On the Metallicity of Blue Compact Dwarfs

Based on the even distribution of metals in Blue Compact Dwarfs (BCDs) spread all over their volume, we show that a large amount of stars (>= 10(8) M-circle dot) are required to justify such a homogeneous metal abundance. We also show that such a mass would imply a large number of bursts similar to the ones presently energizing the giant nebulae. On the other hand, the underlying stellar population in BCDs can easily account for the mass required to justify the homogeneous metal abundance. We also review the recent results concerning the hydrodynamics of the matter reinserted by winds and supernovae in young, massive and compact superstar clusters. In particular we show that clusters undergoing the bimodal hydrodynamic solution, retain a large amount of the reinserted matter and this lowers their mechanical energy power as well as the amount of metals expected to mix with the ISM.