AS

cd

pb

Se

Parameters

0.009

0.484

0.215

0.523

Mean

0.094

0.159

0.838

0.691

Maximum

0

0

0

0.19

Minimum

0.024

0.035

0.02

0.124

Standard deviation

0.01

0.003

0.01

0.01

Maximum permissible limit (WHO)

13

56

33

100

Samples exceeding maximum permissible limit (%)