Red bean defoliant hits land and farmers, all parties push for assessment and change

Two years ago the Council of Agriculture officially approved paraquat as a defoliant for harvesting red beans, and although agricultural authorities have carried out all kinds of detailed studies on paraquat, they still have not been able to dispel consumers' doubts. In fact, every farmer knows that pesticides are harmful, but the current mechanized harvesting and production-and-marketing system leaves them no choice but to follow the rules of this game. In the delicate balance among production, ecology and daily life, perhaps only the power of consumers can persuade more farmers to change the status quo.

Strong light breaks it down easily, and paraquat residues stay within the standard

Given mechanized harvesting and cost considerations, using herbicides seems to have become an unavoidable choice for farmers, and the Kaohsiung District Agricultural Improvement Station, working on the front lines, sees these difficulties clearly. Yet they also know well the public's long-standing doubts about paraquat, and before the approval notice they had already run countless experiments on diluted paraquat concentrations, finally arriving at the 200-fold conclusion. Take a large 3-liter can of paraquat: if diluted 200-fold as recommended by the Council of Agriculture, one can is enough to spray five fen of land, at a cost of less than 400 yuan.

Because paraquat is economical and affordable, since it appeared on the market in 1962 its usage has ranked among the top three worldwide, and Taiwan approved its registered use back in 1968; the only formulation currently permitted is a 24% paraquat solution. According to a recent survey by the Taiwan Plant Protection Industry Association, Taiwan used a total of 2,105 tons of paraquat in 2009, second only to glyphosate, developed by Monsanto, in the herbicide market.

But this great helper in farmers' eyes is a poison that terrifies many members of the public, because cases of people in Taiwan drinking paraquat to commit suicide keep emerging. According to statistics from Lin Jie-liang, a physician in the toxicology department of Linkou Chang Gung Memorial Hospital, half of those who kill themselves by drinking pesticide in Taiwan choose paraquat, and 20,000 to 30,000 people have already died of paraquat poisoning. Many people therefore question whether paraquat residues are possible.

On this point the agricultural improvement station is also full of grievances, repeatedly stressing that paraquat is a contact herbicide that is easily broken down by ultraviolet light. After the leaves absorb it, the cells inside are oxidized by free radicals, destroying the plant cell membranes, and within a few hours the leaves begin to turn yellow and wither; moreover, it affects only the parts of the plant it touches and does not translocate to the roots.

Precisely because paraquat is easily broken down by strong light, and because red beans are protected by their pods, two days after spraying paraquat the residue level has already fallen to 0.05 ppm, far below the domestic permitted level of 0.2 ppm. Huang De-chang, director of the Kaohsiung District Agricultural Improvement Station, states with certainty that experiments at home and abroad have confirmed that correct use of paraquat causes no harm to the human body, and that compared with other herbicides, paraquat raises even fewer concerns about environmental pollution.

In fact, the agricultural improvement station's considerations have a basis. From the perspective of food safety, if correct usage rules and the safe harvest period are followed, paraquat residues are extremely low. Even before approval, farmers had already used it for decades, with no reported cases of paraquat residues, and the crop even passed strict inspections and was successfully exported to Japan. "But as soon as the media reports on herbicide use, the public starts to panic, and no explanation works; in the end prices fall, and the ones who suffer are still the farmers."

Director Huang De-chang says earnestly that it is truly difficult to get farmers to stop using herbicides, and that paraquat has been tested by the Agricultural Chemicals and Toxic Substances Research Institute, the agricultural improvement stations and the Bureau of Animal and Plant Health Inspection and Quarantine, so consumers really can eat red beans with peace of mind.