Gram Research analysis of a 2026 study in Chongqing, China, found that chili peppers grown in plastic-heavy fields contained phthalates, plastic-softening chemicals, that moved from soil into roots and fruit. Estimated dietary exposure from eating the peppers stayed within levels considered acceptable, though the researchers call for continued monitoring of plastic use on farms.
Plastics are used heavily on Chinese farms, and some of their chemicals can move into crops. According to research reviewed by Gram, scientists tested chili pepper farms in Chongqing, a city in Southwest China, and found traces of phthalates, chemicals that make plastic flexible, in the soil and in every part of the pepper plants, including the roots, stems, leaves, and fruit. The most common types were DBP, DIBP, and DEHP. DBP built up the most in the plants, and the chemicals moved easily from the roots up into the parts people eat. The researchers estimated that eating chili peppers exposed people to these chemicals at levels considered acceptable. They also noted that the soil, and chemicals that drift through the air and settle on crops, may both contribute. The authors call for ongoing monitoring and better plastic management on farms.
Key Statistics
A 2026 study of chili pepper farms in Chongqing, China, found that DBP, DIBP, and DEHP were the most common plastic-softening chemicals detected in both the soil and the peppers.
A 2026 Chongqing study of chili peppers found that DBP built up the most in pepper roots, stems, leaves, and fruit, ahead of DIBP and then DEHP.
In a 2026 study that tested 16 priority phthalate esters on Chongqing pepper farms, researchers concluded that estimated dietary exposure from eating chili peppers stayed within acceptable levels.
The Quick Take
- What they studied: Do plastic-softening chemicals called phthalates end up in chili peppers grown on farms in Southwest China, and could eating those peppers pose a health risk?
- Who participated: The study looked at chili pepper growing sites in Chongqing, China, including soil and different parts of the pepper plants. The exact number of samples was not specified in the summary available to Gram.
- Key finding: Three phthalates, DBP, DIBP, and DEHP, were the most common in both soil and peppers. DBP built up the most in the plants, and the estimated dietary exposure from eating the peppers stayed within levels considered acceptable.
- What it means for you: The amounts found appear to be within safety limits, so there is no clear reason to avoid chili peppers based on this study alone. Washing produce and reducing exposure to plastic in general are reasonable habits, and food safety agencies should keep tracking these chemicals.
The Research Details
Phthalates are chemicals added to plastics to make them soft and flexible. Because they are not tightly locked into the plastic, they can leak out and spread into soil, water, and air. This study asked whether these chemicals move from farm soil into chili peppers.
The research team looked at pepper planting sites in Chongqing. They measured 16 priority phthalates in the soil and in different parts of the pepper plants, including roots, stems, leaves, and fruit. This allowed them to see where the chemicals collected and how they traveled through the plant.
The researchers then used standard calculations to measure how strongly plants soaked up the chemicals from soil and how easily the chemicals moved upward through the plant. They also estimated how much a person might take in by eating chili peppers, and compared that amount with accepted safety limits.
Measuring the chemicals in real farm soil and real plants shows what actually happens in the field, not just in a laboratory. Testing each part of the plant reveals whether the chemicals stay in the roots or travel to the parts people eat. Estimating dietary exposure connects these measurements to what a person might actually consume.
The study measured chemicals directly in real soil and plant samples from working farms, which is a strength. However, the summary available does not state how many farms or samples were tested, so the size of the study is hard to judge. Results from one region of China may not apply directly to other farms, climates, or growing methods. Because the study observed what was already present, it cannot prove that plastic use on farms is the sole cause of the contamination.
What the Results Show
The most common chemicals found in both the soil and the peppers were DBP, DIBP, and DEHP. These three phthalates appeared repeatedly across the samples, suggesting they are the main plastic-related contaminants at these farms.
Within the pepper plants, the chemicals built up in a consistent order. DBP was found at the highest levels, followed by DIBP, then DEHP. This pattern appeared across roots, stems, leaves, and fruit, which suggests the same chemicals are moving through the whole plant rather than only settling on the outside of the fruit.
The researchers found that the roots and the above-ground parts of the plants were especially good at collecting DBP from the soil. They also found that all three phthalates could move relatively easily from the roots up to the leaves and fruit. This ease of movement is one reason the chemicals can reach the parts people eat.
Despite these findings, the researchers estimated that eating chili peppers exposed people to these chemicals at levels they considered acceptable in the farms they studied. They also noted that the soil and chemicals carried by air and settled on crops both appear to affect how much ends up in the peppers.
The study pointed to two possible sources of contamination: the soil itself, which may contain plastic residues from long-term farm use, and atmospheric deposition, which means chemicals in the air that settle onto plants. Both may add to the total amount found in the peppers. The researchers also emphasized that agricultural plastics, such as plastic sheeting used to cover fields, may contribute to a slow buildup of these chemicals over many years. This suggests the problem may grow over time if plastic use continues without careful management.
Phthalates are widely detected in farm soils, food, and the environment around the world, and earlier studies have raised concern about their effects on hormones. This study adds evidence that vegetables such as chili peppers can take up these chemicals from soil. Its finding that the chemicals move from roots into fruit is consistent with what is generally known about how plants absorb substances from the ground. The Gram summary does not include specific comparisons with named earlier studies.
The summary does not state the number of farms or samples, which makes it harder to judge how strong the results are. The study looked at one region, so the findings may not apply to other areas with different soils, weather, or farming methods. The exposure estimate depends on assumptions about how many peppers people eat and how much of the chemicals is absorbed by the body, and these assumptions may not match every person’s diet. The study also cannot fully separate how much of the contamination came from plastic mulch, irrigation, soil history, or air pollution.
The Bottom Line
Based on this study, there appears to be no clear reason for most people to stop eating chili peppers, since the researchers estimated that exposure stayed within acceptable levels (moderate confidence, because the estimate depends on assumptions). Rinsing produce before eating and reducing everyday exposure to plastics, such as not heating food in plastic containers, are reasonable steps (low to moderate confidence, since these tips are general and not tested in this study). Farmers and regulators may want to monitor soil and crops over time and manage agricultural plastics more carefully (moderate confidence, supported by the study’s call for continued monitoring).
People who grow chili peppers or other vegetables on plastic-covered fields, food safety and agriculture officials, and researchers studying environmental contamination should pay close attention to these findings. People who eat large amounts of chili peppers or who are pregnant or caring for young children may want to follow updates from health authorities. Most everyday consumers do not need to change their habits based on this study alone.
This study is a snapshot of chemicals in farm soil and peppers at one point in time, so it does not show how quickly any health effects might appear or disappear. Any reduction in soil contamination from better plastic management would likely take years, since the researchers noted that these chemicals can build up over the long term. Individual changes, such as washing produce, would reduce exposure right away, but their effect on overall health is not measured in this study.
Frequently Asked Questions
Are phthalates found in chili peppers grown in China?
A 2026 study of pepper farms in Chongqing found DBP, DIBP, and DEHP in both soil and peppers. These plastic-softening chemicals were present in the roots, stems, leaves, and fruit, with DBP showing the highest buildup among the three.
Is it safe to eat chili peppers that may contain phthalates?
Researchers estimated that dietary exposure from eating chili peppers stayed within acceptable levels in the farms they studied. The study recommends continued monitoring, and people can reduce exposure by rinsing produce and avoiding heating food in plastic containers.
How do phthalates get into vegetables from farm soil?
Phthalates can leak from agricultural plastics into soil and air. Plants can absorb them through their roots, and the chemicals can then move upward into leaves and fruit. Air deposition onto crops may also add to contamination.
What are the main phthalates to watch for in food grown on plastic-covered farms?
A Chongqing study measuring 16 priority phthalate esters found DBP, DIBP, and DEHP to be the predominant types in soil and peppers. DBP accumulated most in plant tissues, and all three moved easily from roots to above-ground parts.
Want to Apply This Research?
- Log each weekly serving of chili peppers and other vegetables, noting whether they were washed, peeled, or bought from a farm that uses plastic covers if that information is known. Track the number of servings per week so you can compare your intake against the general exposure estimate in the study over time.
- Rinse fresh chili peppers and other vegetables under running water before eating, and peel them when appropriate. Avoid heating food in plastic containers or wrapping hot food in plastic film, since heat can help plastic chemicals leach into food. Choose whole, fresh produce when possible and vary your vegetable choices across the week.
- Review your logged pepper intake and other vegetable habits every few months to spot long-term patterns. Watch for updates from food safety agencies and follow new research on phthalates in food, then adjust your habits if official guidance changes. Keep a simple note of major changes in your diet or where your produce comes from.
This article summarizes a single research study on chemical contamination in chili peppers grown in one region of China. It is not medical advice. The findings describe estimated exposure levels and may not apply to every farm, food, or person. If you have health concerns or questions about your diet, please talk with a doctor, registered dietitian, or other qualified health professional.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.