# Contribution of Atmospheric Fallout to the Soil-Root-Leaf Transfer of PAHs in Higher Plants
## 3 Results  
Altogether 19 PAHs were detected in the extract. Table 1 shows the concentrations of accumulated PAHs in different plant compartments, as well as in the soil, in case of direct treatment of the soil with the extract. They included the 16 priority PAHs listed by US EPA [39] and the so-called car PAHs, such as Benzo[a]anthracene, Chrysene, Benzo[b]fluoranthene, Benzo[k]fluoranthene, Benzo[a]pyrene, Dibenzo[a,h]anthracene, Indeno[1,2,3-cd]pyrene, and Benzo[g,h,i]perylene [40].  
In the extract, the prevalence of LMW PAHs could be observed. In addition to naphthalene, the dominant PAHs were the 3-ring Flu (1.472 ug/L) and Phen (0.448 ug/L). Most studies report the dominance of these species in atmospheric samples (reviewed by [41]) as well as in bulk deposition [42]. Phen was the dominant PAH in a study assessing distribution of traffic-related contaminants in urban toposoils [43]. Phen was also characteristic in different diesel blends reported by [PERSON] et al. [44].  
The dominant PAH in the treated soil was 5-ring B(b)f (11.7 ug/kg). [PERSON] et al. also measured the highest share of B(b)f in urban sites (39.94%) [45]. The 4-ring Pyr and Cry were also detected in high concentrations, 9.2 ug/kg and 8.3 ug/kg. These PAHs can be regarded as characteristic in urban soils [46].  
In the case of the soil-root-aerial parts pathway, the distribution of 2-6 ring PAHs in different compartments is shown in Figure 2. Figure 3 gives the ratio of different PAH isomers for the aerial parts-roots pathway.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline  & **PAHs** & **Extract** & **S-Soil** & **S-Root** & **S-Stem** & **S-Leaf** & **A-Root** & **A-Stem** & **A-Leaf** \\ \hline \multirow{2}{*}{**2 rings**} & **Naphthalene** & 0.491 & 32.6 & 78.5 & 50.2 & 30.4 & 32 & 208 & 234 \\  & 2-Methyl-naphthalene & 0.394 & 4.2 & 5.1 & 4.2 & 3.9 & 4.4 & 7.7 & 8.6 \\  & 1-Methyl-naphthalene & 0.367 & 2.1 & 2.5 & 2.3 & 2.2 & 4.1 & 4.4 & 5.5 \\ \hline \multirow{3}{*}{**3 rings**} & **Aeenaphthylene** & 0.12 & 1.4 & 1.9 & 1.6 & 0.7 & 0.8 & 0.5 & 5.2 \\  & **Aeenaphthene** & 0.052 & 1.7 & 2 & 1.9 & 1.5 & 1.87 & 2.4 & 2.4 \\  & **Fluorene** & 0.472 & 1.1 & 4.1 & 4.1 & 2.9 & 3.3 & 4.8 & 5.2 \\  & **Phenanthrene** & 0.448 & 5.4 & 7.8 & 7.5 & 4.9 & 2.9 & 6.4 & 8.6 \\ \hline \multirow{3}{*}{**4 rings**} & **Anthracene** & 0.058 & 2.3 & 3.1 & 1.5 & 0.4 & 1.2 & 0.9 & 2 \\  & **Fluoranthene** & 0.074 & 1.62 & 6.2 & 5.7 & 5.1 & 5.7 & 9.3 & 10.1 \\  & **Pyrene** & 0.081 & 9.2 & 3.5 & 2.9 & 2.9 & 1.8 & 5.1 & 9.1 \\  & **Benzanthracene** & 0.032 & 4.7 & 4.7 & 2.6 & 2.5 & 1.7 & 5.6 & 8.1 \\  & **Chrysene** & 0.013 & 8.3 & 2.4 & 1.6 & 1.1 & 0.4 & 2.5 & 12.7 \\ \hline \multirow{3}{*}{5 rings} & Benzo[b]fluoranthene** & 0.064 & 11.7 & 4.6 & 2.8 & 2.2 & 1.1 & 3.2 & 8.4 \\  & Benzo[k]fluoranthene & 0.036 & 4.9 & 4.7 & 0.8 & 0.7 & 0 & 2.3 & 2.2 \\  & Benzo[k]pyrene & 0.055 & 5.6 & 2.7 & 1.6 & 1.1 & 0 & 1.8 & 4.3 \\  & Benzo[a]pyrene & 0.043 & 3.6 & 3 & 1 & 0 & 0 & 1.1 & 1.4 \\  & Dibenzo[a]anthracene & 0.045 & 4 & 1.9 & 0 & 0 & 0 & 1.5 & 2.3 \\ \hline \multirow{3}{*}{6 rings} & **Indeno[1,2,3-cd]pyrene** & 0.033 & 1.2 & 1.5 & 0 & 0 & 0 & 0.5 & 1 \\  & Benzo[g,h]perylene & 0.035 & 2.1 & 2.8 & 0 & 0 & 0 & 1.3 & 2.1 \\ \hline \multicolumn{3}{c}{**Total PAHs**} & **108** & **143** & **92.3** & **62.5** & **61.3** & **269** & **333** \\ \hline \end{tabular}
\end{table}
Table 1: Concentration of PAHs in the aerosol extract given in ug/L and in the samples given in ug/kg. The limit of PAH detection (LOD) was 0.1 ug/kg dry plant material. US EPA PAHs are given in bold. S: soil treated; A: aerial parts treated.  
Figure 2: Concentration of PAHs with different molecular weight in soil and treated plant compartments, simulating the soil–root–aerial parts pathway.