|Element||Mass||Olin sink DI water, ppb||Schenectady tap water, ppb|
These values were derived by standards-based analysis not long after the lab was commissioned, probably around 2000. Blank water was from a 18.3 MΩ DI system in the ICP-MS hood. Remember that deionized water purification systems, like we have, change in their effectiveness over time. Most critical is the Olin house DI water system, which is the first line of defense for analytical water purity. The lab has a small conductivity meter, which should usually read <1 μSiemens at the sink DI taps if the system is doing its job.
Generally the tap DI water is pretty clean. Olin house water has Fe, Cu, Zn, and Pb. Schenectady tap water has everything, of course, but none are of any health concern at the concentrations analyzed here. Remember that natural waters, in contact with natural soil and rock, will have small amounts of almost every chemical element there is, from lithium to uranium. Schenectady tap water is not unusual. The analyses here say nothing about organic or biological contaminants, which we are unable to analyze in our lab.