| MissingValueCode | DataType | MissingValueDescr | MissingValueComments |
| 00:00 | Time | Not Recorded | default for when no time was provided |
| 01/Jan/1950 | Date | Not Recorded | default for when no date was provided |
| -88 | Numerical | Not Recorded | used in result field when result 1) is not given from laboratory, ie bottle broken; 2) result is non-detect and MDL was not reported (this occurs in older samples only also for depth when samples are integrated over depth, and numeric fields assoc. to NR |
| NA | Text | Not Applicable | |
| NR | Text | Not Recorded | |