Sources, Effects and Risks of Ionizing Radiation

https://wipp.energy.gov/information_repository/cra/2009_cra/references/Others/Langmuir_Herman_1980_Mobility_of_Thorium_in_Natural_Waters_at_low_Temperatures.pdf

The mobility of thorium in natural waters at low temperatures

A public health statement summarizes information about a hazardous substance. The information is taken from a toxicological profile developed by ATSDR’s Division of Toxicology and Human Health Sciences (DTHHS). A toxicological profile is a thorough review of a hazardous substance.This toxicological profile examines uranium. This public health statement summarizes the DTHHS findings on uranium, describes the effects of exposure to it, and describes what you can do to limit that exposure.

Toxicological profile for uranium

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Renewable Energy in the Context of Sustainable Development

Radium sorption efficiencies as a function of temperature, Ra concentration, and secondary mineral sorbate were determined in a 0.01 M NaCl solution. Radium sorption on a characterized clinoptilolite, montmorillonite, nontronite, opal, silica gel, illite, kaolinite, and glauconite under comparable experimental conditions allowed determination of Ra sorption efficiency curves for each, through use of Freundlich constants, over the same temperature and initial Ra solution concentration range. Similar sorption data for U on the same secondary minerals over the same temperatures allowed comparison of sorption efficiencies for Ra and U. Clinoptilolite, illite, and nontronite were the most efficient Ra sorbents, while opal and silica gel were the poorest Ra sorbents. Generally, Ra sorption on secondary minerals was much greater than U sorption under the same experimental conditions.

Sorption of trace constituents from aqueous solutions onto secondary minerals; II, Radium

Ground-water contamination from uranium mining and milling results from the infiltration of mine, mill, and ion-exchange plant effluents containing elevated concentrations of radium, selenium, and nitrate. Available data indicate that radium concentrations in the discharge waters of a producing mine tend to increase substantially as the ore body is developed. Whereas natural background radium concentrations are generally about several picocuries/liter (pCi/l), 100 to 150 pCi/l appear in the effluents of operating mines. The discharge of such highly contaminated mine effluents to streams and seepage from tailings ponds, creates a long-lived source of ground-water contamination. Seepage of mill tailings at two active mills ranges from 126,000 to 491,000 m3/yr and, to date, has contributed an estimated 2400 Curies of uranium, radium, and thorium to the ground-water reservoir. The shallow aquifer in use and downgradient from another mill has been grossly contaminated with selenium, attributable to excessive seepage from a nearby tailings pond.

Radium, selenium, nitrate and, to a lesser extent, uranium, are of most value as indicators of ground-water contamination. Gross alpha results are not consistent indicators of radium or uranium in water, although uranium does appear to be the principal contributor of alpha activity. Accurate radium-s226 analyses yield the most information for radiological evaluation of drinking water.

To date, no adverse impacts on municipal groundwater supplies have been observed. However, industry-sponsored environmental monitoring programs are inadequately designed and implemented, and may not define the full, long-term impact of mining and milling operations on the ground-water quality of the study area.

Effects of Uranium Mining and Milling on Ground Water in the Grants Mineral Belt, New Mexico

A study was conducted by the U.S. Environmental Protection Agency (USEPA) and the New Mexico Environmental Improvement Agency (NMEIA) to evaluate the possible radiological contamination of ground-water supplies in the Grants Mineral Belt area of New Mexico. Ground-water contamination from uranium mining and milling results from the infiltration of mine and mill discharge waters and ion-exchange plant effluents enriched in uranium series decay products. To date, municipal water supplies in the area have not been adversely affected by radionuclides in wastes associated with uranium mining and milling operations. However, ground-water sampling locations show slightly elevated radionuclide concentrations attributable to mining and milling activities. Only seven of the 72 sampling locations of this study had radium-226 concentrations in excess of 3 pCi/l. Thorium isotopes and polonium-210 contents fluctuate about background levels, whereas uranium contents are difficult to distinguish from the naturally elevated concentrations due to proximity to uranium-bearing formations.

Radiological evaluation of the effects of uranium mining and milling operations on selected ground water supplies in the Grants Mineral Belt, New Mexico.

Marked changes in the occurrence and quality of near-surface ground water in Las Vegas Valley, Nevada result from urban and industrial land and water use practices. In-valley recharge has increased tenfold in the period 1943 to 1973 and now amounts to about 40,000 acre-feet/year (49.3 million m3). Ground-water flows leaving the Valley have increased from 250 acre-feet/year to about 12,000 acre-feet/year.

Twenty to 400 tritium units (T.U.) in shallow ground water confirm widespread addition of recent recharge. Trend-surface analysis of recent water-quality data for depth intervals or “slices” of 0 to 50, 51 to 100, and 101 to 300 feet (0 to 15.2 m, 15.5 to 39.5 m, 30.8 to 91.4 m) revealed that natural trends below a depth of 50 feet are explainable in terms of broad hydrogeologic conditions. From 0 to 50 feet quality is highly irregular and markedly more influenced by land and water use practices and waste disposal in particular. Chloride, TDS, and nitrate are particularly diagnostic of return flows as is spring development and (or) a rising water table resulting from increased recharge and low vertical permeability. Statistical tests on water-quality data for the period 1912 to 1968 yielded generally insignificant change with time. However, the extreme paucity of the data base makes any conclusion questionable.

More efficient irrigation practices could reduce the present irrigation water demand by 15,000 acre-feet/year and reduce return flows by 11,000 acre-feet/year. Return flows by the year 2000 could easily amount to 75,000 acre-feet/year or about three times the total water budget of the Valley prior to urbanization. Therefore, groundwater problems are likely to worsen and, if present monitoring practices prevail, go unnoticed.

Land and Water Use Impacts on Ground‐Water Quality in Las Vegas Valleya

Principal U.S. phosphate production is from central Florida where mining, processing, and waste disposal practices intimately associate the industry with water resouces. Available radium-226 data from 1966 and from 1973–1976 in mined and unmined mincralized areas and nonmineralized areas in the primary study area in Polk, Hardee, Hillsborough, Manatee, and De Soto counties were studied using log-normal probability plots and nonparametric statistical tests for significant difference as functions of time, depth, and location. Plots of radium in the water table and Floridan aquifers for mineralized and nonmineralized areas indicate that neither phosphate mineralization nor the industry is a probable factor. For the Lower Floridan aquifer, three separate radium populations are indicated with geometric means of 0.7, 3, and 10 pCi/1. Geometric mean radium-226 content of the water table aquifer is 0.17 pCi/1. Radium in the Floridan aquifer in Manatee and Sarasota Counties is elevated relative to that in the water table and in other areas of Florida. For Sarasota County, geometric mean radium content of the water table is 15 pCi/l versus 7.5 pCi/l in the Floridan. Potential sources include shallow phosphate sediments and monazite sands and possibly crystalline basement rocks or other strata unrelated to phosphatic zones of current economic interest.

The existing radium-226 data base is rather marginal in terms of number and spatial distribution of analyses, particularly for the water table and Upper Floridan aquifer. Existing radium data do not substantiate widespread contamination of ground water as a result of the phosphate industry. However, local contamination associated with specific operations has occurred.

Robert F. Kaufmann

Papers

Effects of Uranium Mining and Milling on Ground Water in the Grants Mineral Belt, New Mexico

Radiological evaluation of the effects of uranium mining and milling operations on selected ground water supplies in the Grants Mineral Belt, New Mexico.

Land and Water Use Impacts on Ground‐Water Quality in Las Vegas Valleya

Radium ‐ 226 in ground water of west central florida

Utility of a computerized data base for hydrogeologic investigations, Las Vegas Valley, Nevada