Vols militaires à basse altitude au labrador

Résumé

Le gouvernement fédéral s'est efforcé d'obtenir de ses alliés l'engagement à long terme qu'ils continueront à former leurs pilotes à Goose Bay, assurant ainsi la survie économique de la région. Les vols militaires d'entraînement à basse altitude actuels et prévus se feraient au-dessus de certaines régions du Labrador et du Nord québébois. Le ministère de la Défense nationale, responsable fédéral de ce projet, a publié, au printemps 1994, une ÉIE portant sur l'impact environnemental de l'augmentation du nombre des vols militaires à basse altitude de 7000 à 18 000 par année (la première ÉIE publiée par le ministère avait été déclarée déficiente par la Commission d'évaluation). Le renouvellement de la trajectoire de vol au-dessus du Labrador a reçu l'appui de la majorité des habitants du Labrador. Toutefois, la plupart des groupes autochtones touchés par le projet se sont vigoureusement opposés à la présence militaire continue au Labrador. Les principales inquiétudes concernaient les aspects environnementaux et socio-économiques des vols à basse altitude, les effets sur la santé publique et l'utilisation du sol par les autochtones. Préoccupations de Santé Canada : Santé Canada avait plusieurs craintes au sujet de la qualité de l'air, de l'élimination des déchets et des eaux usées, de l'approvisionnement en eau potable et, particulièrement, des effets de l'exposition au bruit sur la santé des humains.

** Veuillez noter que lorsqu'une présentation a été effectuée au Comité, la transcription réflète la langue dans laquelle a été présentée. **

Transcripts Regarding Health Canada's Presentation at Panel Concerning

Low Level Military Flights in Labrador-Goose Bay

Introduction by Mr. Tom Humes, Health Canada
Presentation by Dr. Stephen Bly, Health Canada

THE CHAIRMAN: Acoustic Radiation Specialist, Health Protection, Health Canada.

So could you speak now, Dr. Bly?

DR. STEVEN BLY: Certainly.

THE CHAIRMAN: Now, Dr. Bly, I will do ---

MR. TOM HUMES: I do not want to confuse the issue. I am Tom Humes with Health Canada and I have been asked to just give a brief introduction to Dr. Bly.

THE CHAIRMAN: Thank you. That is fine. That is good, because I do not have any information on Dr. Bly. So thanks very much.

MR. TOM HUMES: In my own case I represent Health Canada in the Environmental Assessment process in the Atlantic region out of Halifax. And Dr. Bly is a Health Canada scientist based in Ottawa, and he will do a presentation on the impacts of noise related to human health.

But I would like to just backtrack a little bit to indicate why Health Canada is here. And in brief we have been involved with this environmental assessment process under the EARP guideline order, however, we are also involved from another point of view is that we are also responsible for monitoring occupational and environmental health issues for Environment Canada and for rather Public Service employees.

And Health Canada under this carried out reviews of the EIS as similar to other departments have done. And several months ago deficiencies were raised at that time of which one was the exposure to noise related to human health risks. We also raised air quality, other issues regarding infrastructure for drinking water, waste treatment and waste water treatment on the Base itself which could be impacted by the increased activities.

However, since this time most of these activities have been put to rest by being addressed by the Proponent or satisfied by our own investigations. For example, the Environmental Action Plan prepared by 5 Wing Goose Bay deals with the clean up and control of potentially hazardous sites and also drinking water treatment on the Base and also other activities going on in the area in the pre-planning and pre-construction of improving water systems for the town as well as upgrading sewage treatment to meet Federal guidelines.

However, this still leaves the factor of potential effects of noise exposure. And as such, Health Canada is intervening in effect and has arranged for Dr. Bly to give you a presentation on these effects.

Dr. Bly is a scientist with the Radiation Protection Bureau in Ottawa and as such deals with a number of noise related issues. So I will not hold up the Panel any longer.

Dr. Bly.

DR. STEVEN BLY: This presentation examines the potential for adverse health effects in humans due to exposure to environmental aircraft noise generated by low flying military training flights in Labrador and Quebec.

With regard to the potential effects on human hearing, our review of the available evidence indicated that it was unlikely that people would incur measurable permanent hearing losses either in the vicinity of the airport or in the LLTA due to environmental aircraft noise from low flying military training flights. And that was based on the Proponent's estimates of noise exposure in those two areas.

For the estimates of noise induced hearing loss, we used an international standard called the ISO Standard 1999 to predict hearing loss according to the level continuous average eight hour daily exposure to noise. We also used impulse damage criteria that was published by Pfander et al in 1980. Using these criteria and other damage criteria as well for impulse noise, we came up with the prediction that there would be no expected hearing loss -- no expected permanent hearing loss.

However, some of the studies that e found did indicate that for some of the population in the LLTA, some small but measurable temporary shifts -- temporary shifts in hearing thresholds can occur. And we would -- it has been reported before by Hill in his Master's thesis, there were self-reports of temporary ringing in the ring and earaches from overflights, and those are consistent with some of the German studies that we found as well. So those are the temporary effects on hearing.

Now, in addition we have looked at what are called non-auditory effects, that is effects not directly on the ear. And with regard to those, we could not find any convincing evidence that exposure to aircraft noise in the area surrounding the Goose Bay Airport, or in the low level training areas under present or future conditions as estimated by the Proponent would cause an increase in the incidents of cardiovascular disease or mental illness or psychosomatic illnesses or adverse pregnancy outcomes.

That is based on a number of critical reviews that have been published on the literature in this area over the years, and also it is based on the results of the German studies in low level training areas in Germany where noise levels were similar to those in the LLTAs in Labrador and Quebec.

I just want to comment first on the hearing loss, the increased risk to the fetus because Dr. Hétu mentioned that.

THE CHAIRMAN: Could I suggest, Dr. Bly, if you have the time, you know, within the 20 minutes you are welcome, comment on it. But there will be time later to comment on that too if you would like.

DR. STEVEN BLY: Oh, okay.

THE CHAIRMAN: So it might be that ---

DR. STEVEN BLY: No, it is part of the general presentation and I thought I would bring it up now.

THE CHAIRMAN: Well, it is up to you. I do not want to interfere with that. But I just thought that if you wanted to get into that, it might take away from the rest of your presentation. And we no doubt will get into that later.

DR. STEVEN BLY: Okay.

THE CHAIRMAN: I just want to make sure that there is enough time for you to make all your presentation, that is all. I just want to be fair about getting it all in.

DR. STEVEN BLY: Well, as I said, there are a number of critical reviews that have been published that supported the conclusion that I made that there is no convincing evidence that exposure to LFMTF noise would increase the risk of cardiovascular disease or mental illness or psychosomatic illnesses or adverse pregnancy outcomes.

I would like to give some examples now of some of these reviews that I have indicated that suppo rt this conclusion.

In a review back in 1980 of the research that was done around the busy airports, Taylor and co-workers examined several non-auditory health outcomes due to noise exposure. And at the time, only 47 of 146 papers assessed were judged to have conclusions which were justified by the evidence, and only 10 dealt with these non-auditory health outcomes. And of these 10, no clear evidence was found for non-auditory health effects of noise exposure.

Taylor and Wilkins updated this review in 1987. There were still few rigorous studies and in their analysis the most rigorous studies showed no significant effects of environmental noise exposure on adverse health outcomes.

In the German studies they looked at -- there were psychiatric -- there were different outcomes that were looked at. I will deal with the psychiatric illness and the psychosomatic illness first.

Some of the German researches performed a study in which they did a child psychiatric interview study -- sorry -- a child psychiatric interview to address whether exposure to noise from low flying military training flights led to an increased risk of psychiatric disorders. They looked at four districts in Germany with a high level of noise from low flying military training flights and they compared those to three control districts with a low level of noise from -- a relatively low level of noise from low flying military training flights.

And overall, they found that the psychiatric disturbance of children and adolescents did not differ between the high and low noise areas. They also found that psychosomatic complaints such as headaches or dizziness or illnesses such as asthma did not differ between the high and low noise areas. And in summary, in this particular German study by Schmeck and Poustka, the noise of jetfighters was not associated with a greater amount of medical problems in the exposed population.

Maybe I should tackle cardiovascular disease since it is next up there, although it is not next in my notes.

There have been a number of conflicting reports as to whether environmental aircraft noise can increase the risk of cardiovascular disease. And as assessed in several reviews, few studies of sufficient rigour have been performed. One study that was assessed by Taylor et al, as I mentioned before, was that of Frerichs et al and they found no association of mortality due to cardiovascular disease with noise exposure at the Los Angeles International Airport.

There have been some other recent studies suggesting differences in cardiovascular rates for people above the age of 74, but these have been criticized because these were studies down around the area of Los Angeles Airport again. But these studies have been criticized because no adjustments were made for confounding factors such as family history of cardiovascular disease or smoking.

Another study that had found an association between aircraft noise exposure and increased blood pressure in children around the Los Angeles Airport again was not supported in the follow-up studies by the same co-authors. So there is really no consistent evidence, at least from the studies around busy airports, of increases of cardiovascular disease associated with aircraft noise.

Now, the type of exposure in the LLTA can reach high peaks -- 115 to 125 dBA weighed at maximum levels with rapid onset rates greater than 60 dB per second. And this type of noise causes a significant startle effect.

Some objective measurements of startle reactions have been made by the Germans in the German studies and in some simulations that some of the German researchers did in co-operation with Israeli researchers. They found significant -- these researchers found significant differences between reactions to flights with high and low -- to flight noise with high and low onset rates demonstrating the importance of the combination of onset rate and maximum level to the startle response. You do not get this kind of startle response found in residential areas in the vicinity of busy urban airports.

But the evidence from these studies overall pertaining to non-auditory health outcomes was still inconsistent or inconclusive. In the studies in co-operation with some Israeli researchers, these were simulation studies where they exposed elderly people -- elderly volunteers in the age range of 70 to 89 years to simulated overflights. About 29 of the subjects experienced blood pressure elevations less than five millimetres of mercury. Eight subjects had elevations greater than 25 millimetres of mercury after the second exposure suggesting a short term sensitization.

The average increases in these studies were 23 and 13 millimetres of mercury respectively for systolic and diastolic pressures.

In a similar type of simulation study with healthy young men and women, they found -- they also found significant effects on blood pressure, but only within one minute of the noise and the effects were much smaller with this younger population.

In the East German studies by Ising and co-workers, there were no significant changes in the stress hormones, in the levels of stress hormones. The results of these laboratory studies do not provide sufficient evidence to conclude that low flying military aircraft flyovers would cause an increased risk of acute adverse cardiovascular effects even in a very elderly population.

The results of the German epidemiological studies, which were on the populations who were living in their low level training areas, also do not support the hypothesis that exposure to LFMTF noise leads to increases in hypertension, cardiovascular risk factors or ischemic heart disease.

Schulte and Otten performed an interview study in Northern Germany comparing men and women aged 20 to 60 years in a low flight zone. And they compared them to rural and urban control areas. The interview study found that -- by Schulte and Otten -- found that there were no significant differences between the different areas and the frequency with which men and women reported high blood pressure or high cholesterol levels, and a follow-up medical examination of a subset of the interviewed population verified their interview results.

And also in the interview study, the self-reported prevalence of heart attack and stroke did not vary between the men or women of the three areas.

Similar results were found by Ising and co-workers in a study of subjects aged 20 to 60 in Southern Germany, a similar type of study. There was no indication in those findings that cardiovascular risk factors were more frequent in the low altitude flight territory than in similar zones without low flying aircraft.

Inconsistent or negative findings were obtained in field studies of blood pressure and heart rate in children.

THE CHAIRMAN: Dr. Bly, you should finish up in about five minutes.

DR. STEVEN BLY: Oh, okay.

Well, I will just finish with some comments about some recent reviews that appeared in the literature in 1993.

The Congress on Noises of Public Health Problems, two eminent researchers in the area, Schwarze and Thompson, reviewed the literature published since 1988 on non-auditory health effects. The sorts of outcomes I have up there: cardiovascular disease, mental illness, psychosomatic illness, adverse pregnancy outcomes. And their review notes that recent studies of high speed or low altitude flight noise were difficult to interpret because of low statistical power and inability to adjust for confounders. They also found that, in general, epidemiological evidence of the harmfulness of chronic noise is weak.

So to finish up, in the review I have just presented a considerable amount of research on non-auditory health effects and also there does not -- there is no consistent evidence, convincing evidence for non-auditory adverse health outcomes. The risks, if any, consistent with other published reviews, it appears that the risks, if any, of the adverse non-auditory health effects such as increase in cardiovascular disease or mental illness or psychosomatic illnesses or adverse pregnancy outcomes is either negligible or it is currently too small to be reliably identified.

So no statement -- no reliable statement of an impact can be ascribed to the flight noise from low flying military training flights in either the LLTAs or in the vicinity of the Goose Bay Airport and that is all. That is all about that.

And with regard to hearing loss, we used different criteria, international standards, published criteria for impulse noise damage and our findings were t hat it was unlikely that there would be any permanent hearing loss. This was consistent with the literature such as the recent study by Nixon and co-workers for the U.S. military. A simulated study with overflights with maximum levels of about 130 dBA found very few of the volunteers had significant Temporary Threshold Shifts.

I guess that is it.

THE CHAIRMAN: Thank you. Thank you very much, Dr. Bly.