Evaluation of methods for preservation of water samples for nutrient analysis

Review of robust measurement of phosphorus in river water: sampling, storage, fractionation and sensitivity

“…However, the effectiveness of refrigeration reported in publications is variable. One study showed that river and lake samples could be stored at 4 o C for up to eight days without decreases in SRP or TP (Fishman et al, 1986). However, other studies have demonstrated changes in SRP within (a) 24-48 h for refrigerated soil water samples (Haygarth et al, 1995), (b) 12 hours, especially where samples contained significant quantities of suspended material (Johnson et al, 1975) and (c) four hours of refrigeration (a 28-45% loss of TDP and a 36-58% loss of SRP in lake water samples; Lambert et al, 1992).…”

“…Preservatives commonly used for sample stabilisation (with varying degrees of success) include chloroform (Gilmartin, 1967;Pichet et al, 1979), mercuric chloride (Skjemstad and Reeve, 1978;Fishman et al, 1986), iodine (Mackereth et al, 1978) and H 2 SO 4 (Henriksen, 1969). However, the application of chemical preservatives may be problematic (Haygarth et al, 1995).…”

Delayed Sample Filtration and Storage Effects on Dissolved Nutrients Measured in Agricultural Runoff

“…Researchers collect runoff water samples and analyze them for these nutrients to estimate the runoff's potential effect on aquatic ecosystems. Because they are biologically active, dissolved phosphorus (P) and nitrogen (N) concentrations in collected waters can change with time (Nelson and Römkens 1972;Klingaman and Nelson 1976;Fishman, Schroder, and Shockey 1986;Kotlash and Chessman 1998). Dissolved P concentrations can also change in the presence of sediment in response to sorption or desorption reactions (Bjorneberg et al 2006).…”

“…• C may suffice for 1 to 2 week storage times, particularly if samples do not contain substantial particulate concentrations (Fishman, Schroder, and Shockey 1986;Robards et al 1994). Storing samples at -20…”

Cumulative Uncertainty in Measured Streamflow and Water Quality Data for Small Watersheds

“…Low temperatures (<4.0°C) reduce microbial activity, thereby reducing microbially mediated nutrient transformations. The effectiveness of refrigeration appears to vary, with some previous studies demonstrating effective preservation for up to 8 days at 4.0°C (Fishman et al, 1986) and others reporting significant changes in nutrient concentrations within 4 to 48 h (Johnson et al, 1975;Lambert et al, 1992;Haygarth et al, 1995). Kotlash and Chessman (1998) reported effective preservation by refrigeration for up to 2 days for a broad range of sites and nutrient concentrations under varying weather conditions.…”