Herbicide Glufosinate on Adzuki Beans: Food Safety and Environmental Risks That the Council of Agriculture Must Address
Text / by Upstream and Downstream reporter Li Hui-yi. Interviews / by Upstream and Downstream reporters Li Hui-yi and Lin Yi-chun
(Continued from previous article) Adzuki beans are an important winter crop in the Gaoping area. In recent years the cultivated area has been about 6,000 hectares, with average production of 12,000 metric tons and output value reaching 1 billion yuan, making it an important source of income for farmers in southern Taiwan. The Council of Agriculture has announced that it will permit the herbicide glufosinate for use as a defoliant on adzuki beans, meaning that every year from January to before the Lunar New Year in the Gaoping area, large areas of adzuki bean fields will be sprayed comprehensively with glufosinate.
Because glufosinate is water-soluble, and because the fields are plowed immediately after the adzuki bean harvest to prepare for planting rice, will this cropping pattern bring a huge impact on aquatic environments? Is it possible that it could affect consumers' food safety and health?
Scholars are urging the Council of Agriculture to provide more detailed explanations regarding the risks of glufosinate use. Chang Ming-chun, chair of the Taichung chapter of the Homemakers United Foundation Environmental Protection Fund, said, "For consumers, it is hard to imagine why the Council of Agriculture reversed its policy? Contradicting itself?" She hopes the Council of Agriculture can make the issue public and fulfill consumers' right to know.
Former Director-General of the Bureau of Animal and Plant Health Inspection and Quarantine: Glufosinate Is Only One of the Alternatives
The government announced on May 20 of this year (2020) that it would permit glufosinate for use as a defoliant on adzuki beans, but this policy had already begun experimental trials and established its direction during the tenure of former BAPHIQ Director-General Feng Hai-tung. Feng Hai-tung, who retired in January of this year, said that after paraquat was phased out, there are still many other herbicide alternatives on the market, so the impact on agricultural production is not great, but for adzuki bean farmers who originally used paraquat as a defoliant, the government's difficulty in promoting alternatives will be relatively high.
He further explained that alternatives are not limited to sodium chlorate and nonanoic acid; there is also the variety purification that the Kaohsiung District Agricultural Research and Extension Station has been promoting. If the variety aspect is done well, the harvest period can be unified and farmers' dependence on herbicides can be reduced. As for glufosinate, it is only one of many supporting measures. "It is already a brand on the market, readily available for purchase at any time. How to guide farmers to use it safely and effectively is certainly better than farmers using chemicals indiscriminately!"
The usage method currently proposed for announcement by BAPHIQ is a application rate of 3 liters per hectare, diluted 200-fold. The adzuki bean plants must reach the fully mature stage with more than 80% of the whole plant turned light brown and withered, and a single uniform spray application over the whole plant should be made 7 days before harvest; plowing and rice transplanting operations should then be carried out 14 days after application. In response, Feng Hai-tung further stated that the residue value at 200-fold dilution is within 2 ppm, which is safe for consumers and feasible for producers. "This is a common conclusion that both sides can accept."
Water-Soluble Characteristics of Glufosinate: BAPHIQ Offers Explanation, but Farmers' and Scholars' Doubts Increase Rather Than Decrease
BAPHIQ pointed out that in terms of environmental characteristics, glufosinate is highly water-soluble, does not easily evaporate into the air, and is easily adsorbed by soil organic carbon and not easily leached, so the risk of entering groundwater and the threat of bioaccumulation are both very low.
In addition, glufosinate is also classified as non-persistent in soil. According to sampling and testing conducted by BAPHIQ in 2016 at 8 rivers and bottom sediment in southern Taiwan, glufosinate did not exceed the quantification limit. As long as farmers follow the approved usage method, use normal amounts, and pay attention to waiting 14 days before planting crops, it will not harm the environment or affect the growth of subsequent crops.
However, Tseng Te-tz'u, a retired professor from the Department of Plant Pathology at National Chung Hsing University, believes that when BAPHIQ conducted sampling and testing in 2016, it had not yet expanded the permission for glufosinate as a defoliant on adzuki beans, so no correlation with environmental impact can be seen. Tseng Te-tz'u said, "As far as I understand, this was probably a regular project that BAPHIQ gives to academia. How was the sampling conducted? Is it representative? These all need concrete discussion."
Second, Tseng Te-tz'u believes that since BAPHIQ also acknowledges that glufosinate is highly water-soluble, has it considered the relationship between adzuki beans and sandy soil? If planted in well-drained sandy soil, glufosinate could possibly enter groundwater. As an important scholar in Taiwan pesticide research, Tseng Te-tz'u repeatedly emphasized, "The toxicity of glufosinate to aquatic organisms is very high."
Kuo Hua-jen: Long-Term Human Intake of Glufosinate May Reduce Female Fertility
Kuo Hua-jen, professor emeritus of the Department of Agronomy at National Taiwan University, also agrees with Tseng Te-tz'u's view. He further stated that in 2008 the Pesticide Action Network Asia and the Pacific had issued a report on research from various quarters regarding the risks of glufosinate. If humans ingest glufosinate over the long term, it can cause serious health threats; female fertility may be reduced; pregnant women who ingest it may harm the fetus; and it poses survival risks to aquatic species, natural enemy organisms in fields, and insects.
Li Chin-chuan, 77 years old, is the founding class leader of the first adzuki bean production and marketing group in Wandan, Pingtung. He told reporters, "I myself use natural defoliation to harvest adzuki beans. However, I want to emphasize that paraquat is a contact herbicide and will not affect subsequent crops, while glufosinate is systemic. As long as the field area is even slightly wet, it will absolutely affect the growth of subsequent grains; crops may suffer root rot, and once rice absorbs it, the heading stage will be delayed."
Tseng Te-tz'u: Glufosinate Is a Pesticide Registered Many Years Ago; Has Our Understanding of It Kept Pace with the Times?
Tseng Te-tz'u cited relevant Japanese reports pointing out that glufosinate can affect brain development in mouse embryos. Taiwanese pregnant women have the habit of drinking adzuki bean water to reduce edema. If farmers use glufosinate to harvest adzuki beans, would that affect pregnant women and the fetus in their womb?
Tseng Te-tz'u reminded, "These pesticides like glufosinate were registered twenty or thirty years ago. Has our understanding and management of these pesticides kept pace with the times? Between 1996 and 2000, glufosinate was found to cause neurotoxicity or cardiovascular lesions. The European Union, for example, considers glufosinate a high-risk pesticide, especially for mammals."
He emphasized that if glufosinate is used for weed control, he would absolutely not object, but he worries that using it on crops carries risks. "How should the government control and manage these problems?"
BAPHIQ: Normal Field Use Has Little Impact on Soil Microorganisms
Facing doubts from all sides, former BAPHIQ Director-General Feng Hai-tung stated that the mechanism of action of the herbicide is to inhibit the conversion of ammonium within plant tissues. Terrestrial plants cannot eliminate ammonium and therefore die of poisoning, while aquatic plants, because they are immersed in water, can release ammonium and have higher tolerance, so the problem is not great either. As long as farmers use it according to regulations, the glufosinate content in water will not increase too much, unless someone pours glufosinate into water or uses it at the water's edge and sprays it directly into the aquatic environment.
In response, BAPHIQ issued a written explanation: "The bioaccumulation risk of glufosinate is low. It has moderate toxicity to mammals, shows moderate to low toxicity to birds and most aquatic organisms and honeybees, and has low toxicity to earthworms in soil. When applied at normal field rates, it has no significant effect on soil respiration and nitrogen conversion, and has little impact on soil microorganisms."
Regarding BAPHIQ's statement, Kuo Hua-jen said, "Since BAPHIQ repeatedly emphasizes that it has undergone testing and assessment, then it should disclose the test data and assessment methods for everyone to know."
Routine Pesticide Testing Does Not Include Glufosinate; Who Will Guarantee Consumer Safety?
Another point worth noting is that among the 380 items in the pesticide residue testing methods most commonly used by general agricultural or health units, glufosinate is not included. If one wants to confirm whether adzuki beans have glufosinate residue or exceed the limit, a separate dedicated testing method must be used; otherwise, routine random testing simply cannot detect whether glufosinate residue is present.
In the future, once the Council of Agriculture announces glufosinate as a recommended defoliant for adzuki beans, this will also be a key problem that BAPHIQ cannot avoid facing.
Glufosinate's Impact on the Adzuki Bean Industry's Transformation Brings Unease to Consumers; Information Disclosure and Gatekeeping Are a Major Test for the Council of Agriculture
In early 2013, the Wandan adzuki bean industry experienced its first major crisis in nearly a decade. At that time, the adzuki bean market price fell to 29 yuan per Taiwanese catty (1 catty = 600 g), and the Wandan Farmers' Association had to purchase adzuki beans for three consecutive days to prop up the market price. Having weathered the crisis, Wandan Farmers' Association General Manager Chang Chih-lieh said that in addition to stabilizing the adzuki bean trading market, it is even more necessary to build a reputation for quality. The recent glufosinate incident makes him worry that it will affect consumers' willingness to purchase.
Chang Chih-lieh emphasized, "No matter what the final outcome is, I strongly hope the government will simultaneously do a good job on origin labeling and product traceability systems, and establish open and transparent market information, so that farmers who do not use herbicides and farmers who do use herbicides can be distinguished from each other. Only then will domestically produced adzuki beans have room to survive."
Chang Ming-chun, chair of the Taichung chapter of the Homemakers United Foundation Environmental Protection Fund, said that just when consumers were happy that adzuki bean farmers were producing high-quality adzuki beans through safe cultivation methods, the Council of Agriculture instead wants to permit the herbicide glufosinate as a defoliant for adzuki beans. "For consumers, it is hard to imagine why, during this period when paraquat was banned, the Council of Agriculture reversed its policy and contradicted itself?" Chang Ming-chun hopes the Council of Agriculture can make the issue public and fulfill consumers' right to know.
Adzuki Beans Are Farmers' Livelihood, While Consumers' Lives Are in Producers' Hands
On the first floor of the Wandan Farmers' Association main office, there is a small adzuki bean product display area called "Happiness Shop." In addition to small packages of dried beans in various specifications, there are also many processed products such as sweetened adzuki beans, adzuki bean water, and tea bags. A Mr. Huang, who was on official business from Kaohsiung City to Wandan, made a special detour to the Farmers' Association's "Happiness Shop" to make purchases, buying as many as 12 packs of adzuki beans in one go, with change left from two 1,000-yuan bills.
Mr. Huang said, "In the past, a friend gave me some to eat. They were really very soft, fluffy, sweet, and fragrant, very different from the adzuki bean soup outside. So I came specially this time, wanting to buy more, for myself and to give as gifts." Mr. Huang said that adzuki beans are not rice; you do not need to eat them at every meal. Eaten as a snack, you can cook them once in a long while, so calculated this way they are not expensive. Most importantly, health must be safeguarded. "I trust the Farmers' Association and the farmers who cooperate with the Farmers' Association more."
Mr. Hsieh, an adzuki bean farmer from Pingtung City, specifically mentioned, "In my grandfather's era, the traditional method of hand pulling was used; in my father's era, paraquat was used; and at the beginning of this year, I started using glufosinate. To speak honestly, if I had enough physical strength and enough manpower, I should not use herbicides at all!"
