Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6308192 | Chemosphere | 2015 | 6 Pages |
Abstract
The aquatic ecotoxicity of chemicals involved in the manufacturing process of thin film transistor liquid crystal displays was assessed with a battery of four selected acute toxicity bioassays. We focused on tetramethylammonium hydroxide (TMAH, CAS No. 75-59-2), a widely utilized etchant. The toxicity of TMAH was low when tested in the 72 h-algal growth inhibition test (Pseudokirchneriellia subcapitata, EC50 = 360 mg Lâ1) and the Microtox® test (Vibrio fischeri, IC50 = 6.4 g Lâ1). In contrast, the 24 h-microcrustacean immobilization and the 96 h-fish mortality tests showed relatively higher toxicity (Daphnia magna, EC50 = 32 mg Lâ1 and Oryzias latipes, LC50 = 154 mg Lâ1). Isobologram and mixture toxicity index analyses revealed apparent synergism of the mixture of TMAH and potassium iodide when examined with the D. magna immobilization test. The synergistic action was unique to iodide over other halide salts i.e. fluoride, chloride and bromide. Quaternary ammonium ions with longer alkyl chains such as tetraethylammonium and tetrabutylammonium were more toxic than TMAH in the D. magna immobilization test.
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Environmental Chemistry
Authors
Izumi C. Mori, Carlos R. Arias-Barreiro, Apostolos Koutsaftis, Atsushi Ogo, Tomonori Kawano, Kazuharu Yoshizuka, Salmaan H. Inayat-Hussain, Isao Aoyama,