1 of 27 The EPA 7-Step DQO Process Step 5 - Define Decision Rules (15 minutes) Presenter: Sebastian Tindall Day 2 DQO Training Course Module 5

2 of 27 Step Objective: n This step combines Steps to produce the following major elements to form decision rules: –Parameter of interest –Unit of decision making –Action level –Alternative actions Step 5: Define Decision Rules Step 4: Specify Boundaries Step 2: Identify Decisions Step 3: Identify Inputs Step 1: State the Problem Step 5: Define Decision Rules Step 6 : Specify Error Tolerances Step 7 : Optimize Sample Design

3 of 27 Alternative Actions Step 2 Population of Interest Step 4 Basis for Defining Action Level Step 3 Step 5- Define Decision Rules Develop a Decision Rule If/Then Decision Rule Statements Information INActions Information OUT From Previous Step To Next Step Principal Study Question Step 2 Specify the Parameter of Interest Confirm the Action Level Information Required to Resolve Decision Statement Step 3 Unit of Decision Making Step 4

4 of 27 Major Elements of a Decision Rule: n Parameter of Interest –Population Parameter Background –Sample Statistic –Environmental Variable Chemical/Physical attribute in the population Levels measured (Quantity) n Unit of Decision Making –Geographic Area/Volume –Timeframe –Population n Action Level n Alternative Action(s)

5 of 27 Major Elements of a Decision Rule: n Parameter of Interest –Population Parameter Background –Sample Statistic –Environmental Variable Chemical/Physical attribute in the population Levels measured (Quantity) n Unit of Decision Making –Geographic Area/Volume –Timeframe –Population n Action Level n Alternative Action(s) A descriptive measure (such as a true mean, median, or proportion) that specifies the characteristic or attribute that the decision maker would like to know about the population. By definition, this will always remain unknown. Note: The purpose of any data collection design is to produce environmental data that can be used as a reasonable estimate of this population parameter.

6 of 27 Major Elements of a Decision Rule: n Parameter of Interest –Population Parameter Background –Sample Statistic –Environmental Variable Chemical/Physical attribute in the population Levels measured (Quantity) n Unit of Decision Making –Geographic Area/Volume –Timeframe –Population n Action Level n Alternative Action(s) The sample statistic, e.g., the sample mean, which is obtained from the sampling data is used to estimate the population parameter. It is often the upper confidence limit about the sample mean.

7 of 27 Major Elements of a Decision Rule: n Parameter of Interest –Population Parameter Background –Sample Statistic –Environmental Variable Chemical/Physical attribute in the population Levels measured (Quantity) n Unit of Decision Making –Geographic Area/Volume –Timeframe –Population n Action Level n Alternative Action(s) The variable is both the COPC (chemical and physical) and the level measured. Examples of the level are concentration or activity or result.

8 of 27 Major Elements of a Decision Rule: n Parameter of Interest –Population Parameter Background –Sample Statistic –Environmental Variable Chemical/Physical attribute in the population Levels measured (Quantity) n Unit of Decision Making –Geographic Area/Volume –Timeframe –Population n Action Level n Alternative Action(s) The smallest, most appropriate subset (sub-population) for which separate decisions will be made.

9 of 27 Major Elements of a Decision Rule: n Parameter of Interest –Population Parameter Background –Sample Statistic –Environmental Variable Chemical/Physical attribute in the population Levels measured (Quantity) n Unit of Decision Making –Geographic Area/Volume –Timeframe –Population n Action Level n Alternative Action(s) Spatial Boundary Temporal Boundary

10 of 27 Major Elements of a Decision Rule: n Parameter of Interest –Population Parameter Background –Sample Statistic –Environmental Variable Chemical/Physical attribute in the population Levels measured (Quantity) n Unit of Decision Making –Geographic Area/Volume –Timeframe –Population n Action Level n Alternative Action(s) The total number of objects (samples of soil or sludge or sediment or air, etc.), that are contained within the spatial unit to be studied

11 of 27 Major Elements of a Decision Rule: n Parameter of Interest –Population Parameter Background –Sample Statistic –Environmental Variable Chemical/Physical attribute in the population Levels measured (Quantity) n Unit of Decision Making –Geographic Area/Volume –Timeframe –Population n Action Level n Alternative Action(s) A measurement threshold value of the parameter of interest that provides the criterion for choosing among alternative actions.

12 of 27 Major Elements of a Decision Rule: n Parameter of Interest –Population Parameter Background –Sample Statistic –Environmental Variable Chemical/Physical attribute in the population Levels measured (Quantity) n Unit of Decision Making –Geographic Area/Volume –Timeframe –Population n Action Level n Alternative Action(s) The actions that the decision maker would take depending on the value of the sample statistic which is an estimate of the population parameter.

13 of 27 Alternative Actions Step 2 Population of Interest Step 4 Basis for Defining Action Level Step 3 Develop a Decision Rule If/Then Decision Rule Statements Information INActions Information OUT From Previous Step To Next Step Principal Study Question Step 2 Specify the Parameter of Interest Confirm the Action Level Information Required to Resolve Decision Statement Step 3 Unit of Decision Making Step 4 The purpose of the data collection design is to produce environmental data that can be used as a reasonable estimate of the population (true) parameter. Step 5- Define Decision Rules

14 of 27 Alternative Actions Step 2 Population of Interest Step 4 Basis for Defining Action Level Step 3 Develop a Decision Rule If/Then Decision Rule Statements Information INActions Information OUT From Previous Step To Next Step Principal Study Question Step 2 Specify the Parameter of Interest Confirm the Action Level Information Required to Resolve Decision Statement Step 3 Unit of Decision Making Step 4 If not done in Step 3, specify the numerical value that would cause a person to choose between alternative actions. Confirm that the action level is greater than the detection/ quantitation limits for the potential measurement methods identified in Step 3. Step 5- Define Decision Rules

15 of 27 Alternative Actions Step 2 Population of Interest Step 4 Basis for Defining Action Level Step 3 Develop a Decision Rule If/Then Decision Rule Statements Information INActions Information OUT From Previous Step To Next Step Principal Study Question Step 2 Specify the Parameter of Interest Confirm the Action Level Information Required to Resolve Decision Statement Step 3 Unit of Decision Making Step 4 Develop a decision rule as an “if…then…” statement that incorporates the parameter of interest, the unit of decision making, the action level, and the action(s) that would result from resolution of the decision. Step 5- Define Decision Rules

16 of 27 Decision Rule n General Format If the [parameter of interest (4 elements)] within the [unit of decision (3 elements)] is > the [action level], then take [alternative action A]; or take [alternative action B].

17 of 27 Decision Rule Example 1 If the [“true” mean (as estimated by the 95% UCL of the sample mean) concentration of U-238] within the [surface soil in the perimeter of the backyard to a depth of 6 inches] is > [20 pCi/g], then [dispose of soil in a radiological landfill]; or [leave the soil in place].

18 of 27 If the [“true” mean (as estimated by the one sided 90% UCL of the sample mean) concentration of cadmium] within [the metal turnings in a 55 gallon drum] is > [1 mg/kg], then [the metal turnings will be considered hazardous and will be disposed of in a RCRA facility]; or [the metal turnings will be disposed of in a municipal landfill]. Decision Rule Example 2

19 of 27 n If the vadose zone soil moisture content, contaminant concentration profiles, and soil physical properties from the 1454 site exceed or deviate significantly from the conceptual model, an additional evaluation will be performed to assess priority of performing further analysis. n The data gathered from the characterization boring located at the 1454 site combined with historical process data and geophysical logging (high resolution spectral gamma-ray and neutron logging) of existing wells located in the vicinity of the 1455 site can be used to create an analogous model for the 1455 site. If the data collected from characterization of the 1454 site and the geophysical logging data from the existing wells located near the 1455 site support the conceptual model, the analogous unit approach is valid for the 1455 site. “Typical” Decision Rules

20 of 27 Step 5- Decision Rules CS

21 of 27 Decision Rule 1a If the true mean (as estimated by the 95% UCL of the sample mean) concentration of the contaminant within the surface soil to a depth of 6 inches of the Pad footprint and run-off zone is > the AL, then conduct remedial action; or take no further action. Contaminates/Action Limits 250 mg/kg Lead 240 mg/kg Uranium 100 mg/kg TPH 1 mg/kg PCBs (total Aroclors) CS

22 of 27 If the true mean (as estimated by the 95% UCL of the sample mean) concentration of the contaminant within the surface soil to a depth of 6 inches of the radial buffer zone excluding the Pad and run-off zone is > the AL, then conduct remedial action; or take no further action. Contaminates/Action Limits 250 mg/kg Lead 240 mg/kg Uranium 100 mg/kg TPH 1 mg/kg PCBs (total Aroclors) CS Decision Rule 1b

23 of 27 If the true mean (as estimated by the 95% UCL of the sample mean) concentration of the contaminant within the subsurface soil to a depth of 6” to 10’ of the Pad footprint and run- off zone is > the AL, then conduct remedial action; or take no further action. Contaminates/Action Limits 250 mg/kg Lead 240 mg/kg Uranium 100 mg/kg TPH 1 mg/kg PCBs (total Aroclors) CS Decision Rule 2a

24 of 27 If the true mean (as estimated by the 95% UCL of the sample mean) concentration of the contaminant within the surface soil to a depth of 6” to 10’ of the radial buffer zone excluding the Pad and run-off zone is > the AL, then conduct remedial action; or take no further action. Contaminates/Action Limits 250 mg/kg Lead 240 mg/kg Uranium 100 mg/kg TPH 1 mg/kg PCBs (total Aroclors) CS Decision Rule 2b

25 of 27 Step 5 - Summary n After data are obtained and undergo Data Quality Assessment, decision rules are used to make the decisions n The decision rules encompass the logic used and include inputs from Steps 1-4 and 6 n One may need to perform Step 6 and then update Step 5 to include the statistical decision criteria

26 of 27 Alternative Actions Step 2 Population of Interest Step 4 Basis for Defining Action Level Step 3 Develop a Decision Rule If/Then Decision Rule Statements Information INActions Information OUT From Previous Step To Next Step Principal Study Question Step 2 Specify the Parameter of Interest Confirm the Action Level Information Required to Resolve Decision Statement Step 3 Unit of Decision Making Step 4 Step 5- Define Decision Rules

27 of 27 End of Module 5 Thank you