Interpreting and Reporting Radiological Water-Quality Data

Abstract

This document provides information to U.S. Geological Survey (USGS) Water Science Centers on interpreting and reporting radiological results for samples of environmental matrices, most notably water. The information provided is intended to be broadly useful throughout the United States, but it is recommended that scientists who work at sites containing radioactive hazardous wastes need to consult additional sources for more detailed information. The document is largely based on recognized national standards and guidance documents for radioanalytical sample processing, most notably the Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP), and on documents published by the U.S. Environmental Protection Agency and the American National Standards Institute. It does not include discussion of standard USGS practices including field qualitycontrol sample analysis, interpretive report policies, and related issues, all of which shall always be included in any effort by the Water Science Centers. The use of "shall" in this report signifies a policy requirement of the USGS Office of Water Quality.

An investigation of submarine groundwater—borne nutrient fluxes to the west Florida shelf and recurrent harmful algal blooms

“…Efficiency for the standards varied slightly among the instruments but averaged 9.6 6 0.8 cpm Bq 21 (1 SD) for the 6-liter water to 1-liter air system. Based on the average system backgrounds, critical level (L c ) and minimum detectable activity (MDA) (McCurdy et al 2008) for the procedure were 14.1 6 1.9 and 29.4 6 3.8 Bq m 23 (1 SD, n 5 28), respectively. In comparison, the L c and MDA based on instrumental backgrounds averaged 13.2 6 3.8 and 27.7 6 7.6 Bq m 23 (1 SD, n 5 28), respectively.…”

“…Throughout the document, uncertainty of mean (or average) concentration, radioactivity, temperature, and salinity is presented with 1 SD. In contrast, uncertainty in individual 223,224,226 Ra and 222 Rn measurements is derived from propagated analytical uncertainty based on standard counting statistics (McCurdy et al 2008).…”

Occurrence and Geochemistry of Lead-210 and Polonium-210 Radionuclides in Public-Drinking-Water Supplies from Principal Aquifers of the United States

“…7,37 210 Pb and 210 Po were considered not detected when the individual sample result was less than the calculated samplespecific critical level (C Lss ) for the detection of radiation. 38 The C Lss ranged from 0.12 to 0.58 pCi/L for 210 Pb (with one outlier at 0.88 pCi/L) and from 0.02 to 0.14 pCi/L for 210 Po (with one outlier at 0.30 pCi/L). A time-series comparison of concentrations for 210 Pb and 210 210 Pb pairs (n = 48) and 210 Po pairs (n = 47) were within 2σ combined uncertainty; six and eight pairs (12.5% and 17%), respectively, for 210 Pb and 210 Po were outside 1σ combined uncertainty (Table SI -4).…”

Gross Alpha-Particle Activity and High 226Ra Concentrations Do Not Correspond with High 210Po in the Atlantic and Gulf Coastal Plain Aquifers of the United States

“…Results less than the calculated sample-specific critical level ( C Lss ) for radioactivity were considered as non-detects for radionuclides . The median C Lss was 0.03 pCi/L for both 210 Po and 226 Ra and ranged from 0.01 to 0.07 pCi/L for 210 Po and from 0.01 to 0.33 pCi/L for 226 Ra; the lowest detected concentrations were 0.01 and 0.02 pCi/L, respectively.…”