Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin, China.
College of Urban and Environmental Sciences, Tianjin Normal University, Tianjin, China.
PLoS One. 2018 Oct 2;13(10):e0204812. doi: 10.1371/journal.pone.0204812. eCollection 2018.
This study aimed to determine sediment contamination in the Beidagang Wetland Nature Reserve to describe atmospheric deposition of trace metals. We analyzed Hg, Cd, Pb, TOC, TN, TP, δ13C, and δ15N, and studied their variations in surface sediments and in the vertical profiles of sediment cores collected from the reserve. Evaluation of environmental trace metal contamination using sediment quality guidelines and geochemical background values indicated that the risk of metal pollution in the reserve sediments was relatively low. Concentrations of Hg, Cd, and Pb in the sediments were much lower than concentrations in sediment samples from Bohai Bay and polluted rivers in Tianjin. Enrichment factors indicate that samples are moderately contaminated with Hg, Cd, and Pb; whereas the geo-accumulation index results classify the sediments as uncontaminated to moderately contaminated with Hg, Cd, and Pb. The distribution patterns of trace metal concentrations in the three core samples were uniform. δ13C and δ15N were used to track the sources of TOC and TN in sediments. Results show that TOC mainly originated from the residue and decaying matter of aquatic plants (e.g., algae, reeds, and Typha), while TN was derived from soil N and elevated atmospheric N deposition. Because domestic and industrial waste is not discharged into the Beidagang Wetland Nature Reserve, trace metals found in sediments mainly originate from atmospheric deposition. The results provide baseline data for analysis of trace metal accumulation in Beijing-Tianjin-Hebei, a region subject to atmospheric deposition in northern China.
本研究旨在确定北大港湿地自然保护区的沉积物污染情况，以描述痕量金属的大气沉降。我们分析了 Hg、Cd、Pb、TOC、TN、TP、δ13C 和 δ15N，并研究了它们在保护区表层沉积物和采集的沉积物芯垂直剖面中的变化。利用沉积物质量准则和地球化学背景值评估环境痕量金属污染表明，保护区沉积物中的金属污染风险相对较低。沉积物中 Hg、Cd 和 Pb 的浓度远低于渤海湾和天津受污染河流沉积物样品中的浓度。富集因子表明样品中 Hg、Cd 和 Pb 中度污染；而地积累指数结果将沉积物分类为 Hg、Cd 和 Pb 无污染到中度污染。三个芯样中痕量金属浓度的分布模式是均匀的。δ13C 和 δ15N 用于追踪沉积物中 TOC 和 TN 的来源。结果表明，TOC 主要来源于水生植物（如藻类、芦苇和香蒲）的残体和腐烂物质，而 TN 则来自土壤 N 和大气 N 沉降的增加。由于北大港湿地自然保护区没有排放生活和工业废物，因此沉积物中的痕量金属主要来源于大气沉降。研究结果为分析北京-天津-河北地区（中国北方受大气沉降影响的地区）痕量金属积累提供了基线数据。
