Spectroscopic study of high redshift quasars

We obtained optical spectra of four quasars with 3<z<4 and SDSSp J033829.31 +002156.3 with z=5.0 with FORS1 at the VLT UT1 Antu. To estimate the relati ve abundances of the line emitting gas we used the line ratios NV1240/CIV15 49, NV1240/HeII1640, and OVI1034/HeII1640 as suggested by Hamann & Ferland (1992, 1999). Based on chemical evolutionary models we estimate a metallici ty of Z similar or equal to 7Z. for the quasars with z similar or equal to 3 within the framework of the rapid star formation scenario. Even Q0338+002 1 indicates a comparable high relative abundance. Our results provide suppo rt for supersolar metallicities at very high redshifts of z similar or equa l to 5.