Centro de Estudos do Ambiente e do Mar, Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, 1749-016, Lisboa, Portugal.
Centro de Estudos do Ambiente e do Mar, Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, 1749-016, Lisboa, Portugal.
Environ Pollut. 2023 Jan 1;316(Pt 2):120674. doi: 10.1016/j.envpol.2022.120674. Epub 2022 Nov 17.
Shorebirds and seabirds are abundant predators in coastal habitats worldwide, relying upon a high diversity of benthic invertebrates and fish, respectively. While occupying different trophic guilds, they are differently exposed to element contamination entering the coastal food web. Therefore, these birds have been used as bioindicators of environmental contamination in marine ecosystems. We analysed the concentration of trace elements in blood samples of 16 shorebird and seabird migratory species in a major non-breeding site, the Bijagós Archipelago, in regard to their trophic ecology. Overall, our study shows low exposure of this bird community to toxic elements, except for Hg. Most species presented Hg burdens within the moderate toxicity threshold, but one species (Dunlin) presented values at a potential high Hg toxicity risk. We found a positive relationship between Se and Ni concentrations and δN values (a proxy for trophic level). In addition, a positive relationship was found between δC (a proxy for habitat characteristics) and Hg, Fe, Cu and Mn, while the opposite pattern was recorded for As. Differences were also shown for several trace elements between the two studied trophic guilds: concentrations of As, Pb and Se were higher in pelagic fish consumers (seabirds), whereas Cr, Fe and Sr burdens were higher in benthic invertebrate consumers (shorebirds). Although previous studies in the same site revealed very high concentrations of Cd and Pb in some of the prey species of shorebirds and seabirds (bivalves and fishes), values found in birds for these two elements suggest no toxicological risk. Thus, exposure to toxic elements is not currently a threat to coastal bird populations, namely those facing apparent local declines in Guinea-Bissau, one of the most important non-breeding quarters for of West Africa. Still, Hg burdens were high in some species, deserving further monitoring.
滨鸟和海鸟是全球沿海栖息地中丰富的掠食者，分别依赖于丰富的底栖无脊椎动物和鱼类。虽然它们占据不同的营养阶层，但它们受到进入沿海食物网的元素污染的影响方式不同。因此，这些鸟类被用作海洋生态系统环境污染的生物指标。我们分析了在比热戈斯群岛这个主要的非繁殖地，16 种滨鸟和海鸟迁徙物种的血液样本中痕量元素的浓度，以了解它们的营养生态。总的来说，我们的研究表明，除汞外，这个鸟类群落暴露在有毒元素中的程度较低。大多数物种的汞含量处于中度毒性阈值内，但有一种物种（黑腹滨鹬）的汞含量存在潜在的高毒性风险。我们发现硒和镍浓度与δN 值（营养水平的替代指标）之间存在正相关关系。此外，δC（栖息地特征的替代指标）与汞、铁、铜和锰之间存在正相关关系，而砷则呈现相反的模式。两种研究的营养阶层之间的几种痕量元素也存在差异：砷、铅和硒在远洋鱼类消费者（海鸟）中的浓度较高，而铬、铁和锶的含量在底栖无脊椎动物消费者（滨鸟）中较高。尽管之前在同一地点进行的研究表明，滨鸟和海鸟的一些猎物物种（双壳类和鱼类）中镉和铅的浓度非常高，但鸟类中这两种元素的值表明不存在毒理学风险。因此，有毒元素的暴露目前不是沿海鸟类种群的威胁，尤其是在几内亚比绍，这是西非最重要的非繁殖地之一，鸟类的数量明显下降。尽管如此，一些物种的汞含量仍然很高，需要进一步监测。
