Algae. 1989; 4(2): 191-198.
A New Dialysis Culture Technique for Ecotoxicological Assay
Sinjae Yoo, Sejin Pae, Suk-Hyun Kim
Korea
Ocean Research and Development Institute
ABSTRACT
A new method of bioassay using dialysis culture technique was developed to test seawater quality. Unicellular algae were cultured in dialysis bags and the growth rate and bioaccumulation were measured. To overcome problems of uneven irradiation and agitation a simple device was designed. Using this device the optimal water renewal frequency that can simulate in situ water quality was tested with various copper additions. The volume ratio of the dialysis bags to container was about 1:15. With 20 μg/l of copper addition, one renewal every two days turned out to be the optimal renewal rate. When the copper addition was low the renewal should be made more frequently. With 1 μg/l of copper, which seems the lowest copper concentration of ecotoxicological significance, no definite conclusion was drawn. Two renewals everday were the maximum frequency tested. Further experiments with smaller dialysis bags seem desirable. The conclusions from the present study might be extended to other species of phytoplankton without serious problems, since Chaetoceros compressus, the test organism, showed a very high growth rate. The effects of enrichment on the toxicity of copper were also tested. Although with enriched media a rather high copper addition of 10 μg/l did not affect the growth rate, ten times higher copper accumulation than that of control was detected in the cells. This new culture technique might be considered as an effective method which has the simplicity of batch culture and the sensitivity of continuous culture without its complexity. In addition cellular accumulation can be measured. The new method seems to have a wide applicability including mixed culture experiments.
Keywords : bioaccumulation, dialysis culture