Cataract and skin cancer are caused by

The concentration of fluoride,lead,nitrate and iron in a water sample from an underground lake was found to be $1000 \ ppb, 40 \ ppb, 100 \ ppm$ and $0.2 \ ppm,$ respectively. This water is unsuitable for drinking due to high concentration of:

Give a brief explanation about the international standards for drinking water.

The greenhouse effect is related to

What do you mean by green chemistry? How will it help decrease environmental pollution?

Methemoglobinemia is caused by the presence of $X$ in drinking water. $X$ is