Document V3Qkj7g1gRmxzbpdw5ZZj8yoK

FILE NAME: Asbestos Cement Pipe and Sheet (ACPS) DATE: 1982 DOC#: ACPS104 DOCUMENT DESCRIPTION: Summary of Scientific and Medical Research Asbestos-Cement Pipe and Health - A/C Pipe Producers Assoc. ... NEWSfrom A /C Pipe ProducersAssociation 1600 Wilson Boulevard P Arlington, V irginia 22209 Teleohone 841-1556 Area Coda 703 SUMMARY OF SCIENTIFIC AND MEDICAL RESEARCH ON ASBESTOS-CEMENT PIPE AND HEALTH '5 6 1 3 Some persons who have inhaled heavy concentrations of asbestos fibers in industrial s e ttin g have shown increases in gastrointestinal cancer. Since there is evidence that the inhalation of asbestos under certain conditions can be harmful, some have theorized that the ingestion of asbestos in drinking water may also be harmful. Considerable amounts of asbestos-cement (A/C) water pipe are used in North America, Europe and other parts of the world. Thus, questions have been raised about the possible health hazards associated with drinking water conveyed through A/C pipe. In order to determine whether the swallowing or ingestion of asbestos in drinking water represents a health hazard, two types of studies have been conducted; (1) Statistical or epidemiological* studies, In which the medical experience of one group, exposed to a high level of Ingested asbestos, is compared to the experience of another group, exposed to a lower level or no ingested asbestos; and (2) animal studies, in which conclusions are derived from the ingestion, by animals, of asbestos under scientifically controlled conditions. One of the first major studies was conducted by a panel of government and independent authorities in pathology, epidemiology, analytical methods and public health. Commissioned in 1974 by the American Water Works Association Research Foundation, the committee concluded: "No firm evidence shows th a t the proper use o f asbestos-cem ent pipe posts a hazard to health by reason of ingestion o f asbestos fibers. Calculations 1 comparing the probable ingestion exposure in occupational groups to th a t likely u> occur as a result of ingestion of potable water from asbestos- cement pipe system s suggests th at the probability of risk to health from the use o f such sy stem is small - approaching zero." EPIDEMIOLOGIC STUDIES Thomas J. Mason, et al in 1974 conducted a study entitled "Asbestos-Like Fibers in Duluth Water Supply," The study undertook to determine whether fibers present in the drinking water in Duluth, Minnesota produced increased cancer mortality. The study concluded; Thus, in Duluth, one would expect a greater excess of cancer In the esophagus and stomach than in the rectum, but this did not occur. In 1976, D. S. Levy of the Minnesota Department of Health continued the investigation made by Mason. Levy was the Acting State Epidemiologist for Minnesota and his co-authors were associated with the University of Minnesota School of Public Health and the Mayo Clinic. * Epidemiology; the study of the distribution and dvnamics of disease in human populations. ! --^ Gastrointestinal cancer incidence data for the cities of Duluth, Minneapolis and St. Paul were ' la th e re d and compared in the same manner as in the Mason study. (Minneapolis and St. Paul have populations similar to Duluth, but they have few, if any, asbestos fibers in their water supplies). After a thorough Investigation, the authors concluded: there was no consistent pattern of statistically significant differences, observed" among the three cities. The Levy study was updated in 1981 by Eunice Sigurdson, R. N., Department of Health. She reaffirmed previous findings, stating; of the Minnesota - there is currently no observed tiologie or causal association between exposure to amphibole fibers in the Duluth drinking water supply and th e 6 development of cancer. Thomas R, Fears of the National Cancer Institute published an article in the American Journal of Epidemiology entitled "Cancer Mortality and Asbestos Deposits." The specific question posed in th at study was; "Is them an increase In risk from cancer associated with naturally-occurring bestos?" V The abstract of the study states: The study of cancer mortality rates in these matched counties provides no 1 evidence that naturally-occurring asbestos is a great hazard to the general population of counties with asbestos deposits. Donald T. Wigle, M.D., Ph.D. and Bureau of Epidemiology; Health and Welfare, Canada, conducted an extensive study in 1977 of municipalities in the Province of Quebec. Entitled "Cancer Mortality in Relation to Municipal Water Supplies," these comparison studies presented an unusual scientific opportunity to analyze cancer mortality in populations exposed to as much as 1.3 billion fibers per liter of drinking water. Despite the extremely high levels of asbestos in drinking water, this study concludes: as A study of twenty-two municipalities in Quebec did not reveal excess cancer mortality that could be related to the presence of asbestos fibers in drinking water supplies. ' -, " ,, vf v j i \ >- \ *Y-V ' * '**'' * '* * % Y - , * -3. i Y* V` ' > ' y, <% . The Wlgle study was also updated in 1981 with similar conclusions: The mortality rates for persons living in two localities in which asbestos was ji pwreerseenatnaInlyhziegdh. cAonltcheonutgrhattihonesreinawreasteerriosaums plilmesitfartoiomnsthteo dtihsitsritbyuptieoonfssytsutdeym I no consistent increase of mortality rates for any cancer was dem onstrated. ! The Cotnmins report, published in 1979 under the aegis of the internationally prestigious Water Research Centre, entitled "Asbestos in Drinking Water: A Review," summarized the Wigle study in this fashion: | -i It is reassuring th at ,, recently reported, detailed, epidemiological study i carried out in 22 municipalities in Quebec failed to reveal excess cancer m ortality that could be related to the presence of asbestos fibers in drinking w ater supplies. This was despite the fact that some o f the w ater supplies ;! fed to these m unicipalities were reported to be fairly heavily contam inated with asbestos fibers. 1 The first of two studies made in Connecticut concerning the use of asbestos-cement water pipes and the incidence of cancer was entitled "An Investigation of the Use of Asbestos-Cement Pipe for Public Water Supply and the Incidence of Gastrointestinal Cancer in Connecticut." Referred to as the Harrington study, it was published in the American Journal of Epidemiology in 1978 and was co j authored by officials of the U.S. Center for Disease Control, U.S. Environmental Protection Agency (EPA), Tale University School of Medicine and Connecticut State Health Department. 1 As the Harrington study stated: The possibility o f studying reliable cancer incidence data over a 35-year period through the Connecticut Tumor Registry and linking these data w ith information gathered on asbestos cem ent pipe studies conducted by U-3. Environmental Protection Agency, prompted the present investigation. The findings of the Harrington study are consistent with a determination th at the use of asbestos cement pipe does not create a health hazard: This study detected no changes in incidence rates or patterns in C onnecticut for cancers of th e stom ach, colon, or rectum over the period 1935-1973, th a t could be construed as related to the introduction around 1950 o f A/C pipes to carry dom estic water supplies to som e or most of the residents of certain towns. The Meigs study, entitled "Asbestos Cement Pipe and Cancer in Connecticut 1955-1974," was 75GB f ^^ublished In the January/February, 1980, edition of The Journal of Environmental Health, The principal Investigator, J . Wister Meigs. M.S., Is Director o f the Connecticut Cancer Epidemiology Unit and Clinical Professor of Epidemiology, Yale University School of Medicine, the Meigs study used essentially the same methods as those used in the Harrington study, but the procedures and techniques were more sensitive and refined. The study was supported in part by the National Cancer Institute and the U.S. Environmental Protection Agency. Following are the conclusions of the Meigs study: These analyses give no consistent Indication that use o f A /c pipe in Connecticut public w ater supplies has been followed by increases in incidence either o f *&1I cancers" of the Individual sites considered. therefore, the lack of coherent evidence of cancer risks from use o f A/C pipe fa reassuring. (Emptiaais In article.) ft is consistent with most reports from other areas of the United States. Hence, the Harrington study and the Meigs study represent independent, thorough and competent epidemiological studies carried out for the sole purpose of determining the question at Issue; whether the use of asbestos-cement pipe creates a hazard to public health. Both studies Reached the conclusions: (1) that there was no association between the use of asbestos-cement pipe in Connecticut and incidence of cancer; and (2) in the opinion of the authors of the Meigs study, there was no need to change water distribution policies in this State because of the use of such pipe. The Kanarek study was conducted in five California counties in the San Francisco Bay Area by Dr. Robert C. Cooper (principal investigator), doctoral candidate Marty Kanarek (project coordinator) and others. The study found a weak statistical correlation between the ingestion o f asbestos in drinking water and certain cancers. The Kanarek study was an indirect study in which census tracts with differing amounts of asbestos fibers in their drinking water were compared for cancer incidence, after attempting to take into account certain variables- By its own admission, th e study is of limited value in its relevance to asbestos-cement pipe: Samples we*1 taken before and after passage of water through lengths of asbestos-cement pipe, ft most of the districts sampled, there was not a substantial increase In fiber counts afte r passage through asbestos-cement pipe. The amount of asbestos-cement pipe to the various distribution systems was not included as a variable in the analysis because of difficulty of determining its location, age and dimensions. The study design was that of an indirect epidemiological approeh in which the observational unit was the census tract. Studies such m this one can only suggest associations, and cannot pinpoint definite causation, (Quotation from doctoral thesis), The Ca'.fornia Department of Health Services has taken the following view of the Kanarek 75 GO iXK&&&fijiL:<%1MA-.,. w am m studyt v{v The UC (University of Call fornia) ` doctoral thesis abstract entitled "Asbestos in Drinking Water and Cancer Incidence," contains no new or original evidence of a medical nature about cancer or asbestos, nor does it establish any causal link between asbestos in Bay Area drinking w ater and the incidence of cancer. The U.S. Environmental Protection Agency (EPA) has stated of the Kanarek study The University of California investigators are among the first to report finding an association, between ingested asbestos and cancer rates. They caution that causative inferences must necessarily be lim ited because of the indirect nature of the data being compared, This means that the results of this atudv do not prove th at there is a link between Bay Area w ater and cancer, (Reference 13) Kenny S. Crump, Ph.D., a highly respected, Independent specialist in environmental risk assessment, has made the following observations about the Kanarek study; It is generally accepted among epidemiologists that ecologie studies such as this should not be used to determine cause and effect relationships -- irrespective of their findings, aa a Kanarek et al were unable to control many factors which might have been confounded with asbestos levels. These factors Include smoking, eating and other personal habits; occupational exposures to carcinogens; and exposures to other environmental pollutants, such as organic contaminants in drinking w ater. ** There were apparent discrepancies between two reported analyses of the six year data which this reviewer could not reconcile. * a There was a lack of consistency with respect to many of the associations found by Kanarek et al. A number of the associations were found in one sex only. This lade of consistency (with five similar studies conducted elsewhere) suggests that the positive associations found by Kanarek et al. are the result of confounding. As If these Independent opinions were not sufficient to Invalidate the Kanarek study, a biostatistician a t the University of California-Berkeley School of Public Health) Dr. Michael T arter, reanalyzed the Kanarek data. He found in San Francisco a negative correlation between asbestos in drinking water and cancer, that Is, in census tracts where asbestos levels were high, cancer incidence rates were lower than in census tracts not exposed to asbestos in drinking water. At the U.S. Environmental Protection Agency Summary Workshop on Ingested Asbestos (October 13-14, 1982), Dr, T arter cautioned, "Until this finding is fully understood, one must be very careful about drawing any conclusions from the Kanarek study." EPA recently reported findings of an epidemiologic study in Escambia County. Florida. Asbestos levels ranged from 700,000 to 32.7 million fibers per liter for a period of approximately twenty-five years. EPA scientists concluded; There were no statistically significant differences in cancer mortality between high exposure, modrate exposure and no exposure groups. In August, 1982, Dr. Lincoln Pollssar of the Fred Hutchinson Cancer Research Center published an important study in the American Journal of Epidemiology. This research also was funded by the JJ.S, Environmental Protection Agency. Naturally occurring asbestos levels in this study were from 37 ^million to 556 million fibers per liter of drinking water. The population has been exposed to such levels for over fifty years. The authors concluded; Results o f this study and prior studies o f cancer In relation to waterborne asbestos are inconsistent and provide little evidence that asbestos in community water supplies has altered the ride o f any cancer. A more accurate case control study also was conducted on this same population group. Such studies seek to determine whether persons with a given disease are more apt to have been exposed to the agent under investigation (asbestos) than disease free individuals, The principal investigator, Dr, Polissar. reported at the aforementioned EPA Summary Workshop on Ingested Asbestos, that no correlations were found between cancer incidence and asbestos in drinking water. This is the most sophisticated epidemiologic study ever conducted on the question of the potential health effects of ingested asbestos. i i ''ri ANIMAL FEEDING STUDIES J.-; Animal ingestion studies support and confirm the epidemiologic findings th a t there is no association between the ingestion of asbestos fibers in drinking water and the presence of a health hazard. Test animals have been fed diets containing substantial portions of asbestos, without inducing related tumors or shortening lifespans. All of the following scientific authorities have concluded that animal experiments do not s support the proposition that the ingestion of asbestos in drinking water is harmful. # Bonser. G.M. and Clayson. D.B., "Feeding of Blue Asbestos to Rats," 45th Annual Report of the 1 British Empire's Cancer Campaign, 242 (1976). An experiment was performed to ascertain whether ) feeding asbestos to rats would induce peritoneal tumors. Sixty-five rats were fed 1,500 milligrams of crocidolite asbestos per kilogram body weight for life and no tumors were observed. 1 Smith. W. E., "Asbestos, Talc and Nitrites in Relation to Gastric Cancer," American Industrial Hygiene Association Journal 34:227-228 (1973). This too was a complete life span experiment in which hamsters were fed abnormally large amounts of asbestos. `If* to 45 tiamster maintained throughout their lives on diets containing 1% o f .i5r1 the eisryaotii or am osite varieties o f asbestos, we found no g astric carcinomas and no tumors to the gastrointestinal tra c t except for a neoplasm in the mesentery of the colon. We are unable to relate th at lesion to th e treatm ent, since ashing has revealed no asbestos fibers in it* Webster, I., "The Ingestion of Asbestos Fibers," Environmental Health Perspectives, 9:199-202 (1974). Dr. Webster fed baboons heavy doses of crocidolite over considerable periods of time to determine if peritoneal or gastrointestinal cancers could be induced. The report states: to none of the many baboons used was there any evidence of a peritoneal tumor or gastrointestinal tumor. Gross, P. et al., "Ingested Mineral Fibers: Do They Penetrate Tissue and Cause Cancer?" Arch. Environmental Health. 29(6):341-347 (1974). Twenty-one months of intim ate contact of ra t GI (gastrointestinal) mucosa with very high concentrations of chrysolite asbestos failed to produce cancer or any other kind o f lesion. Short-term and long-term feeding (up to years) of chrysotile and crooidolite by a second laboratory fa u lte d in no tumor production in the GI tra c t or mesothelium during the lifetim e of the anim als. - 8- 7 7!2 M m SiiS a''. 'yrfi ilCfifViiiS-iiM Smith. W. E., et al., "Health of Experimental Animals Drinking Water With and Without Amoslte Asbestos and Other Mineral Particles," Journal of Environmental Pathology and Toxicology. 3;277-330, 1980. In this study, hamsters were administered asbestos in drinking water for their entire lifetimes. Tumor incidence was compared with hamsters that did not consume asbestos. Dr. Smith concluded: In the present experiment, no malignant tumors were found in hamsters maintained on drinking water containing 13,000 million amosite fibers per liter. Hilding. A.C., et aL, "Biological Effects of Ingested Amoslte Asbestos, Taconlte Tailings, Diatomaceous Earth and Lake Superior Water In Rats." Archives of Environmental Health. 36:298-303 (1981). Rats were fed asbestos during their lifetime and were examined at autospy. The dose levels for the treated animals were the equivalent of 5.5 billion fibers per liter (low dose group) and'78 billion fibers per liter (high dose group) of drinking water. The authors concluded! The most significant finding in our study was the absence of gastrointestinal cancer in the animals exposed to the test materials. * * Under the conditions of our study, ingested asbestos had no demonstrable carcinogenic effect on the gastrointestinal tract or on other body tissues o f the rat. Moore. J.H., "Biological Effects of Ingested Asbestos - Status Report, U.S. Department of Health, Education and Welfare, Public Health Service, National Toxicology Program, January, 1981." The National Institute of Environmental Health Sciences sponsored a $6 million study on the effects of Ingested asbestos In rats and hamsters. The asbestos.was administered a t the ra te of 196 of to tal diet for the entire lifetime of the animals. Results released In 1981 were reported as follows: There was no adverse effect of amosite asbestos on body weight gain or survival. Neither the amosite groups showed an increase rate o f neoplasia in any organ or tissue compared to the control groups^ . Under the conditions of the bioassay, the ingestion of amosite asbestos was not carcinogenic in male end female Syrian golden hamsters. NIEHS officials reported in October, 1982 that the lifespans of rats fed ehrysotile anc| crocidolite asbestos also were not affected by exposure. In-house histopathologlcal reviews also showed no carcinogenic effect. These results will be peer-reviewed and published in early 1983. These animal feeding studies conducted by the federal government are the most extensive ever carried out to assess the effect of ingestion of asbestos fibers on animals. Using the highest asbestos levels found in drinking water, a person would have to drinking 14 million gallons of water per day to consume an amount of asbestos shown to be non-hazardous In these laboratory animal studies. i CONCLUSION * Since 1973, when questions were first raised about the potential health effects of A/C pipe and i asbestos in drinking water, U.S. government agencies -- the Environmental Protection Agency, Food and Drug Administration, National Institute of Environmental Health Sciences, National Cancer Institute and others --have spent $12-15 million (U.S.) studying this m atter. Today, nine years later, the conclusions from this extensive, independent research are clear. There are no apparent adverse health effects from asbestos in drinking water or the use of A/.C pipe. On October 13-14, 1982, EPA held its Summary Workshop on Ingested Asbestos. The purpose this Important meeting was to review all available medical evidence on ingested asbestos and A/C pipe. At that time, Dr. Joseph A. Cotruvo, Director, Criteria and Standards, Office of Drinking Water, announced that EPA would conduct no more research on the subject. The National Academy of Sciences (NAS) Committee on Safe Drinking Water is reviewing the epidemiologic studies on asbestos and drinking water, and will submit its conclusions and recommendations to EPA in early 1963. EPA will use the NAS report, along with the animal feeding study results and public comment, to develop a j formal position statem ent on the issue.