Glyphosate is a widely used herbicide that targets and kills broadleaf weeds and grasses. Introduced for agricultural use in 1974 by Monsanto under the trade name Roundup, it has become one of the most frequently applied herbicides globally, both in farming and in home and garden settings. The increasing application of glyphosate has led to growing public and scientific interest in its potential impacts on health and the environment.
Effects on Human Health
Human health concerns often stem from glyphosate’s classification by international agencies. In 2015, the International Agency for Research on Cancer (IARC), part of the World Health Organization, classified glyphosate as “probably carcinogenic to humans” (Group 2A). This classification was based on “limited” evidence of cancer in humans, particularly non-Hodgkin lymphoma (NHL), and “sufficient” evidence of carcinogenicity in experimental animals. The IARC also noted strong evidence that glyphosate can cause genotoxicity and oxidative stress in both experimental animals and human cells in vitro.
The potential for glyphosate to disrupt the gut microbiome is another area of active research. Glyphosate works by inhibiting the shikimate pathway, an enzyme pathway found in plants and some microorganisms, but not in mammals. This pathway produces aromatic amino acids. Studies suggest that glyphosate exposure may inhibit the growth of beneficial gut bacteria, leading to an imbalance in the gut microbiome. This disruption, known as dysbiosis, is associated with various health issues.
Glyphosate may also interfere with the body’s hormone systems, acting as an endocrine disruptor. Research indicates that glyphosate and glyphosate-based herbicides (GBHs) can mimic estrogen and interfere with hormone receptor activity. Animal studies have reported that exposure to glyphosate or GBHs can affect sex hormone levels and reproductive development.
Beyond hormonal effects, studies have explored links between glyphosate exposure and organ damage. Research, including animal studies, suggests that chronic, low-dose exposure to glyphosate in drinking water may affect liver and kidney health. Animal studies have shown changes in gene expression in the liver and kidneys, correlating with signs of organ damage. These findings suggest potential implications for human health.
Concerns extend to reproductive and developmental health. While some reviews suggest no consistent evidence linking glyphosate to adverse reproductive or developmental effects, other animal studies raise questions about its potential impact on fertility. Exposure to GBHs has been linked to alterations in reproductive organ development. Additionally, exposure during gestation could potentially alter offspring development.
Reported cases of allergies and sensitivities associated with glyphosate exposure include skin irritation and respiratory issues. Products containing glyphosate can cause eye or skin irritation upon contact. People who have inhaled spray mist from glyphosate products have reported irritation in the nose and throat. Swallowing glyphosate products can lead to more severe symptoms.
Environmental Impacts
Glyphosate’s widespread application extends its influence beyond agricultural fields. The herbicide’s effects on soil health are a notable concern, as it can affect beneficial soil microorganisms and nutrient cycling. Glyphosate binds tightly to soil, where it can persist for up to six months. This interaction can influence overall soil biodiversity and microbial communities.
Water contamination is another significant environmental impact. Glyphosate can leach into surface and groundwater bodies, potentially affecting aquatic ecosystems and drinking water sources. Its presence in water can be harmful to aquatic life, disrupting their natural habitats and physiological processes. Testing has revealed glyphosate in water, wine, and beer, affecting various consumable products.
The broad-spectrum nature of glyphosate means it kills a wide variety of plants, which can lead to biodiversity loss. Non-target plants are affected, which in turn can impact insects that rely on these plants for food and habitat. The reduction in plant diversity can disrupt the broader ecosystem balance, affecting food webs and the overall health of natural landscapes.
Widespread and repeated use of glyphosate has contributed to the development of herbicide resistance in weeds. This phenomenon occurs when weeds evolve to withstand the effects of glyphosate, making the herbicide less effective over time. As a result, farmers may need to apply higher doses of glyphosate or resort to using other, potentially stronger, herbicides to control these resistant weeds. This escalating use can intensify the impacts on soil, water, and biodiversity.
Regulatory Perspectives and Public Discourse
Regulatory bodies worldwide hold differing views on glyphosate’s safety, leading to ongoing public discourse. National agencies like the U.S. Environmental Protection Agency (EPA) and the European Food Safety Authority (EFSA) have generally concluded that glyphosate is unlikely to pose a carcinogenic risk to humans when used as directed. These differing conclusions often stem from variations in methodologies and the interpretation of available data.
The controversy surrounding glyphosate has fueled numerous legal challenges and public lawsuits. High-profile lawsuits have been filed by individuals alleging that exposure to glyphosate-based herbicides caused their non-Hodgkin lymphoma. These legal actions have resulted in significant settlements, highlighting public concerns about the herbicide’s health effects. The legal findings, while not scientific classifications, underscore the societal response to perceived harms.
Consumer and activist movements have played a role in advocating for stricter regulations or outright bans on glyphosate. These groups often cite scientific studies and classifications as reasons for their demands. Public advocacy campaigns push for changes in agricultural practices and consumer product availability, reflecting a growing desire for alternatives to glyphosate-based products. This societal pressure influences policy discussions and corporate decisions regarding the herbicide’s use.
Strategies to Reduce Exposure
For individuals concerned about glyphosate exposure, several practical strategies can help minimize contact. One effective approach involves dietary choices, such as opting for organic produce. Organic farming standards generally prohibit the use of synthetic herbicides like glyphosate. Thoroughly washing all fruits and vegetables, even organic ones, can also help remove surface residues.
Considering water quality is another important step. Concerns about local water sources can be addressed by using certified water filters designed to remove pesticides, which can help reduce glyphosate levels in drinking water. Selecting a filter that specifically targets herbicides is recommended. Regularly maintaining and replacing filters according to manufacturer guidelines ensures their continued effectiveness.
Individuals who use glyphosate-based products at home should take protective measures. Wearing personal protective equipment can minimize skin contact and inhalation. Avoiding application on windy days helps prevent drift of the spray to unintended areas. Following product label instructions carefully is also important.
Staying informed about agricultural practices and supporting sustainable alternatives can also contribute to broader exposure reduction efforts. Learning about local food systems and advocating for farming methods that prioritize soil health and biodiversity can help reduce overall glyphosate use in the environment. Supporting policies that encourage the adoption of integrated pest management strategies, which rely less on chemical herbicides, offers a long-term approach to minimizing exposure.