Browsing by Author "Tsai, KP"

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A novel algal toxicity testing technique for assessing the toxicity of both metallic and organic toxicants
(2005-05-01)
Lin, JH
;
Kao, WC
;
Tsai, KP
;
Chen, CY
;
環境工程研究所
This study presents a closed-system algal toxicity test technique that is capable of detecting the effects of both organic and metallic toxicants. Toxicity testing was conducted by transferring adequate amounts of algal suspension, dilution water (with culture growth medium), and toxicants into 300-mL BOD bottles. The BOD bottles were completely filled up with no head-space left. The initial cell density and the exposure time were 15,000 cells/mL and 48 h, respectively. The performance of the above test method was evaluated using three heavy metals and six organic toxicants based on three different test endpoints, i.e., dissolved oxygen production, algal growth rate, and cell density. The proposed test revealed excellent test sensitivity and reproducibility. Currently, none of the existing algal toxicity test protocols is adequate for assessing the toxicity of organic chemicals. The closed-system algal toxicity tests developed by previous researchers also may not be ideal because the enlarged headspace and/or enriched bicarbonate buffer may result in either underestimations of the exposure concentrations or insensitive responses to both heavy metals and organic toxicants. Compared to the aforementioned algal toxicity test methods, the proposed technique in the present study has a more general applicability under conditions such as effluent samples containing both metals and organic toxicants or samples with unknown compositions. (c) 2005 Elsevier Ltd. All rights reserved.
The combined toxic effects of nonpolar narcotic chemicals to Pseudokirchneriella subcapitata
(2006-06-01)
Hsieh, SH
;
Tsai, KP
;
Chen, CY
;
環境工程研究所
;
Institute of Environmental Engineering
This paper presents the toxicity data of 10 nonpolar narcotic chemicals on Pseudokirchneriella subcapitata (green algae) assessed by a new algal toxicity testing technique conducted under air-tight environment. Based on DO production, median effective concentration (EC50) varies from 1.73mg/L (1-octanol) to8040 mg/L (2-propanol). The endpoint of algal growth rate reveals similar sensitivity as that from DO production. Compared to literature data, Pseudokirchneriella subcapitata and Nitrosomonas are apparently more sensitive to nonpolar narcotics than other organisms such as minnow, daphnia, and Tetrahymena pyriformis. Furthermore, good correlations between toxic effects observed from Pseudokirchneriella subcapitata and other aquatic organisms were found. Hence, algal toxicity test can be considered as a surrogate test for estimating the toxicity of nonpolar chemicals to fathead minnow, Microtox, activated sludge, Daphina magna, and Tetrohymena pyriformis. The combined effects of 13 binary mixtures of nonpolar chemicals were investigated using both additive-index method and isobologram analysis. overall speaking, the joint actions between these chemicals are strictly additive. Model analyses indicate that these compounds act on identical reaction sites or receptors, which verify that these chemicals are of the same toxicity mechanism (narcosis). (c) 2006 Elsevier Ltd. All rights reserved.