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1000
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Abstract/Summary
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The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated arsenic and its inorganic compounds, with a special focus on gallium arsenide. Available publications and study reports are described in detail. Arsenic and its inorganic compounds are carcinogenic in humans. From the available studies in workers in the semiconductor industry probably exposed to gallium arsenide, no increased cancer risk can be derived. Carcinogenicity studies with inhalation exposure to gallium arsenide revealed lung tumours, mononuclear leukaemia and benign phaeochromocytomas in the adrenal glands in female rats. In animal studies, increased levels of arsenic in blood were determined after exposure to gallium arsenide. The metabolites are the same as those found after exposure to arsenite and arsenate. Although the bioavailability of gallium arsenide is much lower than that of arsenic trioxide, it cannot be completely neglected. Therefore, the classification of arsenic and its inorganic compounds including gallium arsenide as carcinogenic in man (Carcinogen Category 1) has been retained. In vitro genotoxicity studies with inorganic arsenic(III) compounds yielded mostly positive results in tests for sister chromatid exchange, chromosomal aberrations and micronuclei. In in vivo studies with somatic cells, arsenic(III) compounds induced an increase in DNA strand breaks, chromosomal aberrations and micronuclei. In humans exposed long‐term to arsenic, increased incidences of micronuclei, chromosomal aberrations, sister chromatid exchange and DNA damage were observed. Gallium arsenide was not genotoxic in vitro and in vivo. Gallium arsenide, like arsenic, is systemically available and forms the same metabolites as arsenic and its inorganic compounds. For this reason the suspected germ cell mutagenicity of gallium arsenide cannot be unequivocally excluded. Arsenic and its inorganic compounds including gallium arsenide therefore remain in Category 3A for germ cell mutagens which produce mutagenic effects in somatic cells of mammals in vivo and have been shown to reach the germ cells. No MAK value has been derived and thus also no peak limitation has been established, and classification into one of the Pregnancy Risk Groups is not possible. Skin contact is not expected to contribute significantly to systemic toxicity. Sensitizing effects of arsenic and its inorganic compounds cannot be derived from the available data.
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