The study, led by France’s INRAE, the institute specialising in agricultural research and the environment, and Ifremer, France’s institute for marine sciences and technologies, examined the extent to which birds, insects and other living organisms are affected by pesticides.

The study was based on a bibliographic analysis of more than 4,000 international scientific publications and was designed to update the current state of knowledge, to identify that which is solid and that which needs further consolidation or has not been sufficiently explored since previous expert studies. This information is essential, says INRAE, as it will help French and European public authorities shape regulations and research strategies.

INRAE says the 2022 study is far more accurate than previous work due to the development of a denser monitoring network and the improvement of analysis techniques that focus on PPP and some of the products resulting from their degradation or transformation.

It reports: “All environments are affected by the contamination of mixtures of plant protection products, but agricultural areas close to the application sites are the most contaminated. This contamination then affects soils and watercourses to the seas and oceans, with generally decreasing concentrations along this continuum.

“Some pollutants that are very persistent in the environment, such as DDT, lindane and hexachlorobenzene, which have been banned for years, are found as far as the deep sea and the polar zones. Everywhere, mixtures of pollutants are found: phytopharmaceutical products, themselves in mixtures, are present alongside pharmaceuticals and microplastics etc.”

INRAE says chemical pollution, to which PPP contributes, is the third or fourth most important factor in the destruction of biodiversity worldwide. It says there is strong evidence that PPP are one of the main causes of the reduction in terrestrial invertebrates in agricultural areas, including pollinating and beneficial insects and birds, alongside aquatic organisms.  

“For all these terrestrial and aquatic organisms, the direct and indirect non-lethal effects are considerable, something that was not studied to the same extent 15 years ago,” INRAE reports. “These effects can take the form of loss of orientation or flight ability in insects and birds, reduced reproductive efficiency or immune deficiencies. 

“Some of these effects are because of damage to the microbiota, i.e. all the microorganisms present in these organisms (as is, for example, the case with the intestinal flora in humans). Some of these products also affect the endocrine system, which are mainly studied in mammalian and fish model species and whose consequences on populations have yet to be assessed.”

The study emphasises the importance of landscape management for biodiversity resilience. INRAE reports: “It is essential to create refuge areas (terrestrial and aquatic vegetation) that are interconnected: they are reservoirs for species that can then recolonise neighbouring environments. However, these refuge areas, and more generally natural habitats, are threatened by the simplification of agricultural landscapes (larger plots with less varied borders) and by soil artificialisation, with plant protection products playing an aggravating role.”

The study says that while reducing pesticide use remains the number one lever to reduce the impacts of PPP, three more types of levers can be used: mitigation of effects, regulation and the use of less persistent and impacting options such as biocontrol products.

For more information:

• Read the full story (and access the English summary of the expertise) visit the INRAE website here