Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, United States.
Water Res. 2024 Oct 1;263:122167. doi: 10.1016/j.watres.2024.122167. Epub 2024 Aug 5.
Ethylmercury (EtHg), similar to methylmercury (MeHg), is highly neurotoxic and bioaccumulative. Although recent studies suggested its occurrence in natural soils and sediments, the common propylation derivatization for EtHg analysis might generate EtHg artifacts, potentially leading to its overestimation in environmental samples. Furthermore, the extensive environmental prevalence of EtHg remains unverified, keeping its importance largely uncertain. This study investigated the formation of EtHg artifacts during propylation derivatization, evaluating artifacts formation and recoveries under different extraction methods with real samples, and confirmed the widespread occurrence of EtHg in Chinese wetlands. EtHg artifacts were obviously present during the propylation derivatization and strongly dependent on the levels of Hg (0.1-10 ng) in the derivatization solution (R² = 0.99), accounting for 1.38-2.14% of Hg. CuSO-HNOCHCl extraction (effectively removing Hg) combined with propylation derivatization offers excellent recovery (81-86%) and low artifacts (< LOD: 1.98 × 10 ng/g) for EtHg measurement in soils/sediments, with results aligning with those from online solid phase extraction-high performance liquid chromatography-inductively coupled plasma mass spectrometry (R = 0.99). Additionally, we observed the occurrence of EtHg in soil and sediment samples across 14 Chinese wetlands, with concentrations varying from 6.08 to 171 pg/g, similar to MeHg concentrations at some sites. EtHg positively correlates with MeHg, total Hg, and total organic carbon across all samples, indicating a possible biological formation. These findings help better understand and predict the prevalence of EtHg in wetlands and its key role in environmental Hg cycle.
乙基汞（EtHg）与甲基汞（MeHg）相似，具有高度的神经毒性和生物累积性。尽管最近的研究表明它存在于自然土壤和沉积物中，但用于 EtHg 分析的常见丙基化衍生化可能会产生 EtHg 人工产物，从而导致环境样品中 EtHg 的高估。此外，EtHg 在环境中的广泛存在尚未得到验证，其重要性在很大程度上仍不确定。本研究调查了丙基化衍生化过程中 EtHg 人工产物的形成，通过实际样品评估了不同提取方法下人工产物的形成和回收率，并证实了 EtHg 在我国湿地中的广泛存在。丙基化衍生化过程中明显存在 EtHg 人工产物，且强烈依赖于衍生化溶液中 Hg（0.1-10ng）的水平（R²=0.99），占 Hg 的 1.38-2.14%。CuSO₋HNO₃CHCl₃提取（有效去除 Hg）与丙基化衍生化相结合，为土壤/沉积物中 EtHg 的测量提供了极好的回收率（81-86%）和低人工产物（<LOD：1.98×10ng/g），与在线固相萃取-高效液相色谱-电感耦合等离子体质谱（R=0.99）的结果一致。此外，我们观察到 EtHg 存在于我国 14 个湿地的土壤和沉积物样品中，浓度范围为 6.08-171pg/g，与一些地点的 MeHg 浓度相似。EtHg 与 MeHg、总 Hg 和总有机碳在所有样品中均呈正相关，表明可能存在生物形成。这些发现有助于更好地理解和预测 EtHg 在湿地中的普遍性及其在环境 Hg 循环中的关键作用。
