Limitations on the uses of multimedia exposure measurements for multipathway exposure assessment--Part I: Handling observations below detection limits.
Multimedia data from two probability-based exposure studies were investigated in terms of how censoring of nondetects affected estimation of population parameters and associations. Appropriate methods for handling censored below-detection-limit(BDL)values in this context were unclear since sampling weights were involved and since bivariate associations/measures were of interest. Both simple substitution(e.g., using 1/2 or 2/3 of the detection limit(DL)for BDL values)and truncation-based strategies were investigated by creating some artificial DLs and comparing resultant estimates with the original studies'uncensored results. The substitution methods generally outperformed the truncation methods, with the(2/3)DL substitution generally performing best.
Clayton
C Andrew
CA
RTI International, PO Box 12194, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA. clayton@rti.org
Mosquin
Paul L
PL
Pellizzari
Edo D
ED
Quackenboss
James J
JJ
D002648:Child; D002675:Child, Preschool; D003627:Data Interpretation, Statistical; D004781:Environmental Exposure; D006801:Humans; D006838:Hydrocarbons / Q000032:analysis*; D008670:Metals / Q000032:analysis*; D019212:Multimedia; D010755:Organophosphates / Q000032:analysis*; D011159:Population Surveillance / Q000379:methods; D014481:United States; D014484:United States Environmental Protection Agency
D006838:Hydrocarbons; D008670:Metals; D010755:Organophosphates