Featured Topics

Risk Assessment

Risk assessment characterizes current and potential threats to human health and the environment that may have been exposed to contaminants at an Abandoned Uranium Mine (AUM) site. This process helps to determine whether a threat to human health and the environment warrants remedial or “cleanup” action according to requirement established by the federal Superfund law.

The risk assessment process identifies potential contaminants in the environment, evaluates the ways people, plants, and animals may be exposed based on current and future anticipated uses of the area, and includes information about the toxicity of the potential contaminants, and brings all this information together understand the level of risk these contaminants pose to human health and the environment. This information will be shared with the community and will inform cleanup decisions.

Claim 28 Water Study

The Claim 28 AUM has a long history of investigation that continues today. In 2015 and 2016 the Navajo Nation entered into legal settlements with the United States government to fund the assessment and cleanup of 16 priority AUM sites, assess an additional 30 AUM sites, and conduct two water

studies. To carry out this work, the Navajo Nation designated trustees, with concurrence and approval of the United States to manage the funds and direct the work in coordination with the NNEPA and the USEPA. Claim 28 is a priority AUM site and also a site for one of the two water studies.

At Claim 28, the assessment and cleanup work is being done in two phases: Phase 1 and Phase 2. Phase 1 work was an investigation to determine contamination types and their extent by collecting and analyzing soil and water samples. Phase 2 work builds upon the Phase 1 investigation with a water study. The purpose of the water study is to determine if groundwater or surface waters have been affected by the Claim 28 AUM and, if so, whether the affected waters poses a danger to human health or the environment. To do this, the Phase 2 Trust team will determine where and how groundwater flows beneath the site and in the valley bottoms below; investigate the extent to which surface waters are affected; evaluate the impacts of storms; and determine how far and how fast contamination may be spreading away from the site. A significant and important part of the work involves determining whether or not the site is creating unacceptable health risks to humans, plants, and animals in the area. The water study is important and has several complex components that must be completed in sequence. To date, the Phase 2 Trust and its environmental contractor, E & E, have conducted geophysical surveys to assess the physical and chemical properties of soils, rock and ground water and are now writing a technical memorandum of the findings. The next step is the preparation of a work plan to conduct another round of field investigations and sample collections planned for summer 2020. Upon completion of the summer sampling event, the Trust and E & E will conduct a risk assessment and write a final report. Upon completion, the final report will be made available to the community

Yazzie No. 312 Emergency Fencing Action

On December 20 and 21st 2019, the Trusts’ environmental contractor, Ecology & Environment, Inc., (E

& E) and Navajo certified business, Juniper Fencing Company, completed a temporary fencing

installation at Yazzie 312 AUM site. The Yazzie 312 site is in the Coal Mine Canyon Chapter of the Navajo Nation in Coconino County, Arizona. This fencing action is the result of a reconnaissance survey in May 2019, where it was determined there were a series of potentially dangerous pits and holes located in the central part of the mine site. The Phase 2 Trust, NNEPA, and USEPA discussed the hazards and developed the fencing plan to make the area safer for people, domestic animals, and wildlife. Prior to the fence installation, biological evaluation and cultural resource surveys were

conducted to ensure the work and the fencing itself would not pose any risks or threats to plants and wildlife or disturb sacred or ceremonial artifacts. After the site received clearance approvals from the Navajo Nation Fish and Wildlife Department and the Navajo Nation Historical Preservation Office, the Trust and its contractors began the task of securing chain link fence fabric, posts, ties, and other materials for a 6-foot-high temporary fence, approximately 1,600 feet in length, to enclose the pits at Yazzie 312. The fencing will remain in place until the pits are filled and will be monitored for safety and security. If you have any questions about the fencing or any other activities under the Phase 2 Trust Agreement, please contact the Trust at 505.777.2393 or