Hazardous waste reactivity

A sohd waste is considered hazardous if it is either a Hsted waste or a characteristic waste. Listed wastes include a Hst of specific processes that generate a waste and a Hst of discarded commercial chemical products. There are four hazardous waste characteristics ignitabiHty, corrosivity, reactivity, and toxicity. The last refers to the leachabiHty of a waste and the resultant toxicity in the groundwater using the analytical method referred to as toxicity characteristic leaching procedure (TCLP). A Hst of substances included under TCLP is shown in Table 1. 

Hazardous Wastes The U.S. EPA has defined hazardous waste in RCRA regulations, CFR Parts 260 and 261. A waste may be hazardous if it exhibits one or more of the following characteristics (1) ignitability, (2) corrosivity, (3) reactivity, and (4) toxicity. A detailed definition of these terms was first published in the Federal Register on May 19, 1980, pages 33, 121-122. A waste may be hazardous if listed in Appendix Wll. 

In the past, hazardous wastes were often grouped into the following categories (1) radioactive substances, (2) chemicals, (3) biological wastes, (4) flammable wastes, and (5) explosives. The chemical cate-goiy included wastes that were corrosive, reactive, and toxic. The principal sources of hazardous biological wastes are hospitals and biological-research facilities. 

The testing of chemicals/wastes to establish the nature of their hazard capacity/threat in accordance with regulatory requirements falls into four categories (1) reactivity, (2) ignitability/flammability, (3) corrosivity, and (4) EP toxicity. Commercial chemical products, specific wastes, and wastes from specific processes may be listed as hazardous wastes because they are known to present toxic hazards in the manner of the tests above and/or are known to present serious toxic hazards to mammals/humans. In the discussion to follow, various chemical groups will be examined primarily in the context of reactivity, ignitability, and corrosivity. 

Notification to the NRC is required for releases equal to or greater than the reportable quantity of a RCRA hazardous waste. If the waste also is on the CERCLA list, that reportable quantity applies. If not, the reportable quantity is 100 pounds if the waste is ignitable, corrosive, reactive, or toxic. 

Soil Cleanup, or remediation, of hazardous waste sites will often produce contaminated soil. Contaminated soil must be handled as hazardous waste if it contains a listed hazardous waste or if it exhibits a characteristic of hazardous waste. As with hazardous waste, land disposal of hazardous soil is prohibited until the soil has been treated to meet LDR standards. These contaminated soils, due to either their large volume or unique properties, are not always amenable to the waste codespecific treatment standards. Because of this, U.S. EPA promulgated alternative soil treatment standards in 268.49 in May 1998. The alternative soil treatment standards mandate reduction of hazardous constituents in the soil by 90% or 10 times UTS, whichever is higher. Removal of the characteristic is also required if the soil is ignitable, corrosive, or reactive. 

The waste typically exhibits one of the four characteristics of hazardous waste described in the hazardous waste identification regulations (ignitability, corrosivity, reactivity, or toxicity). 

Handy RW, Pellizzari ED, Poppiti JA. 1986. A method for determining the reactivity of hazardous wastes that generate toxic gases. Hazardous and Industrial Solid Waste Testing Fourth Symposium, ASTMSTP 886 106-120. 

Under the authority of the RCRA, a solid waste would be defined as hazardous if it exhibits any of the four (ignitability, corrosivity, reactivity, and toxicity) characteristics used to identify hazardous wastes. 

The use of nanoscale materials in the dean-up of hazardous waste sites is termed nanoremediation. Remediation of soil contaminated with pentachloro phenol using NZVI was studied [198]. In a separate study, soils contaminated with polychlorinated biphenyls was treated using iron nanopartides [194], NZVI and iron oxide have been suggested to be used as a colloidal reactive barrier for in situ groundwater remediation due to its strong and spedfic interactions with Pb and As compounds [199]. 

Phenol is catabolized by liver microsomal monooxygenases to hydroxylated products (e.g., 1,4-dihydroxybenzene) that can undergo further conversion to a variety of electrophilic substances (e.g., benzoquinones). Such reactions may be involved in generating reactive toxic intermediates in the liver (Eastmond et al. 1986 Lunte and Kissinger 1983 Subrahmanyam and O Brien 1985). Based on the available data, hepatic effects are unlikely to occur at the exposure levels found in the environment or near hazardous waste sites. 

This statutory definition of solid waste is pursuant to the regulations of the EPA insofar as a solid waste is a hazardous waste if it exhibits any one of four specific characteristics ignitability, reactivity, corrosivity, and toxicity. 

Reactivity. A material is considered to be a reactive hazardous waste if it is normally unstable, reacts violently with water, generates toxic gases when exposed to water or corrosive materials, or if it is capable of detonation or explosion when exposed to heat or a flame (40 CFR 261.23). Materials that are defined as forbidden explosives or class A or B explosives by the Department of Transportation are also considered reactive hazardous waste. 

The first step to be taken by a generator of waste is to determine whether that waste is hazardous. Waste may be hazardous by being listed in the regulations, or by meeting any of four characteristics ignitability, corrosivity, reactivity, and extraction procedure (EP) toxicity. 

There are four lists of hazardous wastes in the regulations wastes from nonspecific sources (F list), wastes from specific sources (K list), acutely toxic wastes (P list), and toxic wastes (U list) there are also the four characteristics mentioned before ignitability, corrosivity, reactivity, and extraction procedure toxicity. Certain waste materials are excluded from regulation under the RCRA. The various definitions and situations that allow waste to be exempted can be confusing and difficult to interpret. One such case is the interpretation of the mixture and derived-from rules. According to the mixture rule, mixtures of solid waste and listed hazardous wastes are, by definition, considered hazardous. Similarly, the derived-from rule defines solid waste resulting from the management of hazardous waste to be hazardous (40 CFR 261.3a and 40 CFR 261.1c). 

In snmmary, many of the specific chemicals in petroleum are hazardous because of their chemical reactivity, fire hazard, toxicity, and other properties. In fact, a simple definition of a hazardons chemical (or hazardous waste) is that it is a chemical substance (or chemical waste) that has been inadvertently released, discarded, abandoned, neglected, or designated as a waste material and has the potential to be detrimental to the environment. Alternatively, a hazardons chemical may be a chemical that may interact with other (chemical) snbstances to give a prodnct that is hazardous to the environment. Whatever the case, methods of analysis mnst be available to determine the nnrture of the released chemical (waste) and from the data predict the potential hazard to the environment. 

As discussed in Section 2.3.3, the mechanism of chloroform-induced liver toxicity may involve metabolism to the reactive intermediate, phosgene, which binds to lipids and proteins of the endoplasmic reticulum, lipid peroxidation, or depletion of GSH by reactive intermediates. Because liver toxicity has been observed in humans exposed to chloroform levels as low as 2 ppm in the workplace and in several animal species after inhalation and oral exposure, it is possible that liver effects could occur in humans exposed to environmental levels, to levels in drinking water, or to levels found at hazardous waste sites. 

A waste stream may be defined as hazardous under RCRA if it meets certain criteria for ignitability, corrosivity, reactivity, or toxicity, or if the waste stream is specifically identified by EPA as a hazardous waste. An individual waste stream is subject to being classified as hazardous (listed) if it contains any one of approximately 375 chemicals identified by EPA as hazardous constituents. These designated chemicals are frequently referred to as Appendix Vlll compounds because of where they are listed in the published regulation. 

The hazardous waste identification regulations that define the characteristics of toxicity, ignitability, corrosivity, reactivity, and the tests for these characteristics, differ from state to state. In addition, concentration limits may be set out by a state for selected persistent and bioaccumulative toxic substances that commonly occur in hazardous substances. For example, the California Hazardous Waste Control Act requires the California State Department of Health Services (CDHS) to develop and adopt by regulation criteria and guidelines for the identification of hazardous wastes and extremely hazardous wastes. 

California criteria for defining hazardous wastes that are ignitable and reactive are identical to Federal criteria for hazardous wastes under RCRA defined at 40 CFR, Part 261. The California corrosivity criteria differ from the Federal criteria only in the addition of a pH test for nonaqueous wastes. 

Activated carbon adsorption is mainly a waste concentration method. The exhausted carbon must be regenerated or disposed of as hazardous waste. For GAC consumptions larger than 2000 Ib/day, onsite regeneration may be economically justified [7]. Thermal regeneration is the most common method for GAC reactivation, although other methods such as washing the exhausted GAC with acid, alkaline, solvent, or steam are sometimes practiced for specific applications [17]. 

Household Hazardous Waste (HHW) is defined by the U.S. EPA as solid wastes, discarded from homes or similar sources, that are either hazardous wastes or wastes that exhibit any of the following characteristics ignitabiUty, corrosivity, reactivity, or toxicity. A significant fraction of HHW is generated by home mechanics who use such products as motor oil, cleaners and solvents, refrigerants, and batteries. The results indicate that most of the survey respondents perceive automotive products to pose significant health and environmental risks, and they tend to dispose of these wastes in an environmentally conscious manner. There is qnite often a discrepancy between human perception and scientific reality (see table 8.2) (Shorten et al., 1995). 

Waste streams from sites of HDI or HDI polymer production may release HDI or HDI prepolymers to water. No information is available in the TRI database on the release of HDI to water from facilities that produee or proeess HDI because this eompound is not included imder SARA, Title III, and therefore, is not among the ehemieals that facilities are required to report (EPA 1995). HDI and HDI prepolymers may also be released to water at hazardous waste sites however, no information was foimd on detections of HDI in water at any NPL or other Superfund hazardous waste sites (HazDat 1996). Because of its reactivity with water to form amine or polyurea derivatives (Chadwick and Cleveland 1981 Hulse 1984 Kennedy and Brown 1992), monomeric HDI is not likely to be foimd in waste water streams or in other aquatic environments except near sources of release. Small amounts of HDI that have become encapsulated in water-insoluble polyurea agglomerates may persist in water (see Section 5.3.2.2). 

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