Arcellinida (testate lobose amoebae) were examined in near-surface sediment samples from 30 lakes located within the Gold Terra Resource Corporation (GTRC) Yellowknife City Gold Project, Northwest Territories, Canada, to assess the applicability of using the group as a robust tool to assess Arsenic (As) contamination. Lake contamination by As is of concern in the Yellowknife area because it is derived from geogenic (bedrock) and anthropogenic sources (legacy pollution from former mining operations, particularly the Giant Mine [1948–2004]). Statistical multivariate analyses (cluster analysis, non-metric multidimensional scaling [NMDS], and redundancy analysis [RDA]) were performed on geochemical (inductively coupled plasma mass spectrometry [ICP-MS]) and organic (loss-on-ignition) data to identify geochemical and hydrogeological controls on the arcellinidan distribution in the lakes. Three distinct faunal assemblages were identified using Cluster analysis and NMDS: 1) Elevated Arsenic Assemblage (EAA; Approximately Unbiased (AU) p-value = 97 %; median As =272.4 mg/kg, range = 42–1353 mg/kg ; n = 9); 2) Centropyxid-Dominated Assemblage (CDA; AU p-value = 87 %; median As =169.7 mg/kg, range 60–233 mg/kg ; n = 9); and, 3) Difflugiid-Dominated Assemblage (DDA; AU p-value = 95 %; median As =61.3 mg/kg, range = 16–316 mg/kg ; n = 12). Six statistically significant controls on assemblage structure were identified using RDA. These were As, calcium, iron, strontium, water depth, and total organic carbon (Arcellinida variance explained = 36.2 %) — As is the most significant control (12.2 %; p-value < 0.002). Stress-tolerant centropyxids dominate in lakes characterized by elevated sedimentary As concentrations (64 % centropyxids in EAA; 40 % centropyxids in CDA), while stress-sensitive taxa thrived in samples associated with lower As concentrations (DDA). Our results corroborate the findings of previous Arcellinida studies in subarctic Canada and confirms the reliability of using Arcellinida as a reconnaissance tool for tracking As contamination in impacted lakes.

在加拿大西北地区黄金土地资源公司（GTRC）耶洛奈夫市金矿项目中的30个湖泊的近地表沉积物样本中检查了Arcellinida（叶状遗留的变形虫），以评估将该小组作为可靠的工具进行评估的适用性评估砷污染。耶洛奈夫地区的砷对湖泊的污染是令人关注的，因为它来自地源性（基岩）和人为源（以前的采矿作业，特别是巨型矿山[1948-2004]产生的遗留污染）。统计多元分析（聚类分析，非度量多维标度[NMDS]，和地球化学（电感耦合等离子体质谱法[ICP-MS]）和有机（点火损失）数据进行了冗余和冗余分析[RDA]，以识别湖泊中阿塞利尼丹分布的地球化学和水文地质控制。使用聚类分析和NMDS确定了三种不同的动物群落：1）高砷群（EAA;大约无偏（AU）p值= 97％; 中位砷= 272.4 mg / kg，范围= 42–1353 mg / kg; n = 9）；2）以心磷脂为主的组合（CDA； AU p值= 87％；中位As = 169.7 mg / kg，范围60-233 mg / kg；n = 9）；3）以氟虫为主导的组合（DDA； AU p值= 95％；中位As = 61.3 mg / kg，范围= 16–316 mg / kg；n = 12）。使用RDA识别了六种具有统计意义的组合结构对照。这些是砷，钙，铁，锶，水的深度和总有机碳（Arcellinida方差解释为36.2％）—砷是最重要的对照（12.2％；p值）<0.002）。在以沉积砷浓度升高为特征的湖泊中，耐胁迫的拟南芥占主导地位（在EAA中为64％的拟南芥；在CDA中为40％的拟南芥），而与较低的As浓度（DDA）相关的样品中则出现了对压力敏感的类群。我们的研究结果证实了以前在加拿大亚北极地区进行Arcellinida研究的结果，并证实了将Arcellinida用作追踪受影响湖泊中As污染的侦察工具的可靠性。