GenX and PFAS Uptake by Food Plants
Transcript of GenX and PFAS Uptake by Food Plants
GenX and PFAS Uptake by Food Plants
Kathyrn L. Holden, Yuanbo Li, Yue Zhi, Stephen W. Broome, Detlef Knappe, and Owen W. DuckworthDepartment of Crop and Soil Sciences
Department of Civil, Construction, and Environmental EngineeringNorth Carolina State University
Department of Crop and Soil SciencesGenualdi, deJager, Begley, FDA (2019)
Potential food crops uptake and human exposure
Plant uptake is an important process to transport PFAS to food chain.
Accumulation?
PFAS
Spiking concentrations: 10 ng/g
Approach
Lettuce
5% compost
20% compost
10% compost
Shoot
Pore water
Root
SoilSampling: 45 d
0% compost
60% field capacity
Compost increase the soil organic carbon content
Soil pH (H2O) TOCa (%) CECb (cmol/kg) Clay (%) Silt (%) Sand (%)0% compost 6.1 0.57 3.6 5.2 7.9 86.9
5% compost 5.9 0.75 5.1 4.1 8.0 87.9
10% compost 6.1 1.44 8.5 4.6 8.1 87.3
20% compost 6.3 2.02 11.5 5.1 7.2 87.7
aTOC: Total organic carbon
Greenhouse experimentCompound CAS supplier PFMOAA 21837-98-9 fluoryxHFPO-DA/GenX 13252-13-6 SynquestPFBS 375-73-5 SynquestPFHxS 355-46-4 SynquestPFOS 1763-23-1 Synquest6:2 FtS 27619-97-2 fluoryx4:2 FtS 757124-72-4 Synquest8:2 FtS 39108-34-4 Synquest
LettuceOrganic compost was made from wheat straw and cow manure
Sample extraction and analysis
Extraction LC-MS/MSDried and ground
Pore water:
Soil and lettuce plant:
4:2FTS 6:2FTS 8:2FTS GenX PFBS PFHxS PFMOAA PFOS0
500
1000
1500
5000
10000
15000
20000
25000
30000
35000
40000
Pore
wat
er co
ncen
tratio
n (n
g/L)
0% compost 5% compost 10% compost 20% compost
Increasing compost content decrease the bioavailable PFAS concentrations in soil by 68-96%.
Soil pore water
96%
79%
89%
84%
79%
68%
94%
78%
PFAS concentration in soil pore water
Preliminary Data
Genx uptake ─ fill the data gap
0
50
100
150
200
250
300
350
Conc
entra
tion (
ng/g,
dw)
Lettuce shoots (n = 3)
0% compost 5% compost 10% compost 20% compost
0
20
40
60
80
100
120
140
160
Lettuce roots (n = 3)
Conc
entra
tion (
ng/g,
dw) 0% compost
5% compost 10% compost 20% compost
54.3-82.8% decreasing 53.4-87.5% decreasing
Genx uptake into plant was first studied. Genx concentration was decreased by up to 82.8% in shoots
and 87.5% in roots by compost addition.
54%
O
OHO
F F
FF
FF
F
FFF
F
72% 83% 53%
74% 88%
Preliminary Data
Next Steps: Digging Deeper• Surveying real food
products• Understanding
fundamental soil chemistry
Department of Crop and Soil Sciences
Department of Crop and Soil Sciences
WaterSoilBlueberriesCornOkraPecansPotatoesSquashPeachesTomatoesGrapesField BeansGreen Beans
ApplesBlackberriesPearsPeasTurnipsSweet potatoesFigsEggsCucumbersLettuceRadishCeleryPickles
Collection of produce from local residents
Department of Crop and Soil Sciences
Is it safe to eat the food I grow in my garden?Currently, there is no recommendation against eating local produce. DEQ and DHHS arecontinuing to review the scientific literature related to plant uptake of GenX and otherchemicals in the same family (per‐ and polyfluoroalkyl substances, or “PFAS”). Studieshave shown that some other chemicals in the PFAS family can be found in variableamounts in plants and vegetables, but the amount depends on the particular chemicaland the plant type. Direct testing of garden produce for GenX has not been conducted by
NC DEQ, and to our knowledge results of such testing are not available from other sourcesat this time. A study conducted by the Minnesota Department of Health found that the a
mount of exposure to five other PFAS compounds from plants and vegetable sources wasmuch lower than the amount of exposure through drinking water, and concluded that thebenefits of growing and eating homegrown produce outweighed the potential risk fromlow levels of PFAS (https://deq.nc.gov/news/key‐issues/genx‐investigation)
AcknowledgementsThanks to Josh Henson, Yinan Ding, and Becca Weed.
Funding: PFAST Network Team 5, NC Policy Collaboratory Supplement, and USEPA