Monticello Millsite environmental report for calendar year 1991

This report contains information pertaining to environmental activities conducted during calendar year 1991 at and near the inactive uranium millsite in Monticello, Utah. Environmental activities conducted at the Monticello Millsite during 1991 included those associated with remedial action and compliance monitoring. Compliance monitoring consisted of both radiological and nonradiological monitoring of air, surface water, and ground water. Radiological and nonradiological air monitoring at the millsite included measurements of atmospheric radon, particulate matter, and gamma radiation. Surface water monitoring included water quality measurements within Montezuma Creek. Ground water monitoring was conducted for two aquifers underlying the Monticello Millsite -- a shallow, alluvial aquifer and a deeper, confined Burro Canyon aquifer. The shallow aquifer is contaminated by leached products of uranium mill tailings. During 1991, Uranium Mill Tailings Radiation Control Act and state of Utah ground water standards for arsenic, selenium, molybdenum. uranium 234+238, gross alpha particle activity, and radium-226+228 were exceeded in one or more wells. Samples collected from the deeper Burro Canyon aquifer revealed that no federal or state standards were exceeded