Three Environmental Ages

Part 3: The Age of Exclusion

The Age of Exclusion

The third age, the Age of Exclusion, was borne out of the realization that, in many cases, dilution only partially solved acute impacts and often caused or enhanced chronic problems. At times the impacts occurred great distances from the source. As the technology to measure trace compounds improved, and medical and biological research found adverse effects from a growing number of chemicals being released into the environment, it became obvious that only Exclusion is the Solution to Pollution. Exclusion of chemicals from the emission stream is the only true solution to the problems of long-range transport and deposition and bio-accumulation.

The developing philosophies of the Age of Exclusion will significantly revise our thinking and handling of the waste products of human activity. Under these philosophies, emissions of pollutants will be either eliminated from the effluent stack or pipe through increased waste stream treatment, removal at the process level prior to entering the effluent stream, development of closed-loop manufacturing systems, or the complete removal of a chemical from production or use in the process.

Care must be taken in applying exclusion, however, to avoid trading one problem for another. Environmental decisions developed for one medium (e.g., water, air or land disposal) are often made in isolation from other media. As a result, inconsistencies may surface. Exclusion of pollutants from an effluent, for example by the use of filters or chemical scrubbers, may result in a waste product destined for disposal in a landfill. If this waste has a high level of heavy metals or toxins, they may find their way into the soil or water environment causing unforseen problems. Thus, we may be trading one environmental problem for another.

Another concern is the question of how to define exclusion. For example, zero discharge has been championed by a number of environmental organizations on both sides of the Great Lakes in the past decade working diligently to make the public aware and in favour of the zero discharge of toxic chemicals into the Great Lakes. They hope to then pressure Ontario, Quebec and American state and federal governments to revise their regulations to require zero discharge of persistent toxic chemicals. Industry, on the other hand, prefers �virtual elimination' as a goal. A question arises from this exercise in semantics, "What is meant by zero and zero discharge?

We are currently able to measure certain pollutants down to concentrations at approximately the one part-per-quadrillion (ppq) level. Therefore, is anything with a concentration of less than the measurement detection limit zero concentration? Is 0.1 ppq to be considered zero? In a single deep breath, the inhalation of a toxic gas at a concentration of 0.1 ppq translates to approximately one million molecules inhaled. If zero means mathematical zero � nothing, absence of, etc. � how will we know we have attained zero when we cannot distinguish between a sample with one or one million molecules of compound X in it?

While problems such as determining what constitutes exclusion may, in some cases, never be completely resolved, all is not futile. There have already been many important actions in the dawning of the Age of Exclusion. Exclusion is a very real possibility for compounds which are not natural to the environment such as the chlorofluorocarbons (CFCs). Two programs which deal with the philosophy of exclusion � the efforts of the Montreal Protocol to ban emissions of ozone-destroying chemicals, and the 3-plus-Rs programs for waste reduction � are current positive actions ushering in the dawning of the Age of Exclusion.