FOCUS SULL’IMPATTO DEI PESTICIDI NELLE ACQUE

FOCUS SULL’IMPATTO DEI PESTICIDI NELLE ACQUE.

Proponiamo una breve lettura di un articolo, in inglese, pubblicato lo scorso luglio 2023 sugli effetti dei pesticidi nelle acque. Si ringrazia il professor Giuseppe Scapigliati Università della Tuscia, docente del DIBAF –  Dipartimento per la Innovazione nei Sistemi Biologici, Agroalimentari e Forestali – per averlo sottoposto ai lettori del BDLB.

Agricultural pesticide land budget and river discharge to oceans

Pesticides are ubiquitous environmental pollutants negatively affecting ecosystem and human health 2. About 3 g of pesticides are used annually in agriculture to protect crops’. How much of these pesticides remain on land and reach the aquifer or the ocean is uncertain. Monitoring their environmental fate is challenging, and a detailed picture of their mobility in time and space is largely missing*. Here, we develop a process-based model accounting for the hydrology and biogeochemistry of the 92 most used agricultural pesticide active substances to assess their pathways through the principal catchments of the world and draw a near-present picture of the global land and river budgets, including discharge to oceans. Of the 0.94 Tg net annual pesticide input in 2015 used in this study, 82% is biologically degraded, 10% remains as residue in soil and 7.2% leaches below the root zone. Rivers receive 0.73 Gg of pesticides from their drainage at a rate of 10 to more than 100 kg yr ‘ km’. By contrast to their fate in soil, only 1.1% of pesticides entering rivers are degraded along streams, exceeding safety levels (concentrations >1 pg I) in more than 13,000 km of river length, with 0.71 Gg of pesticide active ingredients released to oceans every year. Herbicides represent the prevalent pesticide residue on both land (72%) and river outlets (62%).

Autori: Federico Maggi, Fiona H. M. Tang & Francesco N. Tubiello