Lakes and Watercourses

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TP ref (kg P/ha, year) = 0.002 · x 1 + 0.015 (1) (0.10 · x 2 + 1.2) / (5 · x 2 + 12) (2) 0.91 · x 3 · 10 –3 + 0.02 (3) 2.45 · x 4 · 10 –3 + 0.024 (4) 3.15 · x 1 · 10 –4 · (5 + 60 · x 5 ) (5) TN ref (kg N/ha, year) = 0.018 · x 1 + 0.85 (6) –0.023 · x 2 + 1.25 (7) 0.008 · x 3 + 0.85 (8) 0.03 · x 4 + 0. 90 (9) 3.15 · x 1 · 10 –4 · (125 + 500 · x 5 ) (10) where x 1 = specific flow (l/km 2 , sec) x 2 = lake percentage in catchment x 3 = area-specific loss COD Mn (kg/ha, year) x 4 = area-specific loss silicon (kg/ha, year) x 5 = flow-weighted mean absorbency 420 nm (abs f 420/5 ) The new function (5, 10) uses the absorbency of the water measured using filtered water (0.45 µm membrane filter) in a 5 cm cuvette at a wavelength of 420 nm. Taking account of the element of uncertainty introduced, absorbency (abs f 420/5 ) can be calculated by multiplying water colour (mg Pt/l) by 0.002. COD Mn is derived by dividing the permanganate number by 3.95. One of these equations may be unsuitable for use in some situations. Hence, organic matter may raise the concentration of oxygen-consuming substances, which will render use of COD inappropriate. If the pollutant is largely uncoloured matter, the absorbency function (5, 10) will be a better guide. This should in turn be avoided where it is suspected that water colour is anthropogenically elevated, eg, as a result of discharges from pulp and paper mills, leachate from rubbish tips or because of increased humus losses caused by forestry practices. Silica (4, 9) may also be anthropogenically affected, eg, in the form of lower concentrations due to eutrophication, which will particularly impact on water systems containing many lakes. 27
Comments Classifications must be based on samples taken and analyses made in accordance with the Swedish EPA Environmental Monitoring Handbook. The scales should be used bearing in mind the wide natural variation between individual lakes and watercourses and from year to year. The number of sampling occasions or the time scale on which the various assessments are based represents minimum figures. If and when assessments are made on the basis of more limited data, this should be stated. The scale for N/P ratios in lakes is intended to be used provisionally and with a degree of feedback as to results obtained. The ratios have been obtained using older analytical methods for total nitrogen (Kjeldahl-N + ammonium-N) and are affected in calculation terms by the reduction in the concentrations of total nitrogen obtained using new analytical methods (total-N using Swedish Standard SSO28131). No correction has been made to take account of this, however. The effects the class boundaries are intended to identify may therefore occur at somewhat lower ratios than those given in the criteria. References Alabaster, J.S. & Lloyd, R. (1982): Water quality criteria for freshwater fish. 2nd ed. – Butterworths, London. Swedish Environmental Protection Agency (1991): Bedömningsgrunder för sjöar och vattendrag (”Quality criteria for lakes and watercourses”). Swedish EPA General Guidelines 90:4. Persson, G. Växtnäringsämnen/eutrofiering (”Nutrients/eutrophication”). – From: T. Wiederholm (Ed.). Bedömningsgrunder för miljökvalitet - Sjöar och vattendrag. Bakgrundsrapport 1 – Kemiska och fysikaliska parametrar (”Environmental Quality Criteria – Lakes and Watercourses. Background report 1 – Chemical and physical parameters”). Swedish EPA Report 4920. Premazzi, G. & Chiaudani, G. (1992): Ecological quality of surface waters. Quality assessment for European Community lakes. – ECSC-EEC-EAEC, Brussels, Luxembourg. Wiederholm, T., Welch, E., Persson, G., Karlgren, L. & von Brömssen, U. (1983): Bedömningsgrunder och riktvärden för fosfor i sjöar och vattendrag. Underlag för försöksverksamhet. (”Quality criteria and guide values for phosphorus in lakes and watercourses. Background data for experiments”) – Swedish EPA PM 1705. 28
Page 1 and 2: Environmental Quality Criteria - La
Page 3 and 4: TO ORDER Swedish Environmental Prot
Page 5 and 6: Reference Group Mats Bengtsson, Swe
Page 7 and 8: Summary This report on lakes and wa
Page 11 and 12: included. In addition to a large nu
Page 13 and 14: ased estimates are used. Given that
Page 15 and 16: TABLE 1. SUMMARY of parameters incl
Page 17 and 18: 16 The current conditions scale in
Page 19 and 20: (in Swedish with English summary).
Page 21 and 22: conditions for watercourse flora an
Page 23 and 24: show the availability of nitrogen i
Page 25 and 26: Mean concentration of total phospho
Page 27: TABLE 9. DEVIATION from reference v
Page 31 and 32: winter/spring, i.e. ice-covered per
Page 33 and 34: Light conditions Introduction Light
Page 35 and 36: TABLE 13. CURRENT CONDITIONS: turbi
Page 37 and 38: Acidity / acidification Introductio
Page 39 and 40: industrial pH). The change in acidi
Page 41 and 42: The pre-industrial concentration of
Page 43 and 44: very high degree of reliability and
Page 45 and 46: TABLE 19. CURRENT CONDITIONS: metal
Page 47 and 48: TABLE 22. DEVIATION from reference
Page 49 and 50: TABLE 24. (continued) Cu Zn Cd Pb C
Page 51 and 52: Swedish EPA (1993): Metals and the
Page 53 and 54: Assessment of current conditions TA
Page 55 and 56: TABLE 29. CURRENT CONDITIONS: poten
Page 59 and 60: References Cronberg, G., Lindmark,
Page 61 and 62: (see Appendix 1). If submerged and
Page 63 and 64: References Andersson, B. (1998): Va
Page 65 and 66: The genera in question and their tr
Page 67 and 68: Benthic fauna Introduction Benthic
Page 69 and 70: TABLE 41. CURRENT CONDITIONS: botto
Page 71 and 72: Comments The assessment must be bas
Page 73 and 74: has yielded better results than did
Page 75 and 76: TABLE 45. CURRENT CONDITIONS: fish,
Page 79 and 80:
TABLE 48. DEVIATION from reference
Page 81 and 82:
TABLE 48. (Contd.) Proportion of al
Page 84 and 85:
Presentation of data When using the
Page 86 and 87:
APPENDIX 1 Ceratophyllum demersum 1
Page 88 and 89:
APPENDIX 2 Calculation of index and
Page 90 and 91:
APPENDIX 2 Table 1b. Indicator gene
Page 92 and 93:
Genus Indicator value -------------
Page 94 and 95:
APPENDIX 2 45 Planorbis sp. 46 Anis
Page 96 and 97:
APPENDIX 2 214 Leuctra hippopus 215
Page 98 and 99:
APPENDIX 2 384 Tinodes waeneri 385
Page 100 and 101:
APPENDIX 2 (6) O/C index (Wiederhol
Page 102 and 103:
APPENDIX 3 Dace Stäm Leuciscus leu
Page 106:
REPORT 5050 Environmental Quality C
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