About 40 people showed up at the Humboldt Elementary School gym Wednesday to hear an update on the Superfund site in Dewey-Humboldt and to meet one-on-one with people from six agencies or groups - from the U.S Environmental Protection Agency to a D-H environmental advisory committee.
Jeff Dhont, remedial project manager for the EPA, offered an update on past and recent efforts to locate, measure and clean up contamination from the Iron King Mine on the west side of Highway 69 and the Humboldt smelter on the east side. The EPA declared the two areas eligible for cleanup as a Superfund site in 2008. The agency is still in the remedial investigation phase of the process, but already has taken cleanup action in areas with high contamination levels.
In 2006, the EPA removed from residents' yards soil that contained elevated levels of arsenic and replaced it with clean soil. Twelve residential yard cleanups near the smelter took place in 2011, and the EPA scientists have taken 184 soil samples from residents' yards.
Soil sampling efforts recently have expanded to the northeast and northwest of town to determine what levels of arsenic and lead occur naturally in the area.
Dhont said test results indicated low levels of lead on both sides of Highway 69, with slightly elevated levels near the smelter stack.
Arsenic levels tended to be higher on the east side of the highway, including a hot spot at the former smelter rail loading area.
Working with the EPA is the Agency for Toxic Substances and Disease Registry, a partner with the Center for Disease Control out of Atlanta.
This past Thursday, ATSDR and Arizona Department of Health Services personnel offered blood lead-level tests for local youths. The test consisted of a finger prick to produce a couple of drops of blood that go into a blood lead analyzer.
Parents received test results immediately. Capt. Robert Knowles from ATSDR said if a child has a level greater than 5 grams per deciliter (g/dL), that child should get a venous blood test (taken from a vein in the arm) to confirm the levels. The screening that he does is to answer any concerns quickly in the short term. The full metal test takes longer, is more complicated, and costs more, he said, adding that the CDC recommends all children aged 6 and younger be tested for lead levels.
EPA continues to collect additional soil and groundwater samples at the Iron King Mine tailings pile. It also recently re-applied a temporary soil sealant called Gorilla Snot to the ash piles at the smelter to help contain dust emissions.
Raina Maier, Ph.D., reported on the re-vegetation project taking place on top the main tailings pile at the Iron King Mine. The project began two years ago through the Superfund Research Program at the University of Arizona.
"The plants are thriving far beyond my imagination," Maier said.
North American Industries, the property owners, are supplying irrigation water from one of the on-site wells. Maier said preliminary results indicate that the plants have reduced airborne dust from the tailings by 60 percent. She will be repeating the tests to verify results, she said.
"The next big question is: If we stop irrigation, will the plants survive?" Maier said.
Dr. Walt Klimecki, head of the Metals Exposure Study in Homes, said he has hired four local residents to work with families with children ages 1 to 11 living within 3 miles of the mine or smelter. His study will determine if exposure to contaminants is leading to health effects in children.
David Cooper, EPA community involvement coordinator, said he structured the meeting so people could ask their questions of the professionals after the updates. Some in the audience favored a more public question-and-answer period for everyone's benefit. Cooper said after the previous community EPA meeting, he received comments from attendees requesting their individual questions be answered one-on-one.
Sue Tone is a reporter for the Prescott Valley Tribune.