Chemical and radiation hazards to children: Highlights of a meeting

SPECIAL ARTICLES

Chemical and radiation hazards to children." Highlights of a meeting Robert W. Miller, M . D . , B e t h e s d a , M d .

EVEN PRISTINE IOWA has been sullied by a toxic waste dump, the contents of which have leached into the Cedar River, potentially threatening hundreds of thousands of people who draw their water from this source. This case report initiated the third in a series of symposia on special exposures and susceptibilities of the fetus and child to environmental pollutants. These symposia, organized by the Committee on Environmental Hazards of the American Academy of Pediatrics, began in 1966. The first dealt with the effects of ionizing radiation, of particular concern following the weapons tests and their fallout in the 1950s. ~ The second symposium focused on chemical pollutants, increasingly recognized as pediatric problems: lead poisoning, pulmonary disability from smog, and, among other topics, newborn infants who were small for date because their mothers smoked cigarettes (self-pollution), or because they ingested cooking oil contaminated with polychlorinated biphenyls. Smoldering unnoticed at the time were chemical wastes underground, On river-bottoms, or piled high in fields in metal drums and deteriorating with age. Polybrominated biphenyls, erroneously mixed with cattle feed, have polluted the entire lower peninsula of Michigan; PCBs were also dumped along a 214-mile stretch of highway in North Carolina, near the main laboratories of the Environmental Protection Agency and the National Institute of Environmental Health Sciences. Dioxin spewed from a factory near Milan and caused chloracne in children caught down wind by the toxic cloud. In Moscow Mills, Missouri, more than 60 horses were killed in an indoor arena when dioxin to be discarded was mixed with waste oil and sprayed on

From the National Cancer Institute, Clinical Epidemiology Branch. Reprint address: National Cancer Institute, Clinical Epidemiology Branch, 5A21 Landow Bldg., Bethesda, MD 20205.

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| 1982 The C. V. Mosby Co.

the earthen floor of the horse arena. Extremely high levels of DDT have been found in the people of Triana, Alabama, who ate fish from a contaminated river nearby. High blood lead concentrations in children have been associated with Abbreviations used PCB: polychlorinated biphenyls PBB: polybrominated biphenyls EPA: Environmental Protection Agency deficits in intellect and behavior, and lead encephalopathy has been observed in children living near smelters in Idaho and Texas. Lead and other chemicals have been transported to the home on the parent's work clothes, causing illness in the children. In Globe, Arizona, a subdivision of homes was built near asbestos mill-tailings which contaminated the water and swirled in the wind; exposed children who have lived in the homes since 1973 have thus been put at increased risk of mesothelioma and, if they smoke, of bronchogenic Carcinoma. A lesser exposure to asbestos has occurred in the schoolrooms of the nation, the ceilings of which were sprayed with this substance, which frays over time. Fear of radiation exposures has not diminished. On the contrary, the near melt-down at Three Mile Island and other accidents at nuclear facilities have rekindled anxiety about them and radiation exposures in general. Questions have arisen about the induction of cancer at very low doses of radiation, from claims made on the basis of studies in southwestern Utah related to fallout from weapons tests in the 1950s, and from other exposure s presumed to be at low doses. All of this and more have come to light since the conference in 1973, and formed tl~e agenda for the third symposium in the series, "Chemical and Radiation Hazards to Children," which was held at Innisbrook, Florida, on December 11 and t2, 1981, as the 84th Ross Conference on Pediatric Research. The Journal o f P E D I A T R I C S Vol. 101, No. 4, pp. 495-497

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Miller

MONITORING

The Journal of Pediatrics October 1982

AFTER EXPOSURE

Epidemiologic studies of adverse effects on children from exposure to toxic waste dumps pose difficult scientific problems, even for experts. Current epidemiologic techniques for detecting clinical abnormalities in relation to toxic waste exposures have yet to produce firm evidence of increased disease occurrence. Guidelines for such studies as they relate to mutagenic and reproductive hazards have been published under the auspices of the March of Dimes Birth Defects Foundation. 3 Studies of chromosome breakage, properly done, were said to be a reliable indication of exposure of an individual or of a population to genotoxic compounds, and sister-chromatid exchange frequencies may be an even more sensitive biologic indicator of exposure to chemicals. Sister-chromatid exchanges correlate well with the induction of single gene mutations, whereas chromosomal aberrations represent gross effects on the genetic apparatus of somatic cells. Many cancers are thought to arise in two steps: initiation (mutation) and promotion. Mutagenic chemicals are almost always carcinogenic. Hence, quick screening laboratory procedures for mutagenesis (e.g., the Ames test) correlate well with carcinogenicity. There is little overlap with teratogenesis, however, which usually occurs through mechanisms other than somatic cell mutation. A survey by questionnaire of adolescents near Three Mile Island revealed substantial "affective response" related to the near disaster, but this response dissipated rapidly. LEAD: RECENT

OBSERVATIONS

The average blood lead concentration in children in New York City has decreased from 31 t~g/dl in 1970 to about 16 #g/dl in 1979, apparently because of improved nutrition (iron deficiency increases lead absorption) and, to a lesser extent, the introduction of lead-free gasoline. A survey by the National Center for Health Statistics revealed that 3.9% of all children in the United States under 5 years of age examined between t976 and 1980 had blood lead values of 30/zg/dl or more. Applying that percentage to the entire nation leads to the estimate that 675,000 children between 6 months and 5 years of age have elevated blood lead concentrations. Only 2% of white children are in this category as compared to 12.2% of black children. Once lead enters neuronal cells, it cannot be gotten out. Why do Three Mile Island and the Love Canal capture public interest, when neither has yet been shown to be harmful to health, and yet lead poisoning, which is harmful, receives almost no attention? An unexpected resPonse was that scientific interest remains immense, with about 4,000 publications per year listed in Index Medicus

since 1972. The expected answer, also given, was that the poor do not have political connections. DISASTERS,

SCIENCE

AND THE PUBLIC

At Three Mile Island, as at the Love Canal and other polluted areas, conflicting information from persons at various levels of government and in industry caused great confusion at the time the pollution was first discovered. The idea that a system could be created for coordinating information in the future, when such accidents occur, met the complaint that the system would probably not solve the problem of enormous public distrust. An informed public, it was said, must realize the limits of understanding and the nature of conflicting evidence. The public must play a role in modifying environmental threats. Citizens' groups tend to lead the way to new regulations. Public interest groups have been particularly influential. The power of education is well illustrated by the dramatic reduction i n childhood poisonings. But how can the interest of physicians be engaged? A survey of four pediatric journals revealed that in a recent two-year interval 17 articles on the environment had been published. Five of them were editorials. (On the average, then, each journal published 1.5 unsolicited articles on the environment annually.) Of course, editors cannot publish unless acceptable articles are submitted. Medical students were said to be "totally unreceptive to education concerning environmental medicine and epidemiology." They learn from their mentors that diagnostic payoffs lie elsewhere. Unless motivation is reinforced by finding something of interest through such inquiry, it is difficult to keep the subject alive in the minds of students----or of the faculty. Electives in these subjects for third- and fourth-year students at the National Institute of Occupational Safety and Health and Centers for Disease Control have been popular among a well-chosen group. The question, how to motivate students and practicing physicians, ran throughout the conference. One attempt, through questions on the pediatric specialty board examination, revealed that less than 50% answered correctly. Some conferees thought that etiologic histories need be taken only when medical problems are not easily resolved. Others thought that any case history may harbor information about cause or mechanism that will go undetected because the physician's history, especially about the environment, is too brief. Faculty members might help by directing the student's attention to peculiarities in disease occurrence that may be clarified by more detailed etiologic histories than usual. Faculty members might also identify students with an aptitude to think etiologically, so this talent can be encouraged.

Volume 101 Number 4

When an environmental agent is suspected as the cause for a cluster of disease, local experts and authorities should usually be consulted first. If they need assistance they can and should call on the Centers for Disease Control. The Environmental Protection Agency is responsible for identifying chemicals in environmental emergencies, a key resource for which is the NIH-EPA Chemical Information System. 4 This system contains extensive data on more than 200,000 chemicals. The fear of effects from environmental pollution was referred to as "secondary poisoning"; that is, symptoms caused by anxiety generated by publicity about the event. This was an enormous problem in Michigan with regard to PBBs, at Three Mile Island, and in Hiroshima and Nagasaki. Some participants suggested that the problem might be diminished by not withholding information, but others cautioned that giving premature information may erroneously imply liability. HEALTH POLICY, CHILDREN, AND PEDIATRICIANS Children were a main determinant in preparing several recent health regulations. For example, the EPA argued that in exposures to airborne lead, children were the most susceptible and had to be protected. In consequence, 99.5%

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of the population would be protected if the new standard were achievable. Are pediatricians represented often enough on the inner councils of government in relation to health? Yes, for problems or agencies that primarily concern children, but not when the general population is exposed to newly recognized environmental agents, such as PBBs or chemical dumps. To increase participation by pediatricians, it was suggested that professional societies be persistent in recommending extremely able people. As another participant put it, "That's what doctors have to be, I think, both scientists and social advocates."

REFERENCES 1. Committee on Environmental Hazards, American Academy of Pediatrics: Conference on the Pediatric Significance of Peacetime Radioactive Fallout, Pediatrics 41:165, 1968. 2. Committee on Environmental Hazards, American Academy of Pediatrics: The susceptibility of the fetus and child to chemical pollutants, Pediatrics 53:775, 1974. 3. Bloom AD, editor: Guidelines for studies of human exposed populations to mutagenic and reproductive hazards. White Plains, N. Y., 1981, March of Dimes Birth Defects Foundation. 4. Milne GWA, Fisk CL, Heller SR, and Potenzone R Jr: Environmental uses of the NIH-EPA chemical information system, Science 215:371, 1982.

Oral rehydration for diarrhea Laurence Finberg, M.D.,* Brooklyn, N. Y., Paul A. Harper, M.D., Harold E. Harrison, M.D., and R. Bradley Sack, M.D., Baltimore, Md.

From the State University o f New York, Downstate Medical Center; the Departments o f Maternal and Child Health and Population Dynamics, Johns Hopkins School o f Hygiene; and the Departments o f Pediatrics and Medicine, Division o f Geographic Medicine, Johns Hopkins School o f Medicine. *Reprint address: Department of Pediatrics. SUNY, Downstate Medical Center, 450 Clarkson Ave., Box 49, Brooklyn, NY 11203.

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FROM MARCH 15 to 17, 1982, an international group of 35 pediatricians, epidemiologists, and public health workers, all with interest and extensive experience in the Abbreviations used WHO: WorldHealth Organization ORS: oral rehydrating solution