| 1. |
- Felizeter, Sebastian, et al.
(author)
-
Influence of soil on the uptake of perfluoroalkyl acids by lettuce : A comparison between a hydroponic study and a field study
- 2020
-
In: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 260
-
Journal article (peer-reviewed)abstract
- This study explores whether mechanistic understanding of plant uptake of perfluoroalkyl acids (PFAAs) derived from hydroponic experiments can be applied to soil systems. Lettuces (Lactuca sativa) were grown in outdoor lysimeters in soil spiked with 4 different concentrations of 13 PFAAs. PFAA concentrations were measured in soil, soil pore water, lettuce roots, and foliage. The PFAA uptake by the lettuce was compared with uptake measured in a hydroponic study. The foliage:pore water concentration ratios in the lysimeter were similar to the foliage:water concentration ratios from the hydroponic experiment. In contrast, the root:pore water concentration ratios in the lysimeter were 1-2 orders of magnitude lower than in the hydroponic study for PFAAs with 6 or more perfluorinated carbons. Hence, hydroponic studies can be expected to provide a good quantitative measure of PFAA transfer from soil to foliage if one accounts for soil:pore water partitioning and differences in transpiration rate. However, hydroponic studies will be of little value for estimating PFAA transfer from soil to roots because sorption to the root surface is greatly enhanced under hydroponic conditions.
|
|
| 2. |
- Felizeter, Sebastian, et al.
(author)
-
Uptake of perfluorinated alkyl acids by crops : results from a field study
- 2021
-
In: Environmental Science. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 23:8, s. 1158-1170
-
Journal article (peer-reviewed)abstract
- Four crops with different edible plant parts (radish, lettuce, pea and maize) were grown in outdoor lysimeters on soil spiked with 13 perfluorinated alkyl acids (PFAAs) at 4 different levels. PFAA concentrations were measured in soil, soil pore water, and different plant parts at harvest. Edible part/soil concentration factors ranged over seven orders of magnitude and decreased strongly with increasing PFAA chain length, by a factor of 10 for each additional fluorinated carbon (n(CF)) for pea. Three processes were responsible for most of the variability. The first was sorption to soil; calculating whole plant concentration factors on the basis of concentration in pore water instead of soil reduced the variability from five orders of magnitude to two. Second, the journey of the PFAAs with the transpiration stream to the leaves was hindered by retention in the roots driven by sorption; root retention factors increased by a factor 1.7 for each n(CF). Third, transfer of PFAAs from the leaves to the fruit via the phloem flow was also hindered - presumably by sorption; fruit/leaf concentration factors decreased by a factor 2.5 for each n(CF). A simple mathematical model based on the above principles described the measured concentrations in roots, leaves, fruits and radish bulbs within a factor 4 in most cases. This indicates that the great diversity in PFAA transfer from soil to crops can be largely described with simple concepts for four markedly different species.
|
|
