Mastery Frederick Douglas Elementary School in North Philadelphia tested drinking water fountains to find the presence of lead and failed to adequately notify parents. The Philadelphia school district holds a threshold level of 10 ppb for lead in drinking water while lead inspectors found one fountain in the elementary school with levels exceeding 1,700 pbb and a second fountain with levels around 3,500 ppb. Despite finding such extreme levels of lead in the drinking water, school officials failed to directly communicate the findings to parents. Read More.