Researchers at the Ramazzini Institute in Bologna observed an increased incidence of tumours in several sites following the administration of low doses of glyphosate.
The latest findings from the Global Glyphosate Study, the most comprehensive international toxicological study ever conducted on glyphosate and glyphosate-based herbicides, have shown that this chemical causes several types of tumours even at doses considered safe.
In the course of the research, conducted by the Cesare Maltoni Cancer Research Centre at the Ramazzini Institute in Bologna and published in Environmental Health, glyphosate and two commercial glyphosate-based formulations — Roundup Bioflow, used in the European Union, and RangerPro, used in the United States — were administered to rats via drinking water from prenatal life onwards at doses of 0.5, 5 and 50 mg per kilogram of body weight per day for two years. These are quantities currently considered "safe" by regulatory bodies and correspond to the Acceptable Daily Intake (ADI) and the No Observed Adverse Effect Level (NOAEL) set by the European Union for glyphosate.
In all treatment groups, an increased incidence of benign and malignant tumours in several sites was observed. In particular, tumours developed in the haemolymphopoietic system (leukaemias), the skin, liver, thyroid, nervous system, ovaries, mammary gland, adrenal glands, kidneys, bladder, bones, endocrine pancreas, uterus and spleen. The incidence was increased in both sexes. The majority of these tumours are considered rare in Sprague-Dawley rats, which were used in the experiments. Furthermore, 40 per cent of leukaemia deaths in the treated groups occurred at a young age, and an increase in early deaths was also observed for other solid tumours.
"We observed early onset and premature mortality from several rare malignant tumours, including leukaemias, liver, ovarian and nervous system tumours," said Daniele Mandrioli, director of the Cesare Maltoni Cancer Research Centre at the Ramazzini Institute. "In particular, approximately half of the leukaemia deaths observed in the groups treated with glyphosate and its formulations occurred before one year of age, comparable to an age of between 35 and 40 years in humans."
These new findings provide robust evidence in support of the International Agency for Research on Cancer (IARC)'s 2015 conclusion that there is "sufficient evidence of carcinogenicity of glyphosate in experimental animals".
Previously, the results of the global study on glyphosate toxicity to the microbiome were published, and these highlighted adverse effects even at doses currently considered safe in the EU (0.5 mg per kilogram of body weight per day). In addition, the Ramazzini Institute's research centre had published the results of the pilot phase of the laboratory study, which demonstrated effects of genotoxicity, alterations to the gut microbiome and endocrine disruption at glyphosate doses currently considered safe by United States regulatory agencies (1.75 mg per kilogram of body weight per day). These findings were subsequently confirmed in a human population of mothers and their newborns exposed to glyphosate during pregnancy.
The goal of the Global Glyphosate Study is to provide essential data to regulatory authorities, policymakers and the general public. The next step will be to explore the neurotoxicity component, which is crucial for understanding the role that glyphosate and glyphosate-based herbicides may play in the rise of neurological diseases and disorders.
"In the face of the scientific evidence, we call on the Italian government and the European Commission to take note and act without delay to immediately ban the use of glyphosate," declared Barbara Nappini, president of Slow Food Italia, commenting on the study. "What is at stake is the sanctity of human health and life, in the face of which the interests and influence of the powerful agribusiness lobbies must be subordinated. We therefore expect an immediate halt to the marketing and also to the production of glyphosate for export."
Glyphosate is the most widely used herbicide in the world. Patented in the 1970s by the multinational Monsanto, it is a systemic weedkiller: within a few hours it passes from the leaves to the entire plant and then into the soil. And in the soil it can remain for years.