Chemistry and public health During December and January I attended two workshops that offered entirely different perspectives on the use of chemistry for the protection of public health. In January, a workshop was held at UCLA to discuss current information on the by-products formed when ozone is used for drinking-water treatment. The conference, which included 11 distinguished speakers, was attended by scientists and engineers from North America, six Western European countries, and three Asian countries. I was struck by the nice blend of basic and applied chemistry examined at this workshop; discussions during those three days reminded me of similar meetings that occurred shortly after chlorine by-products were discovered. Chlorine was used in water treatment for more than seven decades before trihalomethanes (THMs) were found. THMs went undetected for that long partly because analytical methods of appropriate sensitivity were not yet available to detect trace-level organics and partly because of the lack of careful investigation. Even after THMs had been found to be ubiquitous in chlorinated natural waters, it was years before chloroacetic acids, haloacetonitriles, and some of the more exotic chlorinated by-products were discovered. Ozone also has been used in water treatment for more than seven decades, but we have yet to find ozone by-products as dreadful as THMs. Is it because they are not present, or are we looking with the wrong tools and techniques? Ozone by-products may be much more polar, perhaps more labile, and less amenable to the procedures that have become familiar to environmental analytical chemists. The UCLA workshop adjourned with the prospect that there may be no analogues of THMs from ozonization and that risk managers may be
0013-936x188/0922-0347$01 S O / O 0 1988 American Chemical Society
forced to deal with the possibility of either regulating the levels of large numbers of trace by-products or not regulating them at all. The conference I attended in December was of an entirely different sort. In Lima, Peru, I met with public health officials from 11 South American countries at a Pan American Health Organization workshop on water disinfection. There we discussed the adaptation of relatively simple technologies to develop workable disinfecting units for small communities and rural areas. The contrast between the two workshops was striking. In Lima we addressed risk levels that were almost certainly orders of magnitude higher than the risks posed by disinfection by-products. In Los Angeles we were speaking of presumed risk levels in the range of one out of a million. In Lima one could speak, if one wished, of the effects of poor water quality on vast numbers of people, of children taken before they could walk or play, and of whole villages deprived of energy by diarrhea. The contrast between the two conferences demonstrated to me the inequitable distribution of resources that are available to address environmental and public health problems in developed vs. underdeveloped parts of the world. The tragedy is not that we have the resources to address low-level risks at workshops such as the one in Los Angeles, but that we must, for some reason, neglect much larger risks that are faced by our fellow human beings in other parts of the world.
Environ. Sci. Technol., Vol. 22, No. 4, 1988 347
