OR/13/031 List of abbreviations and definitions

Tye, A M, Hurst, M D, and Barkwith, A K A P. 2013. Nene phosphate in sediment investigation — Environment Agency project ref: 30258. (Water Framework Directive). British Geological Survey Internal Report, OR/13/031.

Within this report a number of abbreviations and different species of phosphorus are measured. Their definitions and abbreviations are given below:

Total P (TP) is used to define the total concentration of phosphorus in the sediment measured. This is undertaken by dissolving the sediment in strong acid and expressing the result as a concentration (mg kg^-1) on a dry weight basis. This measurement will include both Olsen Extractable Phosphate as well as that Phosphorus locked away or occluded within the mineral and oxide structures.

Phosphate (PO₄-P) is the generic term used for the phosphate ions which in its simplest form is ortho-phosphoric acid (H₃PO₄).

Olsen Extractable PO₄-P (OEP) is a measure of the PO₄-P in the sediment that is considered to be in a bio-available form and which could be readily utilised by water plants and microbial communities. OEP is expressed as a concentration (mg kg^-1) on a dry weight basis and is extracted in a 0.5 m NaHCO₃ solution whereby the carbonate ions in the extracting solution exchange with the phosphate ions held on any mineral and organic matter surfaces. The measurement is expressed as P, therefore multiplying by 3 will give an approximate value for phosphate (PO₄^-).

Soluble Reactive Phosphate (SRP) is the soluble reactive P found in river waters after filtering through a 0.45 µm filter. Multiplying the value given by three will give an approximate result as phosphate (PO₄^-).

Water Framework Directive (WFD) is the EU legislation aimed at improving the quality and biodiversity of surface waters.

Water Body describes a defined length of the River Nene which is managed and monitored with a view to achieve and sustain good ecological status (GES).