International audience | Incidence rates of hematological malignancies have been constantly increasing over the past 40 years. In parallel, an expanding use of agricultural pesticides has been observed. Only a limited number of studies investigated the link between hematological malignancies risk and passive environmental residential exposure to agricultural pesticides in the general population. The purpose of our review was to summarize the current state of knowledge on that question. A systematic literature search was conducted using PubMed and Scopus databases. We built a scoring scale to appraise relevance of each selected articles. We included 23 publications: 13 ecological studies, 9 case-control studies and a cohort study. Positive associations were reported between hematological malignancies and individual pesticides, pesticide groups, all pesticides without distinction, or some crop types. Relevance score was highly various across studies regardless of their design. Children studies were the majority and had overall higher relevance scores. The effect of passive environmental residential exposure to agricultural pesticides on hematological malignancies risk is suggested by the literature. The main limitation of the literature available is the high heterogeneity across studies, especially in terms of exposure assessment approach. Further studies with high methodological relevance should be conducted.

International audience | Metal(loid)s found at many sites as a result of human activities induce contamination of ecosystems, which threatens the environment and public health. Several approaches can be used in order to reduce such negative impacts of pollutants, and among them, phytoremediation has gained attractive attention. The objective of the present study was to assess the capacity of Populus euramericana, Dorskamp cultivar, for the phytoremediation of metal(loid)s on a technosol (former mining site) highly contaminated mainly with Pb and As, and amended with biochars having different particle sizes. In a 46-day mesocosm glasshouse pot experiment, technosol was mixed at three ratios (0, 2, or 5% w/w) with four different hardwood-derived biochars (with various particle sizes) in order to study the biochar application rate and particle size effects on soil pore water (SPW) characteristics, on poplar growth, and on metal(loid) distribution and concentrations in the plant organs. The results showed that all biochars tested had a significant impact on several SPW physico-chemical parameters. Especially, biochar additions reduced available Pb concentrations but with no effect on As. In such conditions, Populus growth in amended technosol increased whatever rate and particle size of biochar used. Metal(loid) concentrations and repartition in plant organs showed the following: (1) for Pb, a higher root concentration with low aerial part translocation, which depended on biochar used, and (2) for As, mainly a root sequestration. We identified biochar with the finest particle size and combined with P. euramericana, Dorskamp, was the most suitable as remediation tools for Pb stabilization in post-mining contaminated soils.

International audience | This study aimed to better understand the impact of different bauxite residues (BR) on the germination and the development of Sinapis alba (white mustard). Unamended BR from Provence, France (PRO), and Guinea (GUI) bauxite were selected, and modified bauxite residues from PRO and GUI (MBRPRO and MBR-GUI) were obtained by gypsum application and repeated leaching, in order to reduce their pH, electrical conductivity (EC), and exchangeable sodium percentage (ESP). Germination rates were monitored in soil-BR mixtures with increasing concentrations of BR. A rhizotron experiment was done, where Sinapis alba was allowed to develop in a layer of soil on the top of a layer of bauxite residue. To assess the impact of the residue on root development, the WhinRhizo (R) software was used to measure the architectural traits of roots. Peroxidase and fluorescein hydrolase activities were also assessed on the roots grown either in the soil or in the residue layers. Results showed that (i) bauxite residue origin, (ii) bauxite residue modification by gypsum, and (iii) bauxite residue concentration had significant effects on the germination, the root development and architecture, and the enzymatic activities of the roots of Sinapis alba. The PRO residue had a far stronger phytotoxic effect compared to the GUI residue on every measured variable. The toxic effect was strongly modulated by the origin of bauxite residue. The gypsum application efficiently reduced the phytotoxic effect of the residues, but significant negative effects on the different variables were still recorded.

Although fungicides were previously considered to be safe for important agricultural pollinators such as honey bees, recent evidence has shown that they can cause a number of behavioral and physiological sublethal effects. Here, we focus on the fungicide Pristine® (active ingredients: 25.2% boscalid, 12.8% pyraclostrobin), which is sprayed during the blooming period on a variety of crops and is known to affect honey bee mitochondria at field-relevant levels. To date, no study has tested the effects of a field-relevant concentration of a fungicide on associative learning ability in honey bees. We tested whether chronic, colony-level exposure at field-relevant and higher concentrations of Pristine® impairs performance on the proboscis extension reflex (PER) paradigm, an associative learning task. Learning performance was reduced at higher field-relevant concentrations of Pristine®. The reductions in learning performance could not be explained by effects on hunger or motivation, as sucrose responsiveness was not affected by Pristine® exposure. To determine whether Pristine®‘s negative effects on learning performance were mediated at a specific life stage, we conducted a cross-fostering experiment that exposed bees to the fungicide either only as larvae, only as adults, or during both stages. We found that exposure across the entire life was necessary to significantly reduce learning performance, although non-significant reductions occurred when bees were exposed during just one stage. Our study provides strong evidence that Pristine® has significant sublethal effects on learning performance. As associative learning is a necessary ability for foraging, our results raise concerns that Pristine® could impair foraging abilities and substantially weaken colony health.

Evidence about the adverse effects of methamphetamine (METH) on invertebrates is scarce. Hence, C. elegans, a representative invertebrate model, was exposed to METH at environmental levels to estimate chronic and transgenerational toxicity. The results of chronic exposure were integrated into an underlying toxicity framework of METH in invertebrates (e.g., benthos) at environmentally relevant concentrations. The induction of cellular oxidative damage-induced apoptosis and fluctuation of ecologically important traits (i.e., feeding and locomotion) might be attributed by the activation of the longevity regulating pathway regulated by DAF-16/FOXO, and detoxification by CYP family enzymes. The adverse effects to the organism level included impaired viability and decreased fecundity. The results from transgenerational exposure elucidated the cumulative METH-induced damage in invertebrates. Finally, a new risk assessment method named toxicity indicator sensitivity distribution (TISD) analysis was proposed by combining multiple toxicity indicator test data (ECₓ) to derive the hazardous concentration for 10% indicators (C₁₀) of one species. The risk quotient (RQ) values calculated by measured environmental concentrations and C₁₀ in southern China, southeastern Australia, and the western US crossed the alarm line (RQ = 5), suggesting a need for long-term monitoring.

This study aimed to analyze the environmental impacts of the oxidative desulfurization (ODS) process catalyzed by metal-free reduced graphene oxide (rGO) through life cycle assessment (LCA). The environmental impacts study containing the rGO production process, the ODS process, the comparison of different oxidants and solvents was developed. This study was performed by using ReCiPe 2016 V1.03 Hierarchist midpoint as well as endpoint approach and SimaPro software. For the production of 1 kg rGO, the results showed that hydrochloric acid (washing), sulfuric acid (mixing), hydrazine (reduction) and electricity were four main contributors in this process, and this process showed a significant impact on human health 14.21 Pt followed by ecosystem 0.845 Pt and resources 0.164 Pt. For the production of 1 kg desulfurized oil (400 ppm), main environmental impacts were terrestrial ecotoxicity (43.256 kg 1,4-DCB), global warming (41.058 kg CO₂), human non-carcinogenic toxicity (19.570 kg 1,4-DCB) and fossil resource scarcity (13.178 kg oil), and the main contributors were electricity, diesel oil and acetonitrile. The whole ODS process also showed a greatest effect on human health. For two common oxidants hydrogen peroxide and oxygen used in ODS, hydrogen peroxide showed a greater impact than oxygen. On the other hand, for three common solvents employed in ODS, N-methyl-2-pyrrolidone had a more serious impact on human health followed by acetonitrile and N,N-dimethylformamide. As such, LCA results demonstrated the detailed environmental impacts originated from the catalytic ODS, hence elucidating systematic guidance for its future development toward practicality.

Dichlorodiphenyltrichloroethane (DDT) poses a significant health risk to humans which is associated with genomic DNA hypomethylation. However, the mechanism and biological consequences remain poorly understood. In vitro assays confirmed that the DDT metabolites 2,2-bis(p-chlorophenyl)-acetic acid (DDA) and 1-chloro-2,2-bis-(p-chlorophenyl)ethylene (DDMU), but not other DDT metabolites, significantly inhibited DNA methyltransferase 1 (DNMT1) activity, leading to genomic hypomethylation in cell culture assays. DNMT1 as a target for DNA hypomethylation induced by DDT metabolites was also confirmed using cell cultures in which DNMT1 was silenced or highly expressed. DDA and DDMU can modify methylation markers in the promoter regions of sexual development-related genes, and change the expression of Sox9 and Oct4 in embryonic stem cells. Molecular docking indicated that DDA and DDMU bound to DNMT1 with high binding affinity. Molecular dynamic simulation revealed that DDA and DDMU acted as allosteric modulators that reshaped the conformation of the catalytic domain of DNMT1. These findings provide a new insight into DDT-induced abnormalities in sexual development and demonstrate that selective binding to DNMT1 by DDA and DDMU can interfere with human DNMT1 activity and regulate the expression of the Sox9 and Oct4 genes.

Road runoff is an important vector for the transport of chemicals originating from tire wear into receiving waters. In this study, samples of surface water were collected in the summer of 2020 from two rivers near high-traffic corridors in the Greater Toronto Area (GTA) in Canada. These samples were analyzed for two additives used in tire production, 1,3-diphenyl guanidine (DPG) and hexamethoxymethylmelamine (HMMM), as well 26 of the transformation compounds of HMMM. In addition, samples were analyzed for 6PPD-quinone (6PPD-q), an oxidation by-product of a tire additive that was recently identified as a candidate compound responsible for mass mortalities of Coho salmon (Oncorhynchus kisutch) in spawning streams in the USA. Grab and composite samples were collected during rain events (i.e., wet events) at both locations. Grab samples were collected from the Don River upstream, downstream and at the point of discharge from a municipal wastewater treatment plant (WWTP) during a period of dry weather. Of the target analytes, 6PPD-q, DPG and HMMM, as well as 15 of the transformation compounds of HMMM, were detected at concentrations above limits of quantitation. The concentrations of 6PPD-q in the receiving waters during wet events were within the range of the LC50 for adult Coho salmon. One of the transformation products (TPs) of HMMM, dimethoxymethylmelamine was detected in a composite sample from Highland Creek at an estimated concentration greater than 10 μg/L, indicating that more research is needed to evaluate the potential hazards to the aquatic environment from this compound. Sampling in the Don River during a dry period showed that discharges of wastewater from WWTPs are also continuous sources of the TPs of HMMM. This study contributes to the growing literature showing that chemicals derived from tire wear are ubiquitous in urban watersheds and may be a significant hazard to aquatic organisms.

The increasing number of chemicals used by society requires accessible, easy to implement tools to perform screening-level ecological risk assessments. However, field data to calibrate and validate screening tools is challenging to obtain for many watersheds. Thus, the evaluation must be done under data limited conditions. Here we employ a fate and transport model, OrganoFate, to predict environmental concentrations of contaminants of emerging concern (CECs) as well as a number of pesticides. CECs evaluated include antibacterial compounds sulfamethoxazole and triclocarban and a flame-retardant tris(1,3-dichloro-2-propyl)phosphate (TDCPP). We also evaluated widely used pesticides chlorpyrifos, bifenthrin and esfenvalerate. We predict concentrations of the contaminants in high-risk watersheds which were dominated by either urban or agricultural development and have small aquatic compartments. Screening-level predictions were in good agreement with observed concentrations in surface water and sediment. Maximum predicted concentrations were close to the highest observed concentrations for CECs, only ~0.1 μg/L greater for sulfamethoxazole and triclocarban concentrations, and for TDCPP <5 μg/L higher. ChemFate was also employed to screen possible aquatic health impacts. Results demonstrated possible CEC aquatic health risk for TDCPP and triclocarban (risk quotients of 0.9 and 1.1 respectively). For pesticides, exceedance of effect (EC50) and lethal (LC50) endpoints was predicted for various taxonomic groups which include aquatic invertebrates, fish, amphibians, and benthic organisms.

Silver nanoparticles (AgNPs) are among the major groups of contaminants of emerging concern for aquatic ecosystems. The massive application of AgNPs relies on the antimicrobial properties of Ag, raising concerns about their potential risk to ecologically important freshwater microbes and the processes they drive. Moreover, it is still uncertain whether the effects of AgNPs are driven by the same mechanisms underlying those of Ag ions (Ag⁺). We employed transcriptomics to better understand AgNP toxicity and disentangle the role of Ag⁺ in the overall toxicity towards aquatic fungi. To that end, the worldwide-distributed aquatic fungus Articulospora tetracladia, that plays a central role in organic matter turnover in freshwaters, was selected and exposed for 3 days to citrate-coated AgNPs (∼20 nm) and Ag⁺ at concentrations inhibiting 20% of growth (EC₂₀). Responses revealed 258 up- and 162 down-regulated genes upon exposure to AgNPs and 448 up- and 84 down-regulated genes under exposure to Ag⁺. Different gene expression patterns were found after exposure to each silver form, suggesting distinct mechanisms of action. Gene ontology (GO) analyses showed that the major cellular targets likely affected by both silver forms were the biological membranes. GO-based biological processes indicated that AgNPs up-regulated the genes involved in transport, nucleobase metabolism and energy production, but down-regulated those associated with redox and carbohydrate metabolism. Ag⁺ up-regulated the genes involved in carbohydrate and steroid metabolism, whereas genes involved in localization and transport were down-regulated. Our results showed, for the first time, distinct profiles of gene expression in aquatic fungi exposed to AgNPs and Ag⁺, supporting different modes of toxicity of each silver form. Also, our results suggest that Ag⁺ had a negligible role in the toxicity induced by AgNPs. Finally, our study highlights the power of transcriptomics in portraying the stress induced by different silver forms in organisms.