DataSheet_1_Biomonitoring of Polycyclic Aromatic Hydrocarbon Deposition in Greenland Using Historical Moss Herbarium Specimens Shows a Decrease in Pollution During the 20th Century.pdf

Although most point sources of persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbons (PAHs), are at lower latitudes, the Arctic region is contaminated. In particular, PAHs now dominate the POP body burden of the region’s marine biota at the lower trophic levels. Greenlandic Inuits have the most elevated levels of POPs in their blood compared to any other population, due to their consumption of seal meat and other marine mammals. PAHs, the by-products of the incomplete combustion of petroleum products, are known carcinogens and have been shown to affect the immune system, reproduction, endocrine functions, and the nervous system. With industrial activities and climate change set to increase local PAH emissions, it is paramount to document changes in atmospheric PAH deposition to further investigate PAH exposure in the region and attribute contaminations to their sources. As a measure of atmospheric pollution, we sampled bryophyte herbarium specimens of three common and widespread species collected in Greenland between the 1920s and 1970s after which time new collections were not available. They were analyzed for 19 PAHs using GC-MS (gas chromatography mass spectrometry). The presence of more low-molecular-weight PAHs than high-molecular-weight PAHs is evidence that the PAH contamination in Greenland is due to long-range transport rather than originating from local sources. The results show peaks in PAH atmospheric deposition in the first part of the 19th century followed by a trend of decrease, which mirror global trends in atmospheric pollution known from those periods. PAHs associated with wood and fossil-fuel combustion decrease in the 1970s coinciding with the disappearance of charcoal pits and foundries in Europe and North America, and a shift away from domestic heating with wood during the 19th century. The results highlight the value of bryophytes as bioindicators to measure PAH atmospheric pollution as well as the unrealized potential of herbaria as historical records of environmental change.

尽管绝大多数持久性有机污染物（persistent organic pollutants, POPs），包括多环芳烃（polycyclic aromatic hydrocarbons, PAHs）的点源均分布于低纬度地区，但北极地区仍遭受了此类污染物的污染。尤为值得注意的是，当前该区域低营养级海洋生物群体内的POPs负荷中，多环芳烃已占据主导地位。格陵兰因纽特人血液中的POPs水平为全球所有人群中最高，这源于他们长期食用海豹肉及其他海洋哺乳动物的饮食习惯。多环芳烃是石油产品不完全燃烧的副产物，属于公认的致癌物，且已被证实会对免疫系统、生殖系统、内分泌功能及神经系统造成损害。随着工业活动与气候变化预计将加剧当地多环芳烃的排放，对大气中多环芳烃沉降的变化进行系统记录，对于进一步研究该区域的多环芳烃暴露情况并精准追踪污染源至关重要。作为大气污染的生物监测手段，研究团队采集了1920年至1970年间在格陵兰收集的3种常见广布苔藓植物的标本馆标本——该时段之后未再有新的采集记录。采用气相色谱-质谱联用仪（gas chromatography mass spectrometry, GC-MS），研究人员对样本中的19种多环芳烃同系物进行了定量分析。相较于高分子量多环芳烃，低分子量多环芳烃的占比更高，这一现象证明格陵兰的多环芳烃污染源自长距离大气传输，而非本地排放源。研究结果显示，19世纪前期大气多环芳烃沉降出现峰值，随后呈现持续下降趋势，这与同期全球大气污染的已知变化趋势高度吻合。与木材及化石燃料燃烧相关的多环芳烃在20世纪70年代出现显著下降，这与欧洲和北美地区炭窑与铸造厂的关停，以及19世纪以来民用取暖燃料从木材转向其他能源的历史进程相契合。本研究结果不仅凸显了苔藓植物作为多环芳烃大气污染生物监测指标的应用价值，同时也展现了标本馆馆藏作为环境变化历史记录载体的未被充分发掘的巨大潜力。