PAH index

Soil contamination is one of the main environmental problems, mainly in industrial countries, and is very often linked to water resource degradation. The diagnosis of potentially 

The soil organic extract corresponding to a concentrated and purified soil PAH solution is obtained through the simple procedure described in Fig. 23. 

This procedure has been applied to nearly 80 samples of soils from various industrial origins. It leads to define two types of UV organic extracts spectra presented in Fig. 24. Each UV spectrum shows a structured shape with high absorbance at the beginning of the spectrum, which decreases after 300 nm. It can be noticed that absorbance value over 350 nm is more important for the type 2, according to the bathochromic effect observed for heavy PAHs. Indeed, it has been shown that UV spectrum of type 1 corresponds to soils mainly contaminated by light PAHs (2 or 3 cycles) and UV spectrum of type 2 to soils mainly contaminated by heavy PAHs (4 or more cycles) [32]. 

Two specific peaks, located respectively at 254 and 288 nm, are always present on UV spectra profiles. The first one is characteristic of the presence of the 16 USEPA PAHs (Chapter 3). Thus, for a quantitative application, the absorbance value at this wavelength measurement is proposed as a PAH index for a simple estimation of global PAH concentration in contaminated soil. A validation of this approach is given by HPLC analysis of the 16 USEPA PAHs (Fig. 25). 

Dealing with the specific absorbance at 288 nm, it has been observed, from the study of UV organic extracts spectra, that the ratio between the absorbance values at 254 and 

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This simple method of UV spectra exploitation (mono wavelength correlation) has been used and leads to the definition of a PAH index suitable for a rapid diagnosis of PAH-contaminated soils. Moreover, the absorbance value ratio of the two main characteristic peaks gives information about the PAH distribution in terms of light and heavy PAHs. These tools appear to be relevant with regard to the management of contaminated soils. 

From a quantitative point of view, the global PAH concentration can be estimated with the use of PAH index previously defined in Chapter 4. The value of the ratio 254 nm 288 nm gives information on the distribution of PAH in the contaminated soils, namely that as higher is this ratio, and higher is the proportion of light PAHs. Table 7 collects the data related to the two studied contaminated soils. 

Early work on the structure of carcinogenic PAHs was done by John Iball at the University of Dundee, Scotland (29) he had suggested the use of the "Iball index" (30) as a measure of the... 

Immunohistochemical study ND not determined GLUT1 facilitative glucose transporter MCT1 monocarboxylate transporter CRT creatine transporter LAT1 L-type amino acid transporter TAUT taurine transporter ENT equilibrative nucleoside transporter Oatp organic anion-transporting polypeptide PAH p-aminohippuric acid RUI retinal uptake index TR-iBRB rat retinal capillary endothelial cells. 

Figure2.19 Ellipsometricthickness (a) and refraction index (b) as a function of electrode potential for a (PAH-Os)7(COx)7 multilayer. Scan rate 5 mVs Taken from Ref [68].

Hepatosomatic index HSl Liver disease, nutritional status PCBs, OCPs, BKME, PCDDs, PAHs Liver 4-30... 

Masclet and co-workers (1986) have also developed a relative PAH decay index. They used it, for example, to identify various major sources of urban pollution and developed a model for PAH concentrations at receptor sites. An interesting and relevant area that is beyond the scope of this chapter is the use of PAHs as organic tracers and incorporating their relative decay rates (reactivities) into such receptor-source, chemical mass balance models. Use of relative rates can significantly improve such model performances (e.g., see Daisey et al., 1986 Masclet et al., 1986 Pistikopoulos et al., 1990a, 1990b Lee et al., 1993 Li and Kamens,... 

The peak with the parent ion of m/e 226 was assigned benzo[ghi]flu granthene. The reference standard was not available, but its retention index was in agreement with that reported (389.6) by Lee et al. (6). The presence of benzo[b,j k]fluoranthenes was also confirmed. They appeared as one broad peak, but the presence of all three was established by their GC retention time in the HPLC subfraction S1-C2C. Benzo[ejpyrene and benzo[a]pyrene were also characterized by MS. PAHs with higher ring systems were not detected in this sample. 

Table n. Physical Properties, SFC Capacity Factors, and GLC Retention Indexes for the PAHs Studied... 

The mixture of PAHs present in a particular sample in many cases mirrors the sources that produce them. Several methods can be used to qualitatively identify the probable sources of PAHs. Commonly used methods include the abundance ratios of individual compounds, the fossil fuel pollution index (FFPI), and diagnostic ratios indicative of sources (petrogenic vs. pyrogenic). Quantitative apportionment of sources needs sophisticated statistical approaches such as the chemical mass balance models (Li et al., 2003). 

Therefore, Ph/An> 15 may point to petrogenic sources and Ph/An< 10 to pyrolytic sources. Due to the wide range of values for this index found in the literature, values between 10 and 15 are considered indeterminate relative to source. In petroleum-derived PAHs, pyrene is more abundant than fluoranthene, while at higher combustion temperatures a predominance of fluoranthene over pyrene is characteristic. So the Fl/Pyr values greater than 1 are obviously related to pyrolytic sources, whereas values less than 1 are attributed to petrogenic sources. In order to avoid erroneous conclusions, the two ratios are often combined. When Ph/An> 15 and Fl/Pyr < 1, the PAH input is mainly from crude oil sources and when Ph/An< 10 and Fl/Pyr > 1, the major input may be related to combustion (Wang et ah, 2004b). 

An electronic parameter that often correlates with metabolic rates is the electrophilic (or nucleophilic) superdelocalizability. This quantity is a reactivity index formulated by Fukui and colleagues as an orbital-weighted electron density.145 The total electrophilic superdelocalizability, 2SE, summed over all atoms in a molecule, exhibits a parallelism with the hydrophobic parameter, log P, in several series of compounds such as PAHs and aliphatic amines, where it is probably approximating molecular volume. 

While the brain levels of PAH in the children who scored low on the mental development index component of the BSlD-11 cannot be known, studies such as the aforementioned are valuable from a translational standpoint as they can assist in the design of molecular neurotoxicity studies. Mechanistic studies that utihze transgenic mouse models will facilitate the understanding of the molecular signaling events that give rise to the observed neurotoxic effects resulting from exposure to PAHs during development. The... 

Jinno and Kawasaki " correlated log k with the connectivity index y of 26 polycyclic aromatic hydrocarbons (PAHs) separated on phenyl (r=0.9926), ethyl (r=0.9905), octyl (r=0.9944), and octadecyl (r=0.9912)... 

Fig. 3 Relationship between the tR (sec) values and Gutman index for 16 PAHs according to Eq. 40. (From Ref. [18].)...

Index Chemical Chemical selected as the basis for standardization of toxicity of components in a chemical class (e.g., 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD] for the assessment of dioxin-like compounds benzo[a]pyrene for the assessment of carcinogenic polycyclic aromatic hydrocarbons [PAHs]). 

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