Effectiveness of flushing on reducing lead and copper levels in school drinking water

Samples from drinking water fountains in 50 schools in New Jersey were collected at specific times during a typical school day and analyzed for lead, copper, pH, alkalinity, and hardness. First-draw lead and copper levels (medians 0.010 mg/l and 0.26 mg/l, respectively) decreased significantly after 10 min of flushing in the morning (medians 0.005 mg/l lead and 0.068 mg/l copper), but levels increased significantly by lunchtime (medians 0.007 mg/l lead and 0.12 mg/l copper) after normal use of fountains in the morning by students. Corrosive water, as defined by the aggressive index, contained significantly higher levels of lead and copper (medians 0.012 mg/l and 0.605 mg/l, respectively) than noncorrosive water (medians 0.005 mg/l and 0.03 mg/l, respectively).