22 



for PAH samples of 14 days from sampling to extraction, and 40 days from extraction to 

 analysis (EPA 1988a). All of the PAH data were qualified as estimated (J/UJ) for exceeded 

 extraction holding times (Table 2-2). 



Each sample analyzed for PAHs was spiked with three surrogate compounds (2- 

 fluorobiphenyl, nitrobenzene-D 5 , and terphenyl-D 14 ) as a measure of accuracy. All PAH 

 surrogate recoveries were within acceptance limits except for two high recoveries of 

 nitrobenzene-D 5 and terphenyl-D 14 in sample MQR5-E, and one high recovery of terphenyl- 

 D 14 in sample MQR-6C. The PAH concentrations in MQR5-E were high; the high surrogate 

 recoveries were potentially caused by matrix interference. Since all data were already 

 qualified for holding time violations, no data were qualified based on these surrogate 

 recoveries. 



The PAH method blank sample results were below the practical quantitation limit 

 (PQL) for all compounds. Three estimated compounds were below the PQL but above the 

 detection limit: benzo(a)anthracene (0.19 ppm), chrysene (0.063 ppm), and phenanthrene 

 (0.075 ppm). Since the samples were already qualified for exceeded holding times, again no 

 further qualifications were necessary. 



Accuracy of the PAH results was evaluated based on the results of standard reference 

 material (SRM) and the blank spike results. The SRM data contained one high recovery of 

 naphthalene and one low recovery of fluoranthene. Once more, no additional qualifications 

 were necessary. The laboratory stated in the Quality Assurance Review that the cause of 

 these results is being investigated. The other PAH compounds were recovered within 

 acceptable ranges. A blank spike and a blank spike duplicate sample were analyzed for two 

 PAH compounds (acenaphthene and pyrene). All recoveries were within limits, indicating 

 acceptable data accuracy. The RPDs of the duplicate spike samples were also within 

 acceptable ranges, indicating acceptable PAH data precision. 



Relatively high concentrations of PAHs detected in MQR3-F and MQR5-E were 

 investigated by the laboratory and confirmed. These two samples were diluted to obtain 

 results for several compounds. Other than the qualifications due to exceeded holding times, 

 the data are considered acceptably accurate and precise. 



2.2.2.4 Volatile Organic Analyses 



Volatile organic compounds (VOCs) were analyzed using EPA protocols (EPA 1986). 

 Five marine sediment samples were analyzed with three accompanying QC samples: a 

 method blank, a blank spike, and a blank spike duplicate sample. Sample data were 

 evaluated using protocols developed by the EPA (EPA 1988a). 



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



