No abstract

Adaptation of the enhanced chemiluminescent reaction (ECLOX test) to water-quality monitoring revealed that pollutants in industrial and domestic effluent and farmyard and dairy washings may suppress or completely inhibit enhanced chemiluminescent light emission. Inhibition or changes in the kinetics of light emission occur in the presence of a wide range of extraneous substances. Interaction of such substances with ECLOX reaction components or reaction intermediates can produce changes in light emission, allowing detection of a broad range of chemical pollutants. This work examined the suitability of the ECLOX test to differentiate between water quality at various points along a rural stream. In addition, the study was used to measure whether changes in water quality detected by the ECLOX test were consistent with measured levels of the protozoan parasite Cryptosporidium parvum. Seven locations along a stream and a farmyard drainage ditch were sampled on the basis of position, continuity of flow, permanence, and evidence of fecal contamination. The stream frequently contained C. parvum (75% of occasions tested), although according to the ECLOX test and other standard parameters (suspended solids and pH), it seemed relatively uncontaminated. The ECLOX test did, however, distinguish among a range of water qualities. The ECLOX test can be considered as a useful qualitative indicator of differing water qualities, but C. parvum can be present in water of any quality; therefore, ECLOX is not an appropriate method for detecting the presence of this parasite. Water Environ. Res., 72, 22 (2000).

Preservation and hold time of radionuclides must account for both nuclear half-lives and nonnuclear loss mechanisms, but variations in the latter are often neglected. Metals-based defaults are inappropriate for long-lived non-metals C-14 and I-129, which are vulnerable to chemical and biological volatilization. Non-acidification is already widely practiced for them. Recommended addition measures from radiological and chemical literature include glass containers where possible, water filtration where possible, headspace minimization, light shielding, cold (4°C) storage and unfiltered water hold time of 28 days. Soil hold time may need to be shortened when waterlogged , excessively sandy, or still adjusting to significant new contamination. Table 1 below summarizes recommendations. Table 1: Summary of C-14/I-129 Preservation and Hold Time Guidance Matrix Collected Fraction Preservation Hold Time Water Total Min. headspace, 4±2°C, amber glass or glass/PTFE stored dark 28 days Dissolved (0.22μ or 0.45μ filter) 180 days Soil: watery, very sandy, or newly contaminated Total Min. headspace, 4±2°C, amber glass or glass/PTFE* stored dark 28 days Soil: other/typical Min. headspace, 4±2°C, glass/plastic* 180 days * Normal soil self-shields for light, but small volumes may need control via container or dark storage.