caspian terns (Hydroprogne caspia) to mercury and selenium bioaccumulation in liver, kidney, and brain

“…Hepatic depletion of GSH and concomitant increase in GSSG:GSH ratio is consistent with the findings of many other studies. Hepatic GSH concentrations were negatively correlated to mercury levels in double-crested cormorant nestlings, snowy egret nestlings, great blue heron (Ardea herodias) embryos, adult surf scoters (Melanitta perspicillata), ruddy ducks (Oxyura jamaicensis), and greater scaup (Aythya marila) [11,13,19,33]. Increased hepatic GSSG:GSH ratio was related to Hg in mallards, greater scaup, and double-crested cormorants.…”

Temporal trends of perfluoroalkyl substances (PFAS) in eggs of coastal and offshore birds: Increasing PFAS levels associated with offshore bird species breeding on the Pacific coast of Canada and wintering near Asia

“…Double-crested cormorants (hereafter cormorant) and great blue herons (hereafter heron) are both widely distributed across North America [47]. Cormorants are found from resident coastal near-shore species in our Salish Sea study area, western Pacific coast of Canada [47], and herons are year-round residents in freshwater and marine habitats within this region and are a widely used indicator species [48,49].…”

In Ovo Exposure to Polychlorinated Biphenyls: Reproductive Effects on Second-Generation American Kestrels

“…In ovo exposure of males may have altered genetic material, which could have affected the hatchability of fertile eggs. DNA damage was observed in Japanese quail (Coturnix coturnix japonica) exposed to Aroclor 1260 (Leonzio et al 1996) and in the embryos of wild great blue herons (Ardea herodias; Custer et al 1997). Alternatively or additionally, changes in the incubation behavior of the male kestrels who incubate for approximately 20% of the time (Balgooyen 1976) may further account for their reduced hatching success.…”