Dredging and contaminant exposure to tree swallows nesting on the upper Mississippi River

Dummer

Enviro Toxic and Chemistry

et al. 2014

Self Cite

In earlier studies, elevated concentrations of polychlorinated biphenyl (PCB) and p,p'-dichlorodiphenyldichloroethylene (DDE) were reported in double-crested cormorant (Phalacrocorax auritus) eggs and tree swallow (Tachycineta bicolor) eggs and nestlings collected from lower Green Bay (WI, USA) in 1994 and 1995 and black-crowned night-heron (Nycticorax nycticorax) eggs collected in 1991. Comparable samples collected in 2010 and 2011 indicated that concentrations of PCBs were 35%, 62%, 70%, and 88% lower than in the early 1990s in tree swallow eggs, tree swallow nestlings, double-crested cormorant eggs, and black-crowned night-heron eggs, respectively; concentrations of DDE were 47%, 43%, 51%, and 80% lower, respectively. These declines are consistent with regional contaminant trends in other species. Concentrations of PCBs were higher in herring gull (Larus argentatus) than in black-crowned night-heron eggs collected from Green Bay in 2010; PCB concentrations in double-crested cormorant and tree swallow eggs were intermediate. The estimated toxicity of the PCB mixture in eggs of the insectivorous tree swallow was the equal to or greater than toxicity in the 3 piscivorous bird species. A multivariate analysis indicated that the composition percentage of lower-numbered PCB congeners was greater in eggs of the insectivorous tree swallow than in eggs of the 3 piscivorous species nesting in Green Bay. Dioxin and furan concentrations and the toxicity of these chemicals were also higher in tree swallows than these other waterbird species nesting in Green Bay.

Section: Discussionsupporting

confidence: 72%

“…The decreasing trend in contaminant exposure to tree swallows in Green Bay over the past decade conforms to regional trends, including the Sheboygan River (WI, USA; C. Herring gull minus tree swallow 20 Black-crowned night-heron minus tree swallow [18].…”

Section: Contaminant Exposure Since the Early 1990smentioning

confidence: 66%

Contaminant exposure of birds nesting in Green Bay, Wisconsin, USA

Dummer

Enviro Toxic and Chemistry

et al. 2014

Self Cite

Enviro Toxic and Chemistry

“…For this reason, longer‐term monitoring is needed at the Kingston spill site. In addition, significant changes have taken place at the spill site because of dredging and other remedial activities that could lead to variability in Se bioaccumulation and potentially mask any increasing trends. The hydrology of the water system around the Kingston Fossil Plant may be another potential reason that Se bioaccumulation at this site has been lower than at other contaminated sites.…”

Section: Resultsmentioning

confidence: 99%

Selenium bioaccumulation in fish exposed to coal ash at the Tennessee Valley Authority Kingston spill site

Mathews

Fortner

Jett

et al. 2014

In December 2008, 4.1 million cubic meters of coal ash were released into the Emory and Clinch Rivers by the Tennessee Valley Authority Kingston Fossil Plant. Coal ash contains several contaminants, including the bioaccumulative metalloid selenium (Se). Because Se is predominantly accumulated in aquatic organisms through dietary rather than aqueous exposure, tissue-based toxicity thresholds for Se are currently being considered. The proposed threshold concentrations range between 4 μg/g and 9 μg/g Se (dry wt.) in whole body fish, with a proposed fillet threshold of 11.8 μg/g. In the present study, the authors examined the spatial and temporal trends in Se bioaccumulation and examined the relationship between the Se content in fillets and in whole bodies of fish collected around the Kingston spill site to determine whether Se bioaccumulation was a significant concern at the ash spill site. Whereas Se concentrations in fish (whole bodies and fillets) were elevated at sampling locations affected by the Kingston ash spill relative to reference locations, concentrations do not appear to be above risk thresholds and have not been increasing over the 5-yr period since the spill. These findings are not only relevant to guiding the human health and ecological risk assessments at the Kingston ash spill site, but because of current national discussions on appropriate guidelines for Se in fish as well for the disposal of coal combustion wastes, the results are also relevant to the general understanding of Se bioaccumulation in contaminated water bodies.

“…In addition, the increasing sediment deposition cost could have important implications for dredging activities in the UMRB. Dredging costed the Army Corps of Engineers about $923 million in 2002 . To continue to support minimum navigation depths in low-flow conditions, the dredging cost will likely continue to increase.…”

Section: Resultsmentioning

confidence: 99%

“…Dredging costed the Army Corps of Engineers about $923 million in 2002. 65 To continue to support minimum navigation depths in low-flow conditions, the dredging cost will likely continue to increase. In addition, as our results clearly illustrate the impacts of FTCs on soil erosion, future conservation planning should consider the effects of conservation practices (e.g., cover crop and conservation tillage) on FTCs to more realistically assess soil erosion cost and effectiveness of mitigation measures.…”

Section: Economic Costs Related To Soil Erosion Asmentioning

confidence: 99%

Pronounced Increases in Future Soil Erosion and Sediment Deposition as Influenced by Freeze–Thaw Cycles in the Upper Mississippi River Basin

Wang

Qiu

et al. 2021

Environ. Sci. Technol.

Soil erosion and sediment deposition are relevant to multiple important ecosystem services essential for natural and human systems. The present study aims to project future soil erosion and sediment deposition in the Upper Mississippi River Basin (UMRB) using climate projections by five Global Circulation Models (GCMs) under the Representative Concentrations Pathway (RCP) 8.5 scenario. To understand the importance of freeze–thaw cycles (FTCs) for soil erosion and sediment deposition estimation with climate change, this study compared two Soil and Water Assessment Tool (SWAT) models with different representations of the FTCs, with the standard SWAT using a simple regression method and SWAT-FT employing a physically based method. Modeling results show that future climate change can pronouncedly intensify soil erosion and increase sediment deposition, and the impacts are sensitive to how FTCs are represented in the model. The standard SWAT projected an increase in soil erosion by nearly 40% by the end of the 21st century, which is much lower than the projected over 65% increase in soil erosion by SWAT-FT. For sediment deposition, the projected percent changes by the standard SWAT and SWAT-FT also deviate from each other (i.e., about 70% by the standard SWAT vs about 120% by SWAT-FT). Overall, these results demonstrate the important roles of FTCs in projecting future soil erosion and sediment deposition and underline the need to consider the effects of conservation practices on FTCs to realistically assess the effectiveness of those measures.