GENOTOXICITY STUDIES IN SEMICONDUCTOR INDUSTRY .1. IN-VITRO MUTAGENICITY AND GENOTOXICITY STUDIES OF WASTE SAMPLES RESULTING FROM PLASMA-ETCHING

Solid waste samples taken from the etching reactor, the turbo pump, an d the waste air system of a plasma etching technology line in semicond uctor production were studied as to their genotoxic properties in a ba cterial repair test, in the Ames/Salmonella microsome assay, in the SO S chromotest, in primary mouse hepatocytes, and in Chinese hamster V79 cell cultures. All three waste samples were found to be active by ind ucing of unscheduled DNA-synthesis in mouse hepatocytes in vitro. In t he bacterial rec-type repair test with Proteus mirabilis, waste sample s taken from the turbo pump and the vacuum pipe system were not genoto xic. The waste sample taken from the chlorine-mediated plasma reactor was clearly positive in the bacterial repair assay and in the SOS chro motest with Escherichia coli. Mutagenic activity was demonstrated for all samples in the presence and absence of S9 mix made from mouse live r homogenate. Again, highest mutagenic activity was recorded for the w aste sample taken from the plasma reactor, while samples collected fro m the turbo pump and from the waste air system before dilution and lib eration of the air were less mutagenic. For all samples chromosomal da mage in V79 cells was not detected, indicating absence of clastogenic activity in vitro. Altogether, these results indicate generation of ge notoxic and mutagenic products as a consequence of chlorine-mediated p lasma etching in the microelectronics industry and the presence of gen otoxins even in places distant from the plasma reactor. Occupational e xposure can be expected both from the precipitated wastes and from che micals reaching the environment with the air stream.