The study of symbiotic systems is of considerable importance in our understanding of binary system stellar evolution in systems where mass loss or transfer takes place .
Elemental abundances are of special significance since they can be used to track mass exchange .
However , there are few symbiotic giants for which the abundances are fairly well determined .
Here we present for the first time a detailed analysis of the chemical composition for the giants in the RW Hya and SY Mus systems .
The analysis is based on high resolution ( R \sim 50000 ) , high S/N , near-IR spectra .
Spectrum synthesis employing standard LTE analysis and atmosphere models was used to obtain photospheric abundances of CNO and elements around the iron peak ( Sc , Ti , Fe , and Ni ) .
Our analysis reveals a significantly sub-solar metallicity , [ Fe/H ] \sim -0.75 , for the RW Hya giant confirming its membership in the Galactic halo population and a near-solar metallicity for the SY Mus giant .
The very low ^ { 12 } C/ ^ { 13 } C isotopic ratios , \sim 6–10 , derived for both objects indicate that the giants have experienced the first dredge-up .