  Recent results are presented on the metal enrichment of low-mass star-forming
(SF) galaxies in local Universe clusters. The environmental effects on the
chemical evolution of these galaxies are discussed. We have used spectroscopic
data from the SDSSIII-DR8 and we have derived the gas-phase O/H and N/O
abundances. We have then examined the Mass-Metallicity Relation (MZR) of this
sample of cluster galaxies, and we have found well defined sequences. A
flattening of the slope of these sequences has been observed for galaxies
located in the core of the two more massive clusters of the sample, suggesting
that the effect of the cluster environment depends both on the galaxy mass and
the host cluster mass. Based on these results we explore cluster-specific
effects (e.g. ram-pressure stripping, pressure confinement etc), predicted by
hydrodynamic models, capable of yielding the observed mass-dependent
enhancement of the metallicity.
