Sexauer Gustin Mae, Saito Laurel, Peacock Mary
Department of Natural Resources and Environmental Sciences MS370, University of Nevada-Reno, Reno, NV 89557, United States.
Sci Total Environ. 2005 Jul 15;347(1-3):282-94. doi: 10.1016/j.scitotenv.2004.12.009.
The lower Truckee River originates at Lake Tahoe, California/Nevada (NV), USA and ends in the terminal water body, Pyramid Lake, NV. The river has minimal anthropogenic inputs of contaminants until it encounters the cities of Reno and Sparks, NV, and receives inflows from Steamboat Creek (SBC). SBC originates at Washoe Lake, NV, where there were approximately six mills that used mercury for gold and silver amalgamation in the late 1800s. Since then, mercury has been distributed down the creek to the Truckee River. In addition, SBC receives agricultural and urban nonpoint source pollution, and treated effluent from the Reno-Sparks water reclamation facility. Fish muscle tissue was collected from different species in SBC and the Truckee River and analyzed for mercury and stable isotopes. Nitrogen (delta(15)N) and carbon (delta(13)C) isotopic values in these tissues provide insight as to fish food resources and help to explain their relative Hg concentrations. Mercury concentrations, and delta(15)N and delta(13)C values in fish muscle from the Truckee River, collected below the SBC confluence, were significantly different than that found in fish collected upstream. Mercury concentrations in fish tissue collected below the confluence for all but three fish sampled were significantly greater (0.1 to 0.65 microg/g wet wt.) than that measured in the tissue collected above the confluence (0.02 to 0.1 microg/g). Delta(15)N and delta(13)C isotopic values of fish muscle collected from the river below the confluence were higher and lower, respectively, than that measured in fish collected up river, most likely reflecting wastewater inputs. The impact of SBC inputs on muscle tissue isotope values declined down river whereas the impact due to Hg inputs showed the opposite trend.
特拉基河下游发源于美国加利福尼亚州/内华达州（NV）的太浩湖，最终流入内华达州的终点水体金字塔湖。在流经内华达州的里诺市和斯帕克斯市之前，该河受到的人为污染物输入极少，之后它接纳了来自斯廷博特溪（SBC）的水流。SBC发源于内华达州的瓦肖湖，在19世纪后期，那里大约有六家工厂使用汞进行金和银的汞齐化处理。从那时起，汞就顺着溪流进入了特拉基河。此外，SBC还接纳农业和城市非点源污染，以及里诺 - 斯帕克斯水回收设施处理后的废水。从SBC和特拉基河的不同物种中采集了鱼的肌肉组织，并对其进行汞和稳定同位素分析。这些组织中的氮（δ¹⁵N）和碳（δ¹³C）同位素值有助于了解鱼类的食物资源，并有助于解释它们相对的汞浓度。在SBC汇流处下游采集的特拉基河鱼类肌肉中的汞浓度、δ¹⁵N和δ¹³C值，与在汇流处上游采集的鱼类有显著差异。除三条采样鱼外，汇流处下游采集的鱼组织中的汞浓度（0.1至0.65微克/克湿重）显著高于汇流处上游采集的组织中的汞浓度（0.02至0.1微克/克）。从汇流处下游河流采集的鱼肌肉的δ¹⁵N和δ¹³C同位素值分别高于和低于上游采集的鱼，这很可能反映了废水输入。SBC输入对肌肉组织同位素值的影响沿河流向下游减弱，而汞输入的影响则呈现相反的趋势。
