The relations between concentrations ofparticular
constituents-namely, Fe, Mn, Ni, and Cr-and
concentration of fumes are presented in the form of
correlation coefficients and regressions of the type
y = a + bx in particular plants (fig 1) and graphically in
the form ofsimplified lines ofthe type y = kx + kfor all
plants (fig 4). A low correlation coefficient and lack of
linear dependence were obtained for total Cr in plant
C (welders and their assistants together; fig 2). Figure
4 presents graphically the relation between concentrations
obtained for all plants (disregarding welders'
assistants from plant C). Total Cr concentration with
regard to fumes was characterised by a high correlation
coefficient (r= 0 89).
The results obtained from regression lines (n= 59,
p= 005) have facilitated calculation of the mean
content of particular elements in fumes (table 2).
Similar relations were determined for concentrations
of particular Cr forms with regard to fume
concentration in all plants tested. Figure 5 presents
these graphically. Table 3 shows the mean content
(%) of particular Cr forms in the fumes. This was
determined from regression lines y = kx + k. Participation
ofparticular Cr forms in relation to total Cr
was determined in the same way (fig 6, table 4). The
relations presented indicate that participation of
particular Cr forms compared with total Cr content
in all samples determined (samples exceeding the
sensitivity of the method) was similar (table 4).
Due to considerable variability in the content of
fumes in the MMA/SS welders' breathing zone, the
evaluation of exposure was based on TWA (8 h)