Certified valuesAs. 29 4 µg/LFe .3.00 mg/LSe. 29 4 µg/LCd . 40 5 µg/LMn.248 µg/LZn . 4.0 mg/LCr . 1.00 mg/LNi .1.20 mg/LCu . 0.90 mg/LPb .0.49 mg/L