Why use of weedkiller glyphosate should be restricted

These chemicals also impact the ecosystem through its adverse effects on non-target organisms

Glyphosate is a weedicide and on application, plants dry up in four to 20 days | Representative Photo: iStock

The Ministry of Agriculture, Government of India, in a draft notification issued on July 8, 2020, had declared its intention to restrict the use of glyphosate, a popular herbicide (weedicide), through allowing the application only through Pest Control Operators (PCOs).

Further, all holders of certificate of registration granted for glyphosate and it’s derivatives are to return their certificates to the Central Insecticide Board and Registration Committee (CIBRC) for incorporation of a  warning in bold letters – that ‘The use of glyphosate formulation are to be allowed only through Pest Control Operators (PCOs)’ on the label and leaflets. One month time is given for raising objections or suggestions.

The ministry has also issued another notification intending to ban 27 chemical pesticides which are used in India due to serious data gaps regarding their suspected harm to humans and animals. While pesticide manufacturers oppose the move, there are supporting signals from other sections of the society.


Pesticides encompass the insecticides (against insects that attack the plant), fungicides and bactericides (against diseases), weedicides (against weeds) and rodenticides. Though pesticide use in general is showing a declining trend, the use of weedicides shows a persistent growth. This is basically due to higher wage rates for manual weed control in states like Kerala and spread of herbicide tolerant cotton varieties in major cotton growing areas in the country. Currently, weedicides constitute only 10 per cent of the total pesticide consumption in India.

Ecological and health impacts of pesticides

A large number of toxicological tests are conducted before a pesticide is registered so as to ensure that no toxicity arises from its use. The major parameters used to indicate the toxicity or biosafety are dermal acute toxicity, oral acute toxicity, acceptable inhalation, acceptable daily intake, carcinogenicity level, teratogenicity, genotoxicity and NOAEL (No observed adverse effect level). The effect on non-target organisms are also studied. These data on biosafety is to be submitted to the Central Insecticides Board and Registration Committee (CIBRC) to take the decision regarding the registration and the same is allowed only if the committee is satisfied with the efficiency and safety of the chemical. Despite these science-based decisions on granting registration, a large number of human health and environmental issues have been caused due to pesticide use, later on.

A report by the World Health Organisation (WHO) states that pesticides cause about 30 lakh cases of poisoning and 2.2 lakh deaths annually across the globe. Comparing this with earlier reports, it is seen that the majority of the health damages are reported from the developing countries and the magnitude shows a rising trend. The human health damages in one of the villages in Kasaragod District of Kerala was attributed to the aerial spray of the chemical endosulfan in cashew plantations in the region. The reports of the contamination of groundwater with pesticides used in agriculture in the Plachimada region was reported as the reason for presence of residue in the soft drink made using the water. The pesticide residue monitoring project in fruits and vegetables in the markets of Kerala reveals the presence of many chemicals which are not recommended for that crop/pests. There are also instances where the residue levels are as much above the MRL fixed for such chemicals, even if it is recommended. The human health damages due to pesticide exposure can be direct or indirect, short-term or long-term effects, and morbidity or mortality, and it can be due to occupational, accidental or intentional exposure.

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Pesticide consumption is reported as the major method of suicides due to its easy access. In the case of suicides reported at one of the Government Medical College in Kerala, it was seen that the major cause of suicidal deaths was due to organo phosphate group of pesticides.

Apart from the human health impacts, these chemicals also impact the ecosystem through its adverse effects on non-target organisms which include, micro and macro flora and fauna.

Studies initiated at the International Rice Research Institute have shown that costs related to pesticide use in crop production are higher than the gains from the reduction in crop yield losses. It is argued that indiscriminate pesticide use in rice crop leads to larger pest related yield losses than not applying pesticides at all. It is also reported that pesticide use had negative effect on farmer health, which in turn passes on to productivity (remembering the simple fact that farmer health and his productivity are positively correlated). Simultaneously large amount of literature is added to the present volume on the value of negative impacts of pesticide use which poses questions on the economic, environmental and social rationality of its use.

The glyphosate case

Glyphosate is a weedicide and on application, plants dry up in four to 20 days. Other ingredients, known as inerts or additives, are also added to the formulation. A surfactant (wetting agent), known as Poly Oxy Ethylene Amine (POEA), which helps the active ingredient penetrate the plant cuticle, is usually added to glyphosate formulations. It was introduced in 1974 and has been used across the world ever since, and the use gained momentum, consequent to the introduction of herbicide tolerant cotton varieties (genetically modified) as well as the labour shortages in agriculture. During the 2018-19 period, 670 tonnes of this chemical was used in India. The label claim of the chemical (for the popular formulation) specifies its use in tea and non-cropped areas only. It is a chemical which is used widely.

Scientific debates on the health and environmental impacts of glyphosate exposure has been growing ever since its use became widespread. Most of these scientific reports were conflicting in nature. Later in 2015, the Environmental Protection Agency (EPA) of the USA released a relieving report which highlighted the low-risk of carcinogenicity, endocrine disruption and teratogenic effects of the chemical.

But after five years, the International Agency for Research on Cancer (IRAC), France, a subsidiary of the WHO, classified glyphosate as “probably carcinogenic to humans”.  Still, the debates continued with the report of the European Food Safety Agency that it was “unlikely that glyphosate pose cancer risk for man.” European Chemicals Agency (ECHA)’s Risk Assessment Committee also endorsed this opinion.

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But a recent landmark verdict by the California Court, after examining all the evidences placed before it, declared conclusively that glyphosate is a substantial factor in causing non-Hodgkin’s lymphoma, a form of cancer. The trial was a bellwether trial (a trial that would inform future litigations). The verdict was based on elaborate review of scientific evidences (epidemiological and animal studies and mechanistic data) and testimonials by 13 experts. The court concluded that exposure to glyphosate at levels normal people would experience, could cause a form of cancer. It also ordered the manufacturer to pay a compensation of $90 million. Since then, there have been a series of litigations in this regard. In June 2020, the company agreed to settle nearly 95,000 cases in the US for $10 billion, reflecting the economic cost of associated health cost.

The chemical, which has been in use for the past 45 years, which was believed to be safe, has now been proved a carcinogen. The registering authorities must have been satisfied by the safety data and claims produced by the manufacturers at the time of registration of the chemical. Later on, the practical experiences proved otherwise. The damage it must have caused during the 45 years to the ecosystem and human health is irreparable and irreversible.

Evidences available suggest that glyphosate also affects non-target organisms in several ways. It has been reported as causing reduced reproduction of soil-dwelling earthworms and pollinators (honeybees) – both of which directly contribute to agricultural production. Adverse impact on aquatic life forms and soil microbes has also been reported. Glyphosate is also associated with changes in plant endophytic and rhizosphere microbiomes, and with disturbances of gut microbiota of animals living near agricultural sites. Glyphosate and commercially-formulated products containing POEA surfactant are toxic to fish and some aquatic invertebrates, and hence not recommended in aquatic systems.

Towards a safer environment

The negative impacts of pesticide exposure is reported to be more in developing countries in comparison to the developed countries. This is mainly due to the unscientific usage, diverse agricultural systems, geographical peculiarities and socioeconomic conditions. In Kerala, this is more evident as the aquatic systems are continuous and interconnected, and the agricultural and human settlements are mixed. It is a prudent decision from the part of the Government of Kerala (or for that matter any state that aim at the welfare of the citizens) to recommend restrictions in the use of harmful chemicals, given the social economic and ecological conditions of the state. It may also be remembered that the environmental policy of our country is based on the precautionary principle. When the impacts of the use of the chemical are proved to be adverse, uncertain and irreversible, it is desired that precautions are taken. The proposal for restriction is to be viewed in this background.

However, there are apprehensions, whether the move to enforce the use through PCOs alone and statement in the label alone are sufficient to achieve the objective. The proposal warrants the presence of pest control operators in agriculture, which is presently non-existent. The Local self-Government Institutions, with technical support from the Department of Agriculture can form trained licensed agents/self-help groups equipped with scientific equipment, technology and knowhow on the use of chemical pesticides in their respective localities. Strict monitoring and surveillance in trade to ensure safe dispensing and handling, is also to be ensured. It is important that the food and environment for healthy living is ensured for the citizens.

(Prof (Dr) P Indira Devi is a retired Professor and Director of Research at the Kerala Agricultural University)

(The Federal seeks to present views and opinions from all sides of the spectrum. The information, ideas or opinions in the articles are of the author and do not necessarily reflect the views of The Federal)

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