Trace Element Speciation Laboratory Aberdeen (TESLA), Department of Chemistry, Meston Walk, University of Aberdeen, Aberdeen AB24 3UE, UK; PS Analytical, Crayfields Industrial Estate, Main Road, Orpington, Kent BR5 3HP, UK; Department of General, Analytical and Physical Chemistry, Chair of General and Analytical Chemistry, Montanuniversität Leoben, Franz Josef-Strasse 18, 8700 Leoben, Austria.
The Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush Campus, Midlothian, Edinburgh, EH25 9RG, UK.
Sci Total Environ. 2022 Jul 10;829:154557. doi: 10.1016/j.scitotenv.2022.154557. Epub 2022 Mar 15.
Knowledge of the uptake and fate of mercury (Hg) compounds in biota is important in understanding the global cycling of Hg and its transfer pathways through food chains. In this study, we analysed total mercury (T-Hg) and methylmercury (MeHg) concentrations in 117 livers of Scottish birds of prey that were found across Scotland and submitted for post-mortem examination through the Raptor Health Scotland project between 2009 and 2019. Statistical comparisons focussed on six species (barn owl, Tyto alba; Eurasian common buzzard, Buteo buteo; golden eagle, Aquila chrysaetos; hen harrier, Circus cyaneus; Eurasian sparrowhawk, Accipiter nisus; and tawny owl, Strix aluco) and showed that golden eagles had a statistically lower fraction of MeHg compared to other raptor species. Further investigation using stable carbon and stable nitrogen isotope ratio measurements carried out for the golden eagles (n = 15) indicated that the increased presence of inorganic mercury (iHg) correlated with a marine influence on the primarily terrestrial diet. Additional bioimaging (n = 1) with laser ablation - inductively coupled plasma - mass spectrometry indicated the co-location of Hg and selenium (Se) within the liver tissue and transmission electron microscopy showed evidence of nanoparticles within the range of 10-20 nm. Further analysis using single particle - inductively coupled plasma - mass spectrometry (n = 4) confirmed the presence of Hg nanoparticles. Together, the evidence suggests the presence of mercury selenide (HgSe) nanoparticles in the liver of some golden eagles that, to our knowledge, has never been directly observed in terrestrial birds of prey. This study points to two alternative hypotheses: these golden eagles may be efficient at breaking down MeHg and form HgSe nanoparticles as a detoxification mechanism (as previously observed in cetaceans), or some golden eagles with elevated iHg may have accumulated these nanoparticles by foraging on stranded cetaceans or seabirds.
了解汞（Hg）化合物在生物群中的摄取和归宿对于理解汞的全球循环及其通过食物链的转移途径非常重要。在这项研究中，我们分析了 2009 年至 2019 年期间通过苏格兰猛禽健康项目在苏格兰各地发现并提交进行死后检查的 117 只苏格兰猛禽的肝脏中的总汞（T-Hg）和甲基汞（MeHg）浓度。统计比较集中在六个物种（仓鸮，Tyto alba；欧亚普通雕鸮，Buteo buteo；金雕，Aquila chrysaetos；红隼，Circus cyaneus；欧亚雀鹰，Accipiter nisus；和长耳鸮，Strix aluco）上，结果表明，与其他猛禽物种相比，金雕的 MeHg 分数统计学上较低。对金雕（n = 15）进行的稳定碳和稳定氮同位素比测量的进一步研究表明，无机汞（iHg）的增加与主要是陆地饮食中海洋的影响有关。对激光烧蚀 - 电感耦合等离子体质谱（n = 1）的额外生物成像表明，Hg 和硒（Se）在肝脏组织中共同存在，透射电子显微镜显示 10-20nm 范围内存在纳米颗粒。使用单颗粒 - 电感耦合等离子体质谱（n = 4）的进一步分析证实了 Hg 纳米颗粒的存在。综上所述，有证据表明一些金雕的肝脏中存在汞硒化物（HgSe）纳米颗粒，据我们所知，这在陆地猛禽中从未直接观察到过。这项研究提出了两种替代假设：这些金雕可能非常善于分解 MeHg 并形成 HgSe 纳米颗粒作为解毒机制（如以前在鲸类动物中观察到的那样），或者一些 iHg 含量升高的金雕可能通过捕食搁浅的鲸类动物或海鸟而积累了这些纳米颗粒。
