Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Examples illustrating multiple forms of the seven classifications used in the study: clear, phase separation, precipitate, skin, crystals, junk and unsure. Junk is used for cases with suspected contamination in the well or liquid-handling malfunctions etc.
