Types of structural chromosomal aberrations were classified into following groups: chromatid breaks (ctb) chromosome breaks (csb), chromatid and
chromosomal gap (ctg) The final results were judged as follows: negative (-) if the frequency of aberrant cells was <5%, inconclusive ([+ or -]) if [greater than or equal to]5 % but <10 % and positive (+) if [greater than or equal to] 10 %.