Residue levels of organochlorine and mercury compounds in unhatched eggs and the relationships to breeding success in white‐tailed sea eagles Haliaeetus albicilla in Sweden

Abstract

Eighty‐five unhatched eggs from 68 white‐tailed sea eagle clutches were collected during 1965–1978 along the Baltic coast and in Lapland. The eggs were analysed individually for residue levels of DDT and its metabolites, PCB and mercury. Pooled samples were analysed for levels of dieldrin and hexachlorobenzene (HCB). The variations in residue levels within and between clutches were studied before the material was grouped for investigations of relationships between reproduction and contamination. Levels of DDE, PCB and mercury were significantly higher in the Baltic as compared to the Lapland material. In the Baltic, the reproductive success on a clutch basis and on a nest basis was significantly and negatively correlated to the egg residue levels of DDE and PCB; no correlation was found with mercury. Critical ranges were estimated to 500–600 mg kg1 of DDE and/or 800–900 mg kg−1 of PCB (lipid basis). The levels of dieldrin and HCB in the pooled samples were not considered important to reproduction. In a comparative study including six sea eagle and six bald eagle populations, productivity showed the strongest correlation with DDE.

Mercury and Persistent Organic Pollutant Concentrations in African Fish Eagles, Marabou Storks, and Nile Tilapia in Uganda

“…The African fish eagle is very sensitive to the effects of persistent organic pollutants (POPs) (Douthwaite, 1992). This characteristic is shared by other piscivorous tertiary avian predators such as the bald eagle (Haliaeetus leucocephalus) in North America (Bowerman et al, 2003) and the white-tailed sea eagle (Haliaeetius albicella) in Sweden (Helander et al, 1982).…”

Breeding Performance, Apparent Survival, Nesting Location and Diet in a Local Population of the Tawny OwlStrix alucoin Central Lithuania Over the Long-Term

“…Tissue and egg samples of white-tailed sea eagles have contained among the highest residue concentrations of persistent organochlorine contaminants and heavy metals in the Baltic and the world (Henriksson et al 1966, Jensen 1966, Jensen et al 1972, Koivusaari et al 1980, Helander 1994b, Helander et al 1982, Olsson et al 2000, Nordlöf et al 2010. Predatory birds are highly exposed to persistent chemicals and are useful in detecting the presence of "new" pollutants that are potentially harmful, as illustrated by the discovery of PCBs in 1966 in a Baltic white-tailed sea eagle (Jensen 1966), and the discovery of the flame retardant congener PBD-209 in peregrine falcon eggs in 2004 (Lindberg et al 2006).…”

A Review of Factors Affecting Productivity of Bald Eagles in the Great Lakes Region: Implications for Recovery

“…It is likely that the observed effects on hatchability of white-tailed sea eagle eggs were due to the effects of organochlorine compounds. Subsequent reports refute the Hg/reproduction theory of Berg et al (53) and link white-tailed sea eagle reproductive problems primarily to p,p'-DDE and PCBs (52,54). The effects of Hg on wild populations of nesting bald eagles is difficult to assess because there are nearly always organochlorine compounds present (55).…”

“…No effects of Hg have been observed on reproduction of the white-tailed sea eagle, a species similar to the bald eagle (52). A theoretical concentration for effect in eggs was given as 1.0 mg Hg/kg in eggs, although no direct link to adverse effects was noted (52). When concentrations of Hg in feathers of white-tailed sea eagles of the Baltic ranged from 40 to 65 mg Hg/kg, eggs from these areas were observed to seldom hatch (53).…”

“…Thus, it would be difficult to ascribe the observed effects to mercury alone. No effects of Hg have been observed on reproduction of the white-tailed sea eagle, a species similar to the bald eagle (52). A theoretical concentration for effect in eggs was given as 1.0 mg Hg/kg in eggs, although no direct link to adverse effects was noted (52).…”