New developments in algal toxicity test methodology
- Technical Univ. of Denmark, Lyngby (Denmark)
- Saskatchewan Research Council, Saskatoon, Saskatchewan (Canada)
Algal toxicity tests are cost effective and generally sensitive bioassays. While in the past results from algal tests could be highly variable, today`s standard protocols perform reasonably well although they have not yet been developed to complete satisfaction. The authors present here some new developments and ideas in algal toxicity testing: (1) A miniature test of 1--2.5 ml volume which fulfills the ISO validity criteria. The test is even superior to large scale standard tests by facilitating control of pH and light uniformity. (2) A method for volatile substances carried out in closed flasks with a CO{sub 2} enriched headspace. (3) Tests for heavy metals with low levels of iron and EDTA in the medium. (4) Tests with absorbable compounds (discussed together with algal density and algal exudate dependent sorption). (5) Flexible duration in tests (normally 2--4 days) adjusting the test time to obtain a 10--100 times biomass increase in the controls (obtained in 2 days for the fast growing standard species Selenastrum capricornutum). (6) Mandatory use of logarithmically transformed data for dose-response evaluation. (7) Weighted non-linear dose-response curve fitting and inverse confidence interval estimation accounting for the co-variance between response and control. (8) The use of in vivo fluorescence as a surrogate biomass measurement. (9) Evaluation of alternative endpoints: rates of {sup 14}C-assimilation, P-uptake or N-uptake. It is concluded that 2.5 ml mini-tests with fluorescence measurements are very cost effective and highly reproducible if just data are processed adequately. It is also pointed out that algal tests can be performed with various complex and difficult test materials (even with soil suspensions) and that in contrast to aquatic animals, algae tolerate ammonia.
- OSTI ID:
- 218447
- Report Number(s):
- CONF-9511137-; ISBN 1-880611-03-1; TRN: IM9619%%168
- Resource Relation:
- Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Efficient algal bioassay based on short-term photosynthetic response. [Selenastrum capricornutum was used as the test organism]
Multispecies methods of testing for toxicity: use of the Rhizobium-legume symbiosis in nitrogen fixation and correlations between responses by algae and terrestrial plants