Requirements for PCBs

Although there are exceptions, such as waste oils used for energy recovery, PCB wastes are generally regulated for disposal under TSCA at concentrations of 50 ppm. The requirements for the disposal of PCB liquids and PCB items will be codified at 40 CFR 761.60. Disposal requirements for PCB remediation waste or PCB bulk product waste will be codified in 40 CFR 761.61 and 761.62, respectively. When the components of a waste are PCBs and non-PCB contaminants, and the PCB component is approved for disposal, the non-PCB component must meet the requirements of all other applicable statues or regulatory authorities prior to disposal (EPA 1998a). 

TABLE 22.4 The Inspection Schedule Required for PCB Transformers and Other Contaminated Devices... 

Supercritical CO2 has also beea tested as a solveat for the removal of organic contaminants from sod. At 60°C and 41.4 MPa (6,000 psi), more than 95% of contaminants, such as diesel fuel and polychlotinated biphenyls (PCBs), may be removed from sod samples (77). Supercritical CO2 can also extract from sod the foUowiag hydrocarbons, polyaromatic hydrocarbons, chlotinated hydrocarbons, phenols, chlotinated phenols, and many pesticides (qv) and herbicides (qv). Sometimes a cosolvent is required for extracting the more polar contaminants (78). 

The requirements for proper disposal of refrigeration and air conditioning waste appliances are very stringent (a) mercury switches and condensers containing PCBs must be removed in advance... 

Specific bans on chemicals or uses have not been the most important outcome of TSCA. Only one type of chemical, PCBs, was specifically targeted in the original law and they are now outlawed in most of their uses. EPA administration of the law in its early years led to a ban of chlorofluorocarbons as aerosol propellants, restrictions on dioxin waste disposal, rules on asbestos use, and testing rules on chlorinated solvents. It has led to a central bank of information on existing commercial chemicals, procedures for further testing of hazardous chemicals, and detailed permit requirements for submission of proposed new commercial chemicals. 

Bioremediation using Biodrain is not possible for compounds resistant to biodegradation. Much longer degradation times are required for compounds such as polychlorinated biphenyls (PCBs) and polynuclear aromatics (PNAs) 3 to 7 years may be required for highly resistant contaminants. Bioremediation is also limited by below-freezing temperatures and free aqueous metals concentrations. Metals can be extracted or immobilized prior to biotreatment. Biodrain cannot be installed in rock or some landfill situations unless holes are drilled first. Current installation limits are approximately 40 ft. 

Treatment of PCBs in soil may require more sodium borohydride than required for pure PCBs due to residual water and reducible humic components that might be present and consume sodium borohydride. 

Hence, the estimated K,Uo values are about 2.6 and 12 times higher than the actual measured bioaccumulation factors. The result for PCB 180 appears substantially outside expected estimation errors. If all of the discrepancies were due to the speciation of the compounds in the culture media [and not because of kinetic effects or due to the large size of the molecules (see Fig. 10.4a)], this would mean that the fraction in truly dissolved form fiv/ (see Chapter 9, Illustrative Example 9.5) would have to be 0.39 (1/2.6) for PCB52 and 0.086 (1/12) for PCB180. From these values and the DOC concentration given in the problem statement, calculate the KiDOC values that would be required for the two compounds (see Illustrative Example 9.5, Eq. 1) ... 

Estimation of pv for PCBs Burkhard et al. [8] compared the predictive capability of 11 different methods to estimate pvap for PCBs at 25°C. The comparison includes solely structure-based methods and methods that require the input of Tm, Th, and the entropy of fusion, ASfUS, or a gas-liquid chromatographic retention index. 

BISMALEIMIDE POLYMERS. These relatively new polymeric materials were developed to serve the increasing requirements for materials of high strength in high-temperature applications. Currently, a high percentage of the bismaleimides produced are used for printed circuit boards (PCBs). The materials usually are cured with aromatic amines and then compression molded into the PCBs. Future uses include aircraft structural components where bismaleimides may prove superior for high-temperature skin surface applications as compared with present epoxy composites. 

The simplex approach to SFC optimization has proven to be extremely helpful with real samples as well as synthetic mixtures. In recent work with Arochlor 1254 (Crow and Foley, manuscript in preparation), a mixture of polychlorinated biphenyls (PCBs), the number of resolved peaks increased from 19 to 28 in going from vertex 1 to vertex 21 (optimum). Resolution was improved sufficiently that baseline resolution of most if not all compounds could have been obtained by transferring the optimized method to a longer column as described earlier in the section on Minimizing the Time Required for Optimization. 

A comprehensive review of the metabolism of PCBs was published in 1976 by Sundstrom et al. (ref. 139a) confirming the importance of degree of substitution and location of halogens on toxicity. The lesser chlorinated biphenyls are more readily metabolized. The presence of at least two adjacent hydrogens—preferably in positions 3. 4, 5 or 3, 4, 5 —is required for the rapid metabolism of PCBs. This requirement is satisfied by all mono-, di- and trichlorobiphenyls, and by the tetrachlorobiphenyls with the exception of the 3. 3. 5. 5 -chlorinated PCB. This compound was reported particularly toxic to monkeys, and the intermediate formation of chlorinated dibenzofuran was postulated to account for this toxicity (ref. 139c). 

No metabolism has been demonstrated for the decachlorobiphenyl (NI0SH, ref. 136, p. 29). This and other highly chlorinated PCBs not readily metabolized may persist in the tissues for years following exposure. Some PCBs lacking the adjacent hydrogens required for rapid metabolism can be slowly metabolized by hydroxylation and oxidative dechlorination. Since arene oxide intermediates may also be involved, there is the risk of chronic exposure to compounds of high carcinogenic activity (ref. 136, p. 30). 

In 40 CRF Section 761 Subpart O, the TSCA specifically addresses the requirements for verification of self-implementing cleanup by defining the numbers and locations of samples to be collected from bulk PCB remediation waste and porous surfaces. Section 761 Subpart P specifies the requirements for non-porous surfaces cleanup verification. These regulation-prescribed sampling designs are discussed in detail in Chapter 3.5.2. 

Requirements for the collection of soil data for cleanup verification of PCB-conta.minat.ed sites are regulated by the TSCA Subparts N and O (EPA, 1998c). These detailed and exacting requirements are summarized in this chapter in the form of procedures. 

For scale-up operations, the selection of the reactor is considered to be the key element in designing SCWO systems. Environmental regulations set the requirement for the destruction efficiency, which in turn sets requirements on the temperature and residence time in the reactor (as an example, the required DRE is 99.99% for principal hazardous components and 99.9999% for polychlorinated biphenyls, PCBs). The reactor parameters for the scale-up designs can be extrapolated from the available bench-scale data. A detailed discussion on available reactor types is given below. 

A New Bedford Harbor Sawyer Street site in Massachusetts has been designated as a superfund site due to PCB contamination of river sediments. Commodore was one of three companies chosen to conduct demonstration studies on-site under contract to Foster Wheeler Environmental Company. The river sediment was first washed with diisopropylamine by the Ionics RCC B.E.S.T process [35], producing an oil concentrate. The PCB level in the B.E.S.T concentrate was approximately 32,800 ppm. Dioxins/furans (TEFs) were also present at 47 ppm. This concentrate was reacted with SET in the SoLV process to destroy the PCBs and dioxins (Table 4). After treatment, the PCB level was 1.3 ppm, well below regulatory requirements for disposal in nonhazardous waste landfills. Dioxins were also readily remediated. This study also illustrates that the SoLV process can remove metals from substrates. The concentrate received was found to have lead, arsenic, and selenium in high parts-per-billion levels. After treatment with the SoLV process, the levels were below detection limits. The metals were... 

Gas- and particle-phase organic compounds can undergo chemical change via a number of routes.76,77 For gas-phase chemicals, these involve photolysis and reaction with the hydroxyl (OH) radical, reaction with the nitrate (N03) radical and reaction with ozone (03).76,77 84 The formation of OH radicals, N03 radicals and 03 in the troposphere, and the requirements for photolysis to occur in the troposphere, are briefly discussed below, prior to presenting the experimental data for the PCBs, PCDDs and PCDFs for these processes. 

Finding 2-4. The requirements for conducting a health and environmental risk assessment for the Newport Chemical Agent Disposal Facility are similar to the state of Indiana requirements for a risk assessment of gaseous emissions from a commercial PCB incinerator. These requirements, which are similar to EPA guidelines for health risk assessments, are a reasonable approach to assessing the health risk posed by the NECDF. 

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