Exposure to cocktail of pesticides and other agrotoxicants, even at the doses allowed in the EU, cause toxicity. And it is possible to measure its effects, thanks to innovative investigation techniques.
The study conducted by an international research group - in which Fiorella Belpoggi, director of the Cancer Research Center at the Ramazzini Institute in Bologna participates - offers new perspectives in scientific risk assessment. (1)
The first comments of Professor Alberto Mantovani of the Istituto Superiore di Sanità (ISS).
Effect cocktail of pesticides, the multiple exposure study
A systematic review being examined for the first time, it compares the results of 'omics' molecular analyzes - the most advanced, in terms of precision and detail - with those obtained through traditional procedures. That is to say, the methods of analysis still applied in the risk assessment required for the authorization of pesticides in the EU.
The objective general research is to identify biochemical markers of toxicity before detecting pathologies in subjects exposed to mix of pesticides and other agrotoxicants. And indeed, omics molecular analyzes have been shown to be able to 'see' the first signs of damage to the organism related to exposure to cocktail of pesticides. The authors of the research therefore suggest adopting these standards in risk assessment procedures, in Europe entrusted to EFSA (European Food Safety Authority).
New frontiers for public health
'Our data suggest that adoption of multi-omics as part of regulatory risk assessment procedures will result in more accurate outcome measures, with positive public health implications'. (1)
The research is currently underway peer-review (peer review, by experts in the field of study), pending its publication in a scientific journal. Its full text is also already available on the BioRxiv pre-press site. (1) Following confirmation, it will be able to offer a significant contribution to the analysis of the risks associated with the so-called effect cocktail (cumulative exposure to hazardous chemicals).
Test on the residues of 6 widespread agrotoxicants
Researchers replicated for 90 days on laboratory animals the conditions to which consumers of 'conventional' (ie non-organic) food are subjected every day. Namely chronic exposure to a mix of the residues of 6 agrotoxicants often found in food: azoxystrobin, boscalid, clorpyrifos, glyphosate, imidacloprid and thiabendazole. Within the limits of the respective acceptable daily doses (Acceptable Daily Intake, ADI).
The diffusion of these molecules in food is confirmed in the latest EFSA report on pesticide residues in food. (2) Where it has been ascertained the presence of 2 or more molecules in more than 1 sample in 4 (27,5%). And the 6 agrotoxicants used in the study under examination often appear in it. Two of the poisons mentioned, for example, have recently even been found in the pulp of bananas not organic.
Acceptable results, applying traditional analysis standards
At a first analysis the guinea pigs showed no damage from exposure to cocktail of pesticides. Food and water consumption, as well as body weight, were similar in the control and exposure groups mix of agrotoxic. The latter showed only 'a non-significant increase in the incidence of liver and kidney injury. A biochemical analysis of the serum found only a small decrease in creatinine levels'.
Risk analysis evaluated according to traditional methods (blood analysis and histological examination of organs) used both by industry and at the institutional level for the authorization of pesticides, it therefore showed little or no physiological effects.
Disturbing results, applying more advanced analysis standards
The use of standards of more advanced analyzes - blood metabolomics, liver transcriptomics and DNA methylation analysis at the genome level - instead reveals metabolic alterations in the intestine and in the metabolome (the sum of metabolites), in the blood of guinea pigs, with effects on liver function.
Further research on in vitro bacterial cultures'further showed that the growth of Lactobacillus rhamnosus and Escherichia coliceppi were adversely affected by the pesticide mixture at concentrations that were not inhibitory when exposure was to a single agent.(1)
The research continues
The results of the study show the inadequacy of the toxicological risk assessments of the molecules currently in use. Demonstrating the presence of exposure-related biochemical changes a mix of pesticides in doses so far deemed acceptable (at least 100 times lower than the one showing no effects).
Further studies they are essential to ascertain the real offensiveness of the detected alterations. It is also necessary to identify the most dangerous synergies, since in different circumstances the pesticide present in a mix produces toxic effects that are not detected in its exclusive use.
The comment of prof. Alberto Mantovani of ISS
Professor Alberto Mantovani is an internationally renowned toxicologist. He is a research director of the Istituto Superiore di Sanità (ISS), former president of the European Society of Teratology. As well as historical member, for 15 years of the scientific panel on feed and pesticides at EFSA (European Food Safety Authority), where he continues to work as an external expert. Mantovani had already shared his considerations on pesticides and microbiome on this site. We have now collected his first comments on the study under consideration.
'Notwithstanding that studies should be considered after they have passed the peer-review, the idea of evaluating effects on the gut microbiome and on liver transcriptomics and epigenetics is scientifically interesting. The intestine and the liver are, in fact, the tissues that surely come into contact with the residues present in the food.
Two problematic aspects are the differences between human and rodent intestinal microbiomes, and above all the consequences of the effects encountered: simple response of the organism to foreign substances that it ingests every day, or first steps towards the establishment of adverse effects, even serious ones?
On hold to discuss the final version of the work, it is undeniable that the study addresses a topical problem for risk assessment, namely the possible metabolic effects of multiple exposures to low residue levels. '
Marta Strinati
Footnotes
(1) Robin Mesnage, Maxime Teixeira, Daniele Mandrioli, Laura Falcioni, Quinten Raymond Ducarmon, Romy Daniëlle Zwittink, Caroline Amiel, Jean-Michel Panoff, Emma Bourne, Emanuel Savage, Charles A Mein, Fiorella Belpoggi, Michael N Antoniou. Multi-omics phenotyping of the gut-liver axis allows health risk predictability from in vivo subchronic toxicity tests of a low-dose pesticide mixture. bioRxiv 2020.08.25.266528; doi: https://doi.org/10.1101/2020.08.25.266528
(2) EFSA (2019). The 2017 European Union report on pesticide residues in food. doi: https://doi.org/10.2903/j.efsa.2019.5743. At https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2019.5743
A professional journalist since January 1995, she has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic studies on food and has published the book "Reading labels to know what we eat".
