5.1 Determinands assessed by monitoring programme

In order to allow information in the metadatabase to be references in terms of determinand, the parameters included have been grouped by means of a look-up table. The types of determinands included and some examples of the standardised determinands grouped into each type are as follows:

Aesthetic determinands: Colour, floating materials, surfactants.

Biological determinands: Benthic fauna, planktonic flora, species list, ecotox test, primary production, tar ball collections, fish disease.

Chemicals: Acidity, calcium, chlorides, cyanides, fluorides etc.

Metals: Aluminium, arsenic, boron, zinc etc.

Microbiological determinands: Coliform, salmonella, total bacteria etc.

Nutrients: Ammonia, nitrogen etc.

Organic pollution: BOD, COD, organic carbon, dissolved oxygen etc.

Physical and physicochemical determinands: Flow, level, pH, temperature, dissolved solids etc.

Radioactive elements: Alpha emissions, caesium, strontium etc.

Synthetic organics: PCB, DDT, BHC, HCH etc.

Table C.1 in Appendix C shows a complete list of the determinands, classified by matrix, for each monitoring programme.

The matrices considered in the metadatabase are biota, water and sediment.

  • Biota
    Determinands assessed in biota are grouped under the following headings:
  • biological determinands;
  • metals;
  • microbiological determinands;
  • synthetic organics; and
  • radioactive elements.

Table D.3 in Appendix D shows, where available, the determinands measured in biota for each monitoring programme, the number of sites where they have been assessed, and the year the programme began.

  • Water
    The determinands measured in suspended matter have been classified in this matrix, although the each determinand has been annotated with the phrase "measured in suspended matter". Similarly, where determinands have been measured in groundwater they are annotated with the term "measured in groundwater". Determinands assessed in water have been grouped under the following headings: aesthetic, biological, chemical, microbiological and physical determinands, radioactive elements and synthetic organics.

Table D.1 in Appendix D shows the determinands measured in water for each monitoring programme, the number of sites where they have been assessed, and the year the programme began. Table D.2 in Appendix D shows the same information for sea waters, whilst Table D.4 in Appendix D displays the list of determinands monitored in groundwater. All the determinands held in the tables in Appendix D are standardised. Further information on each determinand can be found in Table C.1 in Appendix C.

  • Sediments
    The determinands monitored in sediments are listed in Table C.1 in Appendix C.

5.2 Statistics used

The determinands are mainly reported by each monitoring programme as their annual average values although in some cases, the annual average is also complemented with the annual maximum and the annual minimum. Other statistics used include the annual averages of the maxima and minima, the mean monthly averages and total annual values. Flow is recorded in terms of maxima, minima and averages.

5.3 Units

The unit in which a measurement is expressed is dependent on the determinand concerned.

Chemicals (e.g. Ca, Cl, F, Hg) and metals are usually measured as mg (or µg) of each particular element per litre. Other units include m mol/dm3, kg/s and tonnes. When metals are assessed in suspended matter or biota, they are measured as g/kg.

Coliforms, faecal coliforms and faecal streptococci have been recorded in terms of the number per 100 ml (N1 /100ml). Phytoplankton is counted either in N1 /l (or N1 /ml) or the number of species. Chlorophyll is measured in mg/m3 or µg/dm3. Other biological indicators have different units, the carbon dark fixation and the inorganic assimilated carbon are both measured in mg C m3/day, the specimen density in rivers and lakes is measured in indiv/m2 and respiration is measured in mg O2 m3/day.

Nutrients have been recorded in mg (or µg) per litre. Nitrogen compounds are expressed in all cases as mg N/l whilst phosphorous compounds are measured either as mg P/l or mg PO4/l. Silica is measured in mg Si/l or kg Si/s. One programme also uses µmol/dm3.

BOD and COD have both been measured in terms of mg O2/l. Dissolved oxygen has been measured as mg O2/l and %O2. Organic carbon has been measured as mg C/l and kg/s.

Flow has mainly been measured as m3/s, although the stream runoff is reported in l/(s.km2) and groundwater level has been measured in cm from the surface.

Alkalinity has been reported as mg/l and as mmol H ions/l. Conductivity is always measured as µS/cm and temperature is always reported in °C. Suspended and dissolved solids have both been measured in mg/l. The colour in water has been measured in cm-1, and also expressed by the colour number (Pt mg/l)

Radioactivity in water is measured in Bq/l (or mBq/l). The synthetic organics assessed in water are expressed in µg/l or reported as tonnes discharged in effluent. Those assessed in suspended matter and biota are measured in µg/kg (or mg/kg).

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