  We analyzed the relation between the corotation radii and the galactic radii
at which breaks or changes of slope of the metallicity gradients occur in
spiral galaxies. With this purpose we compiled the results from the literature
on rotation curves, corotation radii and radial metallicity distributions of 27
galaxies, of which 16 were considered qualified to be studied in the context of
this work. We re-scaled all references of each galaxy to a same framework in
order to compare the results and to identify the radii where breaks and changes
of slopes are found, when non-linear models fit the radial metallicities better
than a linear model. In most galaxies we have found minima and breaks in radial
metallicity near the corotation radius, revealing a significant correlation
between these two radii, as it occurs in our Galaxy. The results are
interpreted as a consequence of long-lived spiral structures, in which the
star-formation rate depends on the distance to the corotation radius, producing
secular effects in the observed radial metallicity distributions.
