cess changes that actually produce less waste. The definition does not include recycling or treatment to reduce the hazard of a waste. For example, changing to microscale techniques is considered source reduction, but recycling a solvent waste is not.
The distinctions made above are the result of an approach to waste management that incorporates a hierarchy of pollution prevention techniques. At the top of the hierarchy is source reduction, which is always the preferred technique. Source reduction can be achieved by using a smaller quantity of material or a less hazardous material or by making a process more efficient. However, while source reduction is highly desirable, it is not always technically or economically feasible.
The second level of the hierarchy is recycling/reuse/recovery. The distinction here is that the waste requires some input of energy (e.g., distillation) before it can be reused. Because of this additional waste-handling step, there is also an increased potential for spillage and other fugitive losses of material that would not occur had the waste not been generated in the first place. However, when source reduction techniques are not available or practical, recycling, reuse, or recovery can be important alternatives to disposal.
The third level is treatment. Generally, treatment of a waste renders it less hazardous or nonhazardous but does not allow reuse of the material. For materials that have no potential for recovery and are not amenable to source reduction, treatment—such as neutralization of acids, incineration of organic sludges, and oxidation of cyanides—becomes an important part of the waste management system.
The last level (and least desirable alternative) is land disposal. Certain hazardous wastes, particularly the heavy metals, cannot be rendered completely nonhazardous and cannot realistically be recovered. They can, however, be stabilized to reduce the likelihood of movement in the environment, and regulations require this procedure before land disposal is permitted. Whereas land disposal of laboratory waste (in "Lab Packs") was once the most common form of waste management, it is now rarely used, and then only in very specialized situations and locations.
Many advantages can be gained by taking an active pollution prevention approach to laboratory work, and these are well documented throughout this book. Some potential drawbacks do exist, and these are discussed as well and should be kept in mind when planning activities. For example, dramatically reducing the quantity of chemicals used in teaching laboratories may leave the student with an unrealistic appreciation of their behavior when used on a larger scale. Also, certain types of pollution prevention activities, such as solvent recycling, may cost far more in dollars and time than the potential value of recovered solvent. Certain waste treatment procedures may even have regulatory strictures placed against them.
Perhaps the most significant impediment to comprehensive waste reduction in laboratories is the element of scale. Techniques that are practical and cost-effective on a 55-gallon or tank car quantity of material may be highly unrealistic when applied to a 50-gram (or milligram) quantity. Evaluating the costs of both equipment and time becomes especially important when dealing with very small quantities.
Many important changes in the legal and regulatory climate over the last 20 years have added to the changing culture of safety. Because of increased regulation, the collection and disposal of laboratory waste now constitute a major budget item in the operation of every chemical laboratory. Also, it is now widely recognized that protection of students and research personnel from toxic materials is not only a moral obligation but also an economic necessity-the price of accidents in terms of time and money spent on fines for regulatory violations and on litigation can be very high.
In response to the heightened concern for safety in the workplace, the OSHA Laboratory Standard (29 CFR 1910.1450) requires every institution that handles chemicals to develop a Chemical Hygiene Plan. This requirement has generated a greater awareness of safety issues at all educational science and technology departments and research institutions. Although the priority assigned to safety varies widely among personnel within chemistry departments and divisions, increasing pressure is coming from several other directions in addition to the regulatory agencies and accident litigation. In some cases, significant fines to principal investigators who have received citations for safety violations have increased the faculty's concern for laboratory safety. Boards of trustees or regents of educational institutions often include prominent industrial leaders who are highly aware of the increasing national concern with safety and environmental issues and are particularly sensitive to the possibility of institutional liability as a result of laboratory accidents. Academic and government labo-