Another study conducted in a kaolin refinery industry produces hazardous by-product such as Al, Fe, and Zn. In kaolin processing, sulphuric acid is used to improve the whitening (Jordao et al., 2002) is discharged to the river waters. This will influence the well being of aquatic organisms that adapted well at close to neutral pH. Also, in order not to affect the colour and whiteness of paper, impurities such as iron oxides is needed to be removed. This can be made through the reduction of Fe(III) to Fe(II) with metallic Zn. Therefore, Zn, Fe, Al are usually present in the discharge | Dams fish and fisheries Opportunities challenges and conflict resolution FAO FISHERIES TECHNICAL PAPER 419 edited by Gerd Marmulla Fishery Resources Officer Inland Water Resources and Aquaculture Service Fishery Resources Division FAO Fisheries Department Food and Agriculture Organization of the United Nations Rome 2001 This was a working paper for the World Commission on Dams - the report published herein was prepared for the Commission as part of its information gathering activity. The views conclusions and recommendations are those of the authors and are not intended to represent the views of the Commission. Publication by the Commission does not imply endorsement of the authors findings or recommendations. This report is published to share with the public information and ideas gathered and considered by the Commission in its deliberations. The Commission s views conclusions and recommendations will be set forth in the Commission s own report. The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country territory city or area or of its authorities or concerning the delimitation of its frontiers or boundaries. ISBN 92-5-104694-8 All rights reserved. Reproduction and dissemination of material in this information product for educational or other non-commercial purposes are authorized without any prior written permission from the copyright holders provided the source is fully acknowledged. Reproduction of material in this information product for resale or other commercial purposes is prohibited without written permission of the copyright holders. Applications for such permission should be addressed to the Chief Publishing and Multimedia Service Information Division FAO Viale delle Terme di Caracalla 00100 Rome Italy or by e-mail to copyright@ FAO 2001 iii .
