Epidemiology arose primarily out of the study of work place hazards. However, as these hazards encroach more and more on living spaces, we are being pressed to directly assess the effects of workplace hazards on children, and, even on the embryo and fetus. Moreover, the mixture of workplace hazards is often highly specific to the place being studied, and general research (for example, general research such as exposure to one specific chemical through a water pathway) can no longer be undertaken. This means that the classical epidemiological study fails to be relevant on two scores: first, it usually deals with only one hazard at a time, and secondly, it requires large populations, which are seldom available in residential exposure situations. Studying a mobile residential population living near to a toxic waste dump is very different from studying workers who are of a similar age and health status, and who spend some forty hours a week in a very specific industrial environment. An eight- hour workplace exposure allows for a sixteen-hour recovery period away from both the workplace and the exposure. There is no such respite period for a child living in a contaminated residential environment.

Because of the specificity of the mixture of hazards in any one residential area, together with the specificity of the ethnic backgrounds and occupations of the residents, findings in any studies that are undertaken will of necessity be highly site-specific. This means that results are not easily transferred to experiences of other communities, since these new communities will have inevitable differences both in the mixture of hazards and the vulnerability of hosts.

Because of these new complications, it is my opinion that we are on the verge of developing a new medical discipline, which I will tentatively call Community Health Care, and which I see as an expansion of Public Health. It will be important to collect careful Case Studies of Community Diagnoses, Interventions and Outcomes so that commonalties and differences can be analyzed, helpful medical interventions can be assessed and basic theories developed. These Case Studies will provide the input for Preventive Health Action on the community level. My model assumes a community-level parallel to the doctor-patient relationship. The Community Health Care professional will translate the findings of epidemiology into beneficial interventions on the community level to improve the health of the community. These interventions are site specific, and it will take time to develop general principles of care.

Several such Community Health Case Studies are briefly presented here. In no case is there a complete case history including the intervention and outcome results. However, I think that you will be able to follow the deliberate change in attitude which I am proposing, namely, that we no longer consider a community in crisis because of pollution only as an opportunity for studying the health consequences of the exposure and adding to universal epidemiological knowledge. Rather, I am considering the community as patient in need of the epidemiological information gained elsewhere for understanding whether or not its health has been compromised, and whether or not there are remedies which will restore quality of life. Obviously at times both approaches will be legitimate. However, today I will stress the second approach, which has been neglected for too long.

Remember that because this is a new approach, I too am learning!

FIRST CASE STUDY: McCLURE CRESCENT

McClure Crescent is a housing development built on a farm used by the Radium Luminous Industries (RLI), which operated in Toronto in the 1940's painting radium on dials to make them glow in the dark. They painted the cockpit dials for the bombers in World War II. After the war, RLI was shut down, and the area was used as a disposal site for the radium source, its decay products and contaminated work place materials. The contamination was first identified in 1945 by the Canadian Foreign Exchange Control Board, which had been investigating the RLI for the National Research Council. There was incomplete follow up of the concerns.

The Province of Ontario was warned again about the potentially serious contamination in 1975, and then again in I980, when two Ryerson University Journalism students, tipped off by former RLI workers, brought the problem to public attention. The Housing Subdivision, McClure Crescent, was built by the Ontario Housing Corp., which had not been told about the contamination. Homes on the contaminated land were sold under a Home Ownership Made Easy Lottery in 1973. There were 270 homes allocated through the lottery, most of which were won by young couples just starting their families.

After the 1980 public disclosure, MacLaren Engineers tested the area for the Atomic Energy Control Board (AECB), the Federal Regulatory Agency in Canada. It found one place, behind the homes at 110 and 112 McClure, with gamma radiation levels 50 x normal soil levels (50 mSv), and many other homes with levels 2 - 3 x normal (2 to 3 mSv per year). The AECB agreed to remove 4000 tons of contaminated backyard soil from the area. At the same time, it declared that there was no threat to the health of anyone in the neighborhood. At the time the AECB maximum permissible radiation exposure level was five times normal terrestrial background (5 mSv per year). In 1990, this recommended permissible maximum level was reduced to about one times background (one mSv per year). This means that in 1980, except for the buried radium source, the pollution was legal, and after 1990, although it was still technically legal, the Government had declared its intention to implement the new lower standards, which would make the contamination illegal.

EDA Engineering was brought in by individual families to determine the extent of contamination on their property, and they confirmed the MacLaren findings. The Nuclear chemistry laboratory at the University of Waterloo confirmed that the radium in the soil was about one tenth the concentration found in uranium mine tailings piles, which are considered to be quite dangerous. However, unlike uranium mine tailings, this radioactive debris was in the backyard of homes containing young children.

COMMUNITY DIAGNOSIS: At the request of parents who were worried about possible health effects on their children, IICPH undertook urine analysis for polonium 210, a decay product of radium, and blood counts with differential. Blood changes are known to occur at low level radiation exposure. Uranium or radium that is not excreted from the body, becomes incorporated in bone. Its decay product, radon gas, is able to escape the bone and both radon and its decay products can be excreted in urine. Through chemical and radiochemical techniques, it is possible to test for a decay product of the radon gas, polonium 210, as an indicator of the incorporation of uranium or radium in bone. Each participant also completed a short questionnaire, noting the length of residency, age, sex, ethnicity and relevant socioeconomic information.

URINE ANALYSIS: In the first test, urine samples were collected from about 12 children, and the samples combined. The AECB had refused to have the urine measured at the government laboratory, so IICPH requested measurement at the University of Waterloo laboratory. Dr. Sharma, who did the chemical analysis, combined the samples. He did not expect to find anything, and was surprised to find high gross alpha and beta radiation counts. Because of this positive finding we again collected 24-hour urine samples for three exposed children, one control adult and one control child. The children were designated low or high exposed based on the engineering analysis of their family home property. However, it is acknowledged that children are quite mobile in a neighborhood. The measurements were as follows:

Uranium workers' levels of Lead 210 in urine is reported in the literature as between 0.47 and 5.0 pCi per sample, with an average of 1.16 pCi per sample. The expected value of lead 210 in urine for an adult non-smoker is 0.05 pCi per sample. In a study undertaken in Elliot Lake for adults, including smokers and non-smokers, researchers found an average of 0.2 pCi per sample of Lead 210. The McClure Crescent children had levels of Lead 210 in urine, which indicated above normal, even comparable to a uranium miner's exposure to the decay product of radium.

BLOOD COUNT: Fifty-eight children, between ages 5 and 15 years, gave blood samples to the MDS laboratory for Complete Blood Counts and Differentials. The Laboratory handled the blood in the same way for each child's count. Each child had three tests, done one week apart and the findings in absolute count were averaged for the study. Children with a sore throat, fever or possible cold/flu at the time of testing or within two weeks prior to the testing were eliminated from the study by the MDS professional who took the blood. Exposure level for the child was estimated on the basis of the engineering findings on the child's home property. Children were divided into two categories, except for the preliminary study of trend with dose, in which case three categories were used.

In the preliminary examination of the data, we separated the exposed group into three categories: those with buried radioactivity on their home property (HIGHER EXPOSURE), those with only surface contamination as determined by the engineering study (MEDIUM EXPOSURE), and those with no contamination on home property, designated LOW EXPOSURE. The average white blood counts for children in the three exposure categories in the preliminary test were:

An F-test showed that the linear trend with dose was significant (probability of 0.02). The differences were most dramatic for the monocyte, a type of white cell produced by stem cells located in bone marrow. The Lead 210 is stored by the body in bone, and the monocyte stem cells are know to be highly radio-sensitive. The trend with dose for monocyte count was statistically significant by an F- test on the 1 % level (probability 0.006).

AVERAGE MONOCYTE COUNT PER MICROLITRE OF BLOOD:

These findings were unaffected when controlled for race, age or ethnicity. Socioeconomic status in the neighborhood was uniform.

Some children had clinically low monocyte counts, below 200 per microlitre of blood. Four children were referred to medical follow up.

There were 24 children on uncontaminated property (called lower exposure) and 34 living on contaminated property (the combined medium and high exposure groups). Our findings of the differences in monocyte counts for unexposed vs exposed children were as follows:

The monocytes have two important functions; they release a chemical, which activates the cellular immune system, the lymphocytes, and they recycle about 37% of the iron from dead red blood cells into new red blood cells. Their depletion can result in iron deficient anemia and/or immune depression.

INTERVENTION: At the time we envisaged intervention to mean clean up of the property and formation of a register for follow up of the children. The local and provincial government strongly resisted both efforts. However, the federal government did make attempts to find a temporary waste dump for the contaminated soil. Each location announcement precipitated citizen organizing and protests. It was more than ten years before the contaminated soil was moved onto an industrial site. Meanwhile the government re-purchased the homes and turned them into rental property for low-income families. No further human health assessments were made.

OUTCOMES: One of the children with significantly low monocyte count in the blood study and a moderately high level of Lead 210 in urine, died at age 16 years, three years after this investigation. His family's property was contaminated, and removal of soil was advised but had not yet occurred. Another child, the one living closest to the "hot spot" area, who also had significantly low monocyte count, later as a young married woman, had two miscarriages. A third pregnancy resulted in a very difficult Caesarian birth, which was followed by several weeks in intensive care for a severe infection. The doctors found this strange for a young seemingly healthy woman. We did not have specific information on Lead 210 in urine for this individual.

SECOND CASE STUDY: CANONSBURG RADIATION EXPOSURE

Canonsburg, Pennsylvania, site of a closed radium factory with its radioactive waste was the Number One Site under the US Super Fund Clean-ups. The factory's radioactive tailings pond had been capped, and because no weeds grew on this site, it became the local baseball diamond.

Because of the similarity in exposure to that of McClure Crescent, urine analysis of the children exposed to this site was immediately undertaken. Twenty-four hour urine samples were obtained from 45 children between the ages of 3 and 18. Each family filled out a questionnaire on distances, back yard gardens, passive smoking in the household, and other relevant information. This was one of the first attempts to systematize the information gathered on children. After subtracting background levels of lead 210 in the urine samples, the children's urine measurements ranged from 0.002 pCi to 0.770 pCi per 24-hour sample. Fourteen (38.9%) had levels above 0.2 pCi per 24 hour sample. The expected level of lead 210 in adult non-smokers is 0.05 pCi per 24 hour sample. All of the children with more than 0.20 pCi per sample live within 2.5 miles of the dumpsite and/or attend school within 2.5 miles of the dumpsite.

CORRELATION BETWEEN ENVIRONMENTAL INFORMATION AND URANIUM IN URINE:

There was no follow up to this study. In fact, the US government opposed the testing of the children and went so far as to; cancel urine testing for the site clean up workers; close the urine analysis laboratory at Argonne National Laboratory (which was doing all of the urine analysis for uranium workers in the US); and, fire the researcher who had been doing the analyses. This action was taken subsequent to the researcher agreement to test the children. This researcher taught Dr. Hari Sharma, a nuclear chemist at the University of Waterloo, Canada, to do the Lead 210 testing so that all of our analyses used his methodology. The findings are therefore comparable with published data on uranium workers in the US.

There was an unusually high number of childhood cancers reported for the Canonsburg community prior to the clean up, but no thorough study of this was done. The dump had been in the neighborhood since about 1910. Dr. Radford, then at the University of Pittsburgh, included the community in a thyroid abnormality and cancer study he was supervising for student researchers at the time. The Canonsburg population showed a higher than expected level of thyroid abnormalities and cancers. (Evelyn O. Talbott et al, Problems in Determining Health Effects of a Community Exposed to Toxic Waste, Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh.) However, no distinction was made in this study between those born in the area, and therefore potentially exposed in utero, and those born elsewhere. No mechanism for this effect was given.

THIRD CASE STUDY: BROCK WEST MUNICIPAL WASTE LANDFILL

This municipal landfill, located in a rural area of Pickering, outside of Toronto, was given a Certificate of Approval in April 1973. The area was later developed, and the landfill site is now within 500 meters of homes. According to the original plans, the landfill would be open for five years. However, it was used for more than twenty years and, in 1988 it was reported to be seriously leaking. Plumes were identified moving through Metro Toronto Conservation Authority lands to the Duffins Creek. Area children were known to play near or even in the Creek.

A random sample of residents was chosen to fill out a questionnaire which included socioeconomic information on the family, life-style and hobby questions, detailed information on potential household pollutants, school information, outdoor habits and local area potential hazards. A sub-study was included with one child per household chosen in a systematic way so as to neither over-represent those with medical problems nor to over-emphasize households, which might have indoor pollution problems. Detailed medical and life style information on this representative child was collected.

A trend toward more asthma and more eczema was found with three surrogate levels of exposure to the landfill leachate: 1. Plays in or near the Duffin Creek; 2. Does not play near Duffin Creek, but Mother reports odors from the landfill detected in the home, 3. Neither of these two reported. All questionnaires were filled out by the mothers in the randomly chosen households.

The risk of asthma in children who play in or near the Duffin Creek is twice the asthma risk for children who do not play in or near the Duffin creek. This finding was statistically significant on the 5% level. The risk of eczema of these children was also doubled, and was statistically significant on the 5% level. The intermediate level of exposure had an intermediate rate of asthma and eczema.

This research was also resisted by governments. Because of this resistance, the methodology which had consisted of participatory research using local health professionals and volunteers, was scrutinized by the local University Environmental Health Department. They found a potential bias in collection, since the citizens had tired of keeping records on responses. However, internal checks on the data showed that the data was most likely randomly collected since the randomly designated children had a normal sex ratio. There had been no mandate to assure this outcome.

Although the government did not accept the study, they acted to close the landfill.

OTHER RESEARCH:

The International Institute of Concern for Public Health has undertaken other research on the environmental influence on the health of children, which can be found in publications referenced below. The Wisconsin study of the death rate of low-birth-rate babies seems to indicate that separating infant mortality rate by birth weight category in routine vital statistics reporting would (unfortunately) be helpful in assessing air pollution. Since a baby's death certificate does not ordinarily contain the birth weight, this would require a simple change of forms.

The research which the Institute undertook in the Marshall Islands, where residents tried to inhabit Islands which had heavy nuclear fallout after the atmospheric tests at Bikini, showed the same monocyte abnormalities noted at McClure Crescent and Canonsburg.

These residents were not in the initial fallout and did not live on the contaminated Island until after the US Government had declared them safe.

A major study of uranium contamination on the Mississauga Reserve in Northern Ontario is unpublished at the request of the Native Band involved in the study. However, requests for copies the study can be made to the Chief, only if the findings will assist other communities struggling with uranium pollution. The Mississauga Reserve is across the highway and down wind from a uranium processing plant. In this investigation, a grid over the reserve was used to determine the pattern of deposition of the uranium dust and isopleths were made to guide the People in locating their homes and vegetable gardens and in choosing areas for picking herbal medicines and sweet grass for their ceremonies.

Studies of the Mississauga Reserve residents for monocyte depletion and uranium in urine were undertaken and indicated residential contamination, which was internal, and especially affecting the children. In this case study the Band used several interventions including:

Moving the children's daycare centre away from a contaminated area; Substituting distilled water for drinking and cooking purposes in homes for all children. Within three months on the distilled water, the monocytopenia on the Reserve disappeared. The children's counts had averaged 270 per microlitre blood, and they were raised to an averaged 690 per microlitre of blood. This was more than a substitution for local water, since the main pathways for internal contamination on the Reserve were via air and local produce, not water. Distilled water is known to leach inorganic heavy metals from organic material. This increase is also too large an increase to be attributed solely to a placebo effect.

In another project which the Institute undertook in Bukit Merah, Malaysia, a community exposed to the Asian Rare Earth Co., a subsidiary of the Mitsubishi Company, the primary exposures of the community were to radon gas and thorium, both wastes of the chemical separating process. The 60 children, who were tested for total blood count and differential, had an average monocyte count of 207 per microlitre of blood. The expected average for children would be 325. The range of monocyte counts was 72 to 495, as against the normal 200 to 800 per microlitre of blood. One hundred seventy one (171) children in a neighboring village, Carey Island, were also tested. These children were exposed to a palm oil factory, and agricultural pesticides and herbicides, but not radioactive heavy metals. These children had a lower socioeconomic status than the study group, and their nutritional status was lower. However, their blood counts, and the monocyte count in particular, were normally distributed.

The IPOH High Court in Malaysia closed down the Asian Rare Earth factory for two years, for the cleanup and construction of a waste disposal building. The Bukit Merah children were tested three months after the factory-resumed operations (1987) and then again one year later (1988). The progressive deterioration was astonishing:

About 39% of the Bukit Merah children suffered from a triad of mild lymphadenopathy, congested turbinates and recurrent rhinitis. Less than 4% of the 171 Carey Island children presented with these symptoms. All children in the study had normal temperatures and were without obvious cold or sore throat symptoms. In a follow-up visit to Malaysia in 1989, it was found that two children, 5 and 7 years old, had been diagnosed with acute lymphocytic leukemia. A 19-year-old man, born in Bukit Merah and a life long inhabitant, was also diagnosed with acute lymphocytic leukemia. Another 5-year-old child developed a malignant brain tumor. A two-year-old child died of septicemia, and a 22-year-old worker, from the A.R.E. factory, considered by his peers to be very healthy, died with a diagnosis of meningoencephalitis. On admission to the hospital, the workers blood count was reported as abnormally low in view of his overwhelming infection (6,600 per microlitre blood). According to the Malaysian statistics, the elevated leukemia rate alone in this population of 15,000, had a probability of 3 in 100,000 of happening by chance. The expected rate was 0.03 cases per year.

It is my hope that more such biomarkers of exposure will be developed, and more community health interventions will be discovered and undertaken at an early stage in the development of environmentally related disease. I hope also that further studies and confirmation of my work will be undertaken, and that new techniques to diagnose and treat communities at risk from pollution will be a major focus of future medical research.

CONCLUSIONS:

Environmental Health is becoming a new discipline in its own right, different from Occupational Health. I believe that Environmental Health efforts will more and more come to rely on biomarkers of exposure rather than gross biological end points; such a severe tissue damage or cancer deaths. The child with its sensitivity and rapid growth rate will become the most important indicator of community health, and will become the focus of major preventive health action.

Environmental health will need to focus on parameter shifts in the population rather than on the clinically abnormal few. For example, when an individuals' normal monocyte count is about 400 per microlitre of blood, and due to bone incorporation of uranium it drops to 250 per microlitre of blood, he or she would have a bio-marker of exposure but not be clinically ill. The case is obviously clinically more important for the individual whose borderline monocyte count prior to the exposure, moves into moncytopenia. However, in terms of the health of the community, `community-shift' is the focus and not the plight of the individual and, community intervention is the response. The entire community needs assistance, not only those who fall below clinical guidelines. The individual care can be relegated to the usual physician patient relationship. This means carefully distinguishing between a normally distributed community parameter with a few abnormal out-layers, and a clearly distinguishable bell curve moved from its normal mean value. It is also possible to have communities with bimodal characteristics, i.e. a subgroup has the bio-marker for exposure. This is a new field of health investigation, which requires new thinking and new tools.

In this paper four potential bio-markers have been noted: monocyte count, death rate of low birth weight infants, incidence rate of asthma, and incidence rate of eczema.

References:
"Environmental Influence on Survival of Low Birth Weight Infants in Wisconsin in 1963-1975" R. Bertell, N. Jacobson and M. Stogre. International Perspectives in Public Health Vol 1, issue 2 1984.

"Internal Bone Seeking Radio nuclides and Monocyte Counts" R. Bertell. International Perspectives in Public Health Vol. 9,1993.

Health Profile of Area Children. Prepared for Pickering-Ajax Citizens Together for the Environment by the IICPH, May 1995.

Health 2000: Report to the Mississauga First Nation. June 1993. Available through requests to Chief Douglas Daybutch, Mississauga First Nation, Band Office, Box 1299, Village Road, Blind River ON P0R 1B6 CANADA.

A Report to the U. S. Congress on the Health Problems of the Rongelap People, June 1989. Available from the International Institute of Concern for Public Health, Resource Centre, 517 College St. Suite 326, Toronto ON MGG 4A2 CANADA.

Clinical Haematology by Eastham, R.D., Bristol, 1986

Haematology edited by William S. Bede, MIT Press, 1986, p.p. 8-16.