Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP, UK.
Associació Ornitològica Picampall de les Terres de l'Ebre, Amposta, Catalonia, Spain.
Arch Environ Contam Toxicol. 2019 Apr;76(3):394-404. doi: 10.1007/s00244-018-0584-0. Epub 2018 Dec 18.
We examined how coastal mercury contamination varied spatially and temporally across the Iberian Peninsula by measuring mercury concentrations in the eggs of the sentinel biomonitor yellow-legged gull (Larus michahellis). Samples were collected from eight colonies that ranged from the Atlantic across the south and northern areas of the Mediterranean. We also measured Hg residues in eggs of the one of the most endangered gull species in the world, the Audouin's gull (Larus audouinii) from the Ebro Delta, where colonies of yellow-legged and Audouin's gull co-occur. Fresh eggs were collected in 2009 and 2016 and samples were pooled from each colony for analysis. Mercury concentrations in yellow-legged gulls ranged between 0.4 and 2.8 mg/kg dry weight (dw); although there were no significant differences in concentrations between sampling periods, significant differences were found between colonies. Higher concentrations were associated with northern Mediterranean colonies (Columbretes and Ebro Delta), likely due to proximity to emission sources, circulatory marine currents and diet composition. Mercury concentrations in yellow-legged gull eggs were lower than those reported to result in impaired hatching. Residues in Audouin's gull eggs from the Ebro Delta were significantly higher (4.0-5.6 mg/kg dw) than those in yellow-legged gull from the same location, probably associated with dietary differences. Mercury levels in Audouin's gull were ten times above the benchmark suggested to reduce nest success by 10%. Overall, these results raise concern for adverse health impacts in this protected seabird species and further investigation in Audouin's gull eggs from the Ebro Delta is recommended.
我们通过测量黄腿鸥（Larus michahellis）卵中的汞浓度，研究了伊比利亚半岛沿海地区汞污染的时空变化。样本取自 8 个繁殖地，范围从大西洋延伸到地中海的南部和北部地区。我们还测量了埃布罗三角洲（Ebro Delta） Audouin 鸥（Larus audouinii）的卵中的 Hg 残留量，该地区是黄腿鸥和 Audouin 鸥的共同繁殖地。2009 年和 2016 年采集了新鲜的卵，并对每个繁殖地的样本进行了混合分析。黄腿鸥的汞浓度范围在 0.4 到 2.8 毫克/公斤干重（dw）之间；尽管在采样期间浓度没有显著差异，但在繁殖地之间存在显著差异。高浓度与北地中海繁殖地（Columbretes 和埃布罗三角洲）有关，可能是由于接近排放源、循环海洋流和饮食组成。黄腿鸥卵中的汞浓度低于那些导致孵化受损的报道浓度。埃布罗三角洲 Audouin 鸥卵中的残留量明显高于同一地点黄腿鸥的残留量（4.0-5.6 毫克/公斤 dw），可能与饮食差异有关。Audouin 鸥的汞含量是建议降低巢成功率 10%的基准值的 10 倍。总体而言，这些结果令人担忧，因为这对受保护的海鸟物种的健康产生了不利影响，建议进一步调查埃布罗三角洲 Audouin 鸥的卵。
