UK AWMN Water Chemistry Methods
At all stream sites water samples for chemical analysis are collected monthly. At lake sites, where the chemistry is more stable, sampling is undertaken on a quarterly basis. All dip samples are collected in acid-rinsed bottles.
The chemical determinands recorded at each site are those recommended by the Acid Waters Review Group (Warren et al. 1986). Accuracy requirements were established in accordance with Water Research Centre (WRc) recommendations and UK water industry practice. The more stable determinands are analysed at the Centre for Ecology and Hydrology, Lancaster. Those determinands which are considered to require prompt analysis are analysed at two local laboratories; Marine Scotland, Pitlochry and the Centre for Ecology and Hydrology, Bangor. To enhance efficiency and minimise disruption, the local laboratories follow their own routine analytical methods which have a proven performance record. The tables below summarise the methods utilised and detection limits for the analysis of each determinand.
Centre for Ecology and Hydrology Lancaster Methods and Detection Limits
| Determinand | Minimum Detection Limit (mg l -1) | Method |
|---|---|---|
| Alkalinity | Dual end-point Gran titration. Mettler-Toledo DL53 autotitrator | |
| Dissolved Organic Carbon | 0.5 | Shimadzu TOC-Vcph analyser |
| Ca | 0.0029 | Perkin Elmer DV 4300 ICP-OES |
| Mg | 0.0010 | Perkin Elmer DV 4300 ICP-OES |
| Na | 0.0025 | Perkin Elmer DV 4300 ICP-OES |
| K | 0.0094 | Perkin Elmer DV 4300 ICP-OES |
| Fe | 0.0003 | Perkin Elmer DV 4300 ICP-OES |
| Al | 0.0024 | Perkin Elmer DV 4300 ICP-OES |
| V | 0.00002 | Perkin Elmer DRCII ICP-MS |
| Cr | 0.00004 | Perkin Elmer DRCII ICP-MS |
| Mn | 0.000006 | Perkin Elmer DRCII ICP-MS |
| Fe | 0.0003 | Perkin Elmer DRCII ICP-MS |
| Co | 0.000006 | Perkin Elmer DRCII ICP-MS |
| Ni | 0.00001 | Perkin Elmer DRCII ICP-MS |
| Cu | 0.000002 | Perkin Elmer DRCII ICP-MS |
| Zn | 0.001 | Perkin Elmer DRCII ICP-MS |
| As | 0.000008 | Perkin Elmer DRCII ICP-MS |
| Se | 0.000043 | Perkin Elmer DRCII ICP-MS |
| Sb | 0.00013 | Perkin Elmer DRCII ICP-MS |
| Cd | 0.000012 | Perkin Elmer DRCII ICP-MS |
| Pb | 0.000059 | Perkin Elmer DRCII ICP-MS |
| Al | 0.00059 | Perkin Elmer DRCII ICP-MS |
Marine Scotland Laboratory Methods and Detection Limits
| Determinand | Minimum Detection Limit (mg l -1) | Method |
|---|---|---|
| pH | Radiometer TTT81 | |
| H+ | Derived | |
| Alkalinity | Radiometer TTT81 | |
| Conductivity | Conductivity Meter | |
| TON | 0.125 | Ion Chromatography (Dionex ICS 1000) |
| PO4 | 0.001 | Colourimetrically (Molybdate Ascorbic Acid) |
| Soluble Monomeric Al | 0.004 | Colourimetrically (Catechol Violet) |
| Soluble Non-Labile Monomeric Al | 0.004 | Colourimetrically (Catechol Violet) |
| Soluble Labile Monomeric Al | 0.004 | Derived by Difference |
| Dissolved Organic Carbon | 1.000 | Continous Flow Analyser |
| Ca | 0.100 | Ion Chromatography (Dionex DX120) |
| Mg | 0.024 | Ion Chromatography (Dionex DX120) |
| Na | 0.023 | Ion Chromatography (Dionex DX120) |
| NH4 | 0.018 | Ion Chromatography (Dionex DX120) |
| K | 0.039 | Ion Chromatography (Dionex DX120) |
| SO4 | 0.144 | Ion Chromatography (Dionex ICS 1000) |
| Cl | 0.070 | Ion Chromatography (Dionex ICS 1000) |
| Br | 0.080 | Ion Chromatography (Dionex ICS 1000) |
| Excess SO4 | Derived |
Centre for Ecology and Hydrology Bangor Methods and Detection Limits
| Determinand | Minimum Detection Limit (mg l -1) | Method |
|---|---|---|
| pH | Metrohm Auto-titration | |
| H+ | Derived | |
| Alkalinity | 0.001 | Metrohm Auto-titration |
| Conductivity | Jenway 4320 Conductivity Meter | |
| TON | 0.013 | Thermo-oxidation |
| PO4 | 0.004 | Discrete Colorimetric (880 nm) |
| Dissolved Organic Carbon | 0.200 | Thermo-oxidation |
References
Warren, S. C., Bache, B. W., Edmunds, W. M., Egglishaw, H. J., Gee, A. S., Hornung, M., Howells, G. D., Jordan, C., Leeming, J. B., Maitland, P. S., Pugh, K. B., Sutcliffe, D. W., Wells, D. E., Cape, J. N., Ellis, J. C., Hunt, D. T. E., Wilson, R. B. & Watson, D. C. (1986) Acidity in United Kingdom fresh waters. United Kingdom Acid Waters Review Group interim report. Department of the Environment, London.
Page last modified: 4th March, 2011
Page published: 12 March 2010