and laboratory organizations performing the work of the DQOs so that their personnel may

make informed decisions during the course of the project to attain those DQOs. The

procedures that an owner/operator uses to characterize the hydrogeology of a site, to design

and construct a monitoring network, to collect and analyze environmental samples, and to

evaluate analytical results should ensure that the data are of the type and quality necessary to

allow for the detection of contamination when hazardous waste or hazardous constituents have

migrated from the waste management area to the uppermost aquifer ( 264.97(a)(3)).

EPA is using DQOs to define the type and quality of data required to support specific

regulatory decisions. DQOs include both qualitative and quantitative data performance

specifications. The type of data required is defined by a set of qualitative specifications that

indicate the characteristics of the environment to be measured and the circumstances such

measurements are intended to represent. The quality of data required may be specified in two

ways: 1) qualitatively, as a set of procedures to follow for collecting data, or 2)

quantitatively, as the amount of error (imprecision and bias) that may be tolerated in data

without incurring an unacceptable probability of making incorrect or inappropriate decisions.

This Manual represents a qualitative specification of data quality, requiring that certain

procedures be followed when collecting hydrogeologic data. All projects that generate

environmental data in support of RCRA should have a QA Project Plan (QAPjP). The

recommended components of a QAPjP are provided in Chapter One of SW 846.

Field and laboratory operations should be conducted in such a way as to provide

reliable information that meets the DQOs. To achieve this, certain minimal practices and

procedures should be implemented, as outlined in Chapter One of SW 846. The applicable

ground water monitoring regulations contained in 40 CFR Parts 264 and 270 outline

additional required practices and procedures. In addition, Chapter One of SW 846 specifies

the information that should be contained in project documentation. Moreover, both this

Manual and the TEGD provide supplemental information and guidance for conducting field

operations.

November 1992

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