The need to weed out glyphosate

Glyphosate, the world's most widely used weed killer, has become increasingly prevalent in Bangladesh, particularly in agricultural practices.

From rice fields and vegetable farms to tea plantations, it has become so ubiquitous that it's now hard to find a crop that doesn't rely on its application. 

While it promises higher yields and effective weed control, this widespread dependence on glyphosate brings significant risks to the environment, human health and biodiversity.

A recent study by researchers at Arizona State University published in December 2024 revealed that even brief exposure to glyphosate can lead to significant brain inflammation and increase the risk of neurodegenerative diseases, including Alzheimer 's-like effects.

This finding adds to an already extensive list of glyphosate's harmful effects.

"It causes biodiversity loss by reducing habitats for wildlife, including pollinators like bees, which are vital for agriculture as they enable the reproduction of flowering plants by transferring pollen, essential for the production of fruits, seeds and many crops," said Dr Md Abdul Alim, Professor of Food Technology and Rural Industries at Bangladesh Agriculture University.  

Glyphosate also negatively affects microorganisms in the soil, which play a key role in soil health by breaking down organic matter, improving soil structure and enhancing nutrient cycling. The disruption of these microorganisms weakens the soil, making it less fertile and more prone to erosion.

Dr Mashura Shammi, Professor of Environmental Sciences at Jahangirnagar University, explained that when glyphosate breaks down, it releases phosphorus into the environment, which can lead to eutrophication in aquatic ecosystems. While different scientific studies consider the effects of glyphosate to be sublethal, toxicity is most significant in aquatic and marine animals. 

"Children, expectant mothers and agricultural workers are among the vulnerable groups that may be at risk from glyphosate. Acute exposure to glyphosate may result in gastrointestinal problems, respiratory distress and irritation of the skin and eyes. It can disrupt gut microbiota.  Long-term exposure has been connected to liver or kidney damage, endocrine disruption and possible cancer risks," she added. 

The American Journal of Tropical Medicine and Hygiene linked the sudden deaths of 13 children in Dinajpur in 2012 to chemicals sprayed on lychee trees. There have also been numerous reports of people committing suicide by ingesting glyphosate-contained herbicides. It is so toxic that once consumed, it is nearly impossible to save the person, even with immediate medical intervention.

In early 2020, the High Court Division directed the government to submit a plan of action within 90 days to replace the use of the hazardous herbicide brand Roundup.

Despite these risks and court regulations aimed at phasing it out of the market, herbicides containing glyphosate remain readily available in local markets, and their use among farmers continues to increase.

"I visit villages frequently, and I see that nearly all the farmers have become highly dependent on glyphosate," Dr Alim said. He added that herbicide company representatives are often seen in rural areas, encouraging farmers to buy glyphosate, and sometimes offering deals that allow farmers to pay once the harvest comes in.

Farmers, on most occasions, give in to these temptations. The reasons are clear: it is cost-effective and there is a lack of manpower in rural areas.

"To control weeds on one bigha of land (about 33 decimals or 0.33 acres), 15 to 20 workers are needed. By applying poison worth Tk180 in the morning, weeds die by the afternoon, so farmers see it as an opportunity to control weeds at a much lower cost," explained Gawher Nayeem Wahra, a faculty member of the Institute of Disaster Management and Vulnerability Studies at Dhaka University. 

Delowar Jahan, the pioneer of Prakritik Krishi, also pointed out that today's farmers and landowners view agriculture purely as an industry, neglecting their responsibility towards people, the environment, and other living beings. 

"Just like machines are used to increase productivity with less labour and cost, herbicides have become a powerful tool for killing weeds and boosting crop yields. However, many farmers fail to consider that these weeds provide resources for livestock and microorganisms and that the chemicals used can contaminate water, harming fish and other aquatic life," he said. 

According to him, if farmers were also involved in animal husbandry or fish farming, they might be more mindful of these interconnected impacts. 

He also emphasised that most farmers in the country are not highly educated, making it difficult for them to fully understand the harmful effects of herbicides. Therefore, the government should take measures to ensure that harmful herbicides are not easily accessible in the market.

But if the use of glyphosate must be stopped, what alternatives are available?

Dr Alim explained that glyphosate is a non-selective herbicide, meaning it kills all types of weeds, including those that are beneficial to the soil and environment. To minimise its environmental impact, the practice of eradicating all weeds at once with non-selective herbicides should be discontinued. 

Instead, selective herbicides, which target specific weeds while preserving crops and beneficial plants, can be used. Examples include glufosinate, diquat, prodiamine, dicamba, imazapyr and MCPA (2-methyl-4-chlorophenoxyacetic acid).

Dr Shammi recommended using personal protective equipment (PPE), which is often not used by Bangladeshi farmers. She also emphasized the importance of monitoring glyphosate residues in food, beverages (such as juices and soft drinks), tea and water. This is especially crucial in Bangladesh, where proper monitoring systems for such contaminants are currently lacking.

In the meantime, other alternatives to glyphosate include natural methods like suppressive sprays, which prevent weeds from receiving sunlight by forming a physical barrier, and organic solutions like a mixture of salt and vinegar, said Dr Alim. 

Mulching, which involves cutting weeds and covering them with organic material like straw or leaves, is another effective method that improves soil fertility and promotes long-term crop production. 

"Crop rotation is also an important strategy, as alternating crops on the same land can disrupt the growth of weeds specific to certain plants and promote better soil health. For example, planting rice one season and jute the next can prevent the buildup of weed populations and pests," he said. 

Citing Sri Lanka's example, Dr Alim reminded that the country's decision to ban all chemical fertilisers and herbicides resulted in a significant decline in crop yields, including a 35% drop in rice, 50% in tea, 50% in corn, and 30% in coconut production. 

"During the Covid-19 pandemic, Sri Lanka faced severe economic challenges, and the decline in agricultural output, combined with higher food import costs, worsened the crisis," Dr Alim said.  

Therefore, it may not be wise to completely stop using chemicals all at once, but it is important to gradually move away from this practice as we become more aware of the harmful effects of chemicals like glyphosate.