scholarly journals Salting our freshwater lakes

2017 ◽  
Vol 114 (17) ◽  
pp. 4453-4458 ◽  
Author(s):  
Hilary A. Dugan ◽  
Sarah L. Bartlett ◽  
Samantha M. Burke ◽  
Jonathan P. Doubek ◽  
Flora E. Krivak-Tetley ◽  
...  
Keyword(s):  
Land Cover ◽  
North American ◽  
Environmental Protection Agency ◽  
Spatial Scales ◽  
Strong Predictor ◽  
The United States ◽  
Lake Water Quality ◽  
Aquatic Life ◽  
Threshold Criterion

The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a strong predictor of chloride trends in Northeast and Midwest North American lakes. As little as 1% impervious land cover surrounding a lake increased the likelihood of long-term salinization. Considering that 27% of large lakes in the United States have >1% impervious land cover around their perimeters, the potential for steady and long-term salinization of these aquatic systems is high. This study predicts that many lakes will exceed the aquatic life threshold criterion for chronic chloride exposure (230 mg L−1), stipulated by the US Environmental Protection Agency (EPA), in the next 50 y if current trends continue.

scholarly journals Prototyping a Methodology for Long-Term (1680–2100) Historical-to-Future Landscape Modeling for the Conterminous United States

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 536
Author(s):  
Jordan Dornbierer ◽  
Steve Wika ◽  
Charles Robison ◽  
Gregory Rouze ◽  
Terry Sohl
Keyword(s):  
United States ◽  
Land Cover ◽  
River Basin ◽  
Landscape Change ◽  
Spatial Scales ◽  
The United States ◽  
Modeling Framework ◽  
Delaware River ◽  
Future Landscape

Land system change has been identified as one of four major Earth system processes where change has passed a destabilizing threshold. A historical record of landscape change is required to understand the impacts change has had on human and natural systems, while scenarios of future landscape change are required to facilitate planning and mitigation efforts. A methodology for modeling long-term historical and future landscape change was applied in the Delaware River Basin of the United States. A parcel-based modeling framework was used to reconstruct historical landscapes back to 1680, parameterized with a variety of spatial and nonspatial historical datasets. Similarly, scenarios of future landscape change were modeled for multiple scenarios out to 2100. Results demonstrate the ability to represent historical land cover proportions and general patterns at broad spatial scales and model multiple potential future landscape trajectories. The resulting land cover collection provides consistent data from 1680 through 2100, at a 30-m spatial resolution, 10-year intervals, and high thematic resolution. The data are consistent with the spatial and thematic characteristics of widely used national-scale land cover datasets, facilitating use within existing land management and research workflows. The methodology demonstrated in the Delaware River Basin is extensible and scalable, with potential applications at national scales for the United States.

scholarly journals Long-term trends and drought: spatiotemporal variation in juvenile sex ratios of North American ducks

2021 ◽  
Author(s):  
Sage Ellis ◽  
Madeleine Lohman ◽  
James Sedinger ◽  
Perry Williams ◽  
Thomas Riecke
Keyword(s):  
United States ◽  
North American ◽  
Sex Ratios ◽  
Survival Rates ◽  
The United States ◽  
Avian Communities ◽  
Eastern United States ◽  
Bird Populations ◽  
Long Term Trends

Sex ratios affect population dynamics and individual fitness, and changing sex ratios can be indicative of shifts in sex-specific survival at different life stages. While climate- and landscape-change alter sex ratios of wild bird populations, long-term, landscape scale assessments of sex ratios are rare. Further, little work has been done to understand changes in sex ratios in avian communities. In this manuscript, we analyse long-term (1961-2015) data on five species of ducks across five broad climatic regions of the United States to estimate the effects of drought and long-term trends on the proportion of juvenile females captured at banding. As waterfowl have a 1:1 sex ratio at hatch, we interpret changes in sex ratios of captured juveniles as changes in sex-specific survival rates during early life. Seven of twelve species-region pairs exhibited evidence for long-term trends in the proportion of juvenile females at banding. The proportion of juvenile females at banding increased for duck populations in the western United States and typically declined for duck populations in the eastern United States. We only observed evidence for an effect of drought in two of the twelve species-region pairs, where the proportion of females declined during drought. As changes to North American landscapes and climate continue and intensify, we expect continued changes in sex-specific juvenile survival rates. More broadly, we encourage further research examining the mechanisms underlying long-term trends in juvenile sex ratios in avian communities.

Investigating disinfectant by-products in Harare potable water supply, Zimbabwe

2018 ◽  
Vol 8 (3) ◽  
pp. 415-428 ◽  
Author(s):  
Kuitakwashe Nhongo ◽  
Zvikomborero Hoko ◽  
Jameson Kugara
Keyword(s):  
Water Supply ◽  
Environmental Protection Agency ◽  
Distribution System ◽  
Water Distribution ◽  
The United States ◽  
World Health ◽  
Residual Chlorine ◽  
By Products ◽  
Trihalomethanes Formation

Abstract Formation of disinfectant by-products was investigated in the Harare water supply system from February to April 2015. Sampling sites were selected from the lake, Morton Jaffray Water Treatment Works and critical points in the distribution system. The spatial variations of trihalomethanes and selected water quality parameters were investigated for 15 sampling points in 5 sampling campaigns to assess suitability for drinking. All trihalomethane species were measured, namely chloroform, bromodichloromethane, dibromochloromethane and bromoform. Only chloroform and bromodichloromethane were detected. The study confirmed that there is trihalomethanes formation in the Harare water distribution system and that it is affected by the residence time and presence of organic matter in the system. However, the levels of trihalomethanes are generally within the levels suggested by the World Health Organization. Only bromodichloromethane presents a risk for long-term exposure as it had levels that exceeded the limit for long-term exposure suggested by the United States Environmental Protection Agency. Bromodichloromethane, turbidity and free residual chlorine levels were not suitable for drinking in some of the zones. Boosting of chlorine residuals is necessary especially in areas with free chlorine less than 0.2 mg/L. Injection of ammonia, periodic cleaning of storage reservoirs, and flushing of lines will reduce trihalomethanes formation.

Refugee Integration in Canada, Europe, and the United States: Perspectives from Research

2020 ◽  
Vol 690 (1) ◽  
pp. 7-35
Author(s):  
Katharine M. Donato ◽  
Elizabeth Ferris
Keyword(s):  
United States ◽  
Spatial Scales ◽  
The United States ◽  
First Century ◽  
Host Countries ◽  
Refugee Integration ◽  
Complex Process ◽  
Migrant Integration ◽  
Refugees And Asylum Seekers

As the number of migrants, refugees, and asylum seekers have grown worldwide, intense debate has emerged about how long and how well they integrate into host countries. Although integration is a complex process, realized differently by different groups at different times, most prior studies capture, at best, disparate parts of the process. Overcoming this limitation is a tall task because it requires data and research that capture how integration is both dynamic and contextual and requires focusing on conceptual issues, emphasizing how integration varies across spatial scales, and including perspectives of the process through the eyes of both scholars and practitioners. This article reviews recent key studies about refugees in Canada, Europe, and the United States, as a way of putting into context the scholarship presented in this special issue of The ANNALS. We analyze whether and how prior studies capture integration as a dynamic process that unfolds in various aspects of life, such as education, employment, and health. We also consider the extent to which prior studies are shaped by long-standing divides between the terms refugee and migrant, and integration and assimilation, and what those divides mean for research on refugee and migrant integration in the twenty-first century. Throughout, we assess the data needed for researchers to address a wide variety of questions about refugee integration and understand the long-term consequences of the ever-growing number of displaced persons seeking refuge. This volume presents research that uniquely enhances our understanding about the breadth of the integration process in the United States, Canada, and European countries.

scholarly journals Derivation of an aquatic benchmark for invertebrates potentially exposed to imidacloprid

2016 ◽  
Author(s):  
Dwayne RJ Moore ◽  
Colleen D Greer ◽  
Melissa Whitfield-Aslund ◽  
Lisa M Bowers ◽  
Sean McGee ◽  
...  
Keyword(s):  
United States ◽  
Water Quality ◽  
Environmental Protection Agency ◽  
Species Interactions ◽  
The United States ◽  
Toxicity Tests ◽  
Aquatic Life ◽  
Invertebrate Communities ◽  
Us Epa ◽  
Best Fit

Water quality benchmarks are developed by many jurisdictions worldwide with the general goal of identifying concentrations that protect aquatic communities. Imidacloprid is a widely-used neonicotinoid insecticide for which benchmark values vary widely between North America and Europe. For example, the European Food Safety Authority (EFSA) and Dutch National Institute for Public Health and the Environment (RIVM) recently established chronic water quality benchmarks for imidacloprid of 0.009 and 0.0083 µg/L, respectively. In Canada and the United States (US), however, the current chronic water quality benchmarks – termed aquatic life benchmark by the United States Environmental Protection Agency (US EPA) – for freshwater biota are orders of magnitude higher, i.e., 0.23 and 1.05 µg/L, respectively. Historically, aquatic benchmarks for imidacloprid have been derived for invertebrates because they are the most sensitive aquatic receptors. To date, derivation of water quality benchmarks for imidacloprid have relied on the results of laboratory-based toxicity tests on single invertebrate species. Such tests do not account for environmental factors affecting bioavailability and toxicity or species interactions and potential for recovery. Microcosm, mesocosm and field studies are available for aquatic invertebrate communities exposed to imidacloprid. These higher tier studies are more representative of the natural environment and can be used to derive a chronic benchmark for imidacloprid. A water quality benchmark based on the results of higher tier studies is protective of freshwater invertebrate communities without the uncertainty associated with extrapolating from laboratory studies to field conditions. We used the results of higher tier studies to derive a chronic water quality benchmark for imidacloprid as follows: (1) for each taxon (family, subfamily or class depending on the study), we determined the most sensitive 21-day No Observed Effects Concentration (NOEC), (2) we fit the taxon NOECs to five distributions and determined the best-fit distribution, and (3) we determined the HC5 from the best-fit distribution. The higher tier chronic HC5 for imidacloprid is 1.01 µg/L, which is close to the current US EPA chronic aquatic life benchmark of 1.05 µg/L.

North American ECA Regulations and LNG Fuels - A Viable Solution?

2012 ◽  
Author(s):  
Yvonni-Effrosyni Damianidou
Keyword(s):  
North American ◽  
Environmental Protection Agency ◽  
Supply And Demand ◽  
The United States ◽  
Control Area ◽  
Shipping Industry ◽  
International Convention ◽  
Viable Solution ◽  
Pros And Cons ◽  
Emission Control Area

The purpose of this paper is to present an overview of the recent North American Emission Control Area Regulations imposed by the International Marine Organization amendment to the International Convention for the Prevention of Pollution from Ships (MARPOL, Annex VI) in 2010, focusing on how organizations, like the United States Environmental Protection Agency have contributed to their implementation. Furthermore it examines the prospect of liquefied natural gas, potentially becoming “a fuel of the future for the shipping industry” and attempts to answer whether LNG fuels offer a viable alternative solution for the shipping industry, illustrating the pros and cons, while focusing on issues of bunker supply and demand and future global implications.

scholarly journals Monitoring and Modeling the Long-Term Rainfall-Runoff Response of the Jacob K. Javits Center Green Roof

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1494 ◽  
Author(s):  
Noura Abualfaraj ◽  
Joseph Cataldo ◽  
Yara Elborolosy ◽  
Daniel Fagan ◽  
Sloane Woerdeman ◽  
...  
Keyword(s):  
New York ◽  
Environmental Protection Agency ◽  
Green Roof ◽  
Substantial Reduction ◽  
Cost Effective ◽  
Green Roofs ◽  
The United States ◽  
Rainfall Runoff ◽  
Substrate Depth

Drainage from the 27,316-m2 Jacob K. Javits Convention Center (JJCC) green roof was investigated in the field to quantify the system’s long-term rainfall-runoff response. The JJCC hosts one of the largest extensive green roofs in the United States. Utilizing four years of rooftop monitoring data collected using a weather station, custom designed and built drainage systems, three Parshall flumes equipped with pressure transducers, and weighing lysimeters, this study quantified the 25.4-mm-deep green roof’s ability to decrease the volume and peak rate of runoff. With parameters derived from the site, the Environmental Protection Agency Stormwater Management Model (EPA-SWMM) predicted event total runoff volume and event peak runoff rates to within +10% to −20% and +25% to −15% of the observations, respectively. The analysis further indicated that approximately 55% of the cumulative precipitation that fell on the JJCC extensive green roof during the monitoring period (warm weather months, June 2014–November 2017) was captured and retained. The average percent retained on an event-basis was 77%, and average event runoff coefficient was 0.7, implying a substantial reduction in the volume and rate of runoff generated from the roof compared to the pre-green roof condition, when most, if not all, of the precipitated water would have immediately resulted in runoff. Our research suggests that, on average, 96% of rainfall events 6.35 mm or less were retained within the green roof, whereas 27% of the total event volume was retained for events greater than 12.7 mm in depth. A sensitivity analysis suggests if the substrate depth were increased, better stormwater capture performance would be achieved, but only up 127 mm, whereas increased precipitation coupled with warmer temperatures as a result of climate change could decrease the performance by up to 5%, regardless of substrate depth. An equivalency analysis suggested that even shallow green roofs can significantly reduce the required stormwater detention volume that New York City requires on new development. This particular green roof appears to be more than 18 times as cost-effective as a subsurface cistern would be for managing an equivalent volume of stormwater in Midtown Manhattan.

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