Increased urbanization in the United States and the rest of the world, has led to more research on the effects it has on the local ecology. Urbanization can be defined as the creation of impervious cover in areas previously covered by natural vegetation (forest, grassland or farmland) as well as the potential influence of sewage treatment plants. Small increases in impervious cover can cause noticeable changes in stream chemistry. The goal of this study is to quantify the impact of smaller industrial cities on water and sediment geochemistry in a largely agricultural watershed. The study area is in east-central Indiana along the west fork of the White River and includes the cities of Winchester, Muncie and Anderson. This area is dominated by agriculture and the impact of cities in the region on water chemistry has not been studied. To evaluate this impact, sampling sites were selected up- and downstream of the three cities to characterize White River water chemistry before and after it flows through the cities as well as sewage treatment plants. Sampling was done over the course of one year to obtain samples characteristic of high and low flow river conditions. Samples were analyzed for major cation and anion concentrations as well as total suspended solids. Metals data was also obtained in sediments, although sampled only twice throughout the study. Results show that sediment load, on average, increases on the downstream side as the river flows through urbanized areas. Chemical analyses show that major cations and anions, Na, K, SO4 and Cl, have distinct spikes in concentration on the downstream side of the cities, as well. Na and Cl are specifically linked to human and urbanized activity, and were up to four times higher downstream of urbanized cities. The concentration of other major ions, including Ca, Mg and NO3, was mostly due to agricultural land use and local bedrock geology. Trace metals characteristic of pollution from automobiles, including Cd, Cr and Zn, showed large increases downstream of urban areas as well. This indicates that even in an area that is largely dominated by agriculture, smaller cities have a quantifiable impact to White River water quality. / Department of Geology

Indiana University-Purdue University Indianapolis (IUPUI) / An investigation of mercury (Hg) in soils and stream sediments was conducted to understand the impact of urbanization on Hg deposition and accumulation on the upper west fork of the White River watershed in central Indiana. Samples were collected to the north and east (i.e., downwind) of emission sources to understand the anthropogenic influences on Hg distribution in soil. Stream sediment sampling was designed to characterize the riverine particulate deposition of Hg through Indianapolis and to predict the potential for stream sediments with high Hg to become sources of methylmercury (MeHg). Spatial analysis revealed that soil Hg was elevated downwind of known industrial emission sites, indicating a local footprint of Hg deposition in central Indiana. Hg in streambank sediments was generally low in up-river sites to the northeast of Indianapolis, and increased markedly as the White River flowed through downtown, with high Hg persisting to downstream rural locations far to the south approximately 40 miles. The stream sediment results also revealed variations in total Hg (Hg(T)) as a function of local depositional sources, sub-watershed location, combined sewer outflows (CSOs), and impoundments along the White River. Low Hg values were recorded where the White River flow rate increased south of the 16th street dam at the confluence of the Fall Creek, where bankside industry and development confine the river. Three tributaries feeding into the White River were included in this study site, all having CSOs. Fall Creek and Pleasant Run have higher values of Hg with Lick Creek having lower values in comparison to the White River and other tributaries. The highest values occur right before confluences to the White River where the flow rate slows and drops sediment. Mercury values typically increased immediately downstream of dams and impoundments. Hg(T) deposition and transport processes pose a problem to anglers fishing south of Indianapolis who may not be aware of the potential dangers related to elevated stream sediment Hg values and the greater potential for MeHg production from these sediments.