Root concentration factor

A method for estimating the TSCF for equation 14.24 is given in Table 14.10. The root concentration factor is also defined in Table 14.10 as the ratio of the contaminant in the roots to the concentration dissolved in the soil water (pg/kg root per pg/L). This is important in estimating the mass of contaminant sorbed to roots in phytoremediation systems. The values of TSCF and RCF for metals depend on the metals redox states and chemical speciation in soil and groundwater. 

Estimating the Transpiration Stream Concentration Factor (TSCF) and Root Concentration Factor (RCF) for Some Typical Contaminants (8)... 

Root uptake has been proven to be an important pathway for contaminants with intermediate octanol-water partitioning coefficients (Aiow)- Variable uptake of an organic compound by different plants has been observed. Plant species such as Daucus carota (carrot) and Pastinaca sativa (parsnip) with swollen storage roots did not translocate chemicals as well as expected from barley experiments. While the lipid content was considered a factor, plant structure, root types, and other properties may all play a role. The effect of the chemical itself was best illustrated by the increasing root concentration factor (RCF) and the bell-shaped transpiration stream concentration factors (TSCF) relative to logAiow- The physiochemical properties of compounds, including the Ko, solubility, and... 

HMX uptake was evaluated from 21-d hydroponic exposures using hybrid poplar trees (Populus deltoids x nigra) at concentrations of 4.70, 2.84, and 1.37 mg L 1 [80], After 21 d, 44.83% of the HMX in solution was sequestered by the trees. No toxic effects were evident at any of the exposures. The authors also calculated a transpirational stream concentration factor of 0.18 0.03 suggesting that HMX was moderately available for uptake by plant roots. Root concentration factors were also calculated at 5.55 1.78 [80], As with other studies, most HMX was... 

TABLE 5.4 Root Concentration Factors and Transpiration Stream Concentration Factors for Phenyl Ureas in Barley Seedlings... 

Figure 5.7 Root concentration factor (log RCF) expressed as a function of log Ko. O, 0-methylcarbamoyloximes x, substituted pbenylureas. [Reproduced from G. G. Briggs, R. H. Bromilow, and A. A. Evans, Relationships between lipophilicity and root uptake and translocation of non-ionised chemicals by barley Pestic. Sci, 13, 495. Copyright 1982, Society of Chemical Industry. Reproduced with permission granted by John Wiley and Sons, Ltd on behalf of the S.C.I.]...

Figure 9.4. Relationship between the uptake of chemicals by plant roots (expressed as their root concentration factor) and their octan-l-ol/water partition coefficients (as log (a) in barley roots O, 0-methylcarbamoyloximes x, substituted phenylureas (b) literature values for several herbicides and fungicides in different plant species. (Reproduced from Ref. 34.)...

Partitioning of nonionized organic chemicals into the lipophilic root membranes and the root sap has been described as a root concentration factor (RCF), the ratio between the chemical concentration in the roots and that in the exposure media (water or soil) contacting the roots (Briggs et al., 1982,1983 Topp et al 1986). 

Topp et al. (1986) conducted similar uptake experiments with barley plants grown from seed for 7 days in soil containing individual " C-labeled organic chemicals at concentrations of 2 mg/kg. Root concentration factors (CFsoil), defined similarly as the concentration of chemical in the root (fresh weight) divided by the concentration of the chemical in the soil pore water, were determined and found to be correlated with log Kovf as shown ... 

Table 1. Root concentration factor for anthracene and pyrene during hydrocarbon...

The root concentration factor (RCF) describes the potential of a given xenobiotic to accumulate in the plant root, and makes no discrimination between surfaces accumulation and uptake into the root tissue. 

Table 1. Concentration factors. RCF root concentration factor SCF stem concentration factor TF translocation factor. F. arundinacea (F.a) and R curtipendula (B.c). PHE -phenanthrene PYR-pyrene BaP-benzo[a]pyrene.

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