23 



Samples analyzed for VOCs were analyzed 13 days after sample collection. EPA 

 guidelines suggest maximum holding times for VOC samples of 14 days (EPA 1988a). No 

 data were qualified for exceeded holding times. 



Each sample analyzed for VOCs was spiked with three surrogate compounds (1,2- 

 dichloroethane-d 4 , toluene-d 8 , and 4-bromofluorobenzene [BFB]) as a measure of accuracy. 

 All BFB recoveries were within acceptance limits. Two samples and the method blank had 

 unacceptably high recoveries of l,2-dichloroethane-d 4 , and one sample had an unacceptably 

 low recovery of toluene-d g . Because of the high recoveries of l,2-dichloroethane-d 4 in two 

 samples and the method blank, detected volatile data in samples MQR1-CTR and MQR2- 

 CTR were qualified as estimated (J); the undetected volatile data in sample MQR4-CTR were 

 qualified UJ. 



The VOC method blank sample results were below detection for all compounds; 

 therefore, there was no concern about laboratory contamination of the samples. A blank 

 spike and a blank spike duplicate sample were analyzed for five VOC compounds (1,1- 

 dichloroethene [1,1-DCE], benzene, trichloroethene, toluene, and chlorobenzene). One 

 recovery of 1,1-DCE in one blank spike sample was below control limits (54%, under a 

 lower limit of 59%). The RPD of the 1,1-DCE analyses was also unacceptably high due to 

 this one low recovery. No data were qualified based on the low spike recovery. 



Acetone was detected in every sample; concentrations were above the upper 

 calibration limit in samples MQR1-CTR, MQR3-CTR, and MQR4-CTR and below the 

 practical quantitation limit (PQL) in samples MQR2-CTR and MQR5-CTR. The values out 

 of the calibration range were qualified as estimated (J); those below the PQL were already 

 qualified by the laboratory. 



Sediment Core Chemistry Data Summary from the MQR Mound, August and December 1991 



