Wolff Brian A, Johnson Brett M, Lepak Jesse M
Department of Fish, Wildlife and Conservation Biology, Colorado State University, 1474 Campus Delivery, Fort Collins, CO, 80523, USA.
New York Sea Grant Extension, SUNY Oswego, Oswego, NY, 13126, USA.
Arch Environ Contam Toxicol. 2017 Feb;72(2):167-177. doi: 10.1007/s00244-016-0353-x. Epub 2017 Jan 7.
Partial decoupling of mercury (Hg) loading and observed Hg concentrations ([Hg]) in biotic and abiotic samples has been documented in aquatic systems. We studied two Colorado reservoirs to test whether shifts in prey for sport fish would lead to changes in [Hg] independent of external atmospheric Hg deposition. We compared sport fish total mercury concentrations ([T-Hg]) and macroinvertebrate (chironomids and crayfish) methylmercury concentrations ([MeHg]) before and after food web shifts occurred in both reservoirs. We also monitored wet atmospheric Hg deposition and sediment [T-Hg] and [MeHg] at each reservoir. We found rapid shifts in Hg bioaccumulation in each reservoir's sport fish, and these changes could not be attributed to atmospheric Hg deposition. Our study shows that trends in atmospheric deposition, environmental samples (e.g., sediments), and samples of species at the low trophic levels (e.g., chironomids and crayfish) may not accurately reflect conditions that result in fish consumption advisories for high trophic level sport fish. We suggest that in the short-term, monitoring fish [Hg] is necessary to adequately protect human health because natural and anthropogenic perturbations to aquatic food-webs that affect [Hg] in sport fish will continue regardless of trends in atmospheric deposition.
在水生系统中，已记录到汞（Hg）负荷与生物和非生物样本中观测到的汞浓度（[Hg]）之间存在部分解耦现象。我们研究了科罗拉多州的两个水库，以测试游钓鱼类猎物的变化是否会导致[Hg]的变化，而与外部大气汞沉积无关。我们比较了两个水库食物网发生变化前后游钓鱼类的总汞浓度（[T-Hg]）和大型无脊椎动物（摇蚊和小龙虾）的甲基汞浓度（[MeHg]）。我们还监测了每个水库的湿大气汞沉积以及沉积物中的[T-Hg]和[MeHg]。我们发现每个水库游钓鱼类体内汞的生物累积迅速变化，且这些变化不能归因于大气汞沉积。我们的研究表明，大气沉积趋势、环境样本（如沉积物）以及低营养级物种（如摇蚊和小龙虾）的样本可能无法准确反映导致对高营养级游钓鱼类发布鱼类食用建议的情况。我们建议，在短期内，监测鱼类的[Hg]对于充分保护人类健康是必要的，因为无论大气沉积趋势如何，影响游钓鱼类[Hg]的水生食物网的自然和人为扰动都将持续存在。
