Hydrocarbon average polyaromatic

Analysis of variance was used to assess the effects on polyaromatic hydrocarbons extraction at the 99% confidence level for the four factors varied. The percentage of 14C in the extract and soil residue does not total 100% because of degradation and volatilization during incubation and due to losses during analysis. The data are presented in Table 2.3 and represent the average of the three replicates for the extract or soil residue. 

Significant differences at the 99% confidence level were observed for the extraction technique and for the polyaromatic hydrocarbons concentration in the soil. The average recovery by the Soxhlet technique was 74.5% whereas 62.8% was the average Polytron recovery. A much higher proportion was extracted with polyaromatic hydrocarbons at the 50pg/g level (72.6%) than at the 5pg/g level (64.6%) suggesting that the extraction efficiency is not constant with concentration. 

The molar differential heat capacity at the melting point has proved to be negligible only for benzene and rigid, polyaromatic hydrocarbons, and a compilation of literature data indicates that ACpon the average is 80% of the molar entropy of fusion (Neau and Flynn, 1990). Although the Lrst assumption has been applied in many studies, the second assumption has gained favor in recent pharmaceutical literature (Subrahmanyam et al., 1992 Claramonte et al., 1993 Yu et al., 1994). 

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