[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU [ADD1_IRSTEA]Hydrosystèmes et risques naturels | International audience | RECOTOX is a cross-cutting initiative promoting an integrated research to respond to the challenges of monitoring, understanding, and mitigating environmental and health impacts of pesticides in agroecosystems. The added value of RECOTOX is to develop a common culture around spatial ecotoxicology including the whole chain of pressure-exposure-impact, while strengthening an integrated network of in natura specifically equipped sites. In particular, it promotes transversal approaches at relevant socioecological system scales, to capitalize knowledge, expertise, and ongoing research in ecotoxicology and, to a lesser extent, environmental toxicology. Thus, it will open existing research infrastructures in environmental sciences to research programs in ecotoxicology of pesticides.

Leaf-cutting ants are important pests of forests and agricultural crops in the Neotropical region. Atta sexdens colonies can be composed of thousands of individuals, which form a highly complex society with a single reproductive queen. Successful control of this species is achieved only if the queen is affected. Few data are available on the lethal or sublethal effects of toxic compounds on leaf-cutting ant queens. Azadirachtin has been claimed as an effective biopesticide for insect control, but its action on leaf-cutting ants has been little explored. This study shows that azadirachtin affects oviposition in A. sexdens queens, impairing egg development by decreasing protein reserves. Azadirachtin inhibits the synthesis of vitellogenin, the major yolk protein precursor. The negative effects of azadirachtin on the reproduction of leaf-cutting ant queens suggest a potential use for the control of these insects.

Hazard assessment of chemical contaminants often relies on short term or partial life-cycle ecotoxicological tests, while the impact of low dose throughout the entire life cycle of species across multiple generations has been neglected. This study aimed at identifying the individual and population-level consequences of chronic water contamination by environmental concentrations of three organic micropollutants, ibuprofen, bisphenol A and benzo[a]pyrene, on Aedes aegypti mosquito populations in experimental conditions. Life-history assays spanning the full life-cycle of exposed individuals and their progeny associated with population dynamics modelling evidenced life-history traits alterations in unexposed progenies of individuals chronically exposed to 1 μg/L ibuprofen or 0.6 μg/L benzo[a]pyrene. The progeny of individuals exposed to ibuprofen showed an accelerated development while the progeny of individuals exposed to benzo[a]pyrene showed a developmental acceleration associated with an increase in mortality rate during development. These life-history changes due to pollutants exposure resulted in relatively shallow increase of Ae. aegypti asymptotic population growth rate. Multigenerational exposure for six generations revealed an evolution of population response to ibuprofen and benzo[a]pyrene across generations, leading to a loss of previously identified transgenerational effects and to the emergence of a tolerance to the bioinsecticide Bacillus turingiensis israelensis (Bti). This study shed light on the short and long term impact of environmentally relevant doses of ibuprofen and benzo[a]pyrene on Ae. aegypti life-history traits and insecticide tolerance, raising unprecedented perspectives about the influence of surface water pollution on vector-control strategies. Overall, our approach highlights the importance of considering the entire life cycle of organisms, and the necessity to assess the transgenerational effects of pollutants in ecotoxicological studies for ecological risk assessment. Finally, this multi-generational study gives new insight about the influence of surface water pollution on microevolutionary processes.

The area of agricultural wastes valorisation to fertilizers is attracting growing attention because of the increasing fertilizer prices of fertilizers and the higher costs of waste utilization. Despite the scientific and political interest in the concept of circular economy, few studies have considered the practical approach towards the implementation of elaborated technologies. This article outlines innovative strategies for the valorisation of different biobased wastes into fertilizers. The present work makes a significant contribution to the field of new ideas for waste biomass management to recover significant fertilizer nutrients. These results emphasize the importance of the biomass use as a base of renewable resources, which has recently gained special importance, especially in relation to the outbreak of pandemia and war. Broken supply chains and limited access to deposits of raw materials used in fertilizer production (natural gas, potassium salts) meant that now, as never before, it has become more important and feasible to implement the idea of a circular economy and a green deal. We have obtained satisfactory results that demonstrate that appropriate management of biological waste (originating from agriculture, food processing, aquaculture, forest, pharmaceutical industry, and other branches of industry, sewage sludge) will not only reduce environmental nuisance (reducing waste heaps), but will also allow recovery of valuable materials, such as nitrogen (especially valuable amino acids), phosphorus, potassium, microelements, and biologically active substances with properties that stimulate plant growth. The results reported here provide information on production of biobased plant protection products (bioagrochemicals) from agri-food waste. This work reports an overview of biopesticides and biofertilisers production technologies and summarizes their properties and the mechanisms of action.

Bioinsecticides based on the bacterium Bacillus thuringiensis subsp. israelensis (Bti) are increasingly being applied directly into aquatic compartments to control nuisance mosquitoes and blackflies and are generally considered environmentally friendly alternatives to synthetic insecticides. Bti-based insecticides are considered highly selective, being Diptera-specific, and supposedly decompose rapidly in the environment. Nevertheless, their safety to non-target species and freshwater ecosystems has been questioned by recent studies, which in fact document possible indirect effects in aquatic food webs such as the decrease of prey availability to predators. This work aimed to evaluate the potential effects of a Bti-based insecticide (VectoBac® 12AS) on a freshwater macroinvertebrate community and on stream ecological functions by using artificial microcosm streams. Artificial microcosm streams were colonized with a macroinvertebrate community plus periphyton collected in a stream together with Alnus glutinosa leaf packs. They were exposed for 7 days to different Bti treatments (0, 12, 120, 1200 μg/L), which are within the recommended concentrations of application in aquatic compartments for blackfly and mosquito control. Besides invertebrate community structure and abundance, effects were evaluated regarding leaf decomposition and primary production as measures of ecosystem functioning. Community structure was significantly altered in all Bti treatments after 7 days of exposure, mostly due to a decline in chironomids, followed by oligochaetes, which both belong to the deposit-feeders’ functional group. Direct effects on oligochaetes are surprising and require further research. Also, reductions of leaf decomposition due to Bti-induced sublethal effects on shredders (reduced feeding) or mortality of chironomids (that can also feed on coarse organic matter) observed in our study, represent potential indirect effects of Bti in aquatic ecosystems. Our short-exposure experiment evidenced some negative effects on stream benthic invertebrate communities and on ecosystem functioning that must be considered whenever Bti is used in water bodies for blackfly or mosquito control programs.

International audience | Preserving biodiversity against the adverse effects of plant protection products (PPPs) is a major environmental and societal issue. However, despite intensive investigation into the ecotoxicological effects of PPPs, the knowledge produced remains fragmented given the sheer diversity of PPPs. This is due, at least in part, to a strong streetlight effect in the field of ecotoxicology. Indeed, while some PPPs have been investigated in numerous ecotoxicological studies, there are many for which the scientific literature still has little or no information on their ecotoxicological risks and effects. The PPPs under the streetlight include a large variety of legacy substances and a more limited number of more recent or currently-in-use substances, such as the herbicide glyphosate and the neonicotinoid insecticides. Furthermore, many of the most recent PPPs (including those used in biocontrol) and PPP transformation products (TPs) resulting from abiotic and/or biotic degradation are rarely addressed in the international literature in the field of ecotoxicology. Here, based on a recent collective scientific assessment of the effects of PPPs on biodiversity and ecosystem services in the French and European contexts, this article sets out to illustrate the limitations and biases caused by the streetlight effect and numbers of gray areas, and issue recommendations on how to overcome them.

International audience | Biocontrol solutions (macroorganisms, microorganisms, natural substances, semiochemicals) are presented as potential alternatives to conventional plant protection products (PPPs) because they are supposed to have lower impacts on ecosystems and human health. However, to ensure the sustainability of biocontrol solutions, it is necessary to document the unintended effects of their use. Thus, the objectives of this work were to review (1) the available biocontrol solutions and their regulation, (2) the contamination of the environment (soil, water, air) by biocontrol solutions, (3) the fate of biocontrol solutions in the environment, (4) their ecotoxicological impacts on biodiversity, and (5) the impacts of biocontrol solutions compared to those of conventional PPPs. Very few studies concern the presence of biocontrol solutions in the environment, their fate, and their impacts on biodiversity. The most important number of results were found for the organisms that have been used the longest, and most often from the angle of their interactions with other biocontrol agents. However, the use of living organisms (micro and macroorganisms) in biocontrol brings a specific dimension compared to conventional PPPs because they can survive, multiply, move and colonize other environments. The questioning of regulation stems from this specific dimension of the use of living organisms. Concerning natural substances, the few existing results indicate that while most of them have low ecotoxicity, others have a toxicity equivalent to or greater than that of the conventional PPPs. There are almost no result regarding semiochemicals. Knowledge of the unintended effects of biocontrol solutions has proved to be very incomplete. Research remains necessary to ensure their sustainability.

Preserving biodiversity against the adverse effects of plant protection products (PPPs) is a major environmental and societal issue. However, despite intensive investigation into the ecotoxicological effects of PPPs, the knowledge produced remains fragmented given the sheer diversity of PPPs. This is due, at least in part, to a strong streetlight effect in the field of ecotoxicology. Indeed, while some PPPs have been investigated in numerous ecotoxicological studies, there are many for which the scientific literature still has little or no information on their ecotoxicological risks and effects. The PPPs under the streetlight include a large variety of legacy substances and a more limited number of more recent or currently-in-use substances, such as the herbicide glyphosate and the neonicotinoid insecticides. Furthermore, many of the most recent PPPs (including those used in biocontrol) and PPP transformation products (TPs) resulting from abiotic and/or biotic degradation are rarely addressed in the international literature in the field of ecotoxicology. Here, based on a recent collective scientific assessment of the effects of PPPs on biodiversity and ecosystem services in the French and European contexts, this article sets out to illustrate the limitations and biases caused by the streetlight effect and numbers of gray areas, and issue recommendations on how to overcome them.

Insecticides stand out as the most dangerous pesticides, and many of them can cause cytotoxic and genotoxic effects in organisms. For this reason, a systematic review was performed focusing on the effect of insecticides on Allium cepa system by two ways: (1) a scientometric study to identify trends and gaps in the literature on the evaluation of insecticides to guide future research efforts and (2) a meta-analytical approach compiling the information to obtain an overall result about insecticide effect on A. cepa. It was found that there is an increasing production of articles in this research area. The H-index of our data set was 11, with an average of 13.72 citations per item. The leader country in this research area was India, followed by Turkey and Brazil. The best cited research area was “Environmental Sciences” and “Environmental Sciences and Ecology,” followed by “Cell Biology.” The most used keywords were genotoxicity, pesticides, and insecticide. The meta-analytical test showed that the number of micronuclei found in onion cells treated with insecticides is higher than that in untreated ones, and the use of pesticides reduced the mitotic index. In conclusion, it is evident the need for more studies about biotechnology, nanotechnology, and biopesticides to develop safer pesticides.

Sewage sludge is a cost-effective media for the production of Bacillus thuringiensis (Bt) based biopesticides. To enhance the entomotoxicity of the fermentation broth, pretreatments of sewage sludge by alkali and ultrasonic were applied in this study. Effects of alkaline and ultrasonic pretreatments on the soluble COD (SCOD) and total COD (TCOD) were evaluated by altering the alkali addition dose and the ultrasonic specific energy. Suitable pretreatment conditions were optimized with 5 g l-¹ sodium hydroxide (NaOH) for alkaline treatment and 1.2 x 10⁵ kJ kg-¹ of total solid for ultrasonic treatment. Fermentations of raw and pretreated sludge for biopesticides were carried out in a bench scale fermentor. Results revealed that both pretreatments were effective for Bt growth and metabolism. Higher viable cells (VC) and viable spores (VS) counts, δ-endotoxin yields and entomotoxicity were achieved in the pretreated sludge. The enhancement was attributed to more available nutrients and better oxygen transfer. Moreover, ultrasonic pretreated sludge was superior to alkaline pretreated sludge for δ-endotoxin production and entomotoxicity owing to its higher soluble C/N ratio and finer particles.