applied sciences Article A Simple Device for the On-Site Photodegradation of Pesticide Mixes Remnants to Avoid Environmental Point Pollution Biagio Esposito 1, Francesco Riminucci 1,2 , Stefano Di Marco 3 , Elisa Giorgia Metruccio 3, Fabio Osti 3 , Stefano Sangiorgi 4 and Elida Nora Ferri 4,* 1 Proambiente s.c.r.l.—Tecnopolo Bologna CNR, Via P. Gobetti 101, 40129 Bologna, Italy; [email protected] (B.E.); [email protected] (F.R.) 2 National Research Council, Institute of Marine Sciences (CNR-ISMAR), Via P. Gobetti 101, 40129 Bologna, Italy 3 National Research Council—Institute of BioEconomy (CNR-IBE), Via P. Gobetti 101, 40129 Bologna, Italy; [email protected] (S.D.M.); [email protected] (E.G.M.); [email protected] (F.O.) 4 Department of Pharmacy and Biotechnology, University of Bologna, Via S. Donato 15, 40127 Bologna, Italy; [email protected] * Correspondence: [email protected]; Tel.: +39-0512095658 Featured Application: The prototype developed in this work can rapidly detoxify agrochemical solutions directly at farms, allowing for their safe disposal in the environment or water reuse. Abstract: The worldwide increase in the number and use of agrochemicals impacts nearby soil and freshwater ecosystems. Beyond the excess in applications and dosages, the inadequate management of remnants and the rinsing water of containers and application equipment worsen this problem, creating point sources of pollution. Advanced oxidation processes (AOPs) such as photocatalytic Citation: Esposito, B.; Riminucci, F.; and photo-oxidation processes have been successfully applied in degrading organic pollutants. Di Marco, S.; Metruccio, E.G.; Osti, F.; We developed a simple prototype to be used at farms for quickly degrading pesticides in water Sangiorgi, S.; Ferri, E.N. A Simple solutions by exploiting a UV–H O -mediated AOP. As representative compounds, we selected the Device for the On-Site 2 2 Photodegradation of Pesticide Mixes insecticide imidacloprid, the herbicide terbuthylazine, and the fungicide azoxystrobin, all in their Remnants to Avoid Environmental commercial formulation. The device efficiency was investigated through the disappearance of the Point Pollution. Appl. Sci. 2021, 11, parent molecule and the degree of mineralization. The toxicity of the pesticide solutions, before 3593. https://doi.org/10.3390/ and during the treatment, was assessed by Vibrio fischeri and Pseudokirchneriella subcapitata inhibition app11083593 assays. The results obtained have demonstrated a cost-effective, viable alternative for detoxifying the pesticide solutions before their disposal into the environment, even though the compounds, or Academic Editor: Amerigo Capria their photoproducts, showed different sensitivities to physicochemical degradation. The bioassays revealed changes in the inhibitory effects on the organisms in agreement with the analytical data. Received: 25 March 2021 Accepted: 12 April 2021 Keywords: agrochemicals; photo-reactor; advanced oxidation processes; water pollution; point sources Published: 16 April 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in 1. Introduction published maps and institutional affil- iations. Pesticides, herbicides, fertilizers, plant growth regulators, and other agrochemicals play a decisive role in agriculture, protecting crops and improving yields, but the current main challenge is the development of profit-gaining agriculture increasingly geared to environmentally friendly management systems, aimed at reducing the damages produced by agrochemicals to humans and the environment [1]. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. High intensity agricultural models are characterized by a massive use of pesticides This article is an open access article and herbicides contaminating water and soil [2–4]. In 2018, the worldwide quantities of distributed under the terms and applied pesticides corresponded to 4112.3 metric tons, and in Italy alone to 54.1 metric conditions of the Creative Commons tons [5]. Animal waste from farms, sediments, organic debris, pesticides, and fertilizers Attribution (CC BY) license (https:// have long proven to be the major causes of ground and surface water pollution [6,7]. creativecommons.org/licenses/by/ Soil and water bodies risk contamination every time pesticides are manipulated [8]. 4.0/). Pesticide drift, percolation, drainage, runoff, and leaching greatly depend on their cor- Appl. Sci. 2021, 11, 3593. https://doi.org/10.3390/app11083593 https://www.mdpi.com/journal/applsci Appl. Sci. 2021, 11, x FOR PEER REVIEW 2 of 17 tons [5]. Animal waste from farms, sediments, organic debris, pesticides, and fertilizers have long proven to be the major causes of ground and surface water pollution [6,7]. Appl. Sci. 2021, 11, 3593 Soil and water bodies risk contamination every time pesticides are manipulated [8].2 of 16 Pesticide drift, percolation, drainage, runoff, and leaching greatly depend on their correct management, both before and after the treatment, including the correct use of the appli- cation equipment, i.e., the pneumatic sprayers [9–11]. A known source of point source rect management, both before and after the treatment, including the correct use of the pollution is represented by incorrect practices in the disposal of spray remnants and tank application equipment, i.e., the pneumatic sprayers [9–11]. A known source of point rinsing water. Directive 2009/128/EC [12] regulates the disposal of agro-wastewater con- source pollution is represented by incorrect practices in the disposal of spray remnants and taining pesticides; however, it is quite common for, after the application, the spray rem- tank rinsing water. Directive 2009/128/EC [12] regulates the disposal of agro-wastewater nantscontaining in the barrel pesticides; of the however,spray-tank it to is be quite deposited common on for, the after ground the application,or even discarded the spray directlremnantsy into water in the bodies barrel, of often the spray-tankwithout any to bedilution. deposited These on point the ground sources or of even pollution discarded fromdirectly leftover into mixture water and bodies, cleaning often water without disposal any dilution. are a matter These of concern point sources since pesticide of pollution residuesfrom leftovermay persist mixture for a and very cleaning long time water; some disposal compounds are a matter can be of concernstill detected since many pesticide yearsresidues after their may ban persist [13,14]. for a very long time; some compounds can be still detected many yearsSeveral after solutions their ban have [13 ,been14]. studied and proposed to remove or inactivate pesticides in water.Several Most are solutions plants havebased been on water studied evaporation and proposed produced to remove by solar or inactivate radiation pesticides and windin (Heliosec water. Most® , Syngenta are plants Agro based sas, on Guyancourt, water evaporation France) producedor by infrared by solar radiation radiation and and heatwind (Osmofilm (Heliosec® , Panteck®, Syngenta- France Agro sarl, sas, Montesson Guyancourt, France) France) [15]. or by Quicker infrared evaporation radiation and can heat be obtained(Osmofilm by® using, Panteck- electric Franceal resistance, sarl, Montesson filtering France) the vapors [15]. through Quicker activated evaporation carbon can be filtersobtained (Evapofit by® using, Staphytr, electrical Inchy resistance,-en-Artois, filtering France the) [15]. vapors Otherwise, through a activated chemical carbonpretreat- filters ment(Evapofit of coagulation®, Staphytr,–flocculation Inchy-en-Artois, can be used France) to produce [15]. Otherwise, decantation a chemical of the active pretreatment ingre- of dientcoagulation–flocculation as solid material (Sentinel can be® , Alba used toenvironnement produce decantation sas, Cluny, of the France active) ingredient [15]. Various as solid systemsmaterial are based (Sentinel on ®biomass, Alba environnement beds, based on sas, microbial Cluny, France)degradation [15]. Various(using fungi, systems bacteria, are based actinomycetes,on biomass and beds, viruses) based oninto microbial less toxic degradationforms [1,9,16]. (using However, fungi, all bacteria, these solutions actinomycetes, re- quireand a place viruses) and/or into a lessplant toxic where forms they [1 can,9,16 be]. carried However, out. all these solutions require a place and/orMore effective a plant wheretreatment they systems can be carried are required out. , and the most recent and effective wa- ter treatmentMore technologies effective treatment are based systems on advanced are required, oxidation and processes the most recent(AOPs and), a set effective of innovativewater treatment techniques technologies including areUV- basedbased ontechniques advanced, ultrasound, oxidation processes electron (AOPs),beams, γ a set raysof, and innovative plasma techniquesmethods, which including remove UV-based organic techniques, contaminants ultrasound, by mineralization electron beams, [17]. γ Therays, UV treatments and plasma are methods, the easier which and less remove expensive organic ones, contaminants optimized by by the mineralization addition of a [ 17]. photocatalystThe UV treatments or a radical are mediator, the easier such and lessas H expensive2O2, which ones, promotes optimized the radical by the-mediated addition of a degradationphotocatalyst of the or molecules a radical [1 mediator,8–20], according such as Hto2