- Describes ATSDR’s involvement at the site, why ATSDR is writing the report (e.g., the site is on the NPL, it was requested by EPA, or an exposure investigation to fill an exposure data gap), and what the site issues are
- Poses the questions that will be addressed and indicates what the document will and will not discuss
- Includes how contamination was discovered and the affected media (e.g., soil, water)
- Excludes any information not directly relevant to the issues discussed in the main body of the document (you can place this information in an appendix if you judge it important to the reader)
- Discusses the site location, land use (past, current, and future [if known], site geology/hydrogeology (if warranted), site visit, as well as include site maps. You learned about collecting this type of information in the Getting Familiar with the Site section.
- Describes how the contamination was released to the environment and background information pertinent to the reader’s understanding of the site
- Mentions conditions that could increase or decrease exposure such as ground cover, use of unregulated private wells, and high winds
- Uses a timeline of site activities table, such as the example below to point out important activities related to the site. These can be activities related to contamination, cleanup, exposure, community meetings, and ATSDR involvement.
- Ensures the information highlights details tied to your conceptual site model such as when contamination was released, contamination was identified, sample collection occurred, cleanup took place, and actions identified, stopped, or reduced exposure.
- Includes only the key entries that are vital to understanding the activities that took place at your site. Consider date ranges to capture multiple similar events.
Example Timeline of Site Activities
| Date | Site Activity |
|---|---|
| March 2018 | Residents expressed concerns about their air quality because they are located near a concentrated animal feeding operation. |
| January 2019 | Air sampling revealed the presence of ammonia, hydrogen sulfide, and methane above environmental screening levels. |
| December 2019 | EPA proposed placing the site on the National Priorities List. ATSDR began examining the site through its PHA process. |
Community Description and Concerns
This overall heading includes three subsections:
- The Community Demographics section includes the location of the potentially exposed populations and available demographic information pertinent to this evaluation (e.g., subsistence use of natural resources, potential increased risk factors, age groups, sex, and race/ethnicity).
- The Health Equity Considerations section (optional until guidance is developed), describes social vulnerability as reflected in the CDC/ATSDR Environmental Justice Index (EJI), and other environmental and social burdens in the community.
- The Community Concerns section introduces the community concerns that have been documented, as discussed in the Engaging the Community section. In this section, you will:
- Talk about the efforts and steps taken to determine the health concerns, such as how you gathered the community’s concerns.
- Include a brief overview of the health concerns voiced by the site community and if needed, include and reference a later section in the document that goes into more detail to specifically address and respond to individual health concerns (see Addressing Community Concerns section).
- Mention that ATSDR has special considerations for child health issues and describe any children’s health considerations applicable to the site population and exposure.
Sampling Data (for Non-EI PHAs/HCs)
For non-EI PHAs and non-EI HCs, you will include the Sampling Data section. This section will do the following:
- Discuss the data sources for the sampling data you used to evaluate exposures and talk about the data representativeness (e.g., why the data are representative of exposures) and quality (e.g., are of high quality).
- Discuss data gaps as needed.
- May examine estimated contaminant concentrations in measured sampling data or modeled data, as noted in the Selecting Sampling Data section.
It can be challenging to summarize your evaluation of a site’s data, especially for sites with large volumes of data available. Be sure to do the following:
- Consider the information needs of the audience.
- Describe the sampling data for each medium examined, providing an overview of only the data you evaluated that were relevant to the exposure pathways.
- Communicate the information that would be most important to the readers without overwhelming them with unnecessary details — do not list every data point for every contaminant in every medium.
- Provide additional details in appendices of your document, if appropriate.
Methods and Sampling Data (for EI-HCs specific section)
If you are writing an EI-HC, you will include a Methods and Sampling Data section. In this section, you will have these three subsections:
- A Recruitment subsection that describes how participants were selected for the investigation (properties for an air investigation, human subjects for a biomonitoring EI).
- A Data Collection subsection that goes into detail about how and what types of data ATSDR collected throughout the program.
- A Laboratory and Data Analysis subsection that speaks to the laboratory methods to measure the contaminants and how the data were analyzed
Scientific Evaluations
As outlined in this e-manual, there are four scientific evaluations in the PHA process:
- Exposure Pathway Analysis,
- Screening Analysis,
- EPCs and Exposure Calculations, and
- In-Depth Toxicological Effects Analysis.
You will refer readers to these main PHAGM sections, as well as to the Explanation of ATSDR’s PHA Process Evaluation [PDF – 292 KB] [DOC – 50 KB] , for more details on each of these evaluations rather than putting a lot of information about the process in your documents. This section summarizes scientific evaluations based on media-specific (e.g., household water, soil or sediment, outdoor or indoor air) exposures examined at your site, as shown in ATSDR’s document outline [PDF – 217 KB] [DOC – 39 KB] .
For the Exposure Pathway Analysis subsection, you will do the following:
- Highlight the most important exposure pathway evaluation information to clearly describe how and to what extent people are believed to come in contact with site contaminants and what populations you have evaluated.
- Summarize your information in an Exposure Pathways table, as shown in the Exposure Pathways section.
- Provide information for each media-specific (e.g., household water, soil or sediment, outdoor or indoor air) exposure examined at your site.
In the Screening Analysis subsection, you will follow these steps:
- Include a table with the site contaminants that met or exceeded CVs and/or ATSDR screening levels, or that screened in because of a community concern. All of these contaminants will require further evaluation. At some sites, however, no contaminants will be identified as needing further evaluation, and you will need to explain why.
- State all assumptions that you used in your evaluation to select the contaminant concentrations, and to choose ATSDR CVs and non-ATSDR screening levels.
- Include a full list of contaminants in your screening analysis in an appendix if you choose (optional).
In the EPCs and Exposure Calculations subsection, you will do the following:
- Include a table showing the contaminants examined in the EPCs and Exposure Calculations evaluation (with their EPCs, doses/adjusted air concentrations, HQs, and CRs).
- Summarize the identified potential contaminants of concern needing further evaluation based on being above HQs and/or CRs.
- Show all contaminants included in this evaluation within this section of the main body of the document (ATSDR’s preferred method). However, you do have the option of showing only those contaminants identified as needing further evaluation in this section and putting a table with all evaluated contaminants in an appendix. At some sites, however, no contaminants will be identified as needing further evaluation, and you will need to explain why.
- State all assumptions that you used in your evaluation.
In the Health Evaluations subsection, you will do the following:
- Explain how site-specific exposure doses and adjusted air concentrations (and exposure conditions) compared with levels shown to cause harm in relevant scientific studies.
- Describe how the integration of pertinent site-specific data leads you to your overall decisions about whether site-specific conditions are likely to result in harmful health effects.
- State any assumptions used in your estimates (e.g., ingestion rates, exposure duration).
- Tie in exposure condition information that might provide additional perspective (e.g., how exposure levels compare to background and the likelihood of exposures).
- Identify the overall availability of pertinent health effects data for the contaminants and pathways of concern.
- Be sure your discussion supports and helps justify the conclusions.
- Highlight any strengths and weaknesses of contributing evidence that support your public health conclusions.
- State those instances when, because of weak or missing exposure or health effects data, an answer is not possible.
- Present only the decision point information for the highest doses and concentrations that form the reason for your conclusions. For instance, present the exposure groups with the highest level of exposures that drive the conclusions.
- Include information that will help the reader understand the public health conclusions, being sure to focus on the possible health concerns of the potentially exposed populations.
- Summarize information for particular groups on or near the site who, based on your review of contaminant-specific information, might be especially sensitive to toxic effects and were identified as suspected high-risk groups.
- Be as explicit as possible about why exposure levels are or are not expected to be a potential problem.
- Highlight any factors identified during your scientific evaluations that might make a particular exposure more or less likely. For example, explain why the presence of a particular metal in soil is not expected to be bioavailable and therefore unlikely to cause harm. On the other hand, explain why long-term exposures to detected levels of polychlorinated biphenyls (PCBs) in fish, for example, might under site-specific conditions, warrant more concern.
- Give perspective when using qualifying terms such as “low” or “high” to provide a comparison.
- Put additional information in an appendix.
- Decide if you will perform and summarize a mixtures evaluation (optional), as outlined in the Multiple Chemical Exposures section.
Evaluation of Health Outcome Data (HOD)
Include this section in your document if there are available HOD that you evaluated using ATSDR’s HOD criteria framework, as outlined in the Health Outcome Data (HOD) section. If conducted, you will do the following:
- Present a brief description of the requirement to consider health outcome (mortality and morbidity) data and the reasons why a health outcome data analysis was conducted.
- Have a concise description of the methodology used and the results of the analysis.
- Present a discussion of the inherent limitations in some types of Health Outcome Data review.
Addressing Community Concerns
Include this section if there are specific health concerns to address from community members, as noted in the Engaging the Community section. If added, you will do the following:
- Organize the concerns in an easy-to-read manner. For instance, presenting the concerns in a question-and-answer format is often most appropriate, as is organizing similar concerns together and using general categories to consolidate concerns by heading (e.g., health effects, personal and community safety, sampling).
- Be sure to follow the principles of effective communication described in Engaging the Community, which include presenting the information with clarity, accuracy, respect, and sensitivity.
- Protect privacy by not naming persons who expressed concerns, although you can name community groups that have raised concerns.
Summary of Limitations and Uncertainties
Summarize the major limitations from throughout the PHA process at the site that could affect your conclusions and recommended next steps. For example, limited data collected at the point of exposure, statistical limitations, limitations of scientific studies, and indoor air variability.
Conclusions
In this section, briefly present the conclusions (see Example Conclusions). You will do the following:
- List your conclusions in order of public health priority or importance if you have reached more than one conclusion.
- Assign a hazard conclusion category to the site, time period (e.g., past, current, or future), or exposure pathway, as appropriate. Conclusion categories are required in PHAs, HCs, LHCs, and HAs; when appropriate, they are included in EI-HCs. Be sure to clearly describe the basis for any selected conclusion category. Your conclusions will include the contaminant and pathway, length of exposure, and specific place (location of hazard). The conclusions should answer the following questions:
- Who is the exposed population?
- How did exposure occur (e.g., doing what activity)?
- When and where did exposure occur?
- What contaminants and physical hazards were people exposed to?
- Will people be harmed from exposures?
- What symptoms or health endpoints are associated with potential exposures?
