Radioactivity in size-separated municipal incinerator ashes.

Radionuclide concentrations of the 238U- and 232Th-decay series, as well as 40K and 137Cs, were determined in size-separated fly ashes and bottom ashes from two municipal incinerators. Secular equilibrium was observed for several of the series' radionuclides, though 222Rn losses during combustion were evident. The fly-ash samples showed increasing enrichment of 40K, 137Cs, and 210Pb as particle diameters decreased, due to their volatility and subsequent condensation, and typically contained higher activities of these volatile radionuclides. Radon emanation from the bottom ashes was not detected but the fly ashes had an emanting power near 7%. Only 40K and 137Cs were found to be water-soluble, with significantly greater solubilities occurring for the fly ashes. Overall concentrations suggest that municipal incinerator ashes contain the equivalent radioactivity of surface soil and substantially less than ashes from coal combustion. It is shown that an incinerator's contribution to the atmospheric radionuclide burden is minimal and, from a radiological viewpoint, their residual ashes can be safely used in construction materials.

Direct comparison of three methods for the determination of radon in well water.

Radon concentrations obtained using a bubbler device developed to collect and bubble water samples in the laboratory and field were compared with results from conventional liquid scintillation counting. Measurements from standard solutions with a wide concentration range showed excellent agreement between liquid scintillation and results obtained using the bubbler device in conjunction with alpha-scintillation cells. Measurements of waterborne radon concentrations in 110 community and private wells in New York State ranged from 1 to 4,100 Bq L-1, with arithmetic and geometric means of 200 and 30 Bq L-1, respectively. Excellent agreement between the analytical techniques was obtained for each field site.

Radon and thoron emanation from uranium-glazed tableware.

Radon and thoron gas emanation from tableware with ceramic glazes containing elevated uranium levels was determined using alpha-scintillation cells. Though gamma spectroscopy noted significant uranium concentrations in the glazed, no radioactive gas emanation was observed, contradicting a previous report.

Radon measurements and mitigation at a fish hatchery.

Groundwater radon concentration of 83 Bq L(-1) generated indoor radon levels exceeding 3,300 Bq m(-3) at a commercial fish hatchery. Passive and active mitigation strategies to reduce the waterborne radon levels included a packed column, a waterfall through perforated grates, surface aeration, and bottom bubblers. Waterborne concentrations were reduced up to 83% using a combination of mitigation procedures, but a comparable reduction in indoor radon concentrations was not observed. A diurnal cycle showed that indoor radon levels peaked in early afternoon, probably as a result of warmer air being dissolved in the water during mitigation. Reduction of indoor radon levels below 148 Bq m(-3) was seldom achievable with both water mitigation and direct air ventilation at 23 room air changes hourly.

Application of low-background gamma-ray spectrometry to monitor radioactivity in the environment and food.

The results are described of an upgrade of the low-background gamma-ray spectrometry laboratory at New York State Department of Health by acquiring sensitivity to low-energy gamma rays. Tuning of the spectrometer and its low-energy response characteristics are described. The spectrometer has been applied to monitor the environment by measuring aerosols and water in New York State contaminated by the 2011 Fukushima accident plume. In addition, the spectrometer has been used to monitor radioactivity in food by performing a study of cesium in Florida milk.

Assessing radon concentrations in areas with few measurements.

The New York State Department of Health has estimated and mapped radon concentrations for every town and city in the State. Since for many towns there are few indoor radon measurements, the radon estimates for these towns were determined using correlations to surficial geology. A project was conducted to target towns for additional measurements that currently have few data but, based on the surficial geology of the town, are estimated to have elevated levels of indoor radon. The objective of the project was to obtain at least 30 additional measurements for the targeted towns and to compare the measurement results with the estimates based on geology. The study completed 1606 radon measurements from 9080 detector applications mailed to home owners in 94 underserved towns spread throughout the State. Of the 1115 basement measurements, 43% 148 Bq m(-3), with a maximum of 6900 Bq m(-3). Three homes measured in one town had radon concentrations above 2900 Bq m(-3). Of the 491 living-area measurements, 19% exceeded 148 Bq m(-3), with a maximum of 2700 Bq m(-3). About 60% and 86% of measurement results were within one standard deviation and a factor of two, respectively, of estimated concentrations. Results indicate that regardless of the magnitude of radon potential, the estimates are in good agreement with measured concentrations.