Effects of As, Cd and Pb on blackbirds: a multi-marker study

Resumen del trabajo presentado al Society of Environmental Toxicology and Chemistry Europe 24th Annual Meeting, celebrado en Basel (Suiza) del 11 al 15 de mayo de 2014.-- et al.The present study aimed to get insights into the pathways linking effects at individual and population level and how gender-specific responses may affect such links. We used a multi-marker approach on the European blackbird Turdus merula in order to investigate population structure parameters, potential metal toxicity with health biomarkers (haematology, blood biochemistry/enzymatic activities, oxidative stress), potential depletion of quantity/quality of food with nutritional status biomarkers (body condition index, blood biochemistry), and relate these different parameters with exposure to As, Cd and Pb (blood and feather concentrations). Eighty-three blackbirds (55 males, 28 females) were captured during the breeding season in five sites along a pollution gradient in Antwerp (Belgium). The levels of As, Cd and Pb in tissues increased along the pollution gradient and did not vary with gender. Levels in blood and feathers were highly correlated, strongly suggesting that birds were chronically exposed. The sex-ratio did not vary with pollution. The age structure, for males only, differed between sites with an increase of yearling proportion in the most polluted sites, which may be interpreted as a result of higher mortality or emigration in these polluted sites. The proportion of female carrying a visible egg decreased with pollution level although not significantly. No relationships were observed between exposure and markers related to nutritional status. In males, the results suggested some health disorders (anemia, myopathy, kidney dysfunctioning and metabolic homeostasis disorders). No oxidative stress was detected but a modification of oxidative status, with an increase of some circulating antioxidants (lutein, tocopherol) with metals. In females, only few correlations were found, most of them being significant only for females carrying an egg. Like in males, no oxidative damages were detected but an increase of lutein with metal levels. A decrease of GSH with metals, not observed for males, was also found. Altogether, the results suggested a higher sensitivity of males to toxic effects, but may also mirror trade-offs between reproduction and individual survival in the most polluted sites for females. The modification of circulating lutein and tocopherol may be related to the effects of metal(loid)s on oxidative status, but may also be linked to changes in hormone levels, notably stress hormones.Peer Reviewe