PHRAGMITES AUSTRALIS CONTROL ON UTAH LAKE WATER QUALITY

Phragmites australis (common reed) is an invasive species that has some negative ascetic traits in Utah Lake. The Division of Natural Resources is combating Phragmites australis by indiscriminately spraying herbicides and smashing the roots and remaining rhizomes into the lake sediment. Phragmites australis is known to sequester trace metals in their roots and rhizomes. We hypothesize that this method of removal of the common reed will have an adverse impact on water quality in Utah Lake due to the release of trace metals from their roots and rhizomes during decomposition. Phragmites australis, sediment and water samples will be collected from sixteen sites selected at random surrounding Utah Lake, including both treated and untreated areas for a period of 5 months. Five replicate samples will be taken at each site. The samples will be processed in UVU Environmental laboratory, microwave digested in concentrated HNO₃ using EPA Method 3015 and analyzed with the ICP-OES to measure their trace metal (As, Cd, Cr, Ni, Co, Pb and Cu ) content. The rate of release of trace elements will be determined for each site and compared with non-treated areas. An increase in trace metal concentration in the sediment and water over time will indicate a negative impact on Utah lake water quality. To determine factors which may potentially impact trace metal concentration in the lake water and sediment, pH, redox reaction, particle size distribution and organic matter contents will be measured. Results from each sites will be compared and potential reasons for any variations observed will be discussed.