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Many of EPA’s hazardous waste programs involve sampling and analysis of waste or environmental media by the regulated community. While some of the regulations include provisions under which sampling and analysis can be performed at the discretion of the waste handler, others require the waste handler to conduct sampling and analysis.
Sampling and analysis often is employed:
- To make a hazardous waste determination;
- To determine if a waste is subject to treatment or, if already treated, has been adequately treated under the Land Disposal Restrictions program; or
- In responding to other hazardous waste management programs that include routine monitoring, unit closure, or cleanup.
Making a hazardous waste determination
Solid wastes are defined as hazardous wastes in two ways.
First, solid wastes are hazardous wastes if EPA lists them as hazardous wastes.
Second, EPA identifies the characteristics of a hazardous waste. Accordingly, solid wastes are hazardous if they exhibit any of the following four characteristics of a hazardous waste:
- Ignitability,
- Corrosivity,
- Reactivity, or
- Toxicity.
Generators must conduct a hazardous waste determination according to the hierarchy specified in 40 CFR 262.11. Persons who generate a solid waste first must determine if the solid waste is excluded from the definition of hazardous waste.
Once the generator determines that a solid waste is not excluded, the generator must determine if the waste meets one or more of the hazardous waste listing descriptions and determine whether the waste is:
- Mixed with a hazardous waste,
- Derived from a listed hazardous waste, or
- Contains a hazardous waste.
To comply with the Land Disposal Restrictions in 40 CFR Part 268, or if the solid waste is not a listed hazardous waste, the generator must determine if the waste exhibits a characteristic of a hazardous waste. This evaluation involves testing the waste or using knowledge of the process or materials used to produce the waste.
To determine if the waste exhibits any of the four characteristics of a hazardous waste, a waste handler must:
- Obtain a representative sample using the applicable sampling method specified in Appendix I of Part 261 or an alternative method, and
- Test the waste for the hazardous waste characteristics of interest.
For the purposes of identifying hazardous waste, the regulations state that a sample obtained using any of the applicable sampling methods specified in Appendix I of Part 261 is a representative sample. Since these sampling methods are not officially required, anyone desiring to use a different sampling method may do so. The user of an alternate sampling method must use a method that yields samples that “meet the definition of representative sample found in Part 260.” Such methods should enable one to obtain samples that are equally representative as those specified in Appendix I of Part 261.
Certain states also may have requirements for identifying hazardous wastes in addition to those requirements specified by federal regulations. States authorized to implement the solid and hazardous waste programs may pass regulations that are more stringent or broader in scope than federal regulations.
The Land Disposal Restrictions (LDR) program
The LDR program regulations found at 40 CFR Part 268 require that a hazardous waste generator determine if the waste has to be treated before it can be land disposed. This is done by determining if the hazardous waste meets the applicable treatment standards. EPA expresses treatment standards either as:
- Required treatment technologies that must be applied to the waste, or
- Contaminant concentration levels that must be met.
Determining the need for waste treatment can be made by either of two ways (see 268.7(a)):
- Testing the waste, or
- Using knowledge of the waste.
If a hazardous waste generator is managing and treating prohibited waste or contaminated soil in tanks, containers, or containment buildings to meet the applicable treatment standard, then the generator must develop and follow a written waste analysis plan (WAP) in accordance with 268.7(a)(5).
Hazardous waste treaters must test their waste according to the frequency specified in their WAP as required by 40 CFR 264.13 (for permitted facilities) or 40 CFR 265.13 (for interim status facilities).
If testing is performed, no portion of the waste may exceed the applicable treatment standard; otherwise, there is evidence that the standard is not met. Statistical variability is “built in” to the standards. Wastes that do not meet treatment standards can not be land disposed unless EPA has granted a variance, extension, or exclusion (or the waste is managed in a “no-migration unit”).
Other RCRA regulations and programs that may require sampling and testing
In addition to the RCRA hazardous waste identification regulations and the LDR regulations, EPA has passed other regulations and initiated other programs that may involve sampling and testing of solid waste and environmental media (such as ground water or soil). Program-specific EPA guidance should be consulted prior to implementing a sampling or monitoring program under these regulations or programs. For example, EPA has issued program-specific guidance on sampling to support preparation of:
- A delisting petition,
- Ground-water and unsaturated zone monitoring at regulated units,
- Unit closure,
- Corrective action for solid waste management units, and
- Other programs.
Enforcement sampling and analysis
Note that the sampling and analysis conducted by a waste handler during the normal course of operating a waste management operation might be quite different than the sampling and analysis conducted by an enforcement agency. The primary reason is that the data quality objectives of the enforcement agency often may be legitimately different from those of a waste handler.
Consider an example to illustrate this potential difference in approach: Many of RCRA’s standards were developed as concentrations that should not be exceeded (or equaled) or as characteristics that should not be exhibited for the waste or environmental media to comply with the standard. In the case of such a standard, the waste handler and enforcement officials might have very different objectives.
An enforcement official, when conducting a compliance sampling inspection to evaluate a waste handler’s compliance with a “do not exceed” standard, takes only one sample. Such a sample may be purposely selected based on professional judgment. This is because all the enforcement official needs to observe – for example to determine that a waste is hazardous – is a single exceedance of the standard.
A waste handler, however, in responding to the same regulatory standard may want to ensure, with a specified level of confidence, that his or her waste concentrations are low enough so that it would be unlikely, for example, that an additional sample drawn from the waste would exceed the regulatory standard. In designing such an evaluation, the waste handler could decide to take a sufficient number of samples in a manner that would allow evaluation of the results statistically to show, with the desired level of confidence, that there is a low probability that another randomly selected sample would exceed the standard.