TY - JOUR
T1 - Toxicity of tetramethylammonium hydroxide to aquatic organisms and its synergistic action with potassium iodide
AU - Mori, Izumi C.
AU - Arias-Barreiro, Carlos R.
AU - Koutsaftis, Apostolos
AU - Ogo, Atsushi
AU - Kawano, Tomonori
AU - Yoshizuka, Kazuharu
AU - Inayat-Hussain, Salmaan H.
AU - Aoyama, Isao
N1 - Funding Information:
The authors acknowledge funding sources, Kurita Water and Environment Foundation (Japan), Okayama Foundation for Science and Technology (Japan), and JSPS-VCC Japan–Malaysia core program from Japan Society for Promotion of Science .
Publisher Copyright:
© 2014 Elsevier Ltd.
PY - 2015/2/1
Y1 - 2015/2/1
N2 - 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 72h-algal growth inhibition test (Pseudokirchneriellia subcapitata, EC50=360mgL-1) and the Microtox® test (Vibrio fischeri, IC50=6.4gL-1). In contrast, the 24h-microcrustacean immobilization and the 96h-fish mortality tests showed relatively higher toxicity (Daphnia magna, EC50=32mgL-1 and Oryzias latipes, LC50=154mgL-1). 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.
AB - 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 72h-algal growth inhibition test (Pseudokirchneriellia subcapitata, EC50=360mgL-1) and the Microtox® test (Vibrio fischeri, IC50=6.4gL-1). In contrast, the 24h-microcrustacean immobilization and the 96h-fish mortality tests showed relatively higher toxicity (Daphnia magna, EC50=32mgL-1 and Oryzias latipes, LC50=154mgL-1). 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.
KW - Aquatic toxicity
KW - D. magna
KW - Potassium iodide
KW - Semiconductor wastewater
KW - Synergism
KW - Tetramethylammonium hydroxide
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U2 - 10.1016/j.chemosphere.2014.07.011
DO - 10.1016/j.chemosphere.2014.07.011
M3 - Article
C2 - 25151133
AN - SCOPUS:84912116065
SN - 0045-6535
VL - 120
SP - 299
EP - 304
JO - Chemosphere
JF - Chemosphere
ER -
