Document 3ekjbDmmn1VDyg522bBy7wqNy

Dioxin's Peril to Humans: Proof Is Elusive By WAYNE BIDDLE The deadly chemical dioxin, an un wanted byproduct of herbicides, pesti cides and other industrial products, is raising increasing concern among gor* Ieminent agencies, scientific research ers and people who may come in con tact with i t Communities from New York to Ore gon have reported human health protv lems that they fear are linked to expo sure to dioxin, although the links have not been proved scientifically. Officials in Missouri say the number of sites there believed contam inated b y the rhm<rai has risen to about 100, and Gov. Christopher S. Bond has asked his Legislature to set up a special fund to help clean them up. Dioxin, he said, could lead to "public hysteria" if not handled, property. _____ Research biologists and environmen tal scientists generally agree that in laboratory experiments on anim als, dioxin has more harmful effects, and in sm aller doses, than any chemical man has produced. Twenty-five millionths of a gram is known to be potent enough to n il a two-pound animal. There are 28 grams in an ounce. But scientific proof of the efffect on humans has been elusive. Conducting tests of mic chemical* on people is ethically unacceptable, and establish ing epidemiological proof by looking for correlations between exposure and ef fect an a given population is not always possible. In some cases, cancer m ay not develop for 30 years after exposure to a :hemicai carcinogen. Among the other unknowns about dioxin is how much of It there is in the country >i how much is being produced. Dioxin is nearly insoluble in water, but it clings tightly to soil particles and dissolves in organic solvents like alco hol or oil. It can enter the body by direct skin contact. Ingestion or inhalation. Dioxin was contained in ail sprayed aimnut a d******* ago as a dust-control, measure a t horse stables and along roadsides throughout eastern M issouri In recent months, concern has arisen ibout dioxin's long-lasting effects on' residents of Times Beach, Mo., and xher areas, and state and Federal offi cials nave been finding more and more Y).y Tiroes /Jc/a G F M P m n^zts {sites at which the chemical was dumped. Dioxin was among the hazardous rh^m iraia found in 1978 at the Love ran ai near a residential neighborhood of Niagara Falls, N.Y., and it has been found at hkUvidoal dump sites else where In the country. It was also a rh rw irai contaminant of the defoliant Agent Orange, used in Vietnam. Humans who have been exposed to it , near Love (UnaL in Vietnam otin situa tions such as train wrecks or fActory ex plosions have suffered a variety of se vere health problems, including kidney and liver aliments, birth defects and cancer. But whether it was the dioxin that the among the humans exposed to it has not been determ ined to the satisfaction of medical researchers. The Veterans Administration, which has said it will seek to determ ine whether a link exists among Vietnam veterans, has relinquished control of the project to the Federal Centers for Disease Control. Scientists Are Progreeslng Only in recent months have scientists begun to make what they now regard as an important breakthrough. They be lieve a d earer understanding of the ef fect of dioxin on health is emerging. Not until recent years were many physicians even trained to recognize symptoms of so-called chemical dis- eases. Moreover* scientists, underscor ing the. frequent difficulty in proving cause and effect in medicine, empha sise that It took.) y ean to establish a link between cigarette smoking and hmg cancer, even though the evidence seemed to point that way all along. Now, in a series of experiments re{posted most recently in last Novem ber's Issue of the scientific journal NsItore, a member of the dioxin group of compounds, one called 2^,7.8-Tetrechlerodlbenzene-p-diaxin, or TCDD, has been shown to be what Is called a potent "tum or promoter" In rats and mice. According to the paper, by Dr. Alan . Poland and others at the University of Wisconsin's MrArdle Laboratory for Cancer Research, the modal of tum or j production derived from these expert- ] m eats Is rtdevsat to humans because the excessive m nttipllcaticrrof cells in the skin of mice is strikingly sim ilar to that evoked by TCDD In human skin. Dr. Poland said TCDD did not appear to.be a comp ie carcinogen by itself. But he said it enhanced morbid growth In cells already exposed to potential CftDCQPOiaSiSg agents; that is, expo sure to TCDD, in conspiracy with other environmental factors, brings an the cancel'. '' ' "There is no question that dioxin plays a role in tumor formation In ani mals, and almost certainly has th e ' sam e action an human celli," said Dr. Howard E l , a medical officer at the National Institutes of Health. "Tbs basic mechanism Is the same. " TCDD Is the variety of dioxin found in Agent Orange, which is a m ixture of 2,4D and 2,4,5-T herbicides, and the vari ety confirmed in Missouri soil by the Environmental Protection Agency. Members of the dioxin family, imnn polychlorinated dibenzodiaxins, or PCDD's, are byproducts not only of her bicides and pesticides but also of dyes, pharm aceuticals, wood preservatives and other products known generally as chlorinated phenols. In general, these synthetic organic compounds are formed by adding rhin. rine to hydrocarbon molecules th at are denved from petroleum. Two decades ago commercial 2,4,5-T often contained as much as 70,000 parts per billion of TCDD and sometimes more. But manufacturers say current techniques can reduce it to a level of less than 10parts per billion. The indus try m aintains that it can assure safe products, especially since the m aterial .sprayed on fields is heavily diluted. If the TCDD content of commercial 2,4,5-T is 100 parts per billion, for exam ple, a single spraying might cause sur face soil concen trations of 0.02 parts per trillion. Estimates of TCDD soil con tam ination from Agent Orange in Viet nam are about 0.08 parts per billion. Spokesmen at the Dow Chemical Cor poration said that by testing their out put of the dlchlorophenol herbicide 2,4D nine times every 24 hours, they m ake sure dioxin contamination never ex ceeds 1 part per billion. Although 2,4-D Is closely related to 2,4,5-T, it is not generally contaminated with TCDD. It does contain-other less toxic rfimrin, though there has been alm ost no re search an the effects of these sub stances. The passible risk posed by even th at level of dioxin must be weighed, indus try spokesmen say, against the enor mous economic value of the products. Industry specialists say they believe, further, that the risk Is not so high as to require special precautions other than those always tak^n hi h an dlin g h az ard ous substances like herbicides and pes ticides. Advice From Disease Agency Assessing that risk,is, of course, p ert of the problem. Rwaaarrhrn say the risk begins to appear In nim aii with exposure In the parts-per-1,000-billion range. The Centers for Disease Control have advised Missouri nffirij! that I m aterials containing more than one part per billion of TCDD should be re moved from residential areas. But that figure itself has caused some confusion. Dr. Renata D. Kimbrough of the Federal disease agency expressed annoyance with som e news accounts that reported, incorrectly, that the agency considered dioxin concentra tions below 1part per billion is soil to be safe." Although this is the detection < ltiima l iat rbeeaisnginuMseidssionusroi,ilshteesstas iadt, residenit repre- i\//n seats & compromise between health l(C o n t concern! and cleanup practicalities. / 783459 Italy Are Less Than Feared ByJON NOROHEKMER SEVESO, Italy, Jan. 28-- On ad ea r July day seven summers ago, a quiet Saturday In the Lombardy region (of northern Italy just an hour's drive from the Alps, a soft esploRion at a small chemical plant at Seveso sent a column oi smoke and particles of debris mush rooming into the afternoon sky. { The cloud trailed south over the town and nearby villages before slowly dis sipating against the horizon. Children reported playing in the snovr-Uks crys tals that filtered down from the sky. Within weeks, Seveso was known to scientists around the world as "the poi soned city" and one compared its in habitants to the victims of Hiroshima and Nagasaki, fatally exposed to frightening man-made dem ent 1 A byproduct of the production of fertij- lizeis at the chemical plant was dioxin; one of the most toxic substances known to science, so powerful, it was reported; that a few drops In a water reservoir could kill all the Inhabitants of a large1 metropolis. It is the same substance! that contaminates at least 15 sites, and perhaps as many as 100, in Missouri. j Children Developed Rash It was said here that at least 22 pounds and perhaps as much as 132 pounds of dioxin had escaped In the ex plosion's cloud. Children who had frol-1 icfcad in the poison crystals developed an ugly red rash, cbtaracne. Pregnant women were mumrtnrt to haveabcr-1 timet. The center of town was evacuat ed. Serveso, It was said, was a valley of deathand wouldbeoomeadesert. None of the worst predictions have come true. The city looks no worse for wear than other aging northern Italian mmimmjfjw that have mild* uneasy jaccommodations with industry. Nearly everyone agrees that the original esti- jmates of how much dioxin escaped Into the environment was exaggerated. Hoffmann-LaRocfas, the Swiss com pany that operated the plant, places the figure at lea .th a n one-half pound. Others believe It was higher, bat no where near the amount, perhaps w than 50 pounds that was part of waste oil sprayed to contain dost a t the Mis sourirites a decayedago. No new cases of dblaracne have been recorded here since 197S, according to a .group of scientists who continue to monitor the aftereffects of the explo sion. LittleEvidence Found This study has produced evidence that there was a slightly elevated Inci dence In birth defects in the two years after the explosion, but Italy lacks reli able data an birth detects andscientists are not sure that a timitai investigation /\J.y. Times /3/J\$3 of new births in any other urban-indus trial population in northern Italy would notproduce the same deviation. Lancet, the respected medical sci ence publication, last fall reported that with the exception of chloracne, there was no evidence of substantial dioxin poisoning at Seveso. And, the publica tion also reported, the established cases of chloracne were relatively mild ones, suggesting at moot a low level of dioxin poisoning instead of a catastrophic one. Itsaid thatonly a few patches of ground dose to the explosion site ever regis tered dioxin levels approaching those at thecontaminatedsites in Missouri. These findings have reduced, but noteliminated, the sense of doom in Seve so. The cloud's shadow still lingers In the minds of scientists and townsfolk. "1 trust In God the worst Is over and we can go on with our lives and not. worry anymore," said Vittorio Chlapinni, a factoryworkerwho lives inside the monitored danger zone. "We are tired of doctors and technicians invading our shomes and inspecting us like laboratory animals. What will happen has hap pened." Still Unanswered Questions The future, however, holds tbe big gest unanswered questions. "In terms of chronic disease, like cancer or cirrhosis of the liver, we still ;don't know ft something important has happened at Seveso," said Dr. Ericcaldo Stringftd of the btituto Ttimori in Genoa. "We will have to wait another ten or 20years." Thereis also concern thatthe authori ties do not know how much dioxin has been concentrating in fields where produce is now being grown for Italian markets, and how much of the sub stancehascollected in waterways. OniyOn* Autopsy While such fears are discounted by (the Government, a 1900 incident shows that, the dread of dioxin is never far awsV> A local farmer discovered one morning that Us flock of 200slxeep died after grazing in a field that had beat hatred to livestock since the awrtmm. Mtiaa. A chill went through the people. bw it was proven to nearly everyone's satisfaction Uxit the flock dtodtnqLa& ling a grass that is known to be fatal to sheep, and no "unusual" traces of dioxin were found by autopsies, accord ingto Franco Ndo, a biologist. Butthere is no dear understanding of how much dioxin may be collecting in tbe tissues of the living residents. Only one auupsy baa been performed on a human being exposed to the fallout from tbe expiation, an elderly woman who bad already been suffering from cancer of the pancreas. The autopsy found significant levels trf dioxin (n her organ tissues, according to Mr Nelo. G E N P 010649 783460 ~ r* j I I c J n / Cv. Kimbrough said exposure to lower concentrations over extended periods could still present health risk. In one area of Missouri, the Environ* mental Protection Agency said, dioxin was found last fall in surface soil con* 1 centrations of 300 parts per billion. The J. Federal agency calculates that expo- 1 sure to this soil presents an added can* i cer risk, for children who ingest it regu larly, of as much as 35 percent. That Is, CthheasneccehOilfdrCeonnhtaravcetiang35nptenrrc+enr t greater 1q fholr lifetime than those who do not ingest the soil. This is proximately regarded as above 30 percent risk of trh*enna>pr that all Americans face. The special properties of chlorinated phenols, of which dioxins can be a byproduct, are what muk them so use ful to an industrial society. But those properties, such as heat resistance and electrical resistance, insolubility In water, and chemical durability, are also what make the phenols biologically threatening. Among other thing, the substances may collect in living organ isms at higher concentrations than In the surrounding ecosystem, a process known as bioaccumulation. In virtually all types of tissue in every animal species tested. Dr. Poland of the University of Wisconsin** laboratory said in an interview, TCDD induce* the production of enzymes that are the or ganism's attem pt to metabolize, o r ren der harmless, the chemical irritant. But the enzymes are now often thought of as a double-edged sword, because or ganisms that have a high capacity for producing them are more susceptible to tumors at the spot where a carcinogen is administered, while those with a low capacity show distant cancers such as leukemia or lymphomas. DrDanlai Nebert, the branch chief of developmental pharmacology at the National Institutes of Health, who is also active in dioxin research, con curred with Dr. Poland's findings, call ing them a " m ajor breakthrough." Other scientists generally agreed with that assessm ent. , According to Dr. Nancy Kim of the New York State Departm ent of Health's toxic substances assessm ent unit, TCDD fits into one of two m ajor cancer theories. In the first, the hypothesis Is that merely one foreign molecule at taching to DNA can set off the cancer process. Because TCDD does not bind appreciably to DNA, it does not match this scheme. But Its ab ility to cause ex cessive cell m ultiplication, known as hyperplasia, does fit the second theory, that cancer is caused by repeated irrita tion of tissues. Although scientists befievS that cur rent laboratory work showing the simi larities in m im ai i htiman fj rnwf mechanisms has taken the research a crucial step forward, soch theoretical work is only half the puzzie-eoivtng pro cess. The other half is human epidemi ology, a tedious, tim e-consuming m at ter hindered by all the reai-worid ambi guities that laboratory work can filter out. Study of Chemical Plant Workers Scientists a t the National Institute of Occupational Safety and Health are studying an unusually high incidence of soft-tissue sarcom as among workers exposed to dioxin at two chemical com panies in Michigan and West Virginia. In a letter to the medical journal Lancet for the January 1981 issue, the researchera reported that three of 105 workers who died suffered from the rare cancer. This was 2.9 percent of the deaths in the group; the general population would be expected to show only seven one-hun dredths of one percent. The study might provide the first in ternational confirmation of a 1977 re port from Sweden suggesting that for e2,s4tJry-T w orkers have a exposed to 2,4-D and roughly fivefold higher Incidence of soft-tissue sarcomas. In mMitinn, several studies have revealed an increased incidence of Hodgkin's disease in lum berjacks and woodwork* | era. A Lancet editorial noted last year that any change in the pattern of sarco mas, " even in sm all numbers of cases," might strengthen the causative assoda- ; non with dioxin. Studies by Dr. B ertram Camow, an occupational health consultant and edi tor of the Journal of Occupational Medi cine, examined a group of 47 men from 1980 to 1982 who had been exposed to dioxin after a railroad accident in 1979. In an interview, Dr. Camow said the ex posure varied from 8 hours to 90 days a t concentrations in soil or liquid runoff of about 30 parts per billion. Five of the men, or 10.6 percent, have developed skin cancers; the expected incidence in the general population is about 0.17 per cent a year. A significant number of other disorders was also observed. I " The only safe level of rfinrin ta non1detectable," said Dr. Camow, whose medical practice in Chicago has treated nearly 300cases of dioxin exposure. Betides the role of TCDD in cancer, the other great area of medical concern regards apparently related fetus dam age and ocher reproductive problems. For anim ais, the evidence is straightforward and overwhelming. iTCDD injures or kin* anim ai embryos at doses as low as one billionth of a gram adm inistered per kilogram of body weight per day. For humans, how ever, the record so far is circum stan tial. The Environmental Protection Agency used emergency poweia in 1979 to baa virtually all use of 2,4,5-T in the United States after discovering a higher than normal rate of spontaneous abor tions in an Oregon region that had been sprayed. Estimated Risk of Chemical Pollutants, Percentage of Increased risk of cancer, calculated on the baala of ;* animal experiments and human epidemiologic studies, to a person weighing 150 pounds who. over a 70-year lifespan, breathes air containing one microgram of substance per cubic meter. * PERCENT RISKOF SUBSTANCE USE > CANCER Acrylonitrile * .031 Ally! chloride .000099 Arsenic .34 Benne .00074 Berytftunr Cadmium | v ' 27.0 , s .i Dlmethyinitrosamtne Dioxin 100.0 Source: U .3 . Environments/Protection Agency T h N n W k lte i/iM .a .1 The chart shows the projected percentage of iacreesed risk of cancer, based . on animal studies, calculated to occur among people whe weigh 199 pounds and who, hi a 7t-year life spaa, breathe air contahrtng one mlcrofram of chemical particulate per cubic meter of air. GENP 010650 783461