Blood concentrations of 50 elements in Eagle owl (Bubo bubo) at different contamination scenarios and related effects on plasma vitamin levels

Blood Toxic Elements and Effects on Plasma Vitamins and Carotenoids in Two Wild Bird Species: Turdus merula and Columba livia

“…The higher exposure to the most toxic elements for both species in the ancient mine site was expected. This mining area has been exploited for more than 2500 years (mainly for Pb, Zn, Cu, Mn, Ag, Fe, and Sn extraction) [ 49 , 50 ], and similar results have already been observed in several biomonitoring studies developed along the years (1993–2020) in other bird species, including red-necked nightjars ( Caprimulgus ruficollis ) and eagle owls ( Bubo bubo ) [ 16 , 17 , 38 , 40 , 51 , 52 ]. The Pb concentrations detected in blood of T. merula in the mining area are of special concern, being 58 times higher than the levels found in birds from the control area.…”

“…Pollutant-related indirect effects, including poor quality and quantity of food or changes in the diet (due to resource limitations), may contribute to lower essential elements (Mo and Se) and Sr concentrations in the mining-impacted area. Previous studies have also found reduced Mo and Sr levels in red-necked nightjars and eagle owls inhabiting the mining area [ 16 , 17 ]. Although Sr is classically considered a non-essential element, further studies are needed to understand its essentiality, since its supplementation has been shown to increase calcified bone volume and limit bone resorption, which prevents from bone mass loss [ 70 , 71 , 72 ].…”

“…Excessive Mn may increase free radicals, and fighting against them would again deplete antioxidants, such as lutein, in the body. Mn concentrations (and the effect on lutein levels in birds) have rarely been reported [ 16 , 18 ]. However, Mn toxicity on pigment content, including decreased carotenoid levels, has been found in different plant species [ 88 , 89 ].…”

“…In addition to the metals/metalloids classically studied, rare earth elements (REE) and other minor elements (ME) are of emerging concern because of their use in modern technology worldwide, leading to emissions and electronic waste [ 14 , 15 ]. However, reports on exposure to these elements and the potential consequences for wildlife populations have only recently been studied and are still scarce [ 16 , 17 , 18 ]. Therefore, additional research is needed to evaluate toxic elements exposure, spatiotemporal trends, and related adverse effects for different avian species.…”

“…This study aims to evaluate blood concentrations of 50 elements (i.e., ATSDR’s list toxic elements, trace elements, REE, and ME) and their related effects on lutein and vitamin levels in blackbirds and pigeons inhabiting different scenarios of contaminant exposure in the southeast of the Iberian Peninsula (i.e., agricultural–urban area, mining area, and control area). We expect increased Pb, As, and other element concentrations in the mining area, based on previous findings in different wild bird species [ 16 , 17 , 38 ] that may lead to physiologic effects, including reduced hematocrit and vitamin alterations [ 16 , 18 ]. Thus, the potential effects of toxic element exposure on hematocrit levels and body measurements are also tested.…”