Associations of chronic liver disease and liver cancer with glyphosate and its metabolites in Thailand.

Glyphosate [N-(phosphonomethyl) glycine], a systemic herbicide, is used globally (825 million kg/year) in 750+ formulations. The International Agency for Research on Cancer classified glyphosate is a probable human carcinogen (Group 2A), but epidemiological studies have been lacking for its association with liver cancer and chronic liver disease. We analyzed urine specimens from 591 patients with newly diagnosed liver cancer, chronic liver disease (CLD), and healthy individuals from five different medical centers between 2011 to 2016 in Thailand. Gas chromatography electrospray ionization mass spectrometry (GC-ESI/MS) was used to quantify glyphosate and its metabolites, aminomethylphosphonic acid (AMPA) and phosphoric acid (PPA) to study their levels in urine of hepatocellular carcinoma (HCC) and CLD patients in comparison to matched healthy individuals. Significantly higher levels of glyphosate were found in CLD patients compared to HCC cases and hospital controls, while significantly elevated levels of both AMPA and PPA were observed in HCC and CLD patients compared to hospital controls. Glyphosate and its metabolites were also detected at low to moderately high levels in convenience samples of food products and drinking water. These results raise concerns about the potential role of glyphosate in chronic liver disease and liver cancer risk.