Browsing by Subject "Lakes"

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    ItemOpen Access
    An Evaluation of Water Quality Parameters and Flow Dynamics in High Rock Lake, North Carolina to Assist in the Development of Nutrient Criteria for Lakes and Reservoirs in the State
    (2018-04-26) Rudd, Morgan
    High Rock Dam, located in Rowan and Davidson Counties in North Carolina, was constructed on the Yadkin River in 1927. High Rock Lake (HRL) is primarily fed by the Yadkin River and several smaller tributaries, draining a total area of 3974 square miles. HRL has been on the 303d list of impaired waters since 2004 due to elevated levels of turbidity, chlorophyll-a, and pH. North Carolina currently has surface water standards for chlorophyll-a (40 µg/L), turbidity (25 NTU- lakes), and pH (<6 or >9), but not for nutrients. NC DEQ chose HRL as a pilot study to help develop nutrient criteria for lakes throughout the state. There is a high degree of spatial variability in water quality in HRL. Turbidity, total nitrogen, and total phosphorus decrease with increasing proximity to the dam, whereas chlorophyll-a is most elevated within the mid-section of the lake. Phytoplankton taxonomic assemblage varies according to lake section, with the lower-section of the lake experiencing the most elevated levels of cyanobacteria. Riverine discharge appears to influence chlorophyll-a and biovolume, and future studies should aim to identify the impact of discharge on phytoplankton assemblage. An improved understanding of discharge-water quality relationships can help guide nutrient criteria development for the state’s reservoirs, particularly for reservoirs with short residence times (days-weeks).
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    ItemOpen Access
    Legacy of Coal Combustion: Widespread Contamination of Lake Sediments and Implications for Chronic Risks to Aquatic Ecosystems.
    (Environmental science & technology, 2022-10) Wang, Zhen; Cowan, Ellen A; Seramur, Keith C; Dwyer, Gary S; Wilson, Jessie C; Karcher, Randall; Brachfeld, Stefanie; Vengosh, Avner
    Elevated concentrations of toxic elements in coal ash pose human and ecological health risks upon release to the environment. Despite wide public concerns about water quality and human health risks from catastrophic coal ash spills and chronic leaking of coal ash ponds, coal ash disposal has only been partially regulated, and its impacts on aquatic sediment quality and ecological health have been overlooked. Here, we present a multiproxy approach of morphologic, magnetic, geochemical, and Sr isotopic analyses, revealing unmonitored coal ash releases over the past 40 to 70 years preserved in the sediment records of five freshwater lakes adjacent to coal-fired power plants across North Carolina. We detected significant sediment contamination and potential chronic ecological risks posed by the occurrence of hundreds of thousands of tons of coal ash solids mainly resulting from high-magnitude stormwater runoff/flooding and direct effluent discharge from coal ash disposal sites. The proximity of hundreds of disposal sites to natural waterways across the U.S. implies that such contamination is likely prevalent nationwide and expected to worsen with climate change.