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6 Evaluating Toxic Chemical Management Practices INTRODUCTION The third possible use of mass balance in- formation listed in SARA Section 313~1) is for assessing "toxic chemical management practices at facilities currently reporting to the TRI. These practices are considered to encompass transportation across and within facility boundaries, storage and handling, waste reduction, and on-site tracking and treatment of toxic chemicals. This chapter evaluates both EMB and MA practices for their adequacy in providing data on (a) the types and amounts of toxic chemicals managed by a facility; (b) the extent to which changes in amounts of toxic sub- stances are attributable to changes in levels of manufacturing activity; (c) the com- parability among facilities; (~) their useful- ness to chemical managers for enhancing the safety of their management practices; and (e) their usefulness to the public and govern- ment in evaluating whether effective prac- tices are being used to minimize the actual and potential releases of toxic chemicals into the environment. The use of mass balance information for evaluating waste reduction efficiency is discussed in Chapter 5. 57 CHEMICAL MANAGEMENT PRACTICES Transportation Assessing management of transportation of the chemicals outside of facilities is beyond the scope of the committees charge. This section focuses on the movement of chemicals within and across boundaries of facilities. However, the methods used to transport chemicals outside of facilities might affect toxic chemical management practices at a facility. For example, materials brought to a facility by rail might be offloaded and stored differently from materials brought by trucks. Different transportation practices also have different potentials for routine and accidental releases. The single and most relevant piece of in- formation in evaluating toxic chemical management practices is the annual quantity of specific chemicals transported across fa- cility boundaries. Although this information could be obtained through EMB, it would be much cheaper and simpler to obtain it from readily available records, such as invoices and shipping manifest records. In this case,
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58 information obtained through MA would be sufficient. Information supplementing MA data could contribute to a community's ability to estimate risks for types and quantities of chemicals brought to and taken from a site. Descriptions of changes in physical-chemical properties (e.g., from a liquid to a solid material or from a more hazardous to a less hazardous form) or changes in transport methods could provide valuable information to the community in assessing the potential hazards associated with transport practices and for developing emergency response plans. Storage and Handling of Chemicals Storage and handling of chemicals at a facility can encompass a wide range of activities. Conceivably, these could include methods of shipping and transfer, quantities shipped and stored, high-pressure processing or storage of chemicals, form of storage, un- loading systems, unloading procedures, safe- ty systems, frequency of inspection, and other critical pieces of information necessary for the management and handling of chemi- cals. The probability and severity of a sudden release of a toxic chemical at a facility relate to the maximum quantity stored at the fa- cility. Community knowledge of quantities of hazardous materials stored is provided for by TRI reporting. This information, which is reported annually, is important in assess- ing a facility's progress in the reduction of the absolute quantity of chemicals stored on site and indicates to the public the facilities where large quantities of dangerous chemi- cals are stored. However, the quantity of chemicals stored can fluctuate relative to a facility's level of production, which can make interfacility comparisons difficult, even among similar types. In these cases, on a conceptual basis, normalization of the maximum quantity of chemicals stored on site (by dividing this quantity by the level of production) could be useful. However, all proposed normalization factors lack consistency among various chemicals and processes (see Chapter 5~. The probability and severity of a release are also a function of a chemical's properties and reactivity; equipment design safeguards, AL455 BALANCE INFORMATION operating procedures, operator training, quality of maintenance and monitoring; and the chemical's toxicity, transport characteris- tics, release location, and receptor locations. This type of information is not provided through TRI reporting requirements and also would not be provided through the addition- al reporting of any type of mass balance in- formation. The use of mass balance information collected within a facility can support chem- ical management practices that reduce the presence of toxic chemicals on site. For ex- ample, maintaining current information on the chemical quantities stored at a facility provides an owner or operator with greater certainty of chemical amounts available and allows for controlling inventory at a mini- mum level. A chemical inventory could be determined at any point from regularly re- corded mass balance information on the amount of chemicals brought into a facility and the amounts shipped out of the same facility. For users of chemicals in complex opera- tions, such as motor vehicle manufacturing, a unit-specific control of inventory is neces- sary (Bowditch, l988~. In the case of facili- ties in which chemical conversions take place, calculating the usable volume of pro- cess vessels, piping, storage vessels, and con- tainers associated with the chemicals might be needed in addition to mass balance information. On-Site Treatment Waste reduction via process modification should be the management strategy of choice before treatment is considered, since treat- ment always results in residuals and is prone to episodic chemical releases. Treatment as a management process within a facility is used to render chemicals less toxic (e.g., conversion of hexavalent chromium to trivalent chromium or bioxida- tion of chlorinated organic compounds) or to render them less mobile (e.g., solidify heavy-metal wastes). Incinerators, waste- water treatment facilities, and air-pollution control devices are included in treatment processes. The efficiencies of such on-site treatment and the associated releases are requested as part of TRI reporting. Loehr and Ward (1987) note that the
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EVALUATING TOXIC CHEMICAL MANAGEMENT PRACTICES EMB approach can be effective in ensuring that a waste-management system does not unknowingly transfer pollutants from one medium to another in the process of meeting a particular regulation or effluent limit. They also indicate, however, that adequate data rarely are available to permit the development of meaningful mass balances. For waste-water treatment, mass balance information can demonstrate that some organic pollutants can undergo volatilization and accumulation in sludge as opposed to degradation through bioxidation. A 3-week, multimedia sampling study was conducted using the EMB approach at a large petrochemical waste-water treatment facility to determine the fate of eight or- ganic chemicals with various characteristics (Berglund and Whipple, 1986~. This study illustrates the difficulty of using EMB on a facility of any complexity. Primarily be- cause of wide variation in the chemical makeup and concentration in the influent waste water, and because of fluctuations in wind speed and direction (a factor in meas- uring volatilization losses), EMB did not provide sufficient closure to assess the efficacy of waste-water treatment. How- ever, predictive models were developed, be- cause data collected through EMB gave in- sight into the relationship of air release and sorption to biological process conditions and chemical properties. EMB data can also be useful in providing a maximum upper bound on possible atmospheric emissions from waste-water treatment (Noll and DePaul, 1987). There are no obvious applications for MA in assessing treatment processes, because MA information typically is concerned with the flow of chemicals across facility boun- daries. To assess treatment processes, de- tailed information is needed on the amounts of chemicals flowing through the facility be- fore treatment, and thus within-facility in- formation is required. In summary, reporting of mass balance information, obtained through either EMB or MA, would not be appropriate in most cases, for assessing on-site treatment practices because of the within-facility complexity and variability of the waste streams flowing into the treatment systems. However, collecting EMB information on the treatment systems could be a useful manage- ment practice within a facility to indicate 59 the release avenues that require more thorough investigation. Gradual and sudden releases of toxic chemicals can occur as the result of the ab- sence of management guidelines for prudent chemical-handling practices at a facility. Only limited public information is available concerning adequate chemical management practices at facilities and whether these practices are the most effective and are em- ployed continuously. Useful information is provided to evaluate the management prac- tices of a facility when release data reported to the TRI are combiner] with information on causes of the release (e.g., employee er- ror, metal fatigue, inadequate detection and repair of equipment leaks, and equipment failures). However, as demonstrated through the New jersey Industrial Survey, this additional information could be obtained only by evaluating the reported release data in conjunction with a site visit to the report- ing facility (NJDEP, 1986~. CONCLUSIONS EMB and MA are conceptually useful for assessing and sometimes improving manage- ment practices, including transportation of toxic chemicals into and out of a facility, storage, tracking toxic chemicals on site, waste reduction, and waste treatment. How- ever, mass balance information obtained either through EMB or MA practice is gen- erally inappropriate from a practical per- spective. Because of large differences among the processes within facilities report- ing TRI information, the practical usefulness of the EMB and MA data in making com- parisons between facilities is severely limited, for assessing transportation, handling, and storage practices. Only EMB would be appropriate for assessing waste- treatment practices. However, the practical difficulty in achieving closure limits this e e app Cation. The maximum quantity of chemicals on site is one of the more important factors in estimating the likelihood and magnitude of a sudden release. The management practice of reducing stored quantities usually can be as- sessed by directly measuring on an absolute basis the maximum quantity of chemicals present. This information is currently re- ported to the TRI. When it is necessary
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60 either to assess inventory control practice at a facility with widely fluctuating production rates or to compare practices between facili- ties, normalization by dividing inventory by the amount used or produced at the facility is a means of accomplishing the objective. All normalization factors, however, fail to provide a consistent basis for comparisons among various chemicals ant! facilities. Information currently reported to the TRI does not closely link release data to chemi- cal-management practices except for on-site waste-treatment practices. Additional facili- ty-specific information on other manage- ment practices, such as transportation and storage and handling, could assist the public in evaluating whether the most effective management practices are being used to control or prevent releases of TRI-listed chemicals. AL4SS RAL4NCE INFORMATION Mass balance information collected! with- in a facility can be used by that facility to support certain chemical-management practices that reduce the presence and release of TRI-listed chemicals. For example, mass balance information can provide the facility with current information on chemical quantities stored on site and facilitate controlling its inventory at a minimum level. Data obtained through EMB can be used to point out release routes from waste-treatment processes that need more complete and direct measurement. Because MA does not rely on chemical flow data from within a facility, this approach would not be useful in assessing waste-treatment practices.