Exposure Units and Exposure Point Concentrations

Exposure Unit

• Exposure Unit Guidance - In this guidance, you will learn about exposure units and how they are used in the PHA process. Exposure units are physical areas where a person's activities result in contact with a contaminated environmental medium.

Exposure Point Concentration

Training Videos

• EPC Guidance for Discrete Samples - In this webinar, you will learn about ATSDR's guidance for using discrete samples to calculate the EPC. You will understand what EPCs are, the types of statistics used to calculate them, and how to select EPCs based on exposure. Additionally, you will learn how to calculate 95UCLs when appropriate.
• ATSDR Exposure Point Concentration Tool - In this webinar, you will learn how to use the exposure point calculations (EPC) tool. The webinar details each step for handling discrete sample data from importing data into the tool, trouble-shooting data errors, calculating the EPC, and interpreting EPC results.

• ATSDR Exposure Point Concentration (EPC) Tool: Common Issues with Data Inputs - Watch this recorded webinar for an introduction to the EPC tool. Learn each step, from importing data into the tool, trouble-shooting data errors, calculating the EPC, and interpreting EPC results for discrete sampling data. Learn as well (starting at minute 8) how to use the EPC tool to calculate benzo(a)pyrene equivalents and dioxin TEQs.
• EPC Guidance for Non-Discrete (Composite) Sampling - Watch this recorded webinar for an introduction on the guidance for determining the EPC when using non-discrete (composite) samples.

Guidance

• EPC Guidance for Discrete Sampling - Study this document to learn how to use discrete samples to estimate EPCs and how to treat non-detects. Please note that the topic of how to use composite samples is handled in another guidance document.
  • Discrete Sampling Case Study (Questions)
  • Discrete Sampling Case Study (Answers)
    
• EPC Guidance for Non-Discrete (Composite) Sampling - Study this document to learn how to use non-discrete (composite, incremental) samples to estimate EPC.
• Public Health Assessment Guidance Manual (PHAGM) Section 6: Conducting Scientific Evaluations - In this PHAGM section you will find methods and resources that you can use to evaluate environmental exposures associated with environmental contamination.
  • EPC and Exposure Calculations - In this PHAGM subsection you will learn how to estimate oral, inhalation, and dermal doses from exposure to various contaminated medium, such as water, soil, sediment, air, and biota.

Tools

• EPC Tool - Use this tool to calculate EPCs using the procedures identified in ATSDR's EPC Guidance for Discrete Sampling. A special Excel template is required to load environmental data into the calculator. Once calculated, you can enter the EPC into PHAST.
  • EPC Tool User's Guide - Use this guide for a step-by-step explanation of how to use the EPC tool to generate EPCs. You can find the guide on the PHAST resource page in the "Exposure Point Concentration Guidance" subcategory. To gain access to the EPC Tool User's Guide, send a request to phast@cdc.gov