Table 1

Magnesium, calcium, lead, and fluoride concentrations in water zones in north west England, 1990–92

Average number of measurements per zoneMean (SD)MedianMinimumMaximum
Magnesium (mg/l)1619 (20)122111
Calcium (mg/l)1752 (43)365215
Fluoride (mg/l)10 0.08 (0.11)0.050.020.8
Lead (μg/l)18713 (16)101190