Leafy vegetables like spinach and lettuce absorb more than twice as much PFAS (toxic ‘forever chemicals’) as root vegetables like carrots, according to a 2026 research analysis published in Environmental Science & Technology. Gram Research analysis shows that leafy greens contained 32-64 nanograms of PFAS per gram compared to 23-29 nanograms in root vegetables, primarily because leaves absorb these chemicals directly from air pollution rather than from soil. This means people who grow their own vegetables should be aware that leafy greens pose a higher exposure risk than root vegetables.
Researchers in Shanghai studied how harmful chemicals called PFAS get into vegetables grown in home gardens and small farms. They found that leafy vegetables like spinach and lettuce absorb much more of these toxic chemicals than root vegetables like carrots and potatoes. The main culprit? Air pollution settling on the leaves. The study shows that leaves are like sponges that soak up these chemicals from the air, while roots in the soil absorb much less. This research helps us understand food safety for people who grow their own vegetables.
Key Statistics
A 2026 study published in Environmental Science & Technology found that leafy vegetables contained 32-64 nanograms of PFAS per gram, more than twice the 23-29 nanograms found in root vegetables grown in Shanghai subsistence farms.
According to research reviewed by Gram, foliar uptake (absorption through leaves) was significantly more effective at accumulating PFAS than root uptake from soil, with statistical significance of p < 0.01, indicating this difference was not due to chance.
A comprehensive analysis of 31 different PFAS chemicals in vegetables revealed that atmospheric deposition was identified as an important factor contributing to higher PFAS concentrations in leafy vegetables compared to root vegetables.
Mass spectrometry imaging in the 2026 Environmental Science & Technology study showed that PFAS chemicals penetrate through the leaf epidermis and translocate into mesophyll tissue via the apoplastic pathway, meaning they don’t just sit on the surface.
The Quick Take
- What they studied: How toxic chemicals called PFAS (forever chemicals) get into vegetables grown in home gardens and small farms in Shanghai, China
- Who participated: Agricultural samples from 31 different PFAS chemicals collected from open fields used for subsistence farming (small-scale home gardening) in Shanghai
- Key finding: Leafy vegetables like spinach absorbed 32-64 nanograms of PFAS per gram, while root vegetables like carrots had only 23-29 nanograms—meaning leafy greens absorbed more than twice as much toxic chemical
- What it means for you: If you grow your own vegetables, leafy greens may contain more of these harmful chemicals than root vegetables. Washing leaves thoroughly and considering where your garden is located (away from pollution sources) could help reduce exposure
The Research Details
Scientists collected vegetables from small farms and home gardens in Shanghai and tested them for 31 different types of PFAS chemicals. PFAS are ‘forever chemicals’ that don’t break down in nature and can build up in our bodies over time. The researchers measured how much of each chemical was in leafy vegetables (like lettuce and spinach) versus root vegetables (like carrots and potatoes). They also used special imaging technology to see exactly where these chemicals were located inside the plant leaves and how they moved through the plant tissue.
Understanding how these toxic chemicals get into our food is crucial because many people eat vegetables they grow themselves. By identifying that leafy vegetables absorb more PFAS from air pollution, researchers can help people make safer food choices and understand their exposure to these harmful chemicals that can accumulate in the body over years
This study was published in Environmental Science & Technology, a highly respected scientific journal. The researchers used advanced laboratory techniques including mass spectrometry imaging to track exactly where chemicals were in the plants. The study examined 31 different PFAS chemicals, providing comprehensive data. However, the study was conducted only in Shanghai, so results may differ in other regions with different pollution levels and farming practices
What the Results Show
Leafy vegetables contained significantly more PFAS than root vegetables, with leafy greens showing 32-64 nanograms per gram compared to 23-29 nanograms in root vegetables. This difference was statistically significant (p < 0.01), meaning it wasn’t due to chance. The researchers discovered that atmospheric deposition—chemicals falling from the air onto plants—was the main reason for this difference. Leaves act like collectors for air pollution, while roots in the soil are more protected from airborne chemicals.
The study revealed that PFAS chemicals enter plant leaves through the outer layer (epidermis) and then move into the inner tissue through spaces between cells (apoplastic pathway). This means the chemicals don’t just sit on the surface—they actually penetrate deep into the leaf. The research showed that foliar uptake (absorption through leaves) was much more effective at accumulating PFAS than root uptake from soil, even when the total amount of chemical exposure was the same
Previous research suggested that diet, especially vegetable consumption, was a major way people are exposed to PFAS. This study builds on that knowledge by showing exactly which vegetables are most problematic and why. It confirms that air pollution is a significant source of PFAS in food, not just contaminated soil or water. This finding is important because it means people in polluted areas may have higher exposure through vegetables than previously thought
The study was conducted only in Shanghai, China, so results may not apply to other regions with different pollution levels, climates, or farming practices. The research focused on subsistence farming (small home gardens), so results may differ for commercial farms that use different practices. The study didn’t measure how much PFAS people actually absorb when they eat these vegetables, only how much is in the plants. Additionally, the study didn’t examine how cooking or washing vegetables might reduce PFAS levels
The Bottom Line
If you grow vegetables at home, prioritize growing root vegetables like carrots, potatoes, and beets, which absorb less PFAS than leafy greens. Wash leafy vegetables thoroughly before eating. Consider the location of your garden—avoid areas near heavy traffic or industrial pollution. Store-bought vegetables may have different PFAS levels depending on where they’re grown. These recommendations are based on solid research but should be combined with other food safety practices. Confidence level: Moderate to High for the vegetable type differences; Lower for specific protective actions since the study didn’t test them
People who grow their own vegetables, especially leafy greens, should pay attention to this research. Families in areas with air pollution should be particularly concerned. Pregnant women and young children, who are more vulnerable to chemical exposure, should consider these findings when choosing vegetables. People with existing health conditions related to chemical exposure should discuss this with their doctor. This research is less relevant for people who only eat commercially grown vegetables from regulated sources, though it still provides useful context
PFAS chemicals accumulate in the body over months and years, not days or weeks. You won’t notice immediate changes from eating different vegetables. However, reducing PFAS exposure through food choices could help lower your body burden over time. If you switch from growing leafy greens to root vegetables, it may take several months to a year to see measurable differences in your PFAS levels if tested
Frequently Asked Questions
Are homegrown vegetables safer than store-bought vegetables?
Not necessarily. Homegrown leafy vegetables may contain more PFAS from air pollution than store-bought ones, depending on your location. Root vegetables are generally safer. Store-bought vegetables from regulated sources may have lower PFAS levels, but this varies by region and farming practices.
How can I reduce PFAS in the vegetables I grow?
Grow root vegetables like carrots and potatoes instead of leafy greens, which absorb less PFAS. Locate your garden away from heavy traffic and pollution sources. Wash all vegetables thoroughly before eating. Consider using row covers or greenhouses to reduce direct air pollution contact on leaves.
Does cooking or washing remove PFAS from vegetables?
The study didn’t test whether cooking or washing removes PFAS, so we don’t have definitive answers. However, thorough washing may remove some surface chemicals. PFAS that have penetrated into leaf tissue are likely harder to remove through washing alone.
Should I stop eating leafy greens because of PFAS?
No. Leafy greens provide important nutrients. Instead, wash them thoroughly, vary your vegetable choices to include more root vegetables, and be mindful of your garden’s location. The health benefits of eating vegetables generally outweigh the PFAS risk, especially if you take precautions.
Which vegetables have the lowest PFAS levels?
Root vegetables like carrots, potatoes, and beets had the lowest PFAS levels in this study (23-29 nanograms per gram). Leafy vegetables like spinach and lettuce had the highest levels (32-64 nanograms per gram). Growing root vegetables is a safer choice for home gardeners.
Want to Apply This Research?
- Track which vegetables you consume weekly, noting whether they’re leafy (high PFAS risk) or root vegetables (lower PFAS risk). Record the source: homegrown, farmers market, or store-bought. Over time, this helps you see your exposure patterns and make informed choices
- If you use a gardening or food tracking app, add a ‘PFAS consideration’ tag to vegetables. When logging meals, note whether leafy greens were washed thoroughly. Set reminders to wash homegrown vegetables before eating. If you garden, track which vegetables you plant and consider rotating toward more root vegetables
- Monthly: Review your vegetable consumption patterns and identify which leafy greens you eat most. Quarterly: Assess your garden location and consider pollution sources nearby. Annually: Evaluate whether your vegetable choices have shifted toward lower-PFAS options and track any health improvements you notice. Use the app to compare your PFAS exposure from vegetables across seasons
This research describes PFAS contamination in vegetables grown in Shanghai, China, and may not apply to all regions or farming practices. The study measured PFAS levels in vegetables but did not assess actual health effects from consuming these vegetables or test whether cooking or washing reduces PFAS. PFAS exposure is one of many factors affecting health. Individuals concerned about PFAS exposure should consult with their healthcare provider or local health department for personalized guidance. This article is for informational purposes and should not replace professional medical or nutritional advice. If you have specific health concerns related to chemical exposure, please speak with a qualified healthcare professional.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.