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rachels HAZARDOUS WASTE NEWS #120 Fro* Rachel: Weekly news and resources for citizens fighting toxics -- March 14, 1989 NIOSH ISSUES CANCER ALERT FOR DIESEL EXHAUST FUMES One reason w hy people often oppose a new facility is increased tru c k traffic. T r u c k s are big and no isy and subject to accidents, and when accidents occur i n v o l v in g t r u c k s , t h e r e 's a h ig h likelihood of fatalities. However, the federal governm ent has recently concluded bfficially that there is another good reason to be concerned about in c r e a s e d t r u c k t r a f f ic in y o u r neighborhood : five separate studies in the last 3 years have shown that diesel exhaust c e rta in ly causes can ce r in laboratory animals, and two studies of railroad w orkers show that it causes cancer in hum ans as well. A s a result of this determination, the National Institute for Occupational Safety and Health (N IO SH ) has issued a special p u b lic a tio n , C a rc in o g e n ic E ffe cts of E x p o su re to Diesel E x h a u s t , offe ring this recommendation: "A s prudent public health policy, employers should assess the con dition s u n d e r w hich w o rk e rs may be exposed to diesel exhaust and reduce e xp osu re s to the lowest feasible lim its." C itizens may reasonably ask: if N IO S H believes w orke rs should not be exposed to diesel exhaust because of the cancer hazard, can health Officials in other parts of government believe that the general public should continue to be exposed to diesel e xh au st? Taken in this light, risk assessm ents that- d is c u s s only the traffic hazards associated with a facility are m issing the major point: diesel tru ck s can evide ntly kill innocent people even if no traffic accidents occur. Diesel engines are more efficient than gasoline engines; they produce more horsepower per gallon of fuel, and they use a less-refined (thus cheaper and more plentiful) fuel. When diesel fuel b u r n s in an e n g in e 's com bustion cham ber, the resulting exhaust contains gases and particles (soot). The gases include nitric oxide, nitrogen dioxide, oxides of sulfur, and hydrocarbons (e.g., ethylene, for maldehyde, methane, benzene, phenol, 1,3- butadiene, acrolein, and polynuclear aromatic h y d rocarb on s [P A H sj, several of which are known carcinogens). Of the particles in diesel e xh aust, 95% are less than 1 micron in diameter and th us they are respirable, which is to sa y they are easily taken into the deepest portions of the human lung where they may lodge forever. T h e core of each particle is made up of pure carbon, but as many as 18,000 different chemicals from the gaseous portion of the exhaust may be adsorbed (attached) onto the carbon core, and thus diesel exhaust can c a rry a whole host of exotic, toxic and carcinogenic chemicals into the deepest portions of y o u r lu n g -down in the region w here the tra n sfe r of gas occurs to put o x yg e n into y o u r blood stream and to take carbon dioxide out. A s recently as 1986, N IO SH concluded that diesel e x h a u s t did not cause cancer in laboratory anim als. However, in the period 1986-1988, five long-term animal studies, and two epidemiologic studies of humans, all co n clu d e d th at e x p o su re to diesel exhaust causes lung cancer. A s a result, N IO S H re v e rse d itself and in A u g u s t , 1988, issued a special "cu rre n t intelligence bulletin" to get the w ord out that diesel fumes are d a n g e ro u s. N IO SH estimates that 1.35 million American w orkers are routinely exposed to diesel exhausts. Get: Carcinogenic Effects of Exposure to Diesel E x h a u st [C u rre n t Intelligence Bulletin 50; D H H S ( N IO S H ) Publication No. 8 8 -1 1 6 ]. C in c in n a ti, OH: D iv isio n of Standards Development and Technology Transfer, NIO SH, Robert A. Taft Labora tories [4676 Columbia Parkway, Cincinnati, OH 45226], A u g u s t , 1988; phone (513) 5338287. It's 30 pages and free. DANGERS OF DIOXIN EXPOSURES: ABSORPTION THROUGH THE SKIN Traditionally, people concerned about the toxicity of chemicals have mainly worried about the mouth and lungs as a means of entry into the human body. Now new evidence suggests that absorption th ro u g h the sk in may be an important way o o o o ^ f; for some chemicals to enter the body. In addition, the sk in of babies may allow more toxics to pass through it than the skin of older humans. Researchers at the National Institute of Environmental Health Sciences studied the absorption of d ioxin s and fu ra n s in mice and rats. They discovered several new aspects of chemical absorption b y the s k in : (1) the skin presents a more effective b arrie r against some chemicals than against others; (2). mice absorb a greater percent of dioxin when lower doses are administered than when higher doses are administered; (3) young adult rats absorbed a greater percentage of the administered dose than did middle-aged rats. In the past, the theory has been that the skin (which has a total area of 1.8 square meters in the adult human) has served as a passive b arrie r to chemicals. Now it is apparent that the skin is v e ry active in metabolizing (biologically altering) chemicals and that these metabolic proces ses affect the way the body absorbs (or does not absorb) a particular chemical. 'Sw eat glands, sebaceous glands (which produce o ils), and hair follicles can all co n trib u te to the way chemicals are absorbed through the skin. Chemicals adm inistered at low doses are more effectively absorbed through the skin than are chemicals administered at high doses. Mice receiving 0.3 micrograms of dioxin per kilogram of body weight absorbed 40% of the dose; mice receiving 32 to 320 micrograms of dioxin per kilogram of body w eight absorbed less than 20% of the dose. T h is may be important for human exposures, which u sually occur at low doses over long periods rather than in high doses over short periods. Three month old rats (you ng adults) absorbed 16% of dioxin applied to their skin; nine-month-old rats (middle-aged) absorbed less than 5% of a sim ilar dose. Linda Birnbaum, who directed the research, says that her work shows that acute toxicity from skin exposure to dioxins and furans is "u n lik e ly ." Chronic (long term) toxicity is a different matter: T h a t's where "y o u 're going to have the potential to build up a body burden" of the toxic chemicals, she says. Her w ork with young rats also concerns her because there is evidence that the skin of human babies is much more permeable than skin of adults. The importance gf this work for gra ss roots activists seems to be this: if someone is g o in g to expose y o u r community to small amounts of dioxins and furans for a long time, ask them to please consider a b so rp tion through the skin , and especially so in the case of babies and children. A n y risk assessm ents that have been done without considering skin absorption should be redone in light of the new find ings. Get: David Brew ster and others, "Com parative Dermal Absorption o f2,3 ,7 ,8 Tetrachlorodibenzo-p-dioxin and Three Polychlorinated Dibenzofurans." Toxicol o g y and Applied Pharm acology, Vol. 97 (January, 1989), pgs. 156-166. Reprints are free from: Lin d aS. Birnbaum, Systemic Toxicology Branch, National Institute of Environmental Health Sciences, Research Triangle, North C arolina27709; phone (919) 541-3212. A sk Ms. Birnbaum for a copy of her unpublished paper on absorption of dioxins by young rats, which she presented at a meeting of the Society of Toxicology in Atlanta, G A, the week of Feb. 27, 1989. Rachel's Hazardous Haste Hews Is published weekly by Environmental Research Foundation P.0. Box 3541 Princeton NJ 08543. The Foundation is non-profit\ contributions are tax-deductible. Editori Peter Monta gue Ph.D.) Associate Editori Maria B. Pelleranoj Assistant Editori Annette Eubank! Host Coast Editori Tin Montague. The Hews is mailed first class every Tuesday. Subscriptioni $18 per year for individuals and non-profits, $6 for students and senior citizens, $150 for businesses. In Canada, add $4.00) in Europe, add $11.00. SUBSCRIPTION ORDER FORM Name i Address t Environmental Research Foundation P.0. 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