Total Phosphorus, TotP/Total-P

Last changed: 01 April 2019

Known issues with the databases

Anomalous total phosphorus levels have been revealed for the period January 1991 – June 1996. The anomaly has been shown to be likely to result from an absolute error, which ensued in an increase of about 1.2 µg P/l (95% confidence interval = ± 0.2 µg P/l). This was caused by uncertainty at the determination of the base level, associated with an unstable base line of an older instrument. The instrument was replaced in mid-1996, resulting in a rapid improvement of the quality of the analysis, and the results has thereafter been in good comparison with results from other laboratories. The increment in total phosphorus level has largest impact on lakes and watercourses with low levels, in particular those with small intra- and interannual variation, e.g. lakes Vänern and Vättern. However, the levels in tiny lakes and watercourses with large fluctuations in phosphorous content are only affected to a small extent, since influence from the environment is more significant in these cases. The elevated total phosphorus levels have not been shown to have any apparent effect on determining the total amounts of phosphorus that have been transported in the watercourses.

» Read more in our assessment of the total phosporus data and analysis (in Swedish).

Current method of measurement

Valid since January 2002
Method: Bran & Leubbe Method No. G-175-96 Rev. 2 (modified). SS-EN ISO 6878:2005 (modified).
Instrument: Technicon Autoanalyzer 3 (upgraded Autoanalyzer II).
NB: Water samples conserved with H2SO4.

Previous methods

1997-01 – 2001-12
Method: Swedish Standard SS 02 81 27-2 modified for autoanalyser.
Instrument: Technicon Autoanalyzer II.
NB: Water samples conserved with H2SO4.

1971-01 – 1996-12
Method: Schuster, H. H.: 1969. Arch. Hydrobiol. 65:4. Koroleff, F. ICES C.M., 1968, C33. Influx with potassium persulphate.
Instrument: Technicon Autoanalyzer I.
NB: Water samples conserved with HgCl2.

1969-01 – 1970-12
Method: Schuster, H. H.: 1969. Arch. Hydrobiol. 65:4. Influx with oxidation mixture.
Instrument: Technicon Autoanalyzer I.
NB: Water samples conserved with HgCl2.

1965-01 – 1968-12
Method: Proctor, C. & Hood, D. W., 1954. Journal of Marine Research. Vol. 13. No. 1. Modified for autoanalyser. Influx with oxidation mixture.
Instrument: Technicon Autoanalyzer I.
NB: Water samples conserved with HgCl2.


Contact
Page editor: Lars.Sonesten@slu.se