Roundup weedkiller ‘probably’ causes cancer, says WHO study

21 March 2015 (The Guardian) – Roundup, the world’s most widely used weedkiller, “probably” causes cancer, the World Health Organisation (WHO) has said. The International Agency for Research on Cancer (IARC) – WHO’s cancer agency – said that glyphosate, the active ingredient in the herbicide made by agriculture company Monsanto, was “classified as probably carcinogenic to humans”. It also said there was “limited evidence” that glyphosate was carcinogenic in humans for non-Hodgkin’s lymphoma. Monsanto, the world’s largest seed company, said scientific data did not support the conclusions and called on WHO to hold an urgent meeting to explain the findings. “We don’t know how IARC could reach a conclusion that is such a dramatic departure from the conclusion reached by all regulatory agencies around the globe,” said Philip Miller, Monsanto’s vice-president of global regulatory affairs. Concerns about glyphosate on food have been widely debated in the US recently, and contributed to the passage in Vermont last year of the country’s first mandatory labelling law for genetically modified food. The US government considers the herbicide to be safe. In 2013, Monsanto requested and received approval from the US Environmental Protection Agency for increased tolerance levels for glyphosate. [more]

By Kathryn Z Guyton, Dana Loomis, Yann Grosse, Fatiha El Ghissassi, Lamia Benbrahim-Tallaa, Neela Guha, Chiara Scoccianti, Heidi Mattock, Kurt Straif, on behalf of the International Agency for Research on Cancer Monograph Working Group, IARC, Lyon, France
20 March 2015 (The Lancet) – In March, 2015, 17 experts from 11 countries met at the International Agency for Research on Cancer (IARC; Lyon, France) to assess the carcinogenicity of the organophosphate pesticides tetrachlorvinphos, parathion, malathion, diazinon, and glyphosate. These assessments will be published as volume 112 of the IARC Monographs.1 […] Glyphosate is a broad-spectrum herbicide, currently with the highest production volumes of all herbicides. It is used in more than 750 different products for agriculture, forestry, urban, and home applications. Its use has increased sharply with the development of genetically modified glyphosate-resistant crop varieties. Glyphosate has been detected in air during spraying, in water, and in food. There was limited evidence in humans for the carcinogenicity of glyphosate. Case-control studies of occupational exposure in the USA,14 Canada,6 and Sweden7 reported increased risks for non-Hodgkin lymphoma that persisted after adjustment for other pesticides. The AHS cohort did not show a significantly increased risk of non-Hodgkin lymphoma. In male CD-1 mice, glyphosate induced a positive trend in the incidence of a rare tumour, renal tubule carcinoma. A second study reported a positive trend for haemangiosarcoma in male mice.15 Glyphosate increased pancreatic islet-cell adenoma in male rats in two studies. A glyphosate formulation promoted skin tumours in an initiation-promotion study in mice. Glyphosate has been detected in the blood and urine of agricultural workers, indicating absorption. Soil microbes degrade glyphosate to aminomethylphosphoric acid (AMPA). Blood AMPA detection after poisonings suggests intestinal microbial metabolism in humans. Glyphosate and glyphosate formulations induced DNA and chromosomal damage in mammals, and in human and animal cells in vitro. One study reported increases in blood markers of chromosomal damage (micronuclei) in residents of several communities after spraying of glyphosate formulations.16 Bacterial mutagenesis tests were negative. Glyphosate, glyphosate formulations, and AMPA induced oxidative stress in rodents and in vitro. The Working Group classified glyphosate as “probably carcinogenic to humans” (Group 2A). [more]

Carcinogenicity of tetrachlorvinphos, parathion, malathion, diazinon, and glyphosate