Laboratório de Traçadores Wolfgang C. Pfeiffer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Bloco G/CCS/Ilha do Fundão, Rio de Janeiro (RJ) CEP: 21941-902, Brazil.
Laboratório de Limnologia, Departamento de Ecologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Bloco A/CCS/Ilha do Fundão, Rio de Janeiro (RJ) CEP: 21941-902, Brazil.
Chemosphere. 2015 May;127:214-21. doi: 10.1016/j.chemosphere.2015.02.009. Epub 2015 Feb 27.
The presence and formation of methylmercury (MMHg), a highly toxic form of Hg, in mangrove ecosystems is poorly studied. Therefore the aim of this study was to evaluate mercury methylation potentials in sediment, litter and root samples (Avicennia shaueriana and Spartina alterniflora) from different regions of a mangrove ecosystem, as well as the influence of salinity on methylation. Sediment was sampled under different depths and in mangrove regions with different plant covers and salinities. All samples were incubated with (203)Hg and MM(203)Hg was extracted and measured by liquid scintillation. MMHg was formed in all samples and sites tested including plant roots and litter. Higher Hg methylation was found in the superficial fraction of sediments (0.47-7.82%). Infralittoral sandy sediment had low MMHg formation (0.44-1.61%). Sediment under Rhizophora mangle had lower MMHg formation (0.018-2.23%) than under A. shaueriana (0.2-4.63%) and Laguncularia racemosa (0.08-7.82). MMHg formation in sediment tended to increase with salinity but the differences were not significant. Therefore, MMHg formation occurs in different sites of mangrove ecosystems and may be an important threat that requires further study.
红树林生态系统中甲基汞（MMHg）的存在和形成（一种剧毒形式的汞）研究甚少。因此，本研究旨在评估红树林生态系统不同区域沉积物、凋落物和根系样品（海桑和互花米草）中的汞甲基化潜力，以及盐度对甲基化的影响。在不同深度和具有不同植物覆盖和盐度的红树林区域采集沉积物。所有样品均与 (203)Hg 一起孵育，并通过液体闪烁法提取和测量 MM(203)Hg。在所有测试的样品和地点都形成了 MMHg，包括植物根系和凋落物。在沉积物的表层（0.47-7.82%）中发现了更高的 Hg 甲基化。潮下带沙质沉积物的 MMHg 形成量较低（0.44-1.61%）。在无瓣海桑下的沉积物中 MMHg 的形成量（0.018-2.23%）低于白骨壤（0.2-4.63%）和秋茄（0.08-7.82%）。随着盐度的增加，沉积物中 MMHg 的形成趋势增加，但差异不显著。因此，MMHg 的形成发生在红树林生态系统的不同地点，可能是一个需要进一步研究的重要威胁。
