Metals vs Minerals: Impacts of atmospheric dust deposition on the speciation of trace elements in snowmelt and peatland surface waters********

金属与矿物质：大气尘埃沉积对融雪和泥炭地表水中微量元素形态的影响********

• 批准号: 531329-2018
• 负责人: Shotyk, William
• 金额: $ 14.53万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=665110
• 关键词: Metals; vs; Minerals; Impacts; atmospheric

Open pit bitumen mining in northern Alberta generates considerable volumes of dust. The dusts are derived not only from the mines, but from wind erosion of dry tailings and gravel roads, construction activities, and quarries, in addition to natural sources such as river banks and sand bars. The dusts themselves consist mainly of mineral particles, some of which are chemically reactive (e.g. calcite, a calcium carbonate) whereas others are effectively insoluble (such as quartz, a silicate). There are also ongoing concerns about potentially toxic "heavy metals" being released to the atmosphere from bitumen mining and upgrading, but the extent of these emissions, and their ecological significance, is unclear. Most environmental impact studies to date have not clearly distinguished between heavy metals (such as cadmium and lead) from the combustion of fossil fuels needed for bitumen upgrading versus heavy metals which are hosted within the crystal lattice of the mineral particles themselves. Heavy metals which are emitted to the air during combustion at high temperatures tend to be very small (< 1 micron) and in soluble form (such as oxides), whereas mechanically-generated mineral dusts tend to be rather large (10 to 100 microns) and much less soluble (e.g. silicate minerals such as quartz and feldspar). Very small, soluble, metal-containing particles may represent a threat to biota, depending on the pH of soil and water, and other factors, but large, insoluble particles most likely do not. The main goal of this study is to clearly distinguish between these two sources of heavy metals to the air, using size-resolved analyses of snow and Sphagnum moss from bogs. The secondary objective is to understand what impact, if any, the two sources of heavy metals may have for the chemical composition of meltwater and peatland surface waters (from bogs, fens and swamps) which drain into the Athabasca River.********

阿尔伯塔省北部的露天沥青开采产生了大量的灰尘。粉尘不仅来自矿山，还来自干燥尾矿和砾石道路、建筑活动和采石场的风蚀，以及河岸和沙洲等自然来源。粉尘本身主要由矿物颗粒组成，其中一些是化学反应的(如方解石，一种碳酸钙)，而另一些实际上是不溶的(如石英，一种硅酸盐)。人们还在持续关注沥青开采和升级过程中排放到大气中的潜在有毒“重金属”，但这些排放的程度及其生态意义尚不清楚。到目前为止，大多数环境影响研究都没有明确区分来自沥青升级所需化石燃料燃烧的重金属(如镉和铅)和存在于矿物颗粒本身晶格中的重金属。在高温下燃烧时排放到空气中的重金属往往非常小(1微米)，并以可溶形式(如氧化物)存在，而机械产生的矿物粉尘往往相当大(10至100微米)，且不易溶解(如石英和长石等硅酸盐矿物)。非常小的、可溶的、含金属的颗粒可能会对生物群构成威胁，这取决于土壤和水的pH值以及其他因素，但大的、不可溶的颗粒很可能不会。这项研究的主要目标是通过对沼泽中的雪和泥炭苔藓进行尺寸分辨分析，清楚地区分这两种向空气中排放的重金属。第二个目标是了解这两种重金属来源对排入阿萨巴斯卡河的融水和泥炭地地表水(来自沼泽、沼泽和沼泽)的化学成分可能会产生什么影响。