Lakes and Watercourses

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ately eutrophic lakes. To classify current conditions, it is proposed that a taxonomic division be made at genus level, since species analysis requires considerable experience owing to the lack of modern identification keys and uniform flora. TABLE 30. CURRENT CONDITIONS: Gonyostomum semen (mm 3 /l) Class Description Biomass 1 Very small biomass ≤ 0.1 2 Small biomass 0.1 – 1.0 3 Moderate biomass 1.0 – 2.5 4 Large biomass 2.5 – 5.0 5 Very large biomass > 5.0 The class boundaries for Gonyostomum semen have been set to take account of problems in bathing waters. The biomass in the highest classes indicates that sensitive individuals may suffer skin reactions. The boundaries of the various classes coincide roughly with the 25th, 50th, 75th and 90th percentiles in the background material. Assessment of deviation from reference values TABLE 31. DEVIATION from reference value, total phytoplankton volume, spring-developing diatoms, water-blooming cyanobacteria Class Description Recorded volume/reference value 1 No or insignificant deviation ≤ 1.0 2 Slight deviation 1.0 – 2.0 3 Significant deviation 2.0 – 3.0 4 Large deviation 3.0 – 5.0 5 Very large deviation > 5.0 Reference values for various types of lakes are shown in Table 34. The figures have been calculated for lowland lakes on the basis of an assumed pristine mesotrophic state with a typical total phosphorus concentration 55
TABLE 32. DEVIATION from reference value, potentially toxin-producing cyanobacteria Class Description No. of potentially toxic genera/ reference value 1 No or insignificant deviation < 1 3 Significant deviation 1 – 1.5 5 Large to very large deviation ≥ 1.5 TABLE 33. DEVIATION from reference value, Gonyostomum semen Class Description Recorded volume/reference value 1 No or insignificant deviation ≤ 1.0 2 Slight deviation 1.0 – 10 3 Significant deviation 10 – 25 4 Large deviation 25 – 50 5 Very large deviation > 50 of 15 µg/l. The reference values have then been based on correlations with the total biomass of planktonic algae. The biomass in August has been determined by calculating the relationship with the seasonal mean from the Environmental Monitoring Programme database. The volume of diatoms in April/May is based on the maximum figure in the database for mesotrophic lakes having a nutrient status of 15 µg/l (tot-P). Two reference lakes form the basis for assessment of forest lakes. Maximum figures from a number of published studies have been used for mountain lakes, since the Environmental Monitoring Programme database was inadequate. Reference values for potentially toxic genera have been set using the Environmental Monitoring Programme database. Essentially, the reference value for Gonyostomum semen is considered to be an absence of viable communities. The reference value has been set using lakes where there is an influx of humic water capable of carrying limited quantities of Gonyostomum, which will temporarily survive in a given habitat. 56
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 and 28: TABLE 9. DEVIATION from reference v
Page 29 and 30: Comments Classifications must be ba
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: 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 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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