Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1850:p103
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1850 (pt 103/117)
Character Range: 654911–657926

mean concentrations for all chemicals of potential concern were less than the appropriate site criteria).
Step 2 of the DQO process should assist in developing a decision statement linking the principal project objective(s) to the possible actions that will address the problem.

The existing conceptual model can then be reviewed to determine whether existing data is satisfactory to complete the investigation or whether data gaps or an unacceptable level of uncertainty exists.

    18.2.3      Step 3: Identify information inputs
The third step involves identifying the information needed to support any decision and whether new environmental data will be needed.

Decisions made during this step are of a draft or preliminary nature and are reviewed in Step 7 to develop the sampling analytical and quality plan (SAQP).

Step 3 of the DQO process should assist decision-makers to resolve decision statements and make informed, defensible decisions by identifying:
    * the media that needs to be collected, such as fill, soil, groundwater, sediments, surface water and air
    * the environmental parameters that will be measured for each media
    * site criteria for each medium of concern
    * analytical methods that are required for chemicals of potential concern so that assessment can be made relative to the site criteria
    * the basis for any decisions that are to be made from field screening, such as from PID data, and what action is to be taken if a defined concentration is attained
    * any additional information required to make the required decisions.

    18.2.4      Step 4: Define the study boundaries
The fourth step involves specifying the spatial and temporal aspects of the environmental media that the data must represent to support decision(s). The matters to consider at this stage include:
    * the geographical extent of the proposed investigation
    * time and budget constraints
    * spatial extent (property boundaries, accessibility constraints to parts of the site, potential exposure areas)
    * temporal boundaries (the time frame of the investigation, taking into account seasonal conditions, presence of near-surface groundwater or surface water and discharges, access restrictions, availability of key personnel)
    * for large sites, the boundaries of each segment to be investigated (based on proposed use of each area of the site, which will influence the required sample density, appropriate regulatory guidance)
    * the lateral and vertical intervals in which contamination distribution is believed to be uniformly distributed
    * the scale of decisions required: site-wide, each residential lot, etc.
    * the presence of any heterogeneous materials that may require specific sampling methods
    * potential constraints to carrying out the investigation, such as access, presence of infrastructure, health and safety issues.
Step 4 of the DQO process should assist in developing:
    * a detailed description of the spatial and temporal boundaries