How many of the following in dinking water below 30 ppm do not cause any effect on the body as per international standards of water? Pb^(2+), Hg^(2+), Mn^(2+), Cd^(2+), Cl^(-), NO_(3)^(-), SO_(4)^(2), Ca^(2+), Mg^(2+)

How many of the following in dinking water below 30 ppm do not cause a

1.	How many of the following in dinking water below 30 ppm do not cause any effect on the body as per international standards of water? Pb^(2+), Hg^(2+), Mn^(2+), Cd^(2+), Cl^(-), NO_(3)^(-), SO_(4)^(2), Ca^(2+), Mg^(2+)
Answer» 5 2 3 6 Answer :1