PUEBLO DE SAN ILDEFONSO TRIBAL RISK ASSESSMENT
Preserve and Protect Our Community
Pueblo de San
Ildefonso Tribal
Risk Assessment
About
The Pueblo faces unique challenges due to its proximity to the Los Alamos National Laboratory (LANL). LANL is located within the Pueblo’s Ancestral Domain; currently the Pueblo’s boundary is directly adjacent to and downstream of LANL. Historical laboratory activities, including development of the atomic bomb, have left a legacy of contamination of plutonium, other radionuclides, metals, and other contaminants in the local environment.
The Pueblo’s community vision (which is also being used to guide climate resiliency planning) integrates four aspects of Pueblo life – traditional activities, traditional places, community health, and infrastructure and governance. The community is concerned about health risks associated with LANL contaminants.
Therefore, DECP conducted a Tribal risk assessment, based on the community vision, to explain community health risks associated with conducting traditional activities on or near the Pueblo and in other traditional places.
Human Health Risk Assessment
DECP examined health risks based on EPA human health risk assessment guidance1,2. The ultimate goal of a human health risk assessment is to ensure that public health is protected. Therefore, the estimates and assumptions considered in the human health risk assessment are conservative so that health risks are not underestimated.
A human health risk assessment assesses how contaminants enter the body, which contaminants enter the body, and how much of those contaminants enter the body, this is called the exposure assessment. After the exposure is determined, the risk associated with that exposure is characterized. This can be done by determining the increased cancer risk from a lifetime exposure for carcinogenic contaminants or comparing the exposure to a toxicity threshold for non-carcinogenic contaminants.
There are six main components of an exposure assessment. These components are used to estimate the exposure for an average person.
Compared to the general population, members of the Pueblo are more frequently exposed to environmental contamination because of the considerable time spent outdoors practicing traditional and contemporary activities. This increases exposure to soils, sediment, surface water, and other sources of contamination. Members of the Pueblo are also potentially exposed to contamination from consuming plants and animals that are gathered or hunted from the area.
Assessing Risk
The amount of time that individuals participate in activities and the locations where these activities occur impacts risk. Pueblo members spend time participating in activities in many locations including on the Pueblo and on LANL. The concentrations of contaminants on LANL are generally greater than on the Pueblo. To understand potential health risks to members of the Pueblo that participate in activities both on LANL and on the Pueblo, DECP conducted a Tribal risk assessment that examines a range of risk.
ASSESSMENT DETAILS
Risk was examined assuming an individual conducts 100% of their activities on LANL and risk was examined assuming an individual conducts 100% of their activities on the Pueblo. These examples bound a range of potential risk and an individual’s risk is likely somewhere between the risk assessed for each of these locations.
FINDINGS
DECP assessed risk for 5 metals and 5 radionuclides, associated with current and past operations at LANL, on the Pueblo and on LANL. Risk associated with exposure to metals was low. When combining the risk from the complete Tribal Lifeway, excess lifetime cancer risk associated with radionuclide exposure was above levels of concern. Risk from conducting all activities on LANL was an order of magnitude (10 times) greater than risk from conducing all activities on the Pueblo. The risk associated with conducting all activities on LANL was 10 extra cancers per 10,000 people, while the risk associated with conducting all activities on the Pueblo was 1 extra cancer per 10,000 people.
Risk associated with conducting activities on the Pueblo or on LANL. Actual risk is likely somewhere between or less than what is presented here.
The main contaminants driving risk on the Pueblo are different than those that are driving risk on LANL. Plutonium 239/240 explains 21% of the risk on LANL and only 0.1% of the risk on the Pueblo.
The main drivers of risk on LANL are contaminants that are associated with activities at LANL– Cesium-137 and Plutonium-239/240 and naturally occurring Radium-226. There is risk associated with activities that are conducted on the Pueblo, however, it is much lower than the risk on LANL. Most of the risk on the Pueblo is from Radium-226, which is naturally occurring.
FINDINGS BY ACTIVITY
DECP also assessed risk associated with Tribal Lifeway activities. The majority of the risk on LANL came from ceremony and prayer.
Take Action
Some possible ways to reduce risk:
Reduce time spent on LANL and in Pueblo Canyon. Soil in these areas are more contaminated than in other canyons. By gathering plants, wood, and hunting in other areas, you can reduce your risk by 2-3 times.
Reduce consumption of some gathered plants. Another option would be to cultivate these plants nearer to homes using clean soil.
Resources
Publications
Pueblo de San Ildefonso Climate Action Plan
This climate action plan walks through the climate planning process in greater detail, including developing the community vision, assessing the vulnerability of each aspect of the community vision, and identifying adaptation actions that could reduce the Pueblo’s vulnerability to climate change.
Evaluation of the Health Effects of Climate Change and Contaminant Exposure Pueblo de San Ildefonso 2021
In this paper we present a health impact assessment to understand the vulnerability of Pueblo community members to direct, indirect, and combined effects of climate change.
Presentations
Tribal and Indigenous Climate Adaptation Series
2021. Series Session on community engagement, the integration of Indigenous and Pueblo cultures into adaptation planning, and transportation resilience and how it relates to access to health and emergency services. November 17, 2021.
Society of Environmental Toxicology and Chemistry 2021 Meeting
2021. Special Session: Environmental Justice: Methodologies to Incorporate Environmental Justice into Human Health Risk Assessment. Evaluating the Vulnerability of the Pueblo De San Ildefonso to the Combined Effects of Extreme Events and Contaminant Exposure. November 16, 2021.
Institute for Tribal Environmental Professional Tribal Lands and Environment Forum 2021
2021. Assessing Contaminant-Related Health Risks for Tribal Communities: Developing Exposure Scenarios, Exposure Pathways, and Exposure Factors for Tribal Risk Assessments. August 18, 2021.
Incorporating Climate Change Adaptation into Restoration Planning: Anticipating the Impact of Sea Level Rise, Drought-Wildfire Cycles, Vegetation Shifts, and Extreme Storm Events
2019. The Fifth Annual Comprehensive Seminar on Tribal Natural Resource Damage Assessments: Current Best Strategies and Tactics for Conducting Tribal NRD Assessments. Law Seminars International. December 16, 2019. Seattle, WA.
Incorporating Climate Change Impacts and Adaptation Considerations and Natural Resource Damage Assessment and Restoration at Superfund Sites
2019. The 2019 Tribal Lands & Environment Forum: A National Conversation on Tribal Land and Water Resources. Institute for Tribal Environmental Professionals. August 19, 2019. Palm Springs, CA.
Pueblo de San Ildefonso Climate Change Adaptation Planning, with a Focus on LANL Legacy Contamination
2019. Climate Adaptation in Indigenous Lands. National Adaptation Forum. May 24, 2019. Madison, WI.
1
U.S. EPA. 2004. Risk Assessment Guidance for Superfund Volume I: Human Health Evaluation Manual. Part E, Supplemental Guidance for Dermal Risk Assessment Final. EPA/540/R/99/005. OSWER 9285.7-02EP. U.S. Environmental Protection Agency. July.
2
U.S. EPA. 2014a. Radiation Risk Assessment at CERCLA Sites: Q&A. Directive 9200.4-40. U.S. Environmental Protection Agency. May.
Cancer Risk
Cancer risk is assessed by determining the excess lifetime cancer risk (ELCR). The ELCR is the risk of death from cancer above natural risk, resulting from a lifetime exposure to cancer causing chemicals. It is typically described using scientific notation. EPA considers 1 extra cancer per 1,000 people (10-4) an acceptable risk threshold. DECP along with other state agencies, considers fewer numbers of extra cancer more protective. They rely on a threshold 1 extra cancer per 100,000 people (10-5).
Contact Us
This work was supported by Abt Associates.
