WATER AND SEDIMENT QUALITY ASSESSMENT OF A POTENTIALLY IMPAIRED NORTH CAROLINA STREAM

Coal ash contains several elements that can be potentially toxic to the environment and to humans. A water and sediment quality assessment was conducted for a small North Carolina stream that may include outflow water from a coal ash pond at an active power generation plant. Water and sediment samples were collected at the outflow stream site and at a hydrologically disconnected stream (control site) from April 2016 through September 2016. Samples were collected under various weather conditions and analyzed for several elements. Bioavailable elements were extracted from the sediment samples using a modified US EPA 3050B method, and water was sampled for total and dissolved metals. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine elemental concentrations of arsenic, cadmium, chromium, copper, lead, selenium, and zinc in all samples. Preliminary results revealed that dissolved and total selenium and cadmium were consistently present in water samples in concentrations above the North Carolina Department of Environmental Quality standards for dissolved metals in freshwater streams. Bioavailable arsenic and zinc concentrations in sediment exceeded external state standards for sediments. Lead, cadmium, selenium, copper, and zinc were found in highest concentrations in the water samples for samples collected on the spring season sampling day; lead, copper, and zinc were not detected in any water samples from subsequent sampling sessions. High concentrations of these elements have the potential to impact the aquatic ecosystem of the stream by causing chemical stress, reproductive failure, and even death to fish and macroinvertebrates.