nitrate
fluoride
lead
iron
Fluoride = 1000 ppb = 1000/1000 = 1 ppm
Lead = 40 ppb = 40/1000 ppm = 0.04 ppm
We can see that the concentration of nitrate is maximum (100 ppm). Note: > 40 ppm gives blue baby syndrome disease.
Hence, this water is unsuitable for drinking due to the high concentration of nitrate.