Glyphosate Contamination in Soil & Water

Glyphosate is an organophosphorus compound widely used in commercial weed killers such as Roundup. This non-selective herbicide was discovered nearly 50 years ago back in the early 70's and was introduced onto the market by Monsanto (that was acquired by Bayer in 2018) in 1974. Glyphosate use was given a boost in 1996 when genetically engineered 'Roundup Ready' soya, maize and cotton seed varieties were given the green light for planting in the United States. This meant that glyphosate herbicides could be sprayed onto croplands to eradicate weeds even after crops had started growing, effectively widening the timeframe over which these herbicides could be applied. The use of Roundup Ready crop seeds rapidly spread around the world. Consequently, glyphosate is currently the most widely used agricultural chemical on Earth. A recent study, which was published in Environmental Sciences Europe, found that a whopping 9.4 million tons of glyphosate-based herbicides have been applied to agricultural lands globally, with 1.8 million tons being applied to crops grown in the United States alone.

Can glyphosate contaminate soil and drinking water?

Since glyphosate is so abundantly used throughout the world, there are concerns about its potential to contaminate soils and water, and the health consequences thereof.

A 2007 Public Health Goal report for Glyphosate in drinking water prepared by the California Environmental Protection Agency, suggests that as glyphosate tends to have a strong binding affinity to soils, it doesn't readily leach through soils, but rather it adsorbs to the soil and can accumulate in the upper soil layers. However, it can still potentially make its way into surface freshwater systems and groundwater supplies via two main pathways: 1) It can be blown into surface waters lying adjacent to agricultural land that has been sprayed with glyphosate-based herbicide; and 2) It can get into water bodies further afield via runoff when fields sprayed with Roundup are irrigated, or after heavy rainfall events. Since glyphosate does not readily break down in water, it tends to persist in freshwater systems where it can pose both an ecological and human health risk.

Humans can be exposed to glyphosate through direct inhalation or skin contact with Roundup, or by drinking Roundup contaminated water or consuming food that has been sprayed with Roundup. Glyphosate residues have been detected in a variety of food crops, including wheat, barley, soya beans as well as other foods.

Does glyphosate contaminated drinking water pose a health risk?

While Monsanto (the company that manufactures Roundup, as well as the genetically modified seed varieties that can withstand the effects of the herbicide) maintains that glyphosate is not carcinogenic, the International Agency for Research on Cancer (ISCR) and the World Health Organisation (WHO) both hold a different view, categorising glyphosate as a potential carcinogenic Group 2A chemical that probably causes cancer in humans. Scientific studies conducted on animals show a link between glyphosate exposure and cancer, and limited human studies indicate there is a link between glyphosate exposure and the development of non-Hodgkin lymphoma, as well as kidney problems, disruption of the endocrine system, reproductive problems and problems with fatal development.

Recent lawsuits related to glyphosate

In August 2018 a US jury ordered Monsanto to pay critically ill Dewayne Lee Johnson $289 million US dollars in damages after he was diagnosed with non-Hodgkin's lymphoma in 2014 as a result of longterm occupational exposure to Roundup while performing his duties as a groundsman at a local school. This groundbreaking lawsuit opened the door for more than 5,000 other plaintiffs across the US who have filed similar lawsuits against Monsanto.

While many of these cases involve people who suffered ill effects after being directly exposed to glyphosate as a result of using Roundup in their garden, school grounds or farm, there have been cases in the US where glyphosate levels at drinking water utilities have exceeded the safety standard of 0.7 mg/L recommended by the EPA for drinking water and the safer level of 0.5 mg/L proposed by the Environmental Working Group (EWG). Consumers exposed to glyphosate in their drinking water are potentially at greater risk of developing non-Hodgkin's lymphoma, kidney failure, and other health issues than those who do not drink water contaminated with glyphosate. In Australia, regulators have compiled Australian Drinking Water Guidelines that set environmental and human health safety limits of 1 mg/L for glyphosate in drinking water. These levels exceed the safety limits recommended by both the EWG and the EPA. According to Madge, Australia Inc, a 2015 study conducted by scientists from Flinders University in Australia found that glyphosate is harmful to human cells at levels permitted in Australia's drinking water.

Are glyphosate safety standards outdated?

A 2017 study, which was published in the Journal of Epidemiology & Community Health, suggests the current safety standards for glyphosate are in urgent need of review and may not protect the environment or public health, as they do not take recent scientific findings into account. According to this study, current safety standards are based on research conducted over three decades ago which did not undergo a peer review process. In the last 30 years there have been many further studies on the environmental and public health effects of glyphosate, with more than 1500 studies conducted in the last decade alone. The authors also point out that herbicides that combine glyphosate with other 'inert ingredients' may be even more harmful. But since the ingredients in many of these concoctions are considered commercial secrets by their manufacturers, they are not listed for public scrutiny. The authors raise concerns that despite the rapid expansion in glyphosate use around the world, there is currently no way to monitor glyphosate levels in humans and very little is known about its potential health impact on humans.

Considering this gap in knowledge and the potential long term public health risks, it is better to err on the side of caution and ensure that glyphosate is removed from water before it can potentially pose a health risk to humans via their drinking water. The innovative Catalytic Oxidation (CO) based Hydroxon™ technology is a new water treatment solution that is able to degrade glyphosate in water.

Click here for our case study about the treatment of industrial wastewater to remove glyphosate.