At all stream sites water samples for chemical analysis are collected monthly, whereas lake sites, because water chemistry fluctuates less, are sampled 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 UK UWMN laboratories regularly participate in ICP Waters international water chemistry intercalibration exercises (eg. Hovind H., 2004; Hovind H., 2005; Hovind H., 2006; Hovind H., 2007; Hovind H., 2009; Dahl I. and Hagebo E., 2011; Dahl I., 2012; Escudero-Onate C., 2013; Escudero-Onate C., 2014; Escudero-Onate C., 2016).

A range of laboratories used to contribute chemical analyses. Today, most analysis is performed by the analytical chemistry facility at the UK Centre for Ecology & Hydrology, Lancaster. To maintain temporal consistency, determinands considered to require particularly prompt analysis (pH, Gran Alkalinity and electrical conductivity) in samples from sites in Wales are analysed at the UK Centre for Ecology & Hydrology, Bangor. The tables below summarise the methods utilised and detection limits for the analysis of each determinand. The freshwater laboratory at Marine Scotland, Pitlochry, used to provide analysis for a significant proportion of the network, and continues to provide analysis for the Baddoch Burn.

UK Centre for Ecology & Hydrology Lancaster methods and detection limits

DeterminandMinimum Detection Limit (mg l -1)Method
Alkalinity Dual end-point Gran titration. Mettler-Toledo DL53 autotitrator
Dissolved Organic Carbon0.5Shimadzu TOC-Vcph analyser
Ca0.0029Perkin Elmer DV 4300 ICP-OES
Mg0.0010Perkin Elmer DV 4300 ICP-OES
Na0.0025Perkin Elmer DV 4300 ICP-OES
K0.0094Perkin Elmer DV 4300 ICP-OES
Fe0.0003Perkin Elmer DV 4300 ICP-OES
Al0.0024Perkin Elmer DV 4300 ICP-OES
V0.00002Perkin Elmer DRCII ICP-MS
Cr0.00004Perkin Elmer DRCII ICP-MS
Mn0.000006Perkin Elmer DRCII ICP-MS
Fe0.0003Perkin Elmer DRCII ICP-MS
Co0.000006Perkin Elmer DRCII ICP-MS
Ni0.00001Perkin Elmer DRCII ICP-MS
Cu0.000002Perkin Elmer DRCII ICP-MS
Zn0.001Perkin Elmer DRCII ICP-MS
As0.000008Perkin Elmer DRCII ICP-MS
Se0.000043Perkin Elmer DRCII ICP-MS
Sb0.00013Perkin Elmer DRCII ICP-MS
Cd0.000012Perkin Elmer DRCII ICP-MS
Pb0.000059Perkin Elmer DRCII ICP-MS
Al0.00059Perkin Elmer DRCII ICP-MS

UKCEH Lancaster accredited to ISO/IEC 17025:2005. Search for United Kingdom Accreditation Service (UKAS) laboratory details.

UK Centre for Ecology & Hydrology Bangor methods and detection limits

DeterminandMinimum Detection Limit (mg l -1)Method
pH Metrohm Auto-titration
Alkalinity0.001Metrohm Auto-titration
Conductivity Jenway 4320 Conductivity Meter

 

References

  • Dahl I, Hagebo E. International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes. Intercomparison 1125:pH, Conductivity, Alkalinity, NO3-N, Cl, SO4, Ca, Mg, Na, K, TOC, Al, Fe, Mn, Cd, Pb, Cu, Ni and Zn. 1-77. (2011). Oslo, Norway, NIVA.
  • Dahl I. International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes. Intercomparison 1226:pH, Conductivity, Alkalinity, NO3-N, Cl, SO4, Ca, Mg, Na, K, TOC, Al, Fe, Mn, Cd, Pb, Cu, Ni and Zn. 1-92. (2012). Oslo, Norway, NIVA.
  • Escudero-Onate C. International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes. Intercomparison 1327:pH, Conductivity, Alkalinity, NO3-N, Cl, SO4, Ca, Mg, Na, K, TOC, Al, Fe, Mn, Cd, Pb, Cu, Ni and Zn. 1-93. (2013). Oslo, Norway, NIVA.
  • Escudero-Onate C. International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes. Intercomparison 1428:pH, Conductivity, Alkalinity, NO3-N, Cl, SO4, Ca, Mg, Na, K, TOC, Al, Fe, Mn, Cd, Pb, Cu, Ni and Zn. 1-88. (2014). Oslo, Norway, NIVA.
  • Escudero-Onate C. International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes. Intercomparison 1630:pH, Conductivity, Alkalinity, NO3-N, Cl, SO4, Ca, Mg, Na, K, TOC, Al, Fe, Mn, Cd, Pb, Cu, Ni and Zn. 1-71. (2016). Oslo, Norway, NIVA.
  • Hovind H. International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes. Intercomparison 0418: pH,K25,HCO3, NO3+NO2, Cl, SO4, Ca, Mg, Na, K, Fe, Mn, Cd, Pb, Cu, Ni and Zn. 1-69. (2004). Oslo, Norway, NIVA.
  • Hovind H. International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes. Intercomparison 0519: pH, Cond, HCO3, NO3+NO2, C1, SO4, Ca, Mg, Na, K, Fe, Mn, Cd, Pb, Cu, Ni, and Zn. 1-70. (2005). Oslo, Norway, NIVA.
  • Hovind H. International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes. Intercomparison 0620: pH, Cond, HCO3, NO3+NO2, Cl, SO4, Ca, Mg, Na, K, Fe, Mn, Cd, Pb, Cu, Ni and Zn. 1-69. (2006). Oslo, Norway, NIVA.
  • Hovind H. International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes. Intercomparison 0721: pH, Cond, HCO3, NO3-N, C1, SO4, Ca, Mg, Na, K, Fe, Mn, Cd, Pb, Cu, Ni, and Zn. 1-68. (2007). Oslo, Norway, NIVA.
  • Hovind H. International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes. Intercomparison 0923: pH, Cond, HCO3, NO3-N, Cl, SO4, Ca, Mg, Na, K, TOC, Al, Fe, Mn, Cd, Pb, Cu, Ni, and Zn. 1-73. (2009). Oslo, Norway, NIVA.
  • Hovind H. International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes. Intercomparison 1024: pH, Cond, HCO3, NO3-N, Cl, SO4, Ca, Mg, Na, K, TOC, Al, Fe, Mn, Cd, Pb, Cu, Ni, and Zn. 1-77. (2010). Oslo, Norway, NIVA.
  • 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.