Peregrine falcon egg pollutants

ABSTRACT

The role of the peregrine falcon (Falco peregrinus) as a bioindicator for the accumulation of organohalogen compounds and other persistent organic pollutants has been established in field studies. Biometric indices for damage caused by pollutants such as the shell thickness and the shell index were determined and the egg contents were analyzed for various pollutants by gas chromatography/mass spectrometry. A wide range of chemically activated luciferase expression (CALUX®) bioassays were performed on subsamples of the eggs.

The following organohalogen compounds were found in the eggs of 2009: dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethane, heptachlor epoxide, hexachlorobenzene, dieldrin, hexachlorocyclohexane, polychlorobiphenyls and polychlorodibenzodioxins and polychlorodibenzofurans, polybromodiphenyl ethers, hexabromocyclododecane, tetrabromobisphenyl A, perfluoro compounds, and mercury. The DDT metabolite, dichlorodiphenyldichloroethene (DDE) (11,800 ng/g dry matter), was found to be the most highly concentrated egg contaminant followed by 2,2′,4,4′,5,5′-hexachlorobiphenyl (3800 ng/g). After a past general drop in pollution level, most egg contaminants presently plateau at levels that may still exceed limit values in foods of animal origin (DDE) or even toxicological thresholds (polychlorobiphenyls + polychlorodibenzodioxins, polybromodiphenyl ethers, perfluorooctanesulfonate, methylmercury).

Accumulation of DDE could be shown in peregrine falcon eggs from the uplands of Southwest Germany with elevations up to 1500 m, presumably due to its global distribution and its cold condensation in higher altitudes. In contrast, the concentration of polychlorobiphenyls in falcon eggs decreases with elevation, indicating that these pollutants originate mainly from conurbations and local industrial sites.

Significant negative correlations were found between both shell index and thickness and the concentration of Hg. A deleterious effect is also evident from a no-observed-adverse-effect level of 120 ng MeHg per gram egg determined by other authors in chronic feeding studies with ibises, which resulted in decreased egg productivity and male homosexual nesting and courtship behavior. The average Hg concentration in the peregrine falcon eggs from 2009 is almost four times higher than this level. MeHg accounted for 82.5% of the Hg present in the eggs of 2009 and 2010.

The cell test DR CALUX® for screening of dioxin-like activities can be used to detect not only the 29 regulated dioxin-like substances but also many other persistent organic pollutants with dioxin-like potencies, such as mixed halogenated dioxins/biphenyls. In our case, the results of bioanalytical screening methods showed no additional effect of other compounds with dioxin-like activity.

Ninety-three out of 177 analytes sought could be detected in the eggs. Chlorinated paraffins, organotin compounds, some pesticides that are still in use, and phthalic esters with the exception of traces of diethylhexyl phthalate could be excluded. All pollutants found in the eggs belong to substance classes banned by the Stockholm and Minamata Conventions.

KEYWORDS:

• Biomonitoring
• bird eggs
• CALUX®
• egg shell parameters
• hormone-like activity
• long-range atmospheric transport
• organohalogen compounds

Acknowledgments

This paper is a contribution in the series: “Chemical and Biological Environmental Monitoring (CBEM)” of the German Working Group on Environmental Monitoring (editors: H. Rüdel, Schmallenberg; W. Schröder, Vechta; K.T. von der Trenck, Karlsruhe; G.A. Wiesmüller, Cologne). The series CBEM was launched in the journal Environmental Science and Pollution Research (ESPR) with the position paper “Substance Related Environmental Monitoring” (Rüdel, Schröder, von der Trenck, Wiesmüller, ESPR 16: 486–498, 2009).

The work described here would have been impossible without the dedicated efforts to conserve an endangered indigenous raptor species by a group of amateur ornithologists organized in the AGW (Arbeitsgemeinschaft Wanderfalkenschutz – Working Group for the Protection of the Peregrine Falcon) within the NABU (Naturschutzbund – Nature Conservation Society).

Supplemental material for this article can be accessed here.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. Quotation marks, because WHO has readmitted DDT for indoor use to fight the Anopheles vector in areas where Malaria is endemic (→ box “Atmospheric DDT concentrations”).

2. Rauchfuß, K. 2007: “Reevaluierung der Toxizitätsäquivalenzfaktoren für Dioxine und dioxinähnliche Substanzen: WHO 2005 — Auswirkungen auf den Immissionsschutz.” Expertenmeinung aus dem Landesamt für Natur, Umwelt, und Verbraucherschutz Nordrhein-Westfalen (LANUV NRW), Essen. Advisory opinion from the State Agency for Environment, Nature, and Consumer Protection of North Rhine Westphalia, Essen: LANUV NRW, unpublished.

3. PCBs 126, 169, 77, and 81 are readily quantifiable with concentrations at least 60-fold above their LOQ (Table 1). The issue of how to treat values below the LOQ (upper bound vs. lower bound; Malisch, Kotz, and Wahl 2012) is therefore not relevant in this context.

4. PFOS proved embryotoxic and caused inflammation of the portal vein, bile duct hyperplasia, and cellular necrosis in the liver of domestic chicken embryos and also increased the expression of genes regulated via the PPARα, and playing a role in obesity. The PFOS concentrations in glaucous gull (Larus hyperboreus) eggs from a colony of the Norwegian Arctic were similar to the liver levels of adult gulls from the same region (Molina et al. 2006; O‘Brien et al. 2009).