CF002

Attribute: TDNCODE

code		description
*		Value is below detection limit for analysis (used beginning in 1991)
A		Accepted value
C		Value confirmed, contamination suspected (code use begins May 2007)
D		Derived value - mathematically determined from other analytical measurements
D*		Derived value - mathematically determined from other analytical measurements, one or more of which were below the detection limit
DE		Derived value - mathematically determined from other analytical measurements, one or more of which were estimated values
DQ		Derived value - mathematically determined from other analytical measurements, one or more of which were questionable values
E		Estimated value
N		No analytical measurement or no derived value calculated due to missing analytical components
Q		Value is questionable (used beginning in 1991)