title: Ecotoxicity assessment of ionic As(III), As(V), In(III) and Ga(III) species potentially released from novel III-V semiconductor materials.
abstract: III-V materials such as indium arsenide (InAs) and gallium arsenide (GaAs) are increasingly used in electronic and photovoltaic devices. The extensive application of these materials may lead to release of III-V ionic species during semiconductor manufacturing or disposal of decommissioned devices into the environment. Although arsenic is recognized as an important contaminant due to its high toxicity, there is a lack of information about the toxic effects of indium and gallium ions. In this study, acute toxicity of As(III), As(V), In(III) and Ga(III) species was evaluated using two microbial assays testing for methanogenic activity and O2uptake, as well as two bioassays targeting aquatic organisms, including the marine bacterium Aliivibrio fischeri (bioluminescence inhibition) and the crustacean Daphnia magna (mortality). The most noteworthy finding was that the toxicity is mostly impacted by the element tested. Secondarily, the toxicity of these species also depended on the bioassay target. In(III) and Ga(III) were not or only mildly toxic in the experiments. D. magna was the most sensitive organism for In(III) and Ga(III) with 50% lethal concentrations of 0.5 and 3.4mM, respectively. On the other hand, As(III) and As(V) caused clear inhibitory effects, particularly in the methanogenic toxicity bioassay. The 50% inhibitory concentrations of both arsenic species towards methanogens were about 0.02mM, which is lower than the regulated maximum allowable daily effluent discharge concentration (2.09mg/L or 0.03mM) for facilities manufacturing electronic components in the US. Overall, the results indicate that the ecotoxicity of In(III) and Ga(III) is much lower than that of the As species tested. This finding is important in filling the knowledge gap regarding the ecotoxicology of In and Ga.
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ 85704, USA. Electronic address: chaozeng@email.arizona.edu.
authors.forename: Chao
authors.initials: C
authors.lastname: Zeng
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ 85704, USA.
authors.forename: Adrian
authors.initials: A
authors.lastname: Gonzalez-Alvarez
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ 85704, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Orenstein
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ 85704, USA.
authors.forename: Jim A
authors.initials: JA
authors.lastname: Field
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ 85704, USA.
authors.forename: Farhang
authors.initials: F
authors.lastname: Shadman
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ 85704, USA.
authors.forename: Reyes
authors.initials: R
authors.lastname: Sierra-Alvarez
mesh_terms: D048908:Aliivibrio fischeri / Q000187:drug effects; D000818:Animals; D001149:Arsenates / Q000032:analysis / Q000633:toxicity*; D001152:Arsenicals / Q000032:analysis; D018053:Arsenites / Q000032:analysis / Q000633:toxicity*; D001681:Biological Assay / Q000379:methods; D003621:Daphnia / Q000187:drug effects; D054750:Ecotoxicology; D005708:Gallium / Q000032:analysis / Q000633:toxicity*; D007204:Indium / Q000032:analysis / Q000633:toxicity*; D007477:Ions; D012666:Semiconductors; D023382:Toxicity Tests, Acute
chemical_list: D001149:Arsenates; D001152:Arsenicals; D018053:Arsenites; D007477:Ions; D007204:Indium; C043055:gallium arsenide; D005708:Gallium; C076773:indium arsenide
keywords: Arsenic; Ecotoxicity; Gallium; III-V materials; Indium; Microbial toxicity