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1.
Persistence and Microbial Source Tracking of Escherichia coli at a Swimming Beach at Lake of the Ozarks State Park,Missouri 下载免费PDF全文
Jordan L. Wilson John G. Schumacher Joel G. Burken 《Journal of the American Water Resources Association》2016,52(2):508-522
The Missouri Department of Natural Resources (MDNR) has closed or posted advisories at public beaches at Lake of the Ozarks State Park in Missouri because of Escherichia coli (E. coli) concentration exceedances in recent years. Spatial and temporal patterns of E. coli concentrations, microbial source tracking, novel sampling techniques, and beach‐use patterns were studied during the 2012 recreational season to identify possible sources, origins, and occurrence of E. coli contamination at Grand Glaize Beach (GGB). Results indicate an important source of E. coli contamination at GGB was E. coli released into the water column by bathers resuspending avian‐contaminated sediments, especially during high‐use days early in the recreational season. Escherichia coli concentrations in water, sediment, and resuspended sediment samples all decreased throughout the recreational season likely because of decreasing lake levels resulting in sampling locations receding away from the initial spring shoreline as well as natural decay and physical transport out of the cove. Weekly MDNR beach monitoring, based solely on E. coli concentrations, at GGB during this study inaccurately predicted E. coli exceedances, especially on weekends and holidays. Interestingly, E. coli of human origin were measured at concentrations indicative of raw sewage in runoff from an excavation of a nearby abandoned septic tank that had not been used for nearly two years. 相似文献
2.
Holley R Walkty J Blank G Tenuta M Ominski K Krause D Ng LK 《Journal of environmental quality》2008,37(6):2083-2092
Use of hog (Sus scrofa) manure as a fertilizer is a practical solution for waste re-utilization, however, it may serve as a vehicle for environmental and domestic animal contamination. Work was conducted to determine whether pathogens, naturally present in hog manure could be detected in cattle (Bos taurus) grazed on the manure-treated pasture, and whether forage contamination occurred. During two 3 mo summer trials manure was applied to yield < or = 124 kg available N per hectare in a single spring or split spring and fall application. Samples of hog manure, forage, soil, and cattle feces were analyzed for naturally occurring Salmonella, Yersinia enterocolitica, and Escherichia coli. To follow movement of Salmonella in the environment isolates were identified to serovar and serotyped. Transfer of E. coli from hog manure to soil and cattle was examined by randomly amplified polymorphic DNA (RAPD) analysis of >600 E. coli isolates. While Y. enterocolitica was absent from all samples, in both years S. enterica Derby and S. enterica Krefeld were found in most hog manure samples, but were only on forage samples in the second year. Salmonella enterica Typhimurium, absent from hog manure was present on some forage in the first year. Cattle feces and soil samples were consistently Salmonella negative. These contaminations could not be traced to manure application. During this study, Salmonella and E. coli found in hog manure had different RAPD genomic profiles from those found in the feces of cattle grazing on manure-treated pasture. 相似文献
3.
The US Department of Defense (DOD) manages over 10.1 million ha of land, much of which is used for training military personnel.
However, vast sections receive little or no use, and military lands have become refuges for many species. At Fort McCoy, Wisconsin,
USA, populations of the endangered Karner blue butterfly (Lycaeides melissa samuelis) are found in oak and pine barren communities where wild lupine (Lupinus perennis), a perennial forb required by Karner blue butterfly larvae, still occurs. Oak and pine barren communities are disturbance-dependent,
and the barrens ecosystems in the Midwest have declined in extent by 98% because of fire suppression, succession, and habitat
fragmentation. We studied the effects of disturbance by military manuever training on the density of lupine and Karner blue
butterfly at Fort McCoy. We also wanted to determine whether military training activity could enhance Karner blue butterfly
habitat.
At locations where tracked vehicles had driven through lupine patches, the abundance of lupine and nectar-producing plants
was greater in the median strip between vehicle ruts than in vehicle ruts or 5 m outside the vehicle ruts. The proportion
of lupine stems with Karner blue butterfly larvae feeding sign (the ratio of stems fed upon to stems examined) was greater
in areas where military vehicles had traveled than where they had not. The proportion of lupine stems with feeding sign and
lupine stem density was also positively related to the occurrence of prior bivouacs and fires caused by military munitions.
Shrub and forest canopy abundance were lower in areas traveled by tracked vehicles. At the scale of the lupine patch, lupine
abundance and the proportion of lupine stems with feeding sign were positively correlated with military training activities,
suggesting that maintenance of lupine habitat can be achieved in concert with military training. 相似文献
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The effect of clean energy regulations and incentives on green jobs: panel analysis of the United States, 1998–2007 下载免费PDF全文
Taedong Lee 《Natural resources forum》2017,41(3):145-155
‘Green jobs’ are often presented as a simultaneous solution for the economic downturn and the environmental crisis, particularly as they relate to sustainable development in energy and climate change. Federal, state, and municipal authorities have employed a variety of policy tools to boost job creation within their jurisdictions. This study focuses on the role that state policies play in creating green jobs. It examines two generic policy tools – regulations and incentives – each of which can be aimed at advancing energy efficiency or renewable energy production, and assesses the relative impact they have had on generating green jobs. In order to measure this impact, we utilize panel data compiled by the Pew Charitable Trusts, which contain a state‐level count of green jobs from 1998 to 2007. The results of the analysis suggest that regulations, particularly those that mandate action on renewable energy, are likely to increase the number of private sector green jobs in states. Regulations with clear guidelines and targets tend to reduce uncertainty in business, and can lead to increased private sector investment and job availability. This study provides practical lessons regarding the type and design of policy instruments and regulations on renewable energy, which effectively encourage green job growth. 相似文献