u
LETTERS Protection for chemical workers Dear Sir: I found your article, “Protection for chemical workers” (ES&tT, June 1981, p. 616), to be an excellent capsule summary of many of the current concerns facing the occupational health scientist and management. However, I would like to correct an apparent typographical error. Both threshold limit values (TLVs) and permissible exposure limits (PELS) are normally expressed in mg/m3, and not pg/m3 (unlike EPA’s typical unit designations). Therefore, the correct P E L and TLV for nuisance particulates are 15 and 10 mg/m3, respectively. S. Z. Mansdorf Program Manager, Industrial Hygiene Midwest Research Institute 425 Volker Boulevard Kansas City, Mo. 641 10
detection tests for formetdahy&,, along with hundreds of other mentially-toxic materials The instrument continuously samples and rneaSures vapor concentrations and can aetect formaldehyde at the 0 1 ppm level Get laboratory accdacy -and ndustr 91 ruggeaness -in a portable qas analyzer Contact us today
CIRCLE 2 ON READER SERVICE CARD
852
Environmental Science & Technology
Hazardous waste landfills Dear Sir: Landfilling as a disposal of hazardous waste materials must be closely monitored if contamination of groundwater is to be prevented, as was described in the March 1981 issue of ES& T , p. 250. Besides organic, inorganic, and Escherichia coli contaminants, tests should also be conducted for the presence of other microbial contaminants, such as viruses in all groundwater used for human consumption. Viruses, as reported in the November 1980 ES& T , p. 1290, have been responsible for waterborne transmission of many infectious diseases. Viruses causing hepatitis, polio, and gastroenteritis have been isolated from beneath land treatment sites as well as from drinking water wells. Tests for viral contamination should be conducted more often than quarterly since a sudden burst of viruses in groundwater previously negative or pure can occur after periods of heavy rain. Usually samples are tested only after an outbreak of severe illness and contamination is no longer present. Viral contamination may often go undetected since, as compared with other contaminants, they can move greater distances, penetrate deeper into the ground, and only a few viruses that are highly virulent are required for producing a major health hazard. Soil factors such as texture, pH, organics, and even temperature may
provide a key in determining the survival and migration rate of biological contaminants such as viruses. Proper monitoring and testing for all contaminants, including viruses, will help in preventing hazardous waste landfills and will ensure groundwater as another good, clean source of drinking water as our supplies decrease in the years ahead. Dan Monroe University of Tennessee Center for the Health Sciences Research Associate Infectious Diseases Memphis, Tenn. 38138
OSHA rules for laboratories Dear Sir: The statements made in the box, “OSHA rules for laboratories?” (“Protection for chemical workers,” E S & T , June 1981, p. 616), are misleading. Laboratories are already subject to general industry standards, including No. 1910-1000-the standard setting permissible exposure limits for almost 400 air contaminants, including many substances that are common laboratory chemicals. Laboratories have been cited under this and other OSHA health standards, and presumably will continue to be, unless and until some special provisions for laboratories are promulgated. Recognizing the existence of arguments that the general industry standards are not appropriate for laboratories, we began, last fall, to consider whether a separate standard should be developed for laboratories. We are continuing this initiative under the current assistant secretary, who has endorsed our approach and wants us to move ahead quickly with it. Contrary to the conclusion stated in your article, rule making is not “on hold.” I expect that we will develop and propose a standard or guidelines as a substitute for the general industry standards in laboratories within the next few months. Dr. Lucile Adamson Special Assistant to the Director Health Standards Programs U S . Department of Labor Occupational Safety and Health Administration Washington, D.C. 20210
