Use of LC50 in aquatic regulatory toxicology-Disharmony in global harmonization of hazard classification of chemicals
DOI:
https://doi.org/10.5132/eec.2021.01.12Keywords:
LC50, GHS, Trevan, concentration-mortality curve, probit analysis, Litchfield and Wilcoxon, FinneyAbstract
In regulatory aquatic toxicology, acute toxicity studies with chemicals are conducted with a species of fish, crustacea, and or alga. The LC50/EC50 obtained from these studies is used for the hazard classification and labeling of the chemicals. The methods like probit or logit analysis and Litchfield and Wilcoxon method are prescribed in the OECD guidelines to determine the LC50. In the present study, LC50s were calculated using probit analysis, Litchfield & Wilcoxon method, and also using the method by Trevan (the inventor of median lethal dose) using three sets of concentration-mortality data of fish acute toxicity tests. The slopes of the concentration-mortality curves, fiducial limits (95% confidence interval) of LC50s, and ‘mode’ of the concentration-mortality curves were compared. Though the methods used in the study resulted in more or less similar LC50s, the LC10 and LC90, slopes and ‘mode’ differed considerably, indicating that LC50 does not reveal the exact toxicity profile of a chemical. The LC50 calculated using Finney’s probit analysis provides better information on the toxicity profile of a chemical than the LC50calculated by Litchfield & Wilcoxon method. While interpreting LC50, the mortality occurred below 16 % (eg., LC10) and above 84 % (eg.,LC90), slope and ‘mode’ of the concentration-mortality curve may also be considered. It is worth having a relook at the current practice of hazard classification and labeling of the chemicals based only on LC50 in regulatory aquatic toxicology.Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2021 Ecotoxicology and Environmental Contamination
This work is licensed under a Creative Commons Attribution 4.0 International License.
Copyright © 2006 ECOTOX-Brasil
Copyright notice: It is a condition for publication that manuscripts submitted to this journal have not yet been published and will not be simultaneously submitted or published elsewhere. By submitting a manuscript, the authors agree that copyright for their article is transferred to the Sociedade Brasileira de Ecotoxicologia (ECOTOX-Brasil) if and when the article is accepted for publication. The copyright covers the exclusive rights to reproduce and distribute articles, including reprints, photographic reproductions or any other reproduction of a similar nature, including translations. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without permission of the publisher.
Notice: While every effort is made by the EEC, editors and editorial board to see that no inaccurate or misleading data, opinions or statements appear in this journal, they wish to make it clear that the contents of the articles and advertisements published herein are the sole responsibility of the contributors or advertisers concerned. Accordingly, the EEC, the editorial board and editors and their respective employees, officers and agents accept no responsibility or liability whatsoever for the consequences of any inaccurate or misleading data, opinion or statement.