Heavy metals and metalloid levels in the tissues of yellow-legged gulls (Larus michahellis) from Spain: sex, age, and geographical location differences

Abstract

In the present study, mercury (Hg), cadmium (Cd), lead (Pb), selenium (Se), and arsenic (As) were measured in liver, kidney, and feathers of adult, juvenile, and chick seagulls (Larus michahellis) collected from the northwest of Spain. Age, sex, and the geographical location of samples were considered variables that can influence metal bioaccumulation, for which concentrations were determined by means of ICP-MS. The mean concentrations (dry weight) found in seagulls were 7.01 ± 0.37 mg Hg/kg, 22.82 ± 2.83 mg Cd/kg, 7.36 ± 1.36 mg Pb/kg, 18.64 ± 0.63 mg Se/kg, and 10.64 ± 0.59 mg As/kg. Regarding the different factors analyzed, Hg was the only metal showing sex-related differences, being significantly higher (p < 0.05) the concentrations found in feathers of males (1.26 ± 0.12 mg/kg) than those in females (0.99 ± 0.11 mg/kg). A highly significant (p < 0.01) increase in levels of some metals was found in liver related to the increase of age: Hg (adults (A) 3.33 ± 0.22 mg/kg vs chicks (C) 1.76 ± 0.28 mg/kg), Cd (A 4.74 ± 0.62 mg/kg vs C 1.79 ± 0.2), Pb (A 0.65 ± 0.12 mg/kg vs juveniles 0.4 ± 0.11 mg/kg), and Se (A 7.56 ± 0.43 mg/kg vs C 5.24 ± 0.53 mg/kg). Positive correlations between Cd-Hg and Se–Hg were found in liver (p < 0.001), kidney (p < 0.001), and feathers (p < 0.05 and p < 0.001, respectively). The associations found may reflect antagonistic interactions between Se and Cd on Hg toxicity. The results suggest that L. michahellis can reveal local contamination around the foraging and breeding sites and can be a very useful monitoring instrument for assessing heavy metal contamination and sentinel species of environmental health.

Evaluation of the Difference in the Content of Essential and Non-Essential Elements in Wild Boar and Swine Tissues Sampled in the Same Area of Northern Italy

“…Our findings show a lack of statistically significant differences between males and females in the contents of essential and non-essential elements in the tissues of wild boar; except for As, which was significantly higher in the liver of males ( Table 5 ). The influence of sex on the bioavailability, the transfer and the effects of contaminants and other elements has been evaluated in several studies with different and sometimes conflicting results [ 56 ]. Generally, the contents of essential and non-essential elements can be influenced by factors such as the metabolic rate, hormonal pattern and reproductive state [ 57 ].…”

Species Differences and Tissue Distribution of Heavy Metal Residues in Wild Birds

“…The increased sample sizes for all the groups of birds are required to better understand the differences in the deposition patterns of the metals in these bird species. Previous studies have revealed gender and age differences in the accumulation of heavy metals in birds [57,58]; nonetheless, we did not consider sex-depended differences in metal accumulation, and most of the tissue samples were collected from adult birds. In addition to gathered bird organs, the analyses of other environmental samples such as soil, water, and bird feed are also critical to identify the sources and pathways of heavy metal contamination in these wild birds.…”