ISSN:
1573-2932
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
Notes:
Abstract The fixation of radioactive C was used to mesaure the toxicity of Pb(NO3)2 to five species of freshwater algae. Portions of unialgal cultures were inoculated into low salt medium and were used to test all species at 10, 20 and 30 ppm Pb. This medium approximated the salt concentrations of natural aquatic environments. Three different cell weights were used for each concentration of Pb and for the control to determine a relationship between cell weight and toxicity. The concentration of Pb causing a 50% reduction of14CO2 fixation as compared to the control was called the ED50 (median effective dose). These values were extrapolated from graphs of ppm Pb vs dpm mg−1 dry cell weight. The ED50 for three of the species tested (Anabaena, Chlamydomonas andNavicula) was between 15 and 18 ppm Pb. A desmid,Cosmarium, had an ED50 of 5 ppm. This species has a higher surface: volume ratio than the other species tested and this may account for its increased sensitivity. An ED50 forOchromonas was not obtained. Throughout this experiment the fixation of14CO2 increased with increasing Pb concentrations and is not readily explained.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00655696
