Wetfall Deposition and Precipitation Chemistry for a Central Appalachian Forest

Abstract

Although extensive research on acidic deposition has been directed toward spruce-fir forests, less research has been done on the impacts of air pollution on eastern montane hardwood forests. The purpose of this study was to describe precipitation chemistry for several Appalachian hardwood forest sites at or near the Fernow Experimental Forest (FEF) to assess the potential for problems associated with acidic deposition. Emphasis was placed on seasonal patterns of ionic concentrations (H+, Ca++, NH4+; NO3-, and SO4=) and spatial variability of ionic concentrations and deposition among sites. Seasonal patterns of most ions showed highest concentrations during the summer months and deposition of H+ was especially pronounced during this time. Deposition of all ions was generally greater (related to greater precipitation) at three montane forested sample sites compared to a nonforested riverbottom site. Precipitation chemistry at FEF was similar to other sites throughout the eastern United States and contrasted sharply with mid-western and western sites. Eastern sites, including means for FEF sites, were uniformly 3-4 times higher in H+ and SO4= concentration than the mid-western and western sites. Precipitation at FEF was chronically acidic, more so during the growing season, and highest at higher elevations where environmental stresses can be most severe. Furthermore, there were occasional large discrepancies between the low-elevation site and the higher-elevation forested sites for precipitation chemistry and acidic deposition. These results suggest that synoptic-scale (network) data may greatly underestimate the pollutant conditions to which highelevation forest trees are exposed, since network data rarely take elevation into account and typically are based on annual ionic concentration and deposition means that may be considerably lower than those of the growing season.     

Validating a Safety Climate Model in Metal Processing Industries: A Replication Study

This paper attempts to replicate a safety climate model originally tested in Australia to assess its applicability in a different context: namely, across production workers in 22 medium-sized metal processing organizations in Austria. The model postulates that safety knowledge and safety motivation mediate the relation between safety climate on the one hand and safety compliance and participation on the other. Self-report data from 1075 employees were analyzed using structural equation modeling (SEM). The results of the replication study largely confirmed the original safety climate model. However, in addition to indirect effects, direct links between safety climate and actual safety behavior were found.     

The roles of nicotine and natural enemies in determining larval feeding site distributions of Manduca sexta L. and Manduca quinquemaculata (Haworth) on tobacco

Summary. Field observations indicated that hornworms select feeding sites non-randomly on tobacco. We tested the hypotheses that differences in feeding site locations of larvae of Manduca sexta L. and Manduca quinquemaculata (Haworth) (Lepidoptera: Sphingidae) on tobacco could be explained by differential nicotine concentrations within plants and leaves, species-specific responses to nicotine, or pressure exerted by natural enemies. Results showed that third-instar larvae of M. sexta fed more proximally and centrally on the leaf, whereas M. quinquemaculata fed more distally. Within-plant selection of leaves did not differ; both species selected leaves in the middle region of the plant. Nicotine concentrations in a high nicotine genotype, NC95, varied within each leaf, increasing 2—3 fold from the basal to apical portion of the leaf, and within each plant, increasing 7—10 fold from the first fully expanded leaf to the twelfth (lowest) leaf. In laboratory bioassays, both Manduca species responded to nicotine as a feeding deterrent. Electrophysiological studies demonstrated that gustatory organs of both species responded to nicotine at concentrations found in tobacco leaves and that M. quinquemaculata generally showed a less vigorous response to nicotine than M. sexta. Field mortality of M. sexta due to parasitism by Cotesia congregata (Say) and to parasitism and predation combined differed among feeding sites; predation alone did not. Results suggest that although nicotine concentration and species specific responses to nicotine play a role in determining feeding site locations, pressure exerted by natural enemies, especially parasitism by C. congregata, is more important. Received 22 February 2000; accepted 20 July 2001.     

An industrial hygiene characterization of exposure to diesel emissions in an underground coal mine

Problems exist in the United States' effort to achieve energy self-sufficiency. Increasing coal production to assure energy self-sufficiency is a prime problem for the rest of the century and beyond. The use of diesels in underground coal mines has been suggested as a mining method to aid in this needed, increased production. Many questions exist about the effects on humans in such environments. NIOSH Division of Respiratory Disease Studies has undertaken a research effort to characterize the environments of existing diesel coal mines. The results of one of the studies will be presented. Preliminary assessments of carbon monoxide, nitrogen dioxide, C₁-C₅ aldehydes and organic acids, aliphatic hydrocarbons, sulfates, total and respirable dust, and polycyclic aromatic hydrocarbons (PAH) are presented. Nitrogen dioxide and total aldehydes are suggested as possible species to quantify diesel exposure.     

Safety lessons and reflections following incinerator vent commissioning in a chemical plant; a case study of a complex socio-technical system

In a bulk chemical plant producing resins, a flashback from an incinerator through the vent system into the reactor hall occurred during commissioning of a newly installed vent header system. The original design of the vent header system was seriously flawed not being in line with current practice. Subsequently the vent header was re-designed into a rich/lean vent header system. This paper explores the reasons behind a number of incidents and near misses that occurred during both the commissioning of a vent header system and its recommissioning following system re-design. Furthermore, it reflects on some broader implications for approaches to safety around what can be recognised as complex socio-technical systems.     

Determination of volatile organic compound emissions and ozone formation from spraying solvent-based pesticides

Large-scale agricultural activities have come under scrutiny for possible contributions to the emission of ozone precursors. The San Joaquin Valley (SJV) of California is an area with intense agricultural activity that exceeds the federal ozone standards for more than 30 to 40 d yr(-1) and the more stringent state standards for more than 100 d yr(-1). Pesticides are used widely in both agricultural and residential subregions of the SJV, but the largest use, by weight of "active ingredient," is in agriculture. The objective of the study was to determine the role of pesticide application on airborne volatile organic compounds (VOC) concentrations and ozone formation in the SJV. The ozone formation from the pesticide formulation sprayed on commercial orchards was studied using two transportable smog chambers at four application sites during the summers of 2007 and 2008. In addition to the direct measurements of ozone formation, airborne VOC concentrations were measured before and after pesticide spraying using canister and sorbent tube sampling techniques. Soil VOC concentrations were also measured to understand the distribution of VOCs between different environmental compartments. Numerous VOCs were detected in the air and soil samples throughout the experiment but higher molecular weight aromatic hydrocarbons were the primary compounds observed in elevated concentrations immediately after pesticide spraying. Measurements indicate that the ozone concentration formed by VOC downwind of the orchard may increase up to 15 ppb after pesticide application, with a return back to prespray levels after 1 to 2 d.     

Cadmium in moose kidney and liver – age and gender dependency, and standardisation for environmental monitoring

In the northern hemisphere moose has been found to be suitable as a monitoring animal for the presence of cadmium in the environment. The metal accumulates mainly in the kidney and the liver, with the rate of accumulation dependent on age and possibly also on gender. Collection of tissue material often results in sample selections with disparate age and gender composition, which makes comparison between different regions and different studies difficult. A previous large scale investigation of metals in kidney and liver from moose in Sweden provided Cd data (n = 3,817 and 3,802, respectively) to further explore the relation between Cd accumulation and age/gender. Based on local averages, the individual deviations were analysed with respect to the factors age and gender resulting in an 'ageing function' for each gender and organ. In addition, estimates of the pure individual variations were obtained; the standard deviations correspond to a factor 1.7-1.9 for the Cd concentration, which indicates that 25-30 samples are needed to give a representative mean value (with RSD approximately 10%). In order to be able to compare results from different studies, all individual results can be transformed to represent a 'standard moose' with respect to age and gender. A comparison along these lines was undertaken between Cd levels in Alaska and Sweden. Finally, a relationship between the Cd levels in kidney and liver was derived, providing at least rough estimates for kidney from liver values (or vice versa).     

Design and field application of an automated cartridge sampler for VOC concentration and flux measurements

One of the major limitations in advancing the understanding of tropospheric ozone and aerosol generation and developing strategies for their control is the technical ability to accurately measure volatile organic compounds (VOCs). This paper describes the design of a constant flow VOC sampler. The versatile sampler can be used for fully automated concentration and flux measurements of VOCs. The sampler incorporates a microprocessor control unit and provides highly accurate mass flow control and significant ease of operation. Sampling sequences can be programmed directly or by remote control through a PC. All important operational parameters necessary for a complete sampling audit trail are logged. Compact weatherproof housings and low power consumption allow operation at remote sites and locations which are sensitive to disturbances or have restricted access. Inner wetted surfaces of the sampler are constructed from non-contaminating materials that do not sorb or emit VOC, and thus permit the collection of representative samples even in environments with very low VOC concentrations. The cartridge magazine provides a maximum of 20 sequential cartridge samples, which allows for long-term air quality assessments. In the dual channel mode, two samples can be collected simultaneously through two independent sample loops, providing ten sequential sample pairs. This design allows the parallel collection of (a) quality assurance backup samples, (b) samples on two different types of cartridges/sorbents to allow a variety of analyses, or (c) differential samples for flux measurements using enclosure, aerodynamic profile, or relaxed eddy accumulation (REA) methods. Field applications including airplane profile measurements above a tropical rainforest area, as well as gradient and REA measurements over a mid-latitude mixed forest stand are described, and demonstrate the validity and flexibility of the system. In particular, the application of the VOC sampler as an integrated part of a REA system is emphasized.     

Increased metal concentrations in exhaled breath condensate of industrial welders

It was the aim of this study to evaluate the effect of different devices on the metal concentration in exhaled breath condensate (EBC) and to prove whether working conditions in different welding companies result in diverse composition of metallic elements. The influence of two collection devices (ECoScreen, ECoScreen2) on detection of metallic elements in EBC was evaluated in 24 control subjects. Properties of ECoScreen and a frequent use can alter EBC metal content due to contamination from metallic components. ECoScreen2 turned out to be favourable for metal assessment. Concentrations of iron, nickel and chromium in EBC sampled with ECoScreen2 were compared between non-exposed controls and industrial welders. Metal concentrations in EBC were higher in 36 welders recruited from three companies. Exposure to welding fumes could be demonstrated predominantly for increased iron concentrations. Concentrations of iron and nickel differed by working conditions, but chromium could not be detected in EBC.