(Portland, OR)  --  Carole Smith, superintendent of Portland Public Schools, says she'll retire at the end of the next school year.  Smith, who's been on the job for a decade, has been under fire since elevated levels of lead were found in water fountains at two of the district's schools.  She issued a public apology after admitting that PPS failed to follow Environmental Protection Agency protocols.  Protesters disrupted a meeting of the school board yesterday evening, demanding that Smith resign immediately or be fired.