Science in Society Archive

Widespread Glyphosate Contamination in USA

Most comprehensive study reveals glyphosate and AMPA in the environment over 9 years and across 38 states Dr Eva Sirinathsinghji

The most comprehensive research to date on environmental glyphosate levels exposes the widespread contamination of soil and water in the US, as well as its water treatment system. Looking at a wide range of geographical locations, researchers from the US Geological Survey (USGS) analysed 3 732 water and sediment samples and 1 081 quality assurance samples collected between 2001 and 2010 from 38 states in the US and the district of Colombia. They found glyphosate in 39.4 % of samples (1 470 out of 3 732) and its metabolite AMPA (aminomethylphosphonic acid) in 55 % of samples [1]. Water samples included streams, groundwater, ditches and drains, large rivers, soil water, lakes, ponds and wetlands, precipitation, soil and sediment, and waste water treatment plants.

Results expected

These results are to be expected when the use of glyphosate has steadily increased in the US (and similarly in Canada) over the years, particularly since the introduction of genetically-modified crops tolerant to the herbicide. The rise of glyphosate-resistant weeds also means that farmers need to spray more chemicals than before in order to protect their crops (see [2] Monsanto Defeated by Roundup Resistant Weeds, SiS 53). Glyphosate accounted for 32-36% of all pesticide (insecticides, herbicides and fungicides) use in the US in 2007 according to EPA data [3]. It is the top pesticide in agriculture and the second for home and garden and commercial settings. Agricultural use has gone up from 3 180 tonnes (of active ingredient) in 1987 to 82 800 tonnes in 2007. Non-agricultural use of the herbicide has also risen steadily in the US, from 2 270 tonnes in 1993 to 9 300 tonnes in 2007 (Figure 1). The common use of glyphosate in urban areas is also exacerbated by the impervious surfaces of cities, resulting in substantial pesticide inputs to urban drainage systems. Until recently data had been lacking on glyphosate occurrence in the environment, though studies published over the last couple of years are raising concerns. Detecting glyphosate in surface waters, rain and even groundwater, contradicts the producers’ claim that its chemical propensity to bind to sediment will prevent it from leaching into groundwater supplies (see [4] GM Crops and Water - A Recipe for Disaster, SiS 58).

Figure 1              Use of Glyphosate and Planted Hectares of Corn and Soybeans From 1987-2008

Data collection had previously been limited not only by glyphosate’s high solubility and polarity which make its detection more difficult, especially at environmentally relevant levels, but also due to the official line taken by authorities that glyphosate is safe. This makes assessment of its presence in our environment less of a priority, and hence left unstudied and unregulated. The safety claim has also encouraged farmers to overuse glyphosate, mostly sprayed on crops “post-emergence” or after crops and weeds have emerged from the soil and often applied repeatedly throughout the season, especially with the rise of glyphosate-resistant weeds. In addition, they are liberally used on non-GM crops as a dessicant (drying agent) to facilitate harvesting (see [5] How Roundup® Poisoned my Nature Reserve, SiS 64).

To address the lack of knowledge in this area, researchers at the USGS began developing their own methods in the 2000s, using solid-phase extraction and liquid chromatography/mass spectroscopy, which is able to detect both glyphosate and its metabolite AMPA at levels as low as 0.02 μg/l (0.02 part per billion, ppb) for both compounds.

The results are shown in Table 1. Glyphosate and AMPA were most frequently detected in soil, followed by drains and ditches, rain and large rivers. For soil and sediment, and soil water a total of 45 soil and sediment samples were collected from seven sites in Mississippi and Indiana, with both glyphosate and AMPA being detected at least once in samples from all seven sites. Both were detected in 90 % of sediment samples with concentrations frequently above 10 μg/kg, with an average of 9.6 μg/kg. In 116 soil samples glyphosate and AMPA were detected in 34.5 % and 66.5 % respectively. Large rivers showed average levels of 0.03 μg/kg in 53.1 % of samples tested. Least frequent but detectable levels were found in groundwater samples, with 5.8 % and 14 % of samples testing positive for glyphosate and AMPA respectively.

Glyphosate is claimed by biotech proponents not to leach into groundwater supplies, but this work and a previous study performed in Catalonia, Spain have both detected its presence in groundwater supplies [4], a major source of drinking water.

The present study also found an increase in concentrations over time, showing higher levels from 2006-2010 compared to earlier years (2001-2005), consistent with rises in both agricultural, home and commercial use of the herbicide. Temporal patterns however, were not recorded and these likely change with agricultural seasons.  

The study highlights the ubiquitous contamination of the environment with glyphosate herbicides at ever increasing levels. This herbicide is highly toxic to humans, farm animals, and wildlife, and at levels as low as 0.1 ppb; there is indeed a strong case for halting its use altogether (see [6] Ban GMOs Now, Special I-SIS report).

Table 1    Concentrations of both glyphosate and its metabolite AMPA in US environment

Hydrologic Setting

Number of Samples

Percentage and (number) with Glyphosate Detections

Median Glyphosate in μg/l or μg/kg

Maximum Glyphosate in μg/l or μg/kg

Percentage and (number) with AMPA Detections

Median AMPA in μg/l or μg/kg

Maximum AMPA in μg/l or μg/kg

All sites

3 732

39.4 (1,470)



55.0 (2,052)




1 508

52.5 (791)



71.6 (1,079)




1 171

5.8 (68)



14.3 (168)



Ditches and drains


70.9 (265)



80.7 (302)



Large rivers


53.1 (169)



89.3 (284)



Soil water


34.5 (40)



65.5 (76)



Lakes, ponds, and wetlands


33.7 (35)



29.8 (31)





70.6 (60)



71.8 (61)



Soil and sediment


91.1 (41)



93.3 (42)



WWTP outfall


9.09 (1)



81.8 (9)



Article first published 8/10/14


  1. Battaglin WA, Meyer MT, Kuivila KM, and Dietze JE. Glyphosate and Its Degradation Product AMPA Occur Frequently and Widely in U.S. Soils, Surface Water, Groundwater, and Precipitation. Journal of the American Water Resources Association (JAWRA) 2014, 50, 275-290. DOI: 10.1111/jawr.12159
  2. Sirinathsinghji E. Monsanto Defeated By Roundup Resistant Weeds. Science in Society 53, 40-41, 2011.
  3. 2006-2007 Pesticide Market Estimates, 3.4 Amount of Pesticides Used in the United States: Conventional.  US Environmental Protection Agency.
  4. Sirinathsinghji E. GM Crops and Water – A Recipe for Disaster. Science in Society 58, 8-10, 2013.
  5. Mason, R. How Roundup Poisoned My Nature Reserve, SiS 64, to appear
  6. Ho MW and Sirinathsinghji E. Ban GMOs Now, I-SIS, London, June 2013,

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There are 6 comments on this article so far. Add your comment above.

Rory Short Comment left 9th October 2014 23:11:40
Quite simply it should be banned and its producers should be charged as perpetrators of human rights abuses.

mmavis Jan-Lai Comment left 14th October 2014 14:02:37
The world, including the USA, needs to ban GMOs and glyphosates now in order to continue as healthy human beings who support healthy creatures and plants throughout our environment. We all need to work together for the health of human kind. That means scientists, farmers, politicians, ALL working together, even with Mansanto.

Danise Freifeld Comment left 23rd January 2015 19:07:35
Has this study shed any light on the increase in cetacean mortality in US coastal waters? I'm beginning my thesis in my BAS degree program in Veterinary Technology at St. Petersburg College in Fla, and I'm looking for quality data to support "Environmental and human-induced factors influencing the recent rise in cetacean mortality in US coastal waters". If you have any other data that supports pesticides and other chemicals leaching into coastal waters in high enough levels to produce death increases, please let me know.

Cheyenne Anderson Comment left 15th April 2015 19:07:42
Where can I find a detailed analysis of each state that was tested? TIA

Eva Sirinathsinghji Comment left 17th April 2015 04:04:47
Hi Cheyenne, Unfortunately the paper does not go into individual state data, though if you have access to the full paper they include a map of the US to give a visual representation of the levels of contamination. I would suggest writing to the authors for further information. Their details are in the link provided.

Leah Comment left 10th March 2016 03:03:36
Please call your local hardware store for starters..tell them to get roundup off their shelves Asap! my apartment management gave me a citation because I called them complaining about their use of roundup on a dirt area within wind of my home..she even long as you don't drink's perfectly safe we bought it at...!! My old condo association used it right by busy park access where people, animals, children walked. They had the nerve to say..we are not going to stop spraying because of one they're doing us a favor!? Starts with a simple phone call folks..let the stores still selling this stuff..we can do our part by preventing any more bottles from being sold!!!thanks