Twentieth century droughts and agriculture: Examples from impacts on soybean production in Kentucky,USA

Drought is a significant natural hazard that slowly evolves over time. Because of its character, drought is difficult to monitor and impacts are often poorly documented. Agriculture is one of the most sensitive sectors that are prone to drought. The objective of this research is to assess the impacts of drought on soybean production and revenue in Kentucky. Soybeans are one of Kentucky’s most important commodities. In this study, impacts of 1930–1931, 1940–1942, 1952–1955, 1987–1988, 1999–2000, and 2007 droughts were considered. It was found that over the recent years, up to 56 % of the revenue from soybeans was lost due to drought. During the first half of the twentieth century, revenue loss reached up to 77 %. This research is valuable to the general public as well as planners and policy makers. Proper documentation of impacts of past droughts will help identify drought vulnerabilities and results in better risk management and mitigation.     

Guidance for the Field Demonstration of Remediation Technologies

This paper will focus on the demonstration of hazardous waste cleanup technologies in the field. The technologies will be at the pilot- or full-scale, and further referred to as field-scale. The main objectives of demonstration at the field-scale are development of reliable performance and cost data. Technology demonstrations provide performance, cost effectiveness, and reliability data so that potential technology users have sufficient information to make effective decisions as to the applicability of the technology to a specific situation. The demonstration and evaluation of a technology should be conducted with the purpose of characterizing performance, need for pre- and post-processing of the waste feed, identification of waste type and constituents applicable to the technology, system throughput, problems and limitations of the technology, and operating and maintenance costs. Table I provides a summary of remediation activities for demonstration projects.     

Modeling Emissions from Elevated Cylindrical Bins

Abstract

This paper demonstrates how wind tunnel modeling data that accurately describe plume characteristics near an unconventional emission source can be used to improve the near-field downwind plume profiles predicted by conventional air pollution dispersion models. The study considers a vertical, cylindrical-shaped, elevated bin similar to large product storage bins that can be found at many industrial plant sites. Two dispersion models are considered: the U.S. Environmental Protection Agency's ISC2(ST) model and the Ontario Ministry of the Environment and Energy's GAS model. The wind tunnel study showed that plume behavior was contrary to what was predicted using conventional dispersion models such as ISC2(ST) and GAS and default values of input parameters. The wind tunnel data were used to develop a protocol for correcting the dispersion models inputs, resulting in a substantial improvement in the accuracy of the dispersion estimates.     

The Steubenville Comprehensive Air Monitoring Program (SCAMP): Overview and Statistical Considerations

Abstract

Average concentrations of particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM_2.5) in Steubenville, OH, have decreased by more than 10 μg/m³ since the landmark Harvard Six Cities Study¹ associated the city’s elevated PM_2.5 concentrations with adverse health effects in the 1980s. Given the promulgation of a new National Ambient Air Quality Standard (NAAQS) for PM_2.5 in 1997, a current assessment of PM_2.5 in the Steubenville region is warranted. The Steubenville Comprehensive Air Monitoring Program (SCAMP) was conducted from 2000 through 2002 to provide such an assessment. The program included both an outdoor ambient air monitoring component and an indoor and personal air sampling component. This paper, which is the first in a series of four that will present results from the outdoor portion of SCAMP, provides an overview of the outdoor ambient air monitoring program and addresses statistical issues, most notably autocorrelation, that have been overlooked by many PM_2.5 data analyses. The average PM_2.5 concentration measured in Steubenville during SCAMP (18.4 μg/m³) was 3.4g/m³ above the annual PM_2.5 NAAQS. On average, sulfate and organic material accounted for ～31% and 25%, respectively, of the total PM_2.5 mass. Local sources contributed an estimated 4.6 μg/m³ to Steubenville’s mean PM_2.5 concentration. PM_2.5 and each of its major ionic components were significantly correlated in space across all pairs of monitoring sites in the region, suggesting the influence of meteorology and long-range transport on regional PM_2.5 concentrations. Statistically significant autocorrelation was observed among time series of PM_2.5 and component data collected at daily and 1-in-4-day frequencies during SCAMP. Results of spatial analyses that accounted for autocorrelation were generally consistent with findings from previous studies that did not consider autocorrelation; however, these analyses also indicated that failure to account for autocorrelation can lead to incorrect conclusions about statistical significance.     

Identifying Differences Between Off-Highway Vehicle (OHV) and Non-OHV User Groups for Recreation Resource Planning

Off-highway vehicle (OHV) riding is among the fastest growing recreational activities in the United States. However, little research exists about the central components of outcomes-focused management (OFM) as it relates to motorized recreation. Utilizing a two-activity dichotomy, OHV and non-OHV centric user groups were compared on several key concepts associated with OFM, including desired experiences, perceived and desired recreation opportunity spectrum-type settings, and intentional behaviors (i.e., place-protective behavior, spending-time intentions) toward potential changes in settings. Results indicated that the two groups were different in terms of intensity and relative rankings of their perceived experiences and settings. Although both groups preferred social bonding, stress relief, nostalgia and learning experiences, the OHV user group ranked using equipment and achieving physical fitness experiences as more important than the non-OHV group. The non-OHV user group preferred enjoying nature and solitude/tranquility experiences more strongly than the OHV user group. Further analysis found that both groups perceived settings that they recreated in to be pristine and preferred such conditions, and both groups preferred moderate levels of rules and regulations. Finally, the OHV user group was more reactive to rules and regulations, while the non-OHV user group expressed stronger intentions to protect the environmental quality of recreation areas. The results suggest that planners and managers who understand OHV user's perceptions and behaviors could provide enhanced recreation opportunities potentially providing additional beneficial outcomes for motorized and non-motorized groups in spatially different zones. Additional implications for planners and managers and future studies are discussed.     

Organochlorine pesticides in soil under irrigated cotton farming systems in Vertisols of the Namoi Valley, north-western New South Wales, Australia

Organochlorine pesticides (OCPs) such as DDT and DDE have been detected in the surface 0.2 m of Vertisols in the lower Namoi Valley of north western New South Wales, Australia even though they have not been applied to crops since 1982. However, their presence in the deeper soil horizons has not been investigated. The objective of this study was to determine if OCPs were present to a depth of 1.2 m in Vertisols under irrigated cotton farming systems in the lower Namoi Valley of New South Wales. Soil was sampled from the 0-1.2 m depths in three sites, viz. the Australian Cotton Research Institute, ACRI, near Narrabri (149°36′E, 30°12′S), and two cotton farms near Wee Waa (149°27′E, 30°13′S) and Merah North (149°18′E, 30°12′S) in northern New South Wales, Australia. The OCPs detected and their metabolites were α-endosulfan, β-endosulfan, endosulfan sulphate, DDD, DDE, DDT and endrin. The metabolite DDE, a breakdown product of DDT, was the most persistent OCP in all depths analysed. Endosulfan sulphate was the second most persistent followed by endrin > α-endosulfan > β-endosulfan > DDT and DDD. DDT was sprayed extensively in the lower Namoi Valley up to the early 1980s and may explain the persistence of DDE in the majority of soil samples. Dicofol and Dieldrin, two OCPs previously undocumented in Vertisols were also detected. The movement of OCPs into the subsoil of Vertisols may occur when irrigation or rain transports soil colloids and organic matter via preferential flow systems into the deeper layers of a soil profile. Persistence of OCPs was closely correlated to soil organic carbon concentrations. The persistence in soil of OCP’s applied to cotton crops grown more than two decades ago suggests that they could enter the food chain. Their presence at depths of 1.2 m suggests that they could move into groundwater that may eventually be used for domestic and stock consumption.     

Influence of Suwannee River humic acid on particle properties and toxicity of silver nanoparticles

Adsorption of natural organic matter (NOM) on nanoparticles can have dramatic impacts on particle dispersion resulting in altered fate and transport as well as bioavailability and toxicity. In this study, the adsorption of Suwannee River humic acid (SRHA) on silver nanoparticles (nano-Ag) was determined and showed a Langmuir adsorption at pH 7 with an adsorption maximum of 28.6 mg g⁻¹ nano-Ag. It was also revealed that addition of <10 mg L⁻¹ total organic carbon (TOC) increased the total Ag content suspended in the aquatic system, likely due to increased dispersion. Total silver content decreased with concentrations of NOM greater than 10 mg TOC L⁻¹ indicating an increase in nanoparticle agglomeration and settling above this concentration. However, SRHA did not have any significant effect on the equilibrium concentration of ionic Ag dissolved in solution. Exposure of Daphnia to nano-Ag particles (50 μg L⁻¹ and pH 7) produced a linear decrease in toxicity with increasing NOM. These results clearly indicate the importance of water chemistry on the fate and toxicity of nanoparticulates.     

Climate change impacts on the leaching of a heavy metal contamination in a small lowland catchment

The Keersop catchment (43km(2)) in the south of The Netherlands has been contaminated by the emissions of four zinc ore smelters. The objective of this study was to assess the effects of future projected climate change on the hydrology and the leaching of heavy metals (i.e. Cd and Zn) in the catchment. The numerical, quasi-2D, unsaturated zone Soil Water Atmosphere Plant model was used with 100-year simulated daily time series of precipitation and potential evapotranspiration. The time series are representative of stationary climates for the periods 1961-1990 ("baseline") and 2071-2100 ("future"). The time series of future climate were obtained by downscaling the results of eight regional climate model (RCM) experiments, driven by the SRES A2 emissions scenario, using change factors for a series of climate statistics and applying them to stochastic weather generator models. The time series are characterized by increased precipitation in winter, less precipitation in summer, and higher air temperatures (between 2°C and 5°C) throughout the year. Future climate scenarios project higher evapotranspiration rates, more irrigation, less drainage, lower discharge rates and lower groundwater levels, due to increased evapotranspiration and a slowing down of the groundwater system. As a result, lower concentrations of Cd and Zn in surface water are projected. The reduced leaching of heavy metals, due to drying of the catchment, showed a positive impact on a limited aspect of surface water quality.