2.126 Lead in drinking water. The U.S. Environmental Protection

Agency (EPA) sets a limit on the amount of lead permitted in

drinking water. The EPA Action Level for lead is .015 milli-

gram per liter (mg/L) of water. Under EPA guidelines, if 90%

of a water system's study samples have a lead concentration

less than .015 mg/L, the water is considered safe for drink-

ing. I (coauthor Sincich) received a report on a study of lead

levels in the drinking water of homes in my subdivision. The

90th percentile of the study sample had a lead concentration

of .00372 mg/L. Are water customers in my subdivision at risk

of drinking water with unhealthy lead levels? Explain. tion of