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    Ministry of Agriculture and Rural Affairs Science Popularization: “Pesticide Residues and Safety Issues in Agricultural Products”


    Release Date:

    2019-07-11

    What is pesticide residue? Pesticide residue refers to trace amounts of pesticides that remain in organisms, agricultural products (or food), and the environment after pesticide application. In addition to the parent pesticide itself, it also includes its toxic metabolites and impurities, serving as an umbrella term for pesticides and other related substances. The quantity of residual pesticide is called the residue level, expressed in milligrams per kilogram (mg/kg) of sample. Pesticide residues are an inevitable consequence of pesticide use; however, if they exceed the maximum residue limit (MRL) standards, they may pose adverse health risks to humans and animals or threaten organisms within the ecosystem through the food chain. Do all agricultural products contain pesticide residues? During the agricultural production process…

    What are pesticide residues?

     

    Pesticide residues refer to trace amounts of pesticides that remain in organisms, agricultural products (or food), and the environment after pesticide application. In addition to the parent compounds, they also include toxic metabolites and impurities, collectively constituting a broad category of pesticides and related substances. The quantity of residual pesticide is expressed as the residue level, typically reported in milligrams per kilogram (mg/kg) of sample. Pesticide residues are an inevitable consequence of pesticide use; however, when their levels exceed established maximum residue limits, they may pose adverse health risks to humans and animals or, through the food chain, exert toxic effects on organisms within ecosystems.
     
    Do all agricultural products contain pesticide residues?
     
    During agricultural production, crop diseases, pests, and weeds frequently cause damage, necessitating the use of pesticides for control. However, some organic farming practices rely on natural biopesticides, meaning that nearly all agricultural products may contain pesticide residues—both in China and abroad. In fact, the more advanced a country’s agricultural modernization, the greater its pesticide usage; consequently, developed nations generally apply more pesticides than developing countries. According to 2000 statistics from the Food and Agriculture Organization of the United Nations, per-unit-area pesticide application in developed countries is 1.5 to 2.5 times higher than in developing countries. In practical production, due to limitations in pesticide‑application techniques, only about 30% of the applied pesticide is actually retained by the crop; the rest leaches into the environment. On plants, most pesticide residues remain on the surface, while systemic pesticides may be absorbed into the plant tissue. Over time, through weathering, natural degradation, and biodegradation, pesticide residues at harvest are typically very low. Nevertheless, to ensure food safety, maximum residue limits are established to keep pesticide levels within safe thresholds. While complete absence of residues is an idealistic goal that no country can yet achieve, reducing pesticide residues and safeguarding food safety remain key objectives of agricultural and pesticide‑management policies worldwide.
     
    Can we do without pesticides?
    In recent years, incidents involving the safety and quality of agricultural products have occurred from time to time, leading some members of the public to wonder: “Is it possible to do without pesticides?” In fact, the global use of pesticides has a history of just over two centuries. During this period, pesticide consumption has steadily increased—driven by population growth, which has necessitated vigorous expansion of agricultural production to ensure a secure food supply, and by the growing reliance of modern agriculture on chemical inputs. Studies indicate that crop losses caused by pests, diseases, and weeds can reach as high as 70 percent; proper pesticide application can help recover roughly 40 percent of these losses. As a country with a large population and limited arable land, China has long prioritized increasing grain yields and boosting farmers’ incomes—both key objectives of agricultural production. Using pesticides to control pests, diseases, and weeds and thereby mitigate yield reductions is an essential technical measure; without them, the nation would almost certainly face widespread famine. Moreover, modern agricultural technologies such as mechanization rely on pesticides for weed control, height regulation, defoliation, fruit set, and other operations, facilitating efficient mechanized farming. For plants, pesticides are as vital—and indispensable—as medicine is for humans. Nevertheless, several measures can help reduce pesticide residues: first, implementing comprehensive integrated pest management to lower overall pesticide use; second, ensuring the correct and standardized application of pesticides to minimize residue levels; and third, vigorously promoting biopesticides to cut back on chemical inputs and continually bring down residual concentrations. The agricultural sector has been actively pursuing these efforts.
     
    Can agricultural products containing pesticide residues be eaten?
     
    Whether it is safe to consume agricultural products containing pesticide residues depends on the level of residue, the toxicity of the pesticide, and the quantity consumed. To ensure food safety, countries establish maximum residue limits (MRLs) based on the toxicological data of pesticides—primarily the acceptable daily intake and the acute reference dose—as well as factors such as dietary patterns. Products with residue levels below these limits are considered safe and can be consumed without concern, whereas those exceeding the limits pose safety risks and should not be eaten. It should also be noted that, when setting MRLs, a safety factor of at least 100 is applied, providing a substantial margin of safety; theoretically, even if one were to inadvertently consume produce with residues above the limit, an adverse health event would unlikely occur.
     
    To ensure the safety of agricultural products, China maintains strict oversight of pesticide safety. Pesticide registration requires two years of testing, encompassing 18 acute, subchronic, and chronic toxicity studies, and no products with known carcinogenic or teratogenic risks are approved. China has also implemented the most stringent controls on highly toxic pesticides, progressively banning 33 such substances—including compounds like methamidophos that remain widely used in the United States and other developed countries—while vigorously promoting the development of biopesticides. Today, the share of highly toxic pesticides has dropped from the original 30% to less than 2%, while over 72% of registered pesticides are low‑toxicity products. As a result, overall pesticide safety has improved markedly, leading to fewer incidents of poisoning in rural areas and a significant decline in suicide deaths caused by pesticide ingestion. That said, this does not mean Chinese agricultural products are absolutely safe; what is certain is that today’s pesticides are far safer than those of the past. For those concerned about pesticide residues, rinsing fresh fruits and vegetables thoroughly and peeling them can help reduce any potential traces.
     
    Which agricultural products carry a higher risk of residue?
     
    Generally speaking, organic agricultural products, green foods, and pollution‑free agricultural products are relatively safe because they are subject to strict regulations on the types of pesticides used and their application methods, resulting in lower pesticide residues and fewer instances of residue levels exceeding regulatory limits. For staple crops such as wheat, rice, and corn, which have long growing and storage periods, most pesticide residues tend to degrade over time; moreover, processing and cooking further reduce and break down any remaining residues, making these foods comparatively safe. Vegetables and fruits, being mostly consumed fresh, retain more pesticide residues, so national regulations governing pesticide use in these categories are particularly stringent. In addition to banning highly toxic pesticides, authorities impose strict guidelines on application techniques and safety intervals for permitted products, ensuring that normal production practices do not pose safety concerns. However, for certain fresh vegetables and fruits harvested continuously, the risk of residual contamination may be somewhat higher. All agricultural products contain trace amounts of pesticide residues. Thanks to rigorous international oversight of pesticides and their residues, products that meet established residue standards are considered safe. Therefore, it is important to adopt a balanced perspective on pesticide residues and food safety: while awareness of safety is essential, there is no need to overreact or view all pesticides with undue alarm. The levels of pesticide residues are extremely low, and their potential harm is far outweighed by other environmental pollutants and pathogenic microorganisms.
     
    How are the standards for pesticide residues determined?
     
    Pesticide residue standards encompass maximum residue limits (MRLs) as well as methods for detecting pesticide residues. Among these, the MRLs for pesticides in food and edible agricultural products have the most direct relevance to consumers. Like many developed countries—including those in Europe, the United States, Japan, and Australia—China employs internationally recognized risk‑assessment techniques and methodologies, adopting the principle of accounting for the highest possible risk when establishing national MRLs for pesticides. The specific approach and steps are as follows: First, based on the needs of each stage—production, processing, distribution, consumption, and import/export—and on actual pesticide‑use patterns, a list is compiled of the agricultural products (or foods) and corresponding pesticides for which MRLs should be set. Next, dynamic simulation studies on pesticide‑residue degradation, surveys of national dietary patterns, and toxicological assessments of the pesticides are conducted. These efforts yield data on the levels of pesticide residues remaining in agricultural products (or foods) under normal use conditions—including intermediate and maximum residue levels—along with dietary intake data for Chinese consumers (covering daily consumption quantities of various food items across different regions, age groups, and genders), and toxicity information such as the acceptable daily intake and acute reference dose. On this basis, a dietary exposure risk assessment is performed, resulting in recommended MRL values. Finally, after review and approval by the National Food Safety Pesticide Residue Standards Review Committee, the standards are jointly promulgated and implemented by the Ministry of Health and the Ministry of Agriculture.
     
    It is important to note that, when establishing maximum residue limits, the assessment is based on the highest possible risk—meaning the strictest safety requirements are applied. On this basis, an additional safety factor of at least 100 is incorporated. For example, if a pesticide residue level of 50 mg/kg in food were to pose a potential safety risk, the regulatory limit would be set at 0.5 mg/kg.
     
    Are China’s pesticide residue standards lower than those of Europe and the United States?
     
    People often compare China’s pesticide‑residue standards with those of developed countries in Europe and North America. In terms of the sheer number of residue limits, Europe and the United States—both with long histories of pesticide regulation—have established more such standards than China. However, it is difficult to assess whether one country’s standards are stricter or more lenient than another’s. From a technical standpoint, differences in agricultural production practices, patterns of pesticide use, and dietary structures across nations inevitably lead to variations in residue limits. From a regulatory perspective, while the primary goal of setting residue standards is to safeguard food safety, these standards are increasingly being employed by various countries as technical barriers to international trade in agricultural products—and, when necessary, as political bargaining chips.
     
    Differences in pesticide‑residue standards among countries are also influenced by the following factors. First, for pesticides that are neither produced nor used domestically, countries typically set the strictest maximum residue limits; by contrast, for pesticides used within the country—especially those applied to export‑oriented agricultural products—the allowable residue levels are kept as lenient as possible, provided they remain within safe limits. For example, the United States, the European Union, and Japan all apply a uniform default limit of 0.01–0.05 mg/kg to pesticides not registered for use in their respective territories—a threshold that many developing countries’ analytical instruments struggle to detect. Meanwhile, even highly toxic pesticides registered for domestic use are subject to comparatively lax MRLs. In the United States, the MRL for the highly toxic pesticide methamidophos is 1 mg/kg on celery and 0.5 mg/kg on cauliflower, whereas Japan sets its MRL at 5 mg/kg for celery and 1 mg/kg for cauliflower. Second, standards tend to be stricter for crops that are either absent or largely imported. For instance, chlorantraniliprole is a relatively new insecticide: the EU sets an MRL of 1 mg/kg on grapes, but only 0.01 mg/kg on rice and other cereals, and 0.02 mg/kg on tea. Logically, since grapes are consumed fresh, their MRL should be higher; however, grapes are a key crop in Europe, so the standard was deliberately relaxed. Similarly, the widely used fungicide chlorothalonil has an MRL of 1 mg/kg on apples and pears intended for direct consumption, yet only 0.01 mg/kg on rice and other cereals, and 0.1 mg/kg on tea. Third, even for the same crop, national standards can vary significantly. For example, the fungicide captan, which is not particularly safe, has an MRL of 5 mg/kg in rice in Japan, compared with 0.02 mg/kg in the EU—a difference of 100-fold. Likewise, the highly toxic pesticide methyl parathion carries an MRL of 1 mg/kg in Japan versus 0.02 mg/kg in the EU, a disparity of 50-fold.
     
    To coordinate and harmonize maximum residue limits, the Codex Alimentarius Commission is responsible for establishing international standards for pesticide residues. However, even with such international standards in place, most developed countries maintain their own national standards, while the vast majority of developing countries, lacking the capacity to set their own residue limits, often have no choice but to adopt the international standards. As the chair country of the Codex Committee on Pesticide Residues, China strives to align its pesticide residue standards as closely as possible with those of the Codex Alimentarius—rather than with the standards of Europe, the United States, or Japan. Some of China’s limits are lower than those of developed countries, while others are higher. For example, for the new pesticide methoxyfenozide, China’s maximum residue limit in cabbage is 2 mg/kg, compared with 7 mg/kg in the United States and Japan; malathion, an older pesticide, has a limit of 2 mg/kg in citrus, apples, and green beans, 1 mg/kg in brown rice, and 0.5 mg/kg in radishes—each stricter than the U.S. standard of 8 mg/kg; for pyrazosulfuron‑ethyl, China sets a limit of 0.05 mg/kg in soybeans, whereas the U.S. standard is 0.3 mg/kg, and the EU and Japan both have 0.1 mg/kg—making China’s limits 8, 2, and 12 times stricter, respectively. In formulating its pesticide residue standards, China prioritizes food safety and rarely addresses trade‑related concerns. It follows that, regardless of differences in residue limits among countries, these standards are established based on risk assessments; as long as products comply with the applicable limits, they are considered safe. One cannot judge safety by comparing against another country’s standards, nor can one dismiss another country’s standards simply because they differ—such approaches lack scientific rigor. This is because pesticide residue limits are determined not only by risk assessments but also by a comprehensive consideration of factors such as industrial development and international trade.
     
    What is the current status of pesticide residues in China’s agricultural products?
     
    At present, the status of pesticide residues in China’s agricultural products can be summarized in three key points: conditions have steadily improved in recent years, the overall situation remains favorable, yet lingering risks persist. Specifically: First, routine national monitoring of agricultural product safety—conducted three to five times annually—has consistently shown year-on-year progress and substantial improvement. This is evident not only in the steady decline of the rate of samples exceeding maximum residue limits, which has dropped from over 50% a decade ago to below 10% today, but also in the marked reduction of detected residue levels. Ten years ago, many vegetable samples exceeded 1 mg/kg of pesticide residues; such cases are now rare, with occasional instances of levels above this threshold. Second, the overall compliance rate in pesticide‑residue monitoring is currently quite high, with rice and fruits achieving compliance rates exceeding 98%, and vegetables and tea surpassing 95%. Third, the current pesticide‑residue landscape remains unstable, with several persistent risk factors: in southern regions and elsewhere, heavy pest and disease pressure during summer combined with intensive pesticide use can lead to exceedances of regulatory limits; similarly, in protected‑environment, off-season cultivation, high pesticide application rates coupled with poor degradation often result in elevated residue levels. Moreover, as domestic and international maximum residue limits tighten or the range of monitored pesticides expands, previously compliant products may now fall outside acceptable limits. In particular, given the small scale of China’s agricultural sector—characterized by numerous smallholder farmers operating independently—and relatively outdated production technologies, effective implementation of farm‑gate certification and market access standards remains challenging, further complicating oversight. At the same time, the number of established pesticide‑residue standards in China remains comparatively limited compared with that of developed countries; therefore, accelerating the formulation and refinement of such standards is an urgent priority.
     
    How can pesticide residues be removed?
     
    Pesticide residues in agricultural products can be removed or reduced through various methods. Common, straightforward approaches include letting the produce sit, washing, cooking, and peeling. First, letting it sit: pesticide residues degrade over time, so for storable items like potatoes, Chinese cabbage, cucumbers, and tomatoes, leaving them at room temperature for a few days allows further ripening while also reducing residual pesticides. Second, washing: pesticides remaining on the surface or exterior of produce can be effectively rinsed away with water or dish soap. Before cooking, soaking vegetables in water for about half an hour and then gently scrubbing with a bit of dish soap can remove most surface‑level residues. Third, cooking: high temperatures generally accelerate the breakdown of pesticide residues. Fourth, peeling: for fruits and vegetables such as apples, pears, and citrus, pesticide residues tend to be higher on the skin than in the flesh; therefore, peeling is an effective way to reduce exposure.
     
    However, it should be noted that, regardless of the method employed, completely eliminating pesticide residues from agricultural products—especially the trace amounts that have already penetrated the internal tissues—is extremely difficult. Moreover, if other substances such as dishwashing detergents, microbial agents, or enzymatic preparations are used during the removal process, their potential residues and associated safety implications for human health must also be carefully considered. Although these agents can help reduce pesticide residues, they themselves may act as chemical or biological contaminants, potentially leading to secondary contamination of the produce (or food). In some cases, the toxicity of certain detergents can even exceed that of many pesticides. It is reasonable to treat agricultural products with deliberate care, but excessive worry and over‑processing are unnecessary. As long as residue levels remain within regulatory limits, no safety concerns will arise—just as we breathe in microorganisms every day without necessarily falling ill.
     
     

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