ISO INTERNATIONAL STANDARD 7346-2 Second edition 1996-06-15 Water quality Determination of the acute lethal toxicity of substances to a freshwater fish [Brachydanio rerio Hamilton-Buchanan (Teleostei, Cyprinidae)J - Part 2: Semi-static method Qualité de I'eau - Détermination de la toxicite aigue letale de substances vis-a-vis d'un poisson d'eau douce [Brachydanio rerio Hamilton-Buchanan (Téléostei, Cyprinidae -- Partie 2: Methode semi-statique This material is reproduced from Iso documents under International Organization for Standardization (Iso) Copyright License number IHS/ICC/1996. Not for resale. No part of these Iso documents may be reproduced in any form, electronic retrieval system or otherwise, except as allowed in the copyright law of the country of use, or with the prior written consent of Iso (Case postale 56, 1211 Geneva 20, Switzerland, Fax +41 22 7341079),IHsorthe1SoLicensor'smembers. ISO Reference number ISO 7346-2:1996(E) No reproduction or networking permitted without license from IHS Not for Resale ISO 7346-2:1996(E) Foreword isO (the International Organization for Standardization) is a worldwide federation of national standards bodies (lsO member bodies). The work of preparing International Standards is normally carried out through IsO which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. IsO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees sare circulated to the member bodies for voting. Publication as an International a vote. International Standard ISO 7346-2 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 5, Biological methods. This second edition cancels and replacesthe first edition (iS0 7346-2:1984), which has been technically revised. IsO 7346 consists of the following parts, under the general title Water qualityi Determination of the acute lethal toxicity of substances to a freshwater fish [BrachydaniorerioHamilton-Buchanan (Teleostei, Cyprinidae: Part 1: Static method Part 2: Semi-static method Part 3: Flow-through method Annexes A, B and C of this part of ISO 7346 are for information only ISO 1996 All rightsreserved.Unless otherwise specified,nopart of thispublicationmay be reproducec or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization CasePostale56+CH-1211Geneve20-Switzerland Printed in Switzerland ii led without license from IHS Not for Resale CISO ISO 7346-2:1996(E) Introduction The three parts of isO 7346 describe methods of determining the acute Hamilton-Buchanan) but it must be emphasized that the recommended use of the zebra fish does not preclude the use of other species. The freshwater, marine or brackish water fish, with appropriate modifications the test. Within the three parts of ISO 7346, a choice can be made between static, semi-static and flow-through methods. The static test, described in IsO 7346-1, in which the solution is not renewed, has the advantage of requiring simple apparatus, although the substances in the test vessel may the water may deteriorate. The flow-through method, described in ISO 7346-3, in which the test solution is replenished continuously, over- comes such problems but requires the use of more complex apparatus. In the semi-static procedure, described in this part of ISO 7346, the test solutions are renewed every 24 h or 48 h, this method being a compro- mise between the other two. The flow-through method can be used for most types of substances, in- cluding those unstable in water, but the concentrations of the test sub- stance are determined wherever possible. The static metho