INVESTIGATING TEMPORAL AND SPATIAL VARIATIONS OF TRACE METAL LOADING TO UTAH LAKE

Utah Lake has long been considered severely polluted and undesirable for recreation. This is largely due to the fact that Utah Lake has received heavy loadings of various pollutants related to anthropogenic activities. In this project, we collected quarterly water and floc layer sediment samples from the Utah Lake inlets and outlet, and Utah Lake as well as monthly water samples for trace metal analysis. In addition, Utah Lake water depth profile samples were taken at the deepest site of the lake to examine the lake’s vertical mixing condition. The objectives of this project were to 1) quantify seasonal fluctuations of trace metal levels in Utah Lake, its inlets, and its outlet; and 2) build a trace metal budget for Utah Lake. Preliminary data on water and sediment samples have shown that significant variations occur at the sampling sites for various metals of interest, such as arsenic, lead, cadmium, copper, zinc, etc. These results indicate that Utah Lake is not horizontally mixed. However, water samples taken from the depth profile site imply relatively uniform concentrations of trace metals at an interval of 0.5 m in the water column, which is likely due to Utah Lake’s shallow depth and wind actions on the lake. Elevated trace metal concentrations in river water samples have been detected, which could be caused by animal farming, agricultural activities, and mining drainage to rivers. Therefore, trace metals from non-point pollution sources might be a significant contributor to the trace metals in the lake.