The application of chronic (sub-lethal) toxicity endpoints to the development of resource quality objectives

Sponsor: Water Research Commission
Leader: Dr WJ Muller
Staff: Mr AK Gordon, Ms NP Gola, Mr TJ Human
Students: Mr AR Slaughter, Ms N Ketse
Duration: April 2004 - March 2008 (project was extended)

Aims and Objectives

The methods used for determining water quality guidelines in South Africa ascribe greater reliability to ecospecs derived from chronic data. However, there are few chronic data available for South African invertebrates. Consequently, this study aims to investigate methods of extrapolating chronic toxicity data from acute data for indigenous South African invertebrates, and to investigate the applicability of biochemical endpoints as suitable chronic toxicity data for water quality guideline development.


Project aims were to:

•     Undertake comparative acute and chronic toxicity tests using the freshwater shrimp Caridina nilotica and selected metal-ion and organic contaminants, with growth, reproduction and/or development as chronic endpoints.
•     Assess methods for extrapolating chronic toxicity data from acute toxicity data using the results from Aim 1 and apply the results to quantified ecological class boundary values.
•     Undertake an investigation of selected biochemical markers as sub-lethal endpoints in the shrimp C. nilotica.
•     Undertake a laboratory-based population level toxicity trial exposing C. nilotica to LAS.

Last Modified: Fri, 14 Aug 2015 11:37:32 SAST