HYDROCHEMICAL CHARACTERIZATION AND QUALITY ASSESSMENT OF THE WHIPPANY RIVER AT MORRISTOWN, NEW JERSEY

Water chemistry and quality are negatively influenced by urbanization. Implementation of environmental regulations have improved water quality in the United States since the 1970s, but many rivers still have impaired status and suffer from eutrophication during summer months. Thus, it is essential to further understand and mitigate non-point source pollution to waterways. For this study, we selected the Whippany River in Northern New Jersey upstream from the Speedwell Lake outflow. The goals were to characterize the hydrochemistry, assess the nutrient status, and examine potential heavy metal contamination of the river. About 16 sq miles area of the 69.3 sq mile watershed includes Morristown's recycling plant, Morris Township’s wastewater treatment plant, and an urban area drained by Watnong Brook tributary. Water samples were collected at five sites, between upstream from the treatment plants and the outflow of the lake. At each site, one liter of sample was obtained following the USGS grab-sampling method once a month in the summer of 2022. Field parameters were measured on-site using a portable multi-probe, and the chemical composition of both filtered and unfiltered samples was determined following USGS and EPA methods for atomic absorption spectroscopy, ion chromatography, and spectrophotometry.

The main hydrochemistry reflects the composition of the potassic feldspar gneiss bedrock. Elevated chloride concentrations with respect to sodium indicate natural, silicate weathering, and ion exchange sources, in addition to anthropogenic sources of winter deicers, fertilizer use, and chlorinated drinking water usage for lawn irrigation. Dissolved nitrate-nitrogen and total nitrogen as nitrate concentrations are consistently the highest in the tributary draining the urban area and elevated in the lake samples exceeding the maximum contaminant level of the EPA for drinking water. Dissolved heavy metals are negligible in all samples. However, total phosphorus, iron, and manganese concentrations parallel turbidity (particulate matter) levels indicating that the source of potential pollution is surface runoff during rain events. Further monitoring and assessment will help to understand and mitigate the anthropogenic non-point source pollution in order to improve the water quality of the Whippany River Watershed and prevent eutrophication of its lakes.