Detection Limits for Hazardous and Radioactive Elements in Airborne Aerosols Using Inductively Coupled Air Plasma – Atomic Emission Spectrometry

Abstract

This research presents investigations into the use of inductively coupled air plasma – atomic emission spectrometry (air-plasma ICPAES) to determine the presence of inorganic contaminants in airborne aerosols. Limits of detection (LOD) in the ppm to ppb range for 19 hazardous metals and radionuclides were determined for aerosols of solutions nebulized into the air plasma. For many elements, the determined LOD surpass the threshold limit values established by the American Conference of Governmental Industrial Hygienists by one to three orders of magnitude. The potential of air-plasma ICPAES for continuous on-line monitoring of airborne contaminants is discussed.     

Ambient ozone effects on gas exchange and total non-structural carbohydrate levels in cutleaf coneflower (Rudbeckia laciniata L.) growing in Great Smoky Mountains National Park

Ozone-sensitive and -tolerant individuals of cutleaf coneflower (Rudbeckia laciniata L.) were compared for their gas exchange characteristics and total non-structural carbohydrates at Purchase Knob, a high elevation site in Great Smoky Mountains National Park, USA. Photosynthesis and stomatal conductance decreased with increased foliar stipple. Sensitive plants had lower photosynthetic rates for all leaves, except the very youngest and oldest when compared to tolerant plants. Stomatal conductance decreased with increasing leaf age, but no ozone-sensitivity differences were found. Lower leaves had less starch than upper ones, while leaves on sensitive plants had less than those on tolerant plants. These results show that ambient levels of ozone in Great Smoky Mountains National Park can adversely affect gas exchange, water use efficiency and leaf starch content in sensitive coneflower plants. Persistence of sensitive genotypes in the Park may be due to physiological recovery in low ozone years.     

Feedback acceptance in developmental assessment centers: the role of feedback message,participant personality,and affective response to the feedback session

We investigated feedback acceptance by participants (N = 141) in an operational developmental assessment center (AC). Consistent with predictions based on self‐enhancement theory and the Affective Infusion Model, results indicated that higher assessor ratings were associated with higher feedback acceptance, and this relationship was partially mediated by the participant's affective reaction to the feedback session. Participants' self‐ratings of their AC performance did not affect this relationship suggesting no support for our prediction based on self‐verification theory. We also investigated the role of participants' self‐ratings of agreeableness, extraversion, and emotional stability in feedback acceptance by testing specific moderated mediation hypotheses. Extraversion was related to feedback acceptance through the affective reaction to the feedback session. Agreeableness moderated the affective reaction to the feedback session and feedback acceptance relationship such that there was a strong relationship between affective reaction and feedback acceptance for highly agreeable participants, but no relationship for low agreeable individuals. For low agreeable individuals, there was a positive direct relationship between the assessor ratings and feedback acceptance which was not observed for highly agreeable individuals. The hypothesized role of emotional stability in predicting feedback acceptance was not supported. Implications for the delivery of feedback in developmental ACs are discussed in light of these findings. Copyright © 2008 John Wiley & Sons, Ltd.     

Evaluation of the in situ, time-integrated DGT technique by monitoring changes in heavy metal concentrations in estuarine waters

Various natural and anthropogenic processes influence heavy metal concentrations within estuaries. In situ, time-integrated DGT measurements made over concurrent tidal phases found significantly higher concentrations of Cu (probability p=0.017), Zn (p=0.003) and Ni (p=0.003) during the flood phase, because the incoming tide passes several point sources. DGT-reactive Cu concentrations significantly decreased with increased tidal-flushing and vice versa within a marina (correlation r=-0.788, p=0.02). DGT measurements also recorded significant increases in Cu (4 out of 4 sites, p<0.001) and Zn (3 out of 4 sites, p< or =0.015) after a 24 mm rainfall event. Finally, DGT-reactive Cu increased significantly (p<0.001) during peak boating times, due to increased numbers of Cu-antifouled boats. This study demonstrates that, with judicious selection of deployment times, DGT measurements enable changes in heavy metal concentrations to be related to various cycles and events within estuaries.     

History and Development of the NRCS Lag Time Equation1

Abstract: Many of the hydrologic methods that are used in engineering practice today resulted from the Spring Flood of 1936, which blanketed the Northeastern portion of the United States. Because of the flood damage that was caused by this rainfall‐snowmelt event, many federal agencies including the U.S. Army Corp of Engineers and the Soil Conservation Service (SCS) implemented the hydrologic theories that were available in the literature at this time and developed hydrologic procedures for design flow estimation. Sherman had recently published his unit hydrograph theory in 1932, and later in 1938 Snyder, who had been charged by the Water Resource Council to develop a synthetic unit hydrograph, published his famous paper. The SCS unit hydrograph theory was developed by Victor Mockus in the late 1950s. Most if not all of the theories at that time reported the rainfall‐runoff process for floods as a surface phenomenon, and as such those theories all required some type of a timing parameter to estimate watershed response time. This article documents the development of the SCS lag equation.     

Effect of sunlight intensity and albinism on the covering response of the Caribbean sea urchin<Emphasis Type="Italic"> Tripneustes ventricosus</Emphasis>

At Discovery Bay, Jamaica, Tripneustes ventricosus lives in beds of the turtle grass Thalassia testudinum. Especially during daylight hours, it covers its aboral surface with fragments of this plant and other objects. Normally pigmented, wild-type sea urchins covered themselves significantly less with Thalassia when sunlight was experimentally decreased to 66% or 32% ambient intensity. Consistent with this result, naturally occurring sea urchins exhibited significantly less covering at a deep (3.5 m) site than at a shallow (1 m) site, where light intensities at the bottom were 619 and 946 mol s^–1 m^–2, respectively. The graded covering response to light intensity suggests that covering is a defense against damaging solar radiation. Albino sea urchins covered themselves significantly more with Thalassia than wild-type sea urchins in both full and 66% sunlight. In addition, at the shallow site where they accounted for about 4% of the population, they showed significantly greater covering than wild-type urchins. The greater covering response of albino sea urchins suggests a greater susceptibility to solar radiation.Communicated by P. W. Sammarco, Chauvin     

Maintaining high-volume, low-pressure surface-coating regulatory compliance using the U.s. Environmental Protection Agency's data quality objectives process

To effectively reduce the environmental compliance costs associated with meeting specific requirements under the Aerospace Manufacturing and Rework Facility's National Emission Standard for Hazardous Air Pollutants rule, the U.S. Environmental Protection Agency's (EPA) Data Quality Objective (DQO) process has been proposed as a suitable framework for developing a scientifically defensible surface compliance monitoring program. By estimating the variability associated with the air cap pressure of high- volume, low-pressure (HVLP) surface-coating spray equipment, the number of monitoring samples necessary for an affected facility to claim compliance with a desired statistical confidence level was established. Using data taken from the pilot test facility, the DQO process indicated that the mean of at least 21 HVLP air cap pressure samples taken over the compliance period must be < or = 10 pounds per square inch (psig) gauge for the facility to claim regulatory compliance with 99.99% statistical confidence. Fewer compliance samples could be taken, but that decision would lead to a commensurate reduction in the compliance confidence level. Implementation of the DQO-based compliance sampling plan eliminates the need for an affected facility to sample all regulated HVLP surface-coating processes while still maintaining a high level of compliance assurance.