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1. No health based guideline value for hardness in drinking water

Comment received over e-mail from M. Sankaranarayanan

As per the Guidelines for drinking water quality third edition volume-1 recommendation  brought out by WHO Geneva-2004 , chapter-10  acceptability aspects para Hardness page 215 - the taste  threshold for the calcium ions is in the range of 100-300 mgl,depending on the associated anions and the taste threshold for magnesiumis probably lower than that of calcium. In some instances,consumer tolerate water hardness in excess of 500mg/lit no health based guideline value is proposed for hardness in drinking water.

With kind regards,


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