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----- Original Message ----- From: Inhalation Toxicology Newsletter In July and August, a single number will issue at the end of July. Notices and requests should reach the Editor before July 15. Articles/Issues of Current Interest in Inhalation Toxicology Tremolite "Asbestos" in Crayons Recent reports of Tremolite in children's crayons were big news over the Memorial Day weekend and thereafter. The source of this "contaminant" was said to be New York state talc that is used to fortify or otherwise strengthen the crayon as it is manufactured. The Editor (who is also an AHERA Asbestos Inspector for a local school) reports on an experiment he performed with a sample of commercially obtained "children's" crayons. One of the name brand of crayons identified in the news reports was purchased in Waitsfield, Vermont. Twelve were randomly chosen from a larger box, stripped of their paper wrappers, broken into bits (large and small) and agitated by oscillation for a total of 16 hours (4 four hour intervals with low frequency sound, 60 cps using a sound driven "dust" generator developed by Yves Alarie and his colleagues at the University of Pittsburgh). When operated, the generator chamber had an input air flow of 10 liters per minute. The outflow was directed to a closed glass tank with a polycarbonate cover (approx. 50 liter in volume and made from glass and plastic). This so called aquarium was used as a mixing chamber. All of its joints and edges were taped or otherwise sealed; the system was run at positive pressure. The closed "mixing" chamber was then sampled sequentially using a BGI respirable dust cyclone at 2.1 liters per minute (drawn by vacuum, controlled by a critical flow orifice, nominal flow rate of 2 liters per minute). The Millipore filters were of a type used for Asbestos sampling (37 mm, 0.8 micron); they were subsequently analyzed by TEM (Chatfield AHERA method). The final result from the laboratory reported that no Tremolite asbestos structures were detected in the filters examined. While others are invited to repeat this test, the Editor concludes from this one experiment that crayons ( at least this sample of this brand) does not pose a health risk. The tested crayons did not release respirable airborne Tremolite fibers. That is, under the conditions tested, there is no Tremolite exposure hazard from this product. However, we weren't surprised at the announcement that crayons would no longer be made with the suspected talc ingredient. Our readers and colleagues may wish to examine other consumer products outside this limited range to see if this kind of a hazard exists elsewhere. Note added in Proof: Professor Arthur Langer of the Brooklyn Polytechnic Institute reports to the editor (personal communication) that this same experiment was conducted by him at Mount Sinai School of Medicine, New York, some twenty-five years ago with similar negative findings. Sheldon Murphy would have termed this "Re-Search". Aerosols and Size Changes with Drying Doug Cooper outlines the process of aerosol drying and its impact on particle size. He reports that aerosols for inhalation studies can be generated from gas - phase reactions, fragmentation of dust cakes or dispersal of powders, and atomization of liquids, our focus here. Except in an atmosphere that is super - saturated with its vapor, a droplet starts to evaporate as soon as it is formed. The process is not simple. As it evaporates, the droplet cools, losing heat energy to supply the latent heat of vaporization. Cooling slows evaporation, by lowering the vapor pressure, and evaporation may increase the concentration of solutes, also lowering the vapor pressure and slowing evaporation. For more, see the complete article at http://www.inhalation.net/drying.htm Dr. Susan Shami reviews a recent aerosol generation report. Dry submicron particles are important in the chemistry of atmospheric aerosols and climate conditions. Although there are data on the role of liquid particles in the atmosphere, the same is not true for dry particles such as soot, mineral aerosols and salts. The complete report and reference is at: http://www.inhalation.net/fluidized_bed_generator.htm Dr. Shami is in the process of building a useful glossary of terms. http://www.inhalation.net/glossary.htm Some of these appeared in a bulletin from a toxicology lab while others are from textbooks in the field. Two of these are 1- Aerosol Measurement: Principles, Techniques and Applications. Edited by Klaus Willeke and Paul A. Baron. Van Nostrand Reinhold, New York, 1993. 2- Fundamentals of Aerosol Sampling. Gregory D. Wight. Lewis Publishers, CRC Press, 1994. While more texts will be added to the listing, these both are useful books for the well equipped inhalation toxicology library. Prior newsletters and reports Earlier issues and discussion topics have been compiled. The newsletters may be found at http://www.inhalation.net/newsletters.htm Professional Employment Opportunity Mike Brooker of Battelle has asked that the following be posted. For Further information, please contact Mr. Michael Brooker at Brookerm@battelle.org Position Available Manager: Pulmonary Drug Exposure Group, Battelle Memorial Institute Reference Number: 100750 Location: Columbus, OH Minimum Monthly Salary: $3,580.00 Maximum Monthly Salary: $8,640.00 Salary will be based upon the experience level of the individual chosen for the position. Critical Job Functions: Manage the daily operations of a group of 10 to 15 technical staff conducting inhalation toxicology and drug delivery studies for regulatory submission. Interact with clients in a technical role. Work with Study Management for Inhalation Toxicology studies. Read, write and review protocols, data summaries, and reports. Manage budgetary issues on projects. Required Qualifications: minimum B.S. in Biology, or related field, and minimum of ten years experience conducting inhalation toxicology studies or pulmonary drug delivery. Desired Qualifications: Study Director experience in pharmaceutical industry or contract laboratory. Experience managing day-to-day laboratory activities. Additional positions available, at all levels for individuals with pulmonary drug delivery and/or inhalation toxicology experience. INHALATION TOXICOLOGY FORUM One offer of surplus chambers was received. It was not adequate to fill the expressed need. If there are surplus chambers available, let us know. The Bill Mautz of the University of Hawaii reported receipt of the inhalation chamber which was donated by Genentech through the efforts of Dr. Terry Sweeney. A word from our sponsor, CH Technologies Pictures of the most recent Vilnius Generator can be found at the following location: http://www.inhalation.net/vag1.htm Calendar of Upcoming Events: Special note is made of the upcoming Gordon Research Conference in Toxicology. See the calendar for details (below). The calender of current and future events appears at: http://www.inhalation.net/calendar.htm Address for Comments and Letters to the Editor The Editorial staff welcomes your questions and comments. Dr. and Mrs. Jaeger will be on vacation from June 14 through July 4, 2000. You may send email and any news articles to the Editor at sshami@bellatlantic.net Changes or to be removed from the list To make changes or to have your name deleted from our subscriber list, see the section entitled, Additions, Changes and Removals, found at the end of this message. If you find this forum useful, send your web address or email a copy of the newsletter to a colleague. Sponsors http://www.toxics.com http://www.envmed.com Additions, Changes and Removals If a colleague wishes to be added to the
mailing list, send email to "Susan Jaeger" Our list has recently seen a large number of additions and we hope persons previously removed were not "added back". If so, please accept of apologies for the inadvertence. EDITORIAL STAFF Rudolph J. Jaeger, Ph.D., DABT + 201 666 2335 VOICE Publisher/Editor-in-Chief + 201 666 8119 FAX jaegerr@bellatlantic.net + 800 HOT OXIDE Douglas W. Cooper, Ph.D., Editor, Aerosol Science dwcooper_99@yahoo.com Susan G. Shami, ScD, Editor, Respiratory Biology and Inhalation Toxicology sshami@bellatlantic.net Arlene L. Weiss, MS, DABT Editor, Air Pollution, Toxicology and Epidemiology iamalw@bellatlantic.net |