Use of Selenastrum Capricornutum to Assess the Toxicity Potential of Surface and Ground Water Contamination Caused by Chromium Waste

Abstract

United Chrome Products, Inc. (Corvallis, OR), discharged liquid chrome-plating wastes into an on-site dry well from 1957 to 1977. Samples were collected from ground and surface waters during February and December 1984 and evaluated for toxicity potential using 96-h Selenastrum capricornutum bioassays. Bioassays of the February samples were used to calculate predicted EC50 values for different chromium concentrations, which %ere then compared with the chromium concentrations measured in the December samples and with the results of S. capricornutum bioassays on these samples. An excellent correlation was obtained between the predicted EC50 values and the actual bioassay response values for ground water and drainage ditch samples. However, no correlation was obtained with the off-site surface water samples. These results could not be explained by changes in chromium valence, and they demonstrate that, even in simple systems, toxicity cannot readily be predicted based solely on chemical analysis.

Separation of pH, dilution, lonic strength and chemical matrix effects for biological monitoring of urines with the Microtox® test using nicotine, cotinine and reference urines

“…On the contrary, the EC,, values for the SRM low-level urine are lower than for the elevated urine. Zn concentration in the lowlevel urine is much higher (2.7 times) than in the elevated one, and higher than the EC50 value (30). The latter is not so for the elevated supposedly more toxic urine.…”

“…Even with correction for the latter effects, interpretation of biological/environmental monitoring results may not be possible because of matrix effects in uncharacterized samples. However, the approach outlined in this paper is suggested for use in separating the effects of physical factors from those of chemical factors even though Greene et al, (30) suggest otherwise. Since environmental and biological samples are undefined mixtures in general, the initial bioassay results must of necessity include physical as well as chemical factors.…”

“…Thus the toxicity of UCC level I1 is understandable. The EC,, data at 5 min for heavy metals have reproducibility problems (30), and usually decrease with increasing contact time. The EC,, values of the UCCs increase with time unlike those for the SRMs whether pH adjusted or not ( Table 3).…”

“…Chelation of metal ions with other components in complex effluents and biological media might affect transport through cell membranes and decrease/ increase toxic effects. Different compositions of specific metal ions can yield different results (30). Thus interpretation of the results of complex mixtures involves speciation, quantitative analysis and a knowledge of minimum concentration ranges to allow life ('essentiality') and for toxicity for the bacterium.…”

Comparative assessment of herbicide phytotoxicity to Selenastrum capricornutum using microplate and flask bioassay procedures

“…For example, EC50 flask assay values of 217 pg . L-' (confidence interval of 176-570) for Cr6+ (Greene et al, 1988), of 34 (Chiaudani and Vighi, 19781, 45 (Vasseur et al, 1988), and 23-37 pg * L-l for Cu2+ (Blaise et al, 19861, and of 27 (Chiaudani and Vighi, 1978), 54 t 11 (Vasseur et al., 1988) and 45 p g . L-l for Zn2+ (Blaise et al, 1986), have been reported.…”