Browsing by Author "Engstrom, Daniel R"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Paleolimnology of the Lake of the Woods southern basin(University of Minnesota Duluth, 2015) Reavie, Euan D; Edlund, Mark B; Andresen, Norman A; Engstrom, Daniel RTo quantify the environmental history of the southern basin of Lake of the Woods (Ontario, Manitoba and Minnesota), seven core locations were selected for retrospective analyses. Primary goals were to determine pre-European settlement conditions and track the timing and extent of anthropogenic impacts and remediation. Sediments were dated using isotopic analyses and fossil remains, in concord with other stratigraphic indicators (organic and inorganic materials, sedimentation rates, other biological entities), were used to reconstruct the ~150-year history of the lake. Diatom assemblages were assessed from sediment intervals and inferred trophic conditions in the profiles were derived using a regional diatom-based model for Minnesota lakes. Nutrient reconstructions indicated a period of cultural eutrophication throughout much of the 20th century. Despite a known reduction in anthropogenic nutrient flux to the lake in recent decades, there has been no apparent reversal in eutrophication in the pelagic system. Contemporary observations indicate that blooms of blue-green algae are becoming a greater problem. It appears that legacy nutrient recycling and other environmental drivers are maintaining the current condition of pelagic nutrient enrichment. Sedimentary analyses also indicated that physical changes to the lake resulting from warming may be contributing in small part to the recent reorganization of algal assemblages.Item Paleolimnology of the St. Louis River Estuary(University of Minnesota Duluth, 2016-05) Reavie, Euan D; Alexson, Elizabeth; Axler, Richard P; Yost, Chad; Ladwig, Jammi; Nurse, Andrea; Estepp, Lisa; Krasutsky, Pavel A; Kennedy, Kathleen; Yemets, Sergiy; Engstrom, Daniel RThe St. Louis River Watershed which drains to the St. Louis River and its associated estuary near Lake Superior has more than 150 years of human development history since Euro‐Americans first settled there, resulting in critical water quality impacts. In 1987, the U.S. Environmental Protection Agency designated the St. Louis River as an Area of Concern primarily due to that history which entailed inappropriate discharge of untreated wastewater and debris from poor industrial and community practices. The organic matter loading from inadequate treatment of sewage and paper mill products along with the dumping of woody debris from sawmills contributed to low oxygen levels in the river. The result included devastating impacts to the entire food web from the bacteria to vegetation to invertebrates to fish. Concurrently, poorly managed stormwater runoff from this post‐logged, barren landscape contributed excessive loading of suspended sediments resulting in increased turbidity and nutrient concentrations (e.g., phosphorus, nitrogen) to the river. Since then, government and private entities have taken action to restore the water quality in the St. Louis River Estuary, and to eventually remove the eight remaining SLRAOC BUIs. This summary focuses on the research documenting water quality changes over time associated with the excessive loading of sediment and nutrients BUI.Item Quantification of Hydroxylated Polybrominated Diphenyl Ethers (OH-BDEs), Triclosan, and Related Compounds in Freshwater and Coastal Systems(2015-08-28) Kerrigan, Jill F; Engstrom, Daniel R; Yee, Donald; Sueper, Charles; Erickson, Paul R; Grandbois, Matthew; McNeill, Kristopher; Arnold, William A; arnol032@umn.edu; Arnold, William AThe data generated is levels of several target contaminants in freshwater and marine systems. The data is associated with a PLOS article that discusses the importance the natural or anthropogenic sources of these pollutants.Item Sedimentary Record of Antibiotic Accumulation in Minnesota Lakes(2018-01-29) Arnold, William A; Kerrigan, Jill F; Sandberg, Kyle; Engstrom, Daniel R; LaPara, Tim; arnol032@umn.edu; Arnold, William; Arnold, WilliamThe widespread detection of antibiotics in the environment is concerning because antibiotics are designed to be effective at small doses. The objective of this work was to quantify the accumulation rates of antibiotics used by humans and animals, spanning several major antibiotic classes (sulfonamides, tetracyclines, fluoroquinolones, and macrolides), in Minnesota lake-sediment cores. Our goal was to determine temporal trends, the major anthropogenic source to these lacustrine systems, and the importance of natural production. A historical record of usage trends for ten human and/or animal-use antibiotics (four sulfonamides, three fluoroquinolones, one macrolide, trimethoprim, and lincomycin) was faithfully captured in the sediment cores. Nine other antibiotics were not detected. Ofloxacin, trimethoprim, sulfapyridine, and sulfamethazine were detected in all of the anthropogenically-impacted studied lakes. Maximum sediment fluxes reached 20.5 ng cm−2 yr−1 (concentration 66.1 ng/g) for ofloxacin, 1.2 ng cm−2 yr−1 (1.2 ng/g) for trimethoprim, 3.3 ng cm−2 yr−1 (11.3 ng/g) for sulfapyridine, and 1.0 ng cm−2 yr−1 (1.6 ng/g) for sulfamethazine, respectively. Natural production of lincomycin may have occurred in one lake at fluxes ranging from 0.4 to 1.8 ng cm−2 yr−1 (0.1 to 5.8 ng/g).Wastewater effluent appears to be the primary source of antibiotics in the studied lakes, with lesser inputs from agricultural activities.Item Triclosan, Chlorinated Triclosan Derivative, and Dioxin Levels in Minnesota Lakes(2013-12-02) Anger, Cale T; Sueper, Charles; Blumentritt, Dylan J; Mcneill, Kristopher; Engstrom, Daniel R; Arnold, William A; arnol032@umn.edu; Arnold, William AThe data were collected and generated during the period of 2010-2012 by collecting sediment cores from lakes in Minnesota, dating the years the sediment was deposited as a function of depth, and extracting sections of the cores with solvent to determine the levels of triclosan (TCS), chlorinated triclosan derivatives (CTD), and dioxins in the sediment (PCDD). Dating was performed at the St. Croix Watershed Research Station, triclosan and chlorinated triclosan derivative measurements at the University of Minnesota Department of Civil Engineering, and dioxin analysis by Pace Analytical. The data consists of eight Excel files that include the following tabs 1) accumulation rate and focus corrected accumulation rate of the target contaminants as function of time (FF_Flux), 2) the concentrations of the target contaminants and function of time, 3) the calibration curves of the instruments for triclosan and chlorinated triclosan derivatives, and 4) various statistical analyses (ANOVA). Note that the further back in time, the deeper the sediment that the sample was derived from.