Salam and thank you for your question.

 

Initially, I believe you have misunderstood the article on wikipedia. It says that some people were selling unhealthy water and claiming it to be Zamzam.

 

At the end, it clearly said that a French laboratory examined the real Zamzam water and found it to be perfectly healthy to drink. Also the Saudi authorities test the water daily.

 

Abu Zar Al-Ghafari narrated that the Prophet (peace be upon him) said:

 

“Zamzam is food for the hungry and a cure for the sick” (Al-Muntheri -Sahih)

 

Also, Jaber Ibn Abdullah narrated that the Prophet (peace be upon him) said:

 

“Zamzam water is what one intends to drink it for.” (Ad-Dimyati – Sahih)

 

The above hadith means that if a person intends or supplicates when drinking Zamzam water, it will be fulfilled by Allah.