Chemicals designed to eliminate pests and undesirable weeds are currently receiving significant media coverage.
“Ban entire pesticide class to protect children’s health,” The Guardian headlines!
“Exposure to organophosphates increases the risk of reducing IQs, memory and attention deficits, and autism for prenatal children,” writes Arthur Neslen, quoting a paper that was published in Plos Medicine.
“Popular oat cereals, oatmeal, granola and snack bars come with a hefty dose of the weed-killing poison in Roundup,” another news report said.
For one, those commonly-used herbicides can make bacteria develop antibiotic resistance significantly faster, according to a feature published by Newsweek.
“Herbicides are among the most widely used and dispersed manufactured products on Earth,” Jack Heinemann, professor at the University of Canterbury, told Newsweek. “Some form of exposure for people, pets and livestock can be routinely expected.
On the other hand, “antibiotics are used at high rates particularly on people, pets and livestock. Therefore, the combination of exposures for bacteria that live on us is all but guaranteed.”
As early as 1990, a task force from the World Health Organization (WHO) estimated that approximately one million unintentional pesticide poisonings occur each year, resulting in around 20,000 deaths. It was anticipated that two million additional cases would arise from self-harm. It was acknowledged that low-income nations and transitioning countries were especially impacted by the consequences of pesticide poisoning, and the actual figures were likely much higher since many incidents go unreported.
More than 30 years passed before a revised estimate was released, indicating that globally, approximately 385 million cases of unintentional acute pesticide poisoning are expected to occur annually, which includes about 11,000 fatalities. Moreover, recent estimates suggest that between 110,000 and 168,000 deaths occur due to suicidal pesticide poisoning worldwide, predominantly in rural agricultural regions of low- and middle-income countries.
The Fertilizer and Pesticide Authority (FPA) defines pesticide as “any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any insects, rodents, nematodes, fungi or weeds, or any other form of life declared to be pest.”
Pesticide also refers to “any substance or mixture of substances intended for use as a plant regulator, defoliant, or desiccant.”
For a long time, the safety of pesticides went largely unchallenged. It was not until 1962 that marine biologist Rachel Carson published the seminal work, Silent Spring. In this book, she articulated the long-term dangers posed by pesticides to birds, fish, other wildlife, and humans, while highlighting that they offer only temporary benefits in pest control.
“Pesticides are like bombs being dropped in the food web creating enormous destruction,” deplores entomologist Dr. K.L. Heong, who used to work at the International Rice Research Institute (IRRI) in Los Baños, Laguna.
Unknowingly, pesticides are killing more than just the pests. “Some pesticides harm the living organisms other than the targeted pest,” the Davao-based Technical Assistance Center for the Development of Rural and Urban Poor observes. “Some (pesticides) travel to the food chain to bioaccumulate in higher organisms.”
Gretta Goldenman and Sarojini Rengam explain in their book, Pesticides and You, that pesticides concentrated even to toxic levels via the food chain. Thus, an increase in feeding on plants sprayed with pesticides might be eaten by another insect which might be eaten by a bird.
“Traces of pesticides too small to kill the targeted pest can accumulate to levels high enough to harm species further on up the food chain,” the two authors warned.
Pesticides also pose significant risks to human health. According to health professionals, they can infiltrate the human body via the mouth, lungs, digestive tract, or skin. The health repercussions can manifest immediately (acute) or may develop after prolonged exposure to low levels of these chemicals.
Acute poisoning typically results from accidental skin contact or ingestion of pesticides. Medical practitioners indicate that symptoms of acute poisoning can appear within 24 hours, including vomiting, headaches, respiratory issues, and heart failure.
The long-term consequences of pesticide exposure encompass skin ailments, damage to vital organs (such as the liver, kidneys, and lungs), heightened sensitivity to pesticides, and potential effects on offspring, as noted by medical authorities.
Despite the health and environmental hazards, farmers remain dependent on many of the most detrimental substances. They argue that without pesticides, their expenses would soar, yields would decrease, and more individuals would face hunger. It is commonly believed that pesticides are crucial for substantial harvests.
Filipino farmers, however, do not need to resort to pesticides – whether they are natural or synthetic – to eliminate those troublesome pests. A viable alternative to using pesticides is to utilize Bacillus thuringiensis (Bt) for pest control. Bt is a prevalent soil bacterium named after the Thuringia region of Germany, where it was first identified. It generates a protein that immobilizes the larvae of certain harmful insects.
Unknowingly, Bt is naturally present in the Philippine soil and has been in use for years without any harmful effects.
Through the process of genetic engineering, scientists have extracted the Bt gene responsible for producing the insecticidal protein from the bacterium and integrated it into the genetic makeup of plants. Consequently, these plants possess an inherent defense mechanism against specific pests.
Among the crops where Bt is introduced include corn, cotton, poplar, potato, rice, soybean, tomato, and more recently eggplant. “The protein produced by the plants does not get washed away, nor is it destroyed by sunlight,” said a briefing paper published by the Global Knowledge Center on Crop Biotechnology. “The plants are protected from the insects round the clock regardless of the situation.”
Due to their ability to protect themselves from pests, Bt crops lead to a considerable decrease in the application of chemical insecticides.
“Aside from being effective against insect pests, Bt crops have lower incidences of opportunistic microbial pathogens, such as the fungus Fusarium,” the briefing paper said. “This fungus produces mycotoxins that can be deadly to livestock and also cause cancer in humans.”
The briefing paper shares this information on how Bt operates: “When ingested by larva of the target insect, the Bt protein is activated in the gut’s alkaline condition and punctures the mid-gut leaving the insect unable to eat. The insect dies within a few days.”
However, there are several concerns regarding Bt crops. Detractors argue that Bt proteins may also affect predatory and other beneficial or non-harmful insects in addition to the intended pests. According to the University of California, Bt proteins have been utilized as organic insect control sprays in France since 1938 and in the United States since 1958, with no negative environmental impacts reported.
“The specificity of Bt for its target insects is one of the characteristics that make it an ideal method of biological pest control,” the briefing paper explained. “The specificity rests on the fact that the toxicity of the Bt protein is receptor-mediated. This means that for an insect to be affected by the Bt protein, it must have specific receptor sites in its gut where the proteins can bind. Fortunately, humans and the majority of beneficial insects do not have these receptors.”
According to the Extension Toxicology Network (Extonet), a pesticide information project of several universities in the US, “no complaints were made after 18 humans ate one gram of commercial Bt preparation daily for five days, on alternate days… Humans also ate one gram per day for three consecutive days and were not poisoned or infected.”
On tests conducted on dogs, guinea pigs, rats, fish, frogs, salamanders and birds, the Bt protein was found not to have any harmful effects. What was interesting about the study was that no toxic effects were found on beneficial or predator insects, such as honeybees and lady beetles, Extonet reports.
In the Philippines, Bt is used in eggplants. Like other crops grown conventionally, Bt eggplants are safe for human consumption, according to the late Dr. Emiliana Bernardo, an entomologist or a scientist who studies insects.
Some environmentalists claim that because Bt is a toxin, it is also poisonous to human beings. However, Dr. Bernardo explained that an important thing to consider with regard to the bacterium’s safety is its non-absorption into the body.
For the protein in Bt eggplant to be a toxin, she said, it must first be activated under an alkaline environment, which is the condition in the stomach of insects. Fortunately, the digestive system of humans and most animals is highly acidic. As such, the Bt protein will not be activated in a form that is toxic to insects and will just be quickly denatured.
And even if the protein were to be activated, Dr. Bernardo said that it will still not get absorbed into the human’s digestive system because of the absence of receptors. “If there are no receptors, even the activated Bt protein cannot be absorbed, and therefore it can never accumulate and affect our system,” she pointed out.
By cooking the Bt eggplant, the Bt protein is completely denatured. “It is non-detectable in any cooked food therefore there is no human exposure to Bt proteins in eating cooked Bt crops,” Dr. Bernardo said.
Now, it’s really possible to eat crops free from pesticides!
