Bimetallic catalyst system for the degradation of PCBs in sediments.

In this paper, we report the successful application of a patent-pending reduced bimetallic nanoparticle catalytic system developed for the remediation of polychlorinated biphenyl (PCB)-contaminated sediment and aquatic media. The formation of bimetallic nanoparticles associated with the granular activated carbon (GAC) were confirmed by high-resolution transmission electron microscopy. X-ray photoelectron spectroscopy showed the presence of the bimetallic matrix in reduced, albeit mixed, states.

Metal contamination in environmental media in residential areas around Romanian mining sites.

Hard-rock mining for metals, such as gold, silver, copper, zinc, iron and others, is recognized to have a significant impact on the environmental media, soil and water, in particular. Toxic contaminants released from mine waste to surface water and groundwater is the primary concern, but human exposure to soil contaminants either directly, via inhalation of airborne dust particles, or indirectly, via food chain (ingestion of animal products and/or vegetables grown in contaminated areas), is also, significant. In this research, we analyzed data collected in 2007, as part of a larger environmental study performed in the Rosia Montana area in Transylvania, to provide the Romanian governmental authorities with data on the levels of metal contamination in environmental media from this historical mining area.

Issues in the development of epidemiologic studies of workers exposed to engineered nanoparticles.

Objective: Capitalizing on phenomena at the nanoscale may present great benefits to society. Nevertheless, until the hazards and risks of engineered nanoparticles are determined, the technological products and advances of nanotechnology may be impeded by the societal concerns. Although animal data provide the necessary first step in hazard and risk assessment, ultimately epidemiological studies will be required, especially studies of workers exposed to engineered nanoparticles.

Presence of tungsten-containing fibers in tungsten refining and manufacturing processes.

In tungsten refining and manufacturing processes, a series of tungsten oxides are typically formed as intermediates in the production of tungsten powder. The present study was conducted to characterize airborne tungsten-containing fiber dimensions, elemental composition and concentrations in the US tungsten refining and manufacturing industry. During the course of normal employee work activities, seven personal breathing zone and 62 area air samples were collected and analyzed using National Institute for Occupational Safety and Health (NIOSH) fiber sampling and counting methods to determine dimensions, composition and airborne concentrations of fibers.

Presence of airborne fibers in tungsten refining and manufacturing processes: preliminary characterization.

In tungsten refining and manufacturing processes, a series of tungsten oxides (WO(X)) are typically formed as intermediates in the production of tungsten powder. Studies in the Swedish tungsten refining and manufacturing industry have shown that intermediate tungsten refining processes can create WO(X) fibers. The purpose of the present study was to identify and provide a preliminary characterization of airborne tungsten-containing fiber dimensions, elemental composition, and concentrations in the U.

Evaluation of a proposed area equation for improved exothermic process control.

Our understanding of heat transfer and meteorological theories and their applications for engineering control design have been refined since the collective work in ventilation engineering for manufacturing process was published by Hemeon in 1955. These refined theories were reviewed and used to develop a newly proposed equation to estimate buoyant plume area (A). The area is a key parameter in estimating the plume volumetric flow (Q=UA) required for exothermic process control.

Evaluation of a proposed velocity equation for improved exothermic process control.

Exothermic or heated processes create potentially unsafe work environments for an estimated 5-10 million American workers each year. Excessive heat and process contaminants have the potential to cause adverse health effects in exposed workers. Owing to the potential hazards, engineering controls are recommended for these processes.

Ventilation equations for improved exothermic process control.

Exothermic or heated processes create potentially unsafe work environments for an estimated 5-10 million American workers each year. Excessive heat and process contaminants have the potential to cause acute health effects such as heat stroke, and chronic effects such as manganism in welders. Although millions of workers are exposed to exothermic processes, insufficient attention has been given to continuously improving engineering technologies for these processes to provide effective and efficient control.