BS ISO BRITISH STANDARD 20079:2005 BS 6068-5.39:2005 Water quality Determination of the toxic effect of water constituents and waste water on duckweed (Lemna minor) - Duckweed growth inhibition test ICS 13.060.70 BSi NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW British Standards BS ISO 20079:2005 National foreword This British Standard reproduces verbatim IS0 20079:2005 and implements it as the UK national standard. BSI The UK participation in its preparation was entrusted by Technical Committee EH/3, Water quality, to Subcommittee EH/3/5, Biological methods, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled "International Standards Correspondence Index", or by using the“Search" facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity fromlegal obligations. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 23 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. This British Standard was Amendments issued sincepublication Licensed published under the authority of the Standards Policy and Amd. No. Date Comments Strategy Committee on 23January 2006 BSI 23 January 2006 ISBN 0 580 47174 8 BSIS020079:2005 ISO INTERNATIONAL STANDARD 20079 First edition 2005-11-01 Water quality Determination of the toxic effect of water constituents and waste water on duckweed (Lemna minor) Duckweed growth inhibition test QualitedeI'eauDéterminationdeI'effettoxiquedesconstituantsde I'eau et des eaux résiduaires vis-a-vis deslentiles d'eau (Lemna minor)-Essaid'inhibitiondelacroissancedes lentilles d'eau Referencenumber ISO 20079:2005(E) ：= BSISO20079:2005 Contents Page Foreword IV Introductior 1 Scope 2 Normative referenc 3 Terms and definitions. 4 Principle 5 Interferences 6 Apparatus 7 Reagents. 8 9 Stock cultures and pre-cultures 10 Procedure.. 11 Validity criteria ... 12 Expressionofresults. 13 Estimation of Ec(r)values for frond number and the second observation parameter.... 14 Documentation of results .... 15 Precision. 12 16 Test report 13 AnnexA (informative)Preparationof thenutrientmedia 14 Annex B (informative)Measurement of the lowest ineffective dilution (LID)of a waste water Asimplifiedevaluationfortestingofwastewater... AnnexC(informative)SuppliersofLemnaspecies 22 Bibliography...... ii BSIS020079:2005 BS Foreword Copy, (c) IsO (the International Organization for Standardization) is a worldwide federation of national standards bodies ,Uncontrolled International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/lEC Directives, Part 2 The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75% of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent ISO 20079 was prepared by Technical Committee ISO/TC 147, W