• Title/Summary/Keyword: TTBTC

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Comparison of Short-Term Toxicity Tests Based on Feeding Behavior and Temperature Control by Ceriodaphnia dubia (Ceriodaphnia dubia의 먹이섭생 기작과 온도조절에 근거한 급성독성조사법의 비교)

  • Park, Jong-Ho;Lee, Sang-Ill;Cho, Young-Oak
    • Journal of Korean Society on Water Environment
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    • v.20 no.1
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    • pp.48-54
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    • 2004
  • Two methods, a Ceriodaphnia algal uptake suppression test (CAUST) and a new toxicity test based on temperature control (TTBTC) which are based on feeding behaviour and temperature control, respectively, were developed and compared for the adoption as the better methodology for short-term toxicity screening. As previously published by Lee et aI., (1997), the CAUST method is based on the feeding behaviour of C. dubia and requires as little as 1 hour of contact time between C. dubia neonates and toxicant. However, even though CAUST requires only 1 hour of contact time, this method still take many hours for the preparation and measurement. Before the test starts, neonate digestive tracts were cleared by feeding yeast to the daphnids, Neonates were then exposed to toxicant, followed by addition of Scenedesmus subspiatus into the bioassay vessels. Daphnids were examined under the bright-field microscope with the presence of algae (indicated by a green colored digestive tract) or the absence of algae. Uptake indicated no toxic effect, whereas, absence of uptake indicated toxic inhibition. Unlike CAUST, the newly developed method (TTBTC) is based on just temperature control for the toxicity test of C. dubia. Initially, neonates are exposed to toxicants while the temperature of water bath containing media increased to $35.5^{\circ}C$. After 1.25 hour of contact time, the number of the daphnids, either live (no toxic effect) or dead (toxic effect), is counted without the aid of any instrument. In both methods, median effective concentrations ($EC_{50}$ values) were computed based on the results over a range of dosed toxicant concentrations. It showed that TTBTC was as sensitive as the standard 48-hour acute bioassay and CAUST. TTBTC and CAUST were much more sensitive than the I-hour I.Q. test and 30-minute Microtox. This study indicates that TTBTC is an easier and more rapid toxicity test than the standard 48-hour acute bioassay and even CAUST.

Rapid Bioassay Technique Based on Temperature Control of Ceriodaphnia dubia (Ceriodaphnia dubia의 온도조절에 근거한 단기급성독성 조사법)

  • PARK Jong Ho;LEE Sang Ill;CHO Young Oak;LEE Won Ho;YEON Ik Jun;CHO Kyu Seok
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.37 no.3
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    • pp.209-214
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    • 2004
  • A method for rapid acute toxicity test based on temperature control of Ceriodaphnia dubia has been developed and evaluated. A new toxicity test based on temperature control (TTBTC) which are based on temperature control, was developed and compared for the adsorption of the better methodology for short-term toxicity screening. Initially, daphnid larval are exposed to toxicants and at the same time the temperature of the water bath containing media is increased to high temperature $(35.5^{\circ}C).$ After 1.25 hrs of contact time, the number of the daphnids, either living (no toxic effect) or dead (toxic effect), is counted by the naked eyes. Effect of exposure time on test sensitivity was not significantly different between 1 to 1.5 hr. Comparison of the rapid 1.25 hr acute toxicity test developed in this study and the standard 48 hr acute toxicity test using heavy metals, cyanide and pentachlorophenol indicated that the 1.25 hour test provides an acceptable level of sensitivity in toxicity test for C. dubia.