Understanding industrial emissi

chemicals.

1178 Envlmn.&i.Teohnol.,Vol.23, No. 10,1980 0015936~)23-1178501.50n 1989 American Chemical Society

.EPCs); the development of emer- gency plans to deal with sudden ehenucal releases; and reporting by industry of the quantities and charac- tenstics of chemicals on site and those emitted from each facility. In the main, the emissions addressed in SARA Title UI are those released into the air.

Chemicals that are present in the atmosphere and that can cause ad- verse health effects are commonly de- scribed as air toxIcs. For many years, scientific and regulatory efforts were devoted to the monitoring and control of a very few of these air toxics, known as criteria pollutants They were given ttus name because these pollutants are the only ones for which federally enforceable standards have been set. The criteria pollutants in- clude sulfur and nitrogen oxides, car- bon monoxide, lead, and particulates.

The vast majority of chemicals emitted into the atmosphere are not subject to such ambient standard% Recent EPA reports indicate, how- ever, that some of these compounds could be responsible for significant health effects, especially in the urban environment (I, 2). These reports, coupled with the Bhopal incident, have led to calls at the federal and state levels for the establishment of standards for the many air toxics that are released in significant quantities on a regular basis.

In the absence of federal action, a number of states are establishing standards for these air toxics. At present, however, concerned cifjzens must deal with federally mandated in- formation about types and quantities of toxics released into their air with- out any accompanying scientific inter- pretation of these numbers. Thus, leg- islation that intended to empower the community by providing release data IS not l ie ly to achieve its goal without a concomitant effort to explain the significance of these data.

This series of articles has been writ- ten to provide scientists with a sum- mary of the present understanding of the impact of these releases on human health and how this information can best be transmitted to the public. It is important that scientists have this in- formation b u s e they are often the only technically educated people to whom the public can turn for interpre- tation. Indeed, scientists serve on, or as resources fot; LEKS in many lo- calities. Even these scientists, who understand something about the is- sues, can benefit from a comprehen- sive, up-tc-date sununary of what IS

lie. Communication of risk to the pub- lic is a very difficult task. Information on this process can not only lead to better communication, but also can help scientists retain their credibility in potentially adversanal situations.

Series in brief The first article in the series, by Jef-

frey Stevens and Deborah Swackha- mer of the School of Public Health at the University of MiMemta, deals with the assessment of human expo- sure. Often the public equates release or emission with exposure, but the connection between the two is very complex because of the many possible paths of chemical movement in our environment and the variarions in hu- man behavior. Scientists have much to learn about distribution and fate of chemicals in the environment, but ef- forts are under way to try to reduce the uncertainty. The results of some of this work will be presented in this ar- tiele. In addition, the importance of human behavior in exposure is be- coming more widely appreciated; steps are being taken to research this q i c and provide Mer answers than are presently available.

Exposure is one major factor that contributes to toxicological risk; the other is @e inherent toxicity of the chemical to which the population is exposed. The second article in this se ries, Written by Edward Calabrese of the Division of Public Health at the University of Massachusetts, will deal with toxicity assessment for air con- taminants. Although there have been many studies performed on animal species to assess toxicity, most have been feeding, rather than inhalation, studies and have been performed us- ing exposure regimens that do not simulate usual human exposures to toxics in ambient air. In addition, there are some data available from studies of humans exposed regularly to work place air contaminants. This combination of animal and human data has been the basis for the estab- lishment of standards for maximum permissible work place air levels.

The question is then how best to use these data, and perhaps these oecupa- tional standards, to determine the lev- els of risk posed by various concen- trations of chemicals in ambient air. There have been a number of answers proposed, and indeed adopted in m e localities; this second article exam- ines these alternatives and assesses approaches to the question. The reader should gain an understanding of the strengths and l i ta t ions of our

7ts to s issue. -

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