Polynuclear aromatic hydrocarbons in diesel emission particulates

A preliminary characterization of polynuclear aromatic hydrocarbons (PAH) in dichloromethane extracts of diesel exhaust particulates is described. Acid-base liquid-liquid partitioning followed by adsorption chromatography was used to isolate the PAH fraction. Compounds were identified primarily by the mass spectra of high-resolution gas chromatographic effluents. Three four-ring PAHs and their alkyl-substituted homologues were the predominant constituents. In addition, ultraviolet spectra of four high performance liquid chromatography-separated PAHs were superimposable with those of reference compounds leading to their unambiguous identification. These results show the advantage of using several complementary techniques for characterization rather than gas chromatrographapy-mass spectrometry alone.     

Duplex auditory distance assessment in a small passerine bird (Pipilo erythrophthalmus)

Eastern towhees, Pipilo erythrophthalmus, (Emberizidae, Passeriformes) in Florida estimate source sound-pressure level (SPL; i.e., sound amplitude) and often misjudge speaker distance in the field when vocalization source SPL is varied experimentally. Sound frequencies below ~3.5 kHz attenuate reliably with distance in comparison with higher sound frequencies in Florida scrub habitat. As a result, I predicted that towhees should use SPL as an auditory distance cue when they hear stimuli produced with sound frequencies below ~3.5 kHz but use another cue when they hear stimuli produced with sound frequencies above ~3.5 kHz. Subjects often misjudged speaker distance when approaching playbacks of SPL-altered stimuli produced with sound frequencies below ~3.5 kHz but rarely misjudged speaker distance when played SPL-altered stimuli produced with sound frequencies above ~3.5 kHz. I discuss the possibility that towhees employ a duplex sound localization strategy.     

Monitoring parameters and statistics: A land treatment unit monitoring case study

Statistical evaluation procedures for monitoring data at facilities permitted under the Resource Conservation and Recovery Act (RCRA) are frequently established before monitoring begins. Selecting the statistical method before background data have been collected often leads to the use of statistical procedures that are inappropriate for the actual monitoring data. Such was the case for unsaturated zone monitoring at a permitted land treatment unit in the Gulf Coast area of Texas. Due to the large number of “not detected” results in the background database for lysimeters, statistical evaluation procedures specified in the original RCRA permit yielded an artificially low standard deviation, resulting in background values that were strongly biased on the low side. An alternate statistical procedure based on probability plots was developed and was accepted by the state environmental regulatory agency. This technique, which has wide applicability for many types of environmental monitoring data, significantly reduced the chasing of false positives, thus saving potentially expensive investigations and remediations.     

Ventilation requirements in occupied spaces during smoking and nonsmoking occupancy

Ventilation requirements in occupied spaces have traditionally derived largely from odor control. The requirements have rested on the notion that an environment that seems subjectively acceptable to a visitor will in fact be healthful and comfortable for both visitor and occupant alike. Ventilation requirements have derived secondarily from criterion concentrations of notable contaminants (e.g., carbon dioxide). The present investigation looked again at both sensory (odor, irritation) and physical criteria of acceptability, paying particular attention to the difference between smoking and nonsmoking occupancy in a well-controlled environmental chamber. More than 200 persons (visitors) made judgments of odor intensity and acceptability under various conditions of occupancy (up to 12 nonsmoking occupants; a temperature of up to 25.5°C; up to 16 cigarettes smoked per hour). The results implied that under nonsmoking conditions and moderate humidity only about 7.5 cfm (3.8 L sec⁻¹) of fresh air per occupant sufficed to satisfy visitors, but that under smoking conditions at least 5 times as much fresh air is necessary. Our estimate of ventilation requirements for smoking were derived in part from measurements of carbon monoxide and total suspended particulate (TSP) mass concentration. Levels of TSP achieved during realistic smoking and ventilation rates exceeded levels deemed acceptable outdoors. Surfaces in the chamber played an important role in the elimination of particles, presumably via adsorption. Use of an electrostatic precipitator could keep TSP levels under control. Nevertheless, it remains to be seen whether control of TSP will eliminate the need for enormous ventilation for odor control during smoking occupancy.     

New regulatory structure being considered for devices containing radioactivity

The U. S. Nuclear Regulatory Commission has established a Working Group to evaluate methods for improving control of devices containing radioactivity in industry. These devices include radiography equipment and moisture/density gauges. The Working Group was the result of a number of incidents in which these devices were inadvertently shipped to scrap dealers and steel recycling facilities. The resulting release of radioactivity when the devices were processed has cost millions of dollars to clean up. This article discusses the Working Group's conclusions and the potential impact of these conclusions on the remediation industry. It also makes recommendations for both current and prospective owners of devices containing radioactivity on how to prepare for regulatory changes likely to occur as a result of the Working Group's conclusions.     

Towards a re-evaluation of the role of finance in the causation of environmental degradation

This paper relates the long-neglected Douglas/New Age texts to contemporary concerns at the relationship between economic activity and environmental degradation. Although completed by the early 1920s, these texts anticipated the adverse social and environmental impacts of an increase of centralisation and globalisation of finance upon local policy formation.