This is 3 miles from my house . i have well water oh boy
The total semi-radiative liquid is being reported as 980000000 litres, which translates to 784 acre feet of water - That would have had to have been some pond, but certainly possible from industrial applications. The average family would use about half an acre foot of water a year, the total amount of water we're talking about would be what 6k people would consume in the average year.
As the majority of the material is far heavier than natural water, it's doubtful that anything would be detectable by even the most sensitive equipment more than a mile away from the site.