Emmerton Craig A, Cooke Colin A, Wentworth Gregory R, Graydon Jennifer A, Ryjkov Andrei, Dastoor Ashu
Environmental Monitoring and Science Division , Alberta Environment and Parks , Edmonton , Alberta T5J 5C6, Canada.
Air Quality Research Division , Environment and Climate Change Canada , Dorval , Quebec H9P 1J3, Canada.
Environ Sci Technol. 2018 Oct 2;52(19):10946-10955. doi: 10.1021/acs.est.8b01680. Epub 2018 Sep 19.
Increased delivery of mercury to ecosystems is a common consequence of industrialization, including in the Athabasca Oil Sands Region (AOSR) of Canada. Atmospheric mercury deposition has been studied previously in the AOSR; however, less is known about the impact of regional industry on toxic methylmercury (MeHg) concentrations in lake ecosystems. We measured total mercury (THg) and MeHg concentrations for five years from 50 lakes throughout the AOSR. Mean lake water concentrations of THg (0.4-5.3 ng L) and MeHg (0.01-0.34 ng L) were similar to those of other boreal lakes and <5% of all samples exceeded Provincial water quality guidelines. Lakes with the highest THg concentrations were found >100 km northwest of oil sands mines and received runoff from geological formations high in metals concentrations. MeHg concentrations were highest in those lakes, and in smaller productive lakes closer to oil sands mines. Simulated annual average direct deposition of THg to sampled lakes using an atmospheric chemical transport model showed <2% of all mercury deposited to sampled lakes was emitted from oil sands activities. Consequently, spatial patterns of mercury in AOSR lakes were likely most influenced by watershed and lake conditions, though mercury concentrations in these lakes may be perturbed with future development and climatic change.
汞向生态系统的输送增加是工业化的一个常见后果，在加拿大的阿萨巴斯卡油砂地区（AOSR）也是如此。此前已对AOSR地区的大气汞沉降进行过研究；然而，对于区域工业对湖泊生态系统中有毒甲基汞（MeHg）浓度的影响，人们了解较少。我们对AOSR地区50个湖泊的总汞（THg）和MeHg浓度进行了为期五年的测量。湖泊水中THg（0.4 - 5.3 ng/L）和MeHg（0.01 - 0.34 ng/L）的平均浓度与其他北方湖泊相似，所有样本中<5%超过了省级水质标准。THg浓度最高的湖泊位于油砂矿西北100多公里处，接收来自金属浓度高的地质构造的径流。这些湖泊以及靠近油砂矿的较小的高产湖泊中MeHg浓度最高。使用大气化学传输模型模拟的THg向采样湖泊的年平均直接沉降显示，沉降到采样湖泊的所有汞中，<2%来自油砂活动。因此，AOSR湖泊中汞的空间分布模式可能主要受流域和湖泊条件的影响，尽管这些湖泊中的汞浓度可能会因未来的发展和气候变化而受到干扰。
