Toxicology of Industrial Compounds

environmental pollution was low and the adduct levels in the controls were
about 1/10 of their level in the winter (Grzybowska et al., 1993).
Adducts and other endpoints
K.HEMMINKI 161
Figure 12.1 A boxplot of the white blood cell DNA adduct levels (per 10 8
nucleotides) among bus maintenance and truck terminal workers and controls
(Hemminki et al., 1994).
It has become customary to include many types of endpoints to
biomonitoring studies. The foundry study cited in Table 12.1 belongs to
the most versatile of them. Exposure is measured by ambient air and 1hydroxypyrene
monitoring (Santella et al., 1993). DNA adducts are
assayed for by postlabelling and immunoassay. Plasma albumin PAH
adducts are measured. Hypoxanthin guanine phosphoribosyl transferase
(HPRT) and glycophorin A mutations are assayed for in lymphocytes and
erythrocytes, respectively (Perera et al., 1993, 1994). Single-stand breaks in
DNA and three types of cytogenetic parameters, chromosomal aberrations,
sister chromatid exchanges and micronuclei, are analysed, in addition to
genotyping of drug metabolising enzyme genes. Sampling of workers was
repeated in four consecutive years, each at the same time of the year. As the
last sampling was in the end of 1993, it will take some time before the
complete data set will be available for analysis.
In some published work from this data set an increase in DNA adducts
and mutation frequency in the HPRT and glycophorin A genes was
reported (Figure 12.2). Yet unreported results appear to show an increase