**8. RCF and TF values of specific crops**

Following the extensive literature evaluation by Dobslaw et al. [52] twelve crops with the highest documented data density were selected and the occurring RCF and TF values for BDE-47 and BDE-209 were compared. The highest data density regarding the transition of PBDEs from soil to root or from root to plant was available for BDE-209 followed by BDE-47. In contrast to lower brominated

BDEs the concentrations of BDE-209 found in literature range over several decades, which facilitates an evaluation of the literature data concerning transition rates. In particular, the following species were selected: Rice (*Oryza sativa* L.), maize (*Zea mays* L.), prince's-feather (*Amaranthus hypochondriacus* L.), the group of bok choy, Chinese cabbage, broccoli, and filder cabbage (*Brassica* sp.), lettuce (*Lactuca sativa sp.), spinach* (*Spinacia oleracea* L.), sweet potato vine (*Ipomoea batatas* L.), radish (*Raphanus sativus* L.), carrot (*Daucus carota* L.), taro root (*Colocasia esculenta* L. Schott), pea (*Pisum sativum* L.), and pumpkin (*Cucurbita pepo ssp. pepo*).

**Figure 2** shows the concentrations of BDE-209 in the roots of these crops as a function of the corresponding soil concentrations (RCF), indicating the dependency of BDE-209 uptake on the soil concentration with a ratio of about 1:10 (croot:csoil). Comparing shoots and corresponding soil a similar dependency on soil concentration with a ratio of about 1:18 (croot:csoil) was found (**Figure 3**). This representation was chosen because of the higher data density being available. However,

#### **Figure 2.**

*BDE-209 – Root concentration factor (RCF), concentration in root as function of corresponding soil concentration.*

**77**

**Figure 5.**

*concentration.*

*Plant Uptake, Translocation and Metabolism of PBDEs in Plants*

a TF could be derived from the comparison of the existing data pairs, which points to the dependence of the shoot concentrations on the concentrations in the root

*BDE-209 – Translocation factor (TF), concentration in shoot as function of corresponding root concentration.*

The extent of transition of the tetrabrominated BDE-47 from soil to root and shoot was also determined by the concentration of the flame retardant in the soil (**Figures 5** and **6**). For BDE-47, despite its lower logKOW in comparison to BDE-209, the transition rates are higher with about 1.1:1 (croot:csoil) and 1:6 (cshoot:csoil). Too few

TF. A graphical summary of the results for the congeners 47 and 209 is given in **Figure 7**. The results are consistent with the prediction models described in Section 7 (see also **Figure 1**). Due to its high log KOW, BDE-209 is expected to have a lower uptake compared to BDE-47. With the models mentioned above, it is possible to adequately describe the uptake behavior of lipophilic PBDEs. Of particular interest is the trend that the uptake of the substances is primarily determined by the

*BDE-47 – Root concentration factor (RCF), concentration in root as function of corresponding soil* 

corresponding data pairs were available for the representation of the

*DOI: http://dx.doi.org/10.5772/intechopen.95790*

(**Figure 4**) with a ratio of about 1:9 (cshoot:croot).

**Figure 4.**

**Figure 3.** *BDE-209 – Concentration in shoot as function of corresponding soil concentration.*

*Plant Uptake, Translocation and Metabolism of PBDEs in Plants DOI: http://dx.doi.org/10.5772/intechopen.95790*

#### **Figure 4.**

*Flame Retardant and Thermally Insulating Polymers*

BDEs the concentrations of BDE-209 found in literature range over several decades, which facilitates an evaluation of the literature data concerning transition rates. In particular, the following species were selected: Rice (*Oryza sativa* L.), maize (*Zea mays* L.), prince's-feather (*Amaranthus hypochondriacus* L.), the group of bok choy, Chinese cabbage, broccoli, and filder cabbage (*Brassica* sp.), lettuce (*Lactuca sativa sp.), spinach* (*Spinacia oleracea* L.), sweet potato vine (*Ipomoea batatas* L.), radish (*Raphanus sativus* L.), carrot (*Daucus carota* L.), taro root (*Colocasia esculenta* L. Schott), pea (*Pisum sativum* L.), and pumpkin (*Cucurbita pepo ssp. pepo*).

**Figure 2** shows the concentrations of BDE-209 in the roots of these crops as a function of the corresponding soil concentrations (RCF), indicating the dependency of BDE-209 uptake on the soil concentration with a ratio of about 1:10 (croot:csoil). Comparing shoots and corresponding soil a similar dependency on soil concentration with a ratio of about 1:18 (croot:csoil) was found (**Figure 3**). This representation was chosen because of the higher data density being available. However,

*BDE-209 – Root concentration factor (RCF), concentration in root as function of corresponding soil* 

*BDE-209 – Concentration in shoot as function of corresponding soil concentration.*

**76**

**Figure 3.**

**Figure 2.**

*concentration.*

*BDE-209 – Translocation factor (TF), concentration in shoot as function of corresponding root concentration.*

a TF could be derived from the comparison of the existing data pairs, which points to the dependence of the shoot concentrations on the concentrations in the root (**Figure 4**) with a ratio of about 1:9 (cshoot:croot).

The extent of transition of the tetrabrominated BDE-47 from soil to root and shoot was also determined by the concentration of the flame retardant in the soil (**Figures 5** and **6**). For BDE-47, despite its lower logKOW in comparison to BDE-209, the transition rates are higher with about 1.1:1 (croot:csoil) and 1:6 (cshoot:csoil). Too few corresponding data pairs were available for the representation of the TF. A graphical summary of the results for the congeners 47 and 209 is given in **Figure 7**. The results are consistent with the prediction models described in Section 7 (see also **Figure 1**). Due to its high log KOW, BDE-209 is expected to have a lower uptake compared to BDE-47. With the models mentioned above, it is possible to adequately describe the uptake behavior of lipophilic PBDEs. Of particular interest is the trend that the uptake of the substances is primarily determined by the

#### **Figure 5.**

*BDE-47 – Root concentration factor (RCF), concentration in root as function of corresponding soil concentration.*

**Figure 6.** *BDE-47 – Concentration in shoot as function of corresponding soil concentration.*

**Figure 7.** *BDE-47 and BDE-209 – Comparison of concentrations in soil, root and shoot (normalized, c(soil) =1).*

concentration of the compounds in soil. A dependency of the uptake on the crop species might have been expected, but cannot be proven by the present data set.
