The depuration of PSP toxins from naturally- contaminated green mussels, Perna viridis harvested from commercial shellstock culture sites in Limay, Bataan, Philippines from February 1998 - May 1999 was studied. The effects of varying salinities from 20-35 ppt at 20-25ºC of the recirculating seawater of the ultraviolet (UV) depuration set-up during the 72h continuous shellfish purification to eliminate PSP toxins and microbial contaminants from the mussels were monitored. A seawater salinity-temperature combination of 31-35 ppt at 20-25°C was observed to be most effective condition in eliminating PSP toxins and microbial contaminants from the mussel meats during depuration. Percent decrease of PSP toxin burdens in whole mussel meats at salinity ranges of 20-25, 26-30, and 31-35ppt, after 72h purification as determined using standard mousebioassay, were established to be approximately 13, 8, and 38 %, respectively. The relative anatomical distribution of PSP toxins in depurated green mussels showed the following trend: adductor muscles > digestive tissues and gonads > gills and mantle > foot. Counts of indicator microorganisms of fecal origin including coliforms and Escherichia coli from naturally-contaminated green mussels showed > 80% decrease after the application of the test purification procedure.