Increased wind erosion from forest wildfire: implications for contaminant-related risks

Assessments of contaminant-related human and ecological risk require estimation of transport rates, but few data exist on wind-driven transport rates in nonagricultural systems, particularly in response to ecosystem disturbances such as forest wildfire and also relative to water-driven transport. The Cerro Grande wildfire in May of 2000 burned across ponderosa pine (Pinus ponderosa Douglas ex P.&C. Lawson var. scopulorum Englem.) forest within Los Alamos National Laboratory in northern New Mexico, where contaminant transport and associated post-fire inhalation risks are of concern. In response, the objectives of this study were to measure and compare wind-driven horizontal and vertical dust fluxes, metrics of transport related to wind erosion, for 3 yr for sites differentially affected by the Cerro Grande wildfire: unburned, moderately burned (fire mostly confined to ground vegetation), and severely burned (crown fire). Wind-driven dust flux was significantly greater in both types of burned areas relative to unburned areas, by more than one order of magnitude initially and by two to three times 1 yr after the fire. Unexpectedly, the elevated dust fluxes did not decrease during the second and third years in burned areas, apparently because ongoing drought delayed post-fire recovery. Our estimates enable assessment of amplification in contaminant-related risks following a major type of disturbance-wildfire, which is expected to increase in intensity and frequency due to climate change. More generally, our results highlight the importance of considering wind- as well as water-driven transport and erosion, particularly following disturbance, for ecosystem biogeochemistry in general and human and ecological risk assessment in particular.     

Preferential flow estimates to an agricultural tile drain with implications for glyphosate transport

Agricultural subsurface drains, commonly referred to as tile drains, are potentially significant pathways for the movement of fertilizers and pesticides to streams and ditches in much of the Midwest. Preferential flow in the unsaturated zone provides a route for water and solutes to bypass the soil matrix and reach tile drains faster than predicted by traditional displacement theory. This paper uses chloride concentrations to estimate preferential flow contributions to a tile drain during two storms in May 2004. Chloride, a conservative anion, was selected as the tracer because of differences in chloride concentrations between the two sources of water to the tile drain, preferential and matrix flow. A strong correlation between specific conductance and chloride concentration provided a mechanism to estimate chloride concentrations in the tile drain throughout the storm hydrographs. A simple mixing analysis was used to identify the preferential flow component of the storm hydrograph. During two storms, preferential flow contributed 11 and 51% of total storm tile drain flow; the peak contributions, 40 and 81%, coincided with the peak tile drain flow. Positive relations between glyphosate [N-(phosphonomethyl)glycine] concentrations and preferential flow for the two storms suggest that preferential flow is an important transport pathway to the tile drain.     

Non-UV based germicidal activity of metal-doped TiO2 coating on solid surfaces

A stain-based screening method was developed to screen different catalyst coatings for their germicidal activity. A Baclight dead/live bacteria viability kit （invitrogen, molecular probes） was used for staining the cell. The screening was carried out following a standard procedure. This included loading cell suspension to solid surface and maintaining contact for 30 min, then staining with a mixture containing dyes. The stained cells were observed using an epifluorescent microscope and photographed with a CCD camera under UV. Metal-doped TiO2 coatings on AI plates were prepared and tested for non-UV germicidal activity without using UV. It was tested using model microorganisms such as Bakers Yeast （Saccharomyces cerevisiae）, Bacillus subtilis, Pseudomonas putida, and Escherichia coli. On the basis of the germicidal activity of catalyst and the degree of damage caused to the cells, the stained cells may appear green （viable）, green with red or yellow nuclei and yellow （compromised） or red （nonviable）. According to their stained color, cells were counted to calculate the percentage of dead, live, and compromised cells. Compromised cells are cells that grow very slowly after reculturing indicating a degree of reversible cell damage. Screening the germicidal activity using this staining method is accurate and efficient, and requires less time than the culture-based method. A modification to the procedure for measuring germicidal activity of rough surfaces or fibrous coatings was developed. Both TiO2 and metal-doped TiO2 （Ag, Pt, Au, Cu） possess non-UV based germicidal activity. The germicidal activity of TiO2 was found to be related with its wetting property and can be improved by UV irradiation before testing. It is not greatly affected by contact time, indicating a fast acting germicidal activity.     

Thallium: a review of public health and environmental concerns

Thallium (Tl) is a rare but widely dispersed element. All forms of thallium are soluble enough to be toxic to living organisms. Thallium is more toxic to humans than mercury, cadmium, lead, copper or zinc and has been responsible for many accidental, occupational, deliberate, and therapeutic poisonings since its discovery in 1861. Its chemical behavior resembles the heavy metals (lead, gold and silver) on the one hand and the alkali metals (K, Rb, Cs) on the other. It occurs almost exclusively in natural waters as monovalent thallous cation. The solubility of thallous compounds is relatively high so that monovalent thallium is readily transported through aqueous routes into the environment. Tl can be transferred from soils to crops readily and accrues in food crops. The fascinating chemistry and high toxicity potential make thallium and its compounds of particular scientific interest and environmental concern. Thallium was detected in base-metal mining effluents. The conventional removal of heavy metals from wastewater has little effect on thallium. In this review, various treatment options and removal technologies are enumerated in order to protect the environment from thallium toxicity.     

An improvement selection methodology for key performance indicators

Key performance indicators (KPIs) are critical measures for determining the health of a manufacturing plant in relationship to the plant’s goals. In today’s competitive environment, manufacturers cannot be careless about their business; in fact, they must ensure that their KPIs are effective and use them to make improvements when necessary. This paper describes a method for suggesting improvements to a manufacturer’s KPIs, based on the results achieved from a workshop to score the KPI on a number of predefined criteria. The approach uses a prospect theory approach to weight the scoring. Different problem formulations were derived that allow for both recommendations for improvements and the recommendations for disinvestments to over-performing KPIs. The authors applied the developed approach to two workshop outputs, each from independent manufacturers, and the results highlighted the significant difference between the two manufacturers in terms of improvement priorities and KPI assessment. The optimal improvement suggestions were compared to those found through a fast heuristic. It was determined that given the underlying assumptions of the approach that the heuristic solutions were just as adequate as the optimal ones.     

Influencing climate change regulations: examining responses from large-scale firms

Recent climate change projections and a push towards a universal agreement on carbon emission reductions suggest that firms will need to respond to future regulatory changes. This paper employs an influencing strategies lens to examine how large-scale firms might respond to future climate change regulations. The study uses a structured qualitative methodology to explore and explicate the strategic responses from 21 international firms to the proposed emissions trading scheme outlined in Australia's Garnaut Climate Change Review. The results of the analysis show that firms can use pre-emptive influencing strategies in attempts to shape and mould regulatory design parameters, secure high levels of transitional economic support, and shift the balance of public policies and expenditure. Complementary defensive strategies may also target policy makers and regulators with some of the potential negative consequences of the new regulations.     

Benchmarking Optical/Thermal Satellite Imagery for Estimating Evapotranspiration and Soil Moisture in Decision Support Tools

Generally, one expects evapotranspiration (ET) maps derived from optical/thermal Landsat and MODIS satellite imagery to improve decision support tools and lead to superior decisions regarding water resources management. However, there is lack of supportive evidence to accept or reject this expectation. We “benchmark” three existing hydrologic decision support tools with the following benchmarks: annual ET for the ET Toolbox developed by the United States Bureau of Reclamation, predicted rainfall‐runoff hydrographs for the Gridded Surface/Subsurface Hydrologic Analysis model developed by the U.S. Army Corps of Engineers, and the average annual groundwater recharge for the Distributed Parameter Watershed Model used by Daniel B. Stephens & Associates. The conclusion of this benchmark study is that the use of NASA/USGS optical/thermal satellite imagery can considerably improve hydrologic decision support tools compared to their traditional implementations. The benefits of improved decision making, resulting from more accurate results of hydrologic support systems using optical/thermal satellite imagery, should substantially exceed the costs for acquiring such imagery and implementing the remote sensing algorithms. In fact, the value of reduced error in estimating average annual groundwater recharge in the San Gabriel Mountains, California alone, in terms of value of water, may be as large as $1 billion, more than sufficient to pay for one new Landsat satellite.