Intel Corp., in testing its own water after Portland Public Schools revealed it found lead in fountains at at least two facilities, said Monday three of its fixtures have tested for higher lead levels. The vast majority of sinks tested "returned negative results," meaning the levels were below Environmental Protection Agency "action levels" of 15 parts per billion. The three sinks were shut off and are being replaced and retested. Here's the text of a letter Intel sent to employees on Monday. In…