The systematic meta-analysis review of 9 independent scientific studies involving 184.389 people associated theexposure to herbicides (e.g. glyphosate, glufosinate ammonium, dicamba) to the significant increase (+ 85%) in the risk of developing skin melanoma. (1)
The need to collect signatures for the European citizens' initiative is reaffirmed #SaveLeApi and farmers. The only way to get the European Commission to actually adopt a rigorous and restrictive policy on the use of these and other toxic substances in agriculture and green spaces. (2)
Cutaneous melanoma it is one of the forms of cancer whose incidence has increased significantly over the past 50 years, as well as being the deadliest of dermal cancers. (3) It develops from tumor formations involving melanocytes, ie the cells present in the epidermis responsible for the production of melanin (which in turn is useful for protecting the harmful effects of the sun's rays).
The risk factors they are numerous, of an endogenous nature (linked to some phenotypes such as light skin, red or blond hair, green or blue eyes) and exogenous (eg exposure to herbicides). (4) Chronic exposure to UV (ultraviolet) radiation, historically considered one of the most important risk factors, would appear to reduce the risk of developing skin melanoma. Numerous epidemiological studies of a descriptive nature have indeed found the reduction of risk in people who work outdoors. (5)
Skin exposure to herbicides
Skin exposure herbicides is very common and frequent, due to their wide and continuous use in agriculture and in other activities related to green management (eg parks, nurseries, flower beds, roadsides and railway tracks). The environmental exposure - linked to the so-called drift effect of agrotoxicants - and food (through the consumption of 'conventional', that is, non-organic foods). With possible negative effects on public health, potentially aggravated bymultiple exposure. (6)
The skin barrier unfortunately it is not enough to mitigate the absorption of toxic substances by pesticides which occurs through the epidermis. It can take place during the preparation and use phases or following these activities, during the change and handling of the clothing used by the operators. Some parameters have a decisive influence on the effect of this exposure. In particular:
- extent and duration of exposure,
- presence of other materials on the skin,
- ambient temperature and humidity,
- use of tools and personal protective clothing (7,8).
Synergistic effects. Effect cocktail, sun and sunscreen
The so-called effect cocktail - ie exposure to two or more active substances (eg glyphosate and ammonium glufosinate) - it was found to amplify the exposure to agrotoxicants. With synergistic effects so far poorly explored, in particular as regards the possible carcinogenic effects of pesticide mixtures. In fact, the studies focus mainly on single active ingredients or, at most, on their reference classes. (9)
Exposure to the sun, in turn, it appears to promote a synergistic effect with pesticides in professional operators. Solar radiation can lead to an increase in skin temperature and increase blood flow and sweating, along with the skin permeability of pesticides. And the use of sun protection creams further contributes to the skin absorption of pesticides, particularly in products that contain titanium dioxide or zinc oxide. (10)
Meta-analysis, research results
The meta-analysis conducted by researchers of the Italian Melanoma Intergroup (IMI), together with those of the Romagna Scientific Institute for the Study and Treatment of Tumors (IRST), demonstrated a significant increase in the risk of melanoma development in subjects exposed to herbicides - especially professional operators - with respect to non-exposed individuals.
Those most at risk appear to be men, due to the greater occupational exposure. Other agrochemicals (eg pesticides, insecticides) have also shown a high risk, both at high and continuous exposures, although it did not appear statistically significant as regards specifically cutaneous melanoma. In any case, the set of results will need to be confirmed in further studies.
Legal systems in comparison
Levels of protection of public health and ecosystems are very different in different legal systems. If on one hand the European Union is struggling to address the risks associated with multiple exposure (effect cocktail), other countries continue to authorize agrotoxicants that have long been banned in the EU. Among these the first exporters of commodities agricultural as Brazil, India and Indonesia (where paraquat is still in use), USA, .. (11,12,13).
Dario Dongo and Andrea Adelmo Della Penna
Cover image by NSAE
Footnotes to the story
(1) Stanganelli I, De Felici MB, Mandel VD, Caini S, Raimondi S, Corso F, Bellerba F, Quaglino P, Sanlorenzo M, Ribero S, Medri M, Farnetani F, Feliciani C, Pellacani G, Gandini S; IMI the Italian Melanoma Intergroup. (2020). The association between pesticide use and cutaneous melanoma: a systematic review and meta-analysis. JEADV (Journal of the European Academy of Dermatology and Venereology) 2020 Apr; 34 (4): 691-708. doi: 10.1111 / jdv.15964. Epub 2019 Oct 28. PMID: 31541557
(2) Dario Dongo. Savethebees! Let's save bees, an initiative of European citizens. Egalité. 15.1.21, https://www.egalite.org/savethebees-salviamo-le-api-iniziativa-dei-cittadini-europei/
(3) Gandini et al. (2005). Meta-analysis of risk factors for cutaneous melanoma: I. Common and atypical naevi. Eur. J. Cancer 41: 28–44, doi: 10.1016 / j.ejca. 2004.10.015
(4) Leonardi et al. (2018). Cutaneous melanoma: from pathogenesis to therapy (Review). International Journal of Oncology 52 (4): 1071-1080, doi: 10.3892 / ijo.2018.4287
(5) Parkin et al. (2011) 13. Cancers attributable to solar (ultraviolet) radiation exposure in the UK in 2010. Br. J. Cancer 105 (Suppl. 2): S66 – S69, doi: 10.1038 / bjc.2011.486
(6) Alavanja (2009). Introduction: pesticides use and exposure extensive worldwide. Rev. Environ. Health 24 (4): 303-309, https://doi.org/10.1515/REVEH.2009.24.4.303
(7) Anderson et al. (2014). Potential health effects associated with dermal exposure to occupational chemicals. Environ. Health Insights 8 (Suppl 1): 51–62, doi: 10.4137 / EHI.S15258
(8) Damalas et al. (2011). Pesticide exposure, safety issues, and risk assessment indicators. Int. J. Environ. Res. Public Health 8 (5): 1402-19, doi: 10.3390 / ijerph8051402
(9) Fortes et al. (2016). Occupational exposure to pesticides with occupational sun exposure increases the risk for cutaneous melanoma. J. Occup. Environ. Med. 58: 370-375, doi: 10.1097 / JOM.0000000000000665
(10) Gordon et al. (2005). Thermal stress and the physiological response to environmental toxicants. Rev. Environ. Health 20: 235-263, doi: 10.1515 / reveh.2005.20.4.235
(11) Donley (2019). The USA lags behind other agricultural nations in banning harmful pesticides. Environs. Health 18:44 pm, https://doi.org/10.1186/s12940-019-0488-0
(12) Muhamad Ramdan, Iwan & Candra, Krishna Purnawan. (2020). Factors Associated with Cholinesterase Level of Spraying Workers Using Paraquat Herbicide at Oil Palm Plantation in East Kalimantan, Indonesia. doi: 10.14710 / jkli.19.1.16-20
(13) Dario Dongo, Donato Ferrucci. Pesticides, acute toxicity in the US agricultural system. Scientific study. GIFTS (Great Italian Food Trade). 25.8.19/XNUMX/XNUMX, https://www.greatitalianfoodtrade.it/idee/pesticidi-tossicità-acuta-nel-sistema-agricolo-usa-studio-scientifico