Trace Elements in Three Marine Birds Breeding on Reunion Island (Western Indian Ocean): Part 1—Factors Influencing Their Bioaccumulation

Abstract

This work aims to use seabirds as bioindicators of trace element levels in the tropical waters and food webs of the Western Indian ocean. The accumulation patterns of selected toxic (Cd and Hg) and essential (Cu, Fe, Mn, Se and Zn) elements were determined in liver, kidney and pectoral muscles of three species of 162 marine birds collected in Reunion Island between 2002 and 2004. These pelagic seabirds belong to the following species : Barau's Petrel (Pterodroma baraui), Audubon's Shearwater (Puffinus lherminieri bailloni) and the White-tailed Tropicbird (Phaethon lepturus). Mercury levels were also measured in breast feathers. Highest mean kidney Cd and liver Hg levels (respectively 27.79 ± 13.78 µg.g −1 d.w. and 24.31 ± 14.13 µg.g −1 d.w.) were found in the squid-eating Barau's Petrel. Barau's Petrel feather Hg levels fell in the 0.6-2.7 µg.g −1 d.w. range previously reported for other petrels and shearwaters. The values of the other elements were also in the same range as those previously reported in the published literature concerning related seabirds, although Se and Zn burdens in the Reunion birds were amongs the highest values. Levels of Zn, Fe and, to a lesser extent, Cu appeared to be regulated in seabird tissues. Uptake and pathways of metabolism and storage seemed to be similar for the five essential elements. The reproductive status of the bird did not seem to affect elemental levels which, moreover, were not significantly different between males and females. However, trace elements in sampled birds varied according to the tissue considered, the age of the animal and its species. The diet was seemingly a major influencing factor. The health status also appeared to have an impact on elemental levels.

Trophic ecology of marine birds and pelagic fishes from Reunion Island as determined by stable isotope analysis

“…data), which can have fairly high δ 15 N signatures (Froese et al 2005). These δ 15 N results substantiate predictions of a previous study of these birds in which lower mercury levels in Audubon's shearwater were an argument for the lower trophic level of its prey (Kojadinovic et al 2007). This is also coherent with what is known of the foraging behavior of white-tailed tropicbird and Barau's petrel.…”

Bioaccumulation of trace elements in pelagic fish from the Western Indian Ocean

“…Tropical waters are less monitored than marine environments from temperate and polar regions, more particularly southern tropical oceans which are often considered as less contaminated than the northern ones. Accordingly, the tropical zone of the Indian Ocean has, up to the present day, received little attention from researchers with reference to levels of trace elements in marine organisms (Kureishy et al, 1979;Matthews, 1983;Mwashote, 2003;Robinson and Shroff, 2004;Kojadinovic et al, 2007).…”

Tissue Distribution of Heavy Metals in Heron and Egret Chicks from Pyeongtaek, Korea

“…The cadmium concentration in the sediment of foraging site was 0.07 lg/g dw. Species-and tissue-specific accumulations have been reported various birds; passerines (Deng et al 2007), three seabird species (Kojadinovic et al 2007), heron and egret adults (Horai et al 2007) and chicks and Magpies (Pica pica) (Włostowski et al 2010) and Rook (Corvus frugilegus) nestlings (Orłowski et al 2012). In general, cadmium is predominantly accumulated in kidneys of birds and the kidney for cadmium is considered a longterm storage tissue.…”