The impact of land use and aging infrastructure in the Mill Creek Watershed (MCW) have resulted in various water and sediment quality concerns related to human and ecological health, including recreational contact bans and fish consumption advisories. Urban and residential are the dominate land use types in the lower watershed, while the upper watershed is primarily agricultural and forested. Sediment loading from point and non-point sources, as well as erosion potentially introduces contaminants that impact aquatic organisms. This study evaluated the influence of various land uses on physical and chemical properties of the sediment. Short cores (15cm) from 13 locations in MCW were collected and split into a top and bottom 7.5 cm sample. MCW was delineated into 13 drainage basins based on the sampling sites for a detailed comparison of land use with sediment properties. Sediments were analyzed for organic matter (OM%), pH, soil texture, trace metals and total phosphorus (TP). Geostatistical maps were created using the measured results with the inverse distance weighted (IDW) tool in ArcGIS version 10.41. Statistical analyses (correlations) were also done using SPSS at 95% confidence level.
Results/Conclusions
The correlation between land use and analyzed parameters were statistically significant in some instances. Specifically, Zn, Mn, V, Cr, Ni, Cd and Pb at some of the sites exceeded the sediment reference values set by the Ohio Environmental Protection Agency. Total phosphorus within the sites in the upper and middle watershed (near agricultural land use and a wastewater treatment plant effluent), were approximately twice as high as other sites. Geospatial statistical maps created showed regions of the lower watershed (predominantly urban areas) had higher concentrations of trace metals suggesting a source of localized pollution. Barium significantly correlated with agricultural land use. Total phosphorus was also positively correlated with agricultural land use but not statistically significant. These results have been integrated with episodic water and macroinvertebrate analyses for a better understanding the role of mixed-land use types in aquatic ecosystems, which can benefit decisions to improve recreation opportunities and other activities.