International audience | Azoles represent the most used family of organic fungicides worldwide and they are used in agriculture to circumvent the detrimental impact of fungi on yields. Although it is known that these triazoles can contaminate the air, the soil, and the water, field data are currently and dramatically lacking to assess if, and to what extent, the use of triazoles could contaminate non-target wild vertebrate species, notably in agroecosystems. In this study, we aimed to document for the first time the degree of blood contamination of a generalist wild bird species by multiple azoles which are used for plant protection and fungi pest control in various habitats. We deployed passive air samplers and captured 118 Common blackbirds (Turdus merula) in an agroecosystem (vineyard), a protected forest, and a city in western France. We collected blood and analyzed the plasma levels of 13 triazoles and 2 imidazoles. We found that a significant percentage of blackbirds living in vineyards have extremely high plasma levels of multiple azoles (means (pg.g⁻¹); tebuconazole: 149.23, difenoconazole: 44.27, fenbuconazole: 239.38, tetraconazole: 1194.16), while contamination was very limited in the blackbirds from the protected forest and absent in urban blackbirds. Interestingly, we also report that the contamination of blackbirds living in vineyard was especially high at the end of Spring and the beginning of Summer and this matches perfectly with the results from the passive air samplers (i.e., high levels of azoles in the air of vineyards during June and July). However, we did not find any correlation between the levels of plasma contamination by azoles and two simple integrative biomarkers of health (feather density and body condition) in this sentinel species. Future experimental studies are now needed to assess the potential sub-lethal effects of such levels of contamination on the physiology of non-target vertebrate species.

As a common fungicide, tebuconazole are ubiquitous in the natural environment and poses many potential risks. In this study, we examined the effects of exposure to tebuconazole on colitis in mice and explored its underlying mechanism. Specifically, exposure to tebuconazole could cause structural damage and inflammatory cell infiltration in colon tissue, activate the expression of inflammation-related genes, disrupt the expression of barrier function-related genes, and induce the colonic inflammation in mice. Similarly, exposure to tebuconazole could also exacerbate DSS-induced colitis in mice. In addition, we found that tebuconazole also could change the composition of the gut microbiota. In particular, tebuconazole significantly increases the relative abundance of Akkermansia of mice. Moreover, tebuconazole resulted in metabolic profiles disorders of the serum, leading to significant changes in the relative contents of metabolites involving glycolipid metabolism and amino acid metabolism. Particularly, the results of the gut microbiota transplantation experiment showed that exposure to tebuconazole could induced colonic inflammation in mice in a gut microbiota–dependent manner. Taken together, these results indicated that tebuconazole could induce colitis in mice via regulating gut microbiota. Our findings strongly support the concept that the gut microbiota is a key trigger of inflammatory bowel disease caused by pesticide intake.

Exposure to environmental endocrine disrupting chemicals (EDCs) is highly suspected in prostate carcinogenesis. Though, estrogenicity is the most studied behavior of EDCs, the androgenic potential of most of the EDCs remains elusive. This study investigates the androgen mimicking potential of some common EDCs and their effect in androgen-dependent prostate cancer (LNCaP) cells. Based on the In silico interaction study, all the 8 EDCs tested were found to interact with androgen receptor with different binding energies. Further, the luciferase reporter activity confirmed the androgen mimicking potential of 4 EDCs namely benzo[a]pyrene, dichlorvos, genistein and β-endosulfan. Whereas, aldrin, malathion, tebuconazole and DDT were reported as antiandrogenic in luciferase reporter activity assay. Next, the nanomolar concentration of androgen mimicking EDCs (benzo[a]pyrene, dichlorvos, genistein and β-endosulfan) significantly enhanced the expression of AR protein and subsequent nuclear translocation in LNCaP cells. Our In silico studies further demonstrated that androgenic EDCs also bind with epigenetic regulatory enzymes namely DNMT1 and HDAC1. Moreover, exposure to these EDCs enhanced the protein expression of DNMT1 and HDAC1 in LNCaP cells. These observations suggest that EDCs may regulate proliferation in androgen sensitive LNCaP cells by acting as androgen mimicking ligands for AR signaling as well as by regulating epigenetic machinery. Both androgenic potential and epigenetic modulatory effects of EDCs may underlie the development and growth of prostate cancer.

Tebuconazole is a broad-spectrum triazole fungicide that has been extensively applied in agriculture, but its toxicity on soil ecology remains unknown after repeated introduction to soil. This study investigated the degradation of tebuconazole and the changes in soil microbial community composition and functional diversity as well as network complexity in soil repeatedly treated with tebuconazole. Tebuconazole degraded slowly as the degradation half-life initially increased and then decreased during the four repeated treatments. High concentration of tebuconazole treatment significantly delayed the degradation of tebuconazole. The soil microbial functional diversity in tebuconazole-treated soils showed an inhibition-recovery-stimulation trend with increasing treatment frequency, which was related to the increased degradation rates of tebuconazole. Tebuconazole significantly decreased soil microbial biomass and bacterial community diversity, and this decreasing trend became more pronounced with increasing treatment frequency and concentration. Moreover, tebuconazole significantly decreased soil bacterial community network complexity, particularly at high concentration of tebuconazole treatment. Notably, four bacterial genera, Methylobacterium, Burkholderia, Hyphomicrobium, and Dermacoccus, were identified as the potential tebuconazole-degrading bacteria, with the relative abundances in the tebuconazole treatment significantly increasing by 42.1–34687.1% compared to the control. High concentration of tebuconazole treatment delayed increases in the relative abundances of Methylobacterium but promoted those of Burkholderia, Hyphomicrobium and Dermacoccus. Additionally, repeated tebuconazole treatments improved only four metabolic pathways, cell motility, membrane transport, environmental information processing, and xenobiotics biodegradation and metabolism, which were associated with the degradation of tebuconazole. The above results indicated that repeated tebuconazole treatments resulted in the significant accumulation of residues and long-term negative effects on soil ecology, and also emphasized the potential roles of dominant indigenous microbial bacteria in the degradation of tebuconazole.

The agroeconomic benefits of the routine use of triazole fungicides on crops have been evident for more than 40 years. However, increasing evidence shows that residues of triazoles are ubiquitous in various foods and thus could pose a potential health risk to humans. We analyzed 3406 samples of 13 food commodities that were collected from markets in 9 regions across China, and assessed the health risk of both chronic and acute exposure to the triazoles for Chinese children (1–6 years old) and the general population. Among all samples, 55.52% had triazoles in concentrations of 0.10–803.30 μg/kg, and 29.77% of samples contained a combination of 2–7 triazoles. Tebuconazole and difenoconazole were the most commonly found triazoles in the foods, being detected in 33.44% and 30.45% of samples, respectively. Chronic and acute cumulative risk assessment for total triazoles based on a relative potency factor method revealed that exposure to triazoles from these particular commodities was below the levels that might pose a health risk (chronic hazard index range, 5.90×10⁻⁷ to 1.83×10⁻³; acute hazard index range, 7.77×10⁻⁵ to 0.39, below 1). Notably, dietary exposure risk for children was greater than that for the general population—particularly for the acute intake of mandarin, grape, and cucumber (acute hazard index values of 0.35–0.39). Despite the low health risk, the potential hazards of exposure to triazoles should raise public concern owing to their ubiquitous presence in common foods and potential cumulative effects.

Aspergillus fumigatus is the primary agent of invasive aspergillosis (IA) causing high morbidity and mortality in immunocompromised patients. Triazole resistance in A. fumigatus and its sources have gained wide attention. For several years, environmental fungicides use has been proposed as the major cause for triazole resistance in A. fumigatus. However, there are few studies on azole-resistant A. fumigatus (ARAF) selected by triazole fungicides in agricultural systems. We studied the possible emergence of ARAF in the field after exposure to triazole fungicide tebuconazole. Our results showed that exposure to tebuconazole in soil selects for resistance to triazoles in A. fumigatus. The probability of ARAF developing in soils depends upon the concentrations of tebuconazole after application. We suggest that tebuconazole applications should be minimized to reduce selective pressure for the generation of ARAFs.

Waterborne exposure towards fungicides is known to trigger negative effects in aquatic leaf-associated microbial decomposers and leaf-shredding macroinvertebrates. We expected similar effects when these organisms use leaf material from terrestrial plants that were treated with systemic fungicides as a food source since the fungicides may remain within the leaves when entering aquatic systems. To test this hypothesis, we treated black alder (Alnus glutinosa) trees with a tap water control or a systemic fungicide mixture (azoxystrobin, cyprodinil, quinoxyfen, and tebuconazole) at two worst-case application rates. Leaves of these trees were used in an experiment targeting alterations in two functions provided by leaf-associated microorganisms, namely the decomposition and conditioning of leaf material. The latter was addressed via the food-choice response of the amphipod shredder Gammarus fossarum. During a second experiment, the potential impact of long-term consumption of leaves from trees treated with systemic fungicides on G. fossarum was assessed. Systemic fungicide treatment altered the resource quality of the leaf material resulting in trends of increased fungal spore production and an altered community composition of leaf-associated fungi. These changes in turn caused a significant preference of Gammarus for microbially conditioned leaves that had received the highest fungicide treatment over control leaves. This higher food quality ultimately resulted in a higher gammarid growth (up to 300% increase) during the long-term feeding assay. Although the underlying mechanisms still need to be addressed, the present study demonstrates a positive indirect response in aquatic organisms due to systemic pesticide application in a terrestrial system. As the effects from the introduction of plant material treated with systemic fungicides strongly differ from those mediated via other pathways (e.g., waterborne exposure), our study provides a novel perspective of fungicide-triggered effects in aquatic detritus-based food webs.

Phytoremediation of realistic environmental concentrations (10 μg L−1) of the chiral pesticides tebuconazole and imazalil by Phragmites australis was investigated. This study focussed on removal dynamics, enantioselective mechanisms and transformation products (TPs) in both hydroponic growth solutions and plant tissues. For the first time, we documented uptake, translocation and metabolisation of these pesticides inside wetland plants, using enantioselective analysis. Tebuconazole and imazalil removal efficiencies from water reached 96.1% and 99.8%, respectively, by the end of the experiment (day 24). Removal from the solutions could be described by first-order removal kinetics with removal rate constants of 0.14 d−1 for tebuconazole and 0.31 d−1 for imazalil. Removal of the pesticides from the hydroponic solution, plant uptake, within plant translocation and degradation occurred simultaneously. Tebuconazole and imazalil concentrations inside Phragmites peaked at day 10 and 5d, respectively, and decreased thereafter. TPs of tebuconazole i.e., (5-(4-Chlorophenyl)-2,2-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)-1,3-pentanediol and 5-(3-((1H-1,2,4-Triazol-1-yl)methyl)-3-hydroxy-4,4-dimethylpentyl)-2-chlorophenol) were quantified in solution, while the imazalil TPs (α-(2,4-Dichlorophenyl)-1H-imidazole-1-ethanol and 3-[1-(2,4-Dichlorophenyl)-2-(1H-imidazol-1-yl)ethoxy]-1,2-propanediol) were quantified in both solution and plant tissue. Pesticide uptake by Phragmites was positively correlated with evapotranspiration. Pesticide removal from the hydroponic solution was not enantioselective. However, tebuconazole was degraded enantioselectively both in the roots and shoots. Imazalil translocation and degradation inside Phragmites were also enantioselective: R-imazalil translocated faster than S-imazalil.

Triazole fungicides are widely used as broad-spectrum fungicides, non-steroidal antiestrogens and for various industrial applications. Their residues have been frequently detected in multiple environmental and human matrices. The increasingly reported toxicity incidents have led triazole fungicides as emerging contaminants of environmental and public health concern. However, whether triazole fungicides behave as endocrine disruptors by directly mimicking environmental androgens/antiandrogens or exerting potential androgenic disruption indirectly through the inhibition of cytochrome P450 (CYP450) enzyme activity is yet an unresolved question. We herein evaluated five commonly used triazole fungicides including bitertanol, hexaconazole, penconazole, tebuconazole and uniconazole for the androgenic and anti-androgenic activity using two-hybrid recombinant human androgen receptor (AR) yeast bioassay and comparatively evaluated their effects on enzymatic activity of CYP3A4 by P450-Glo™ CYP3A4 bioassay. All five fungicides showed moderate anti-androgenic activity toward human AR with the IC50 ranging from 9.34 μM to 79.85 μM. The anti-androgenic activity remained no significant change after the metabolism mediated by human liver microsomes. These fungicides significantly inhibited the activity of CYP3A4 at the environmental relevant concentrations and the potency ranks as tebuconazole > uniconazole > hexaconazole > penconazole > bitertanol with the corresponding IC50 of 0.81 μM, 0.93 μM, 1.27 μM, 2.22 μM, and 2.74 μM, respectively. We found that their anti-androgenic activity and the inhibition potency toward CYP3A4 inhibition was significantly correlated (R2 between 0.83 and 0.97, p < 0.001). Our results indicated that the risk assessment of triazole pesticides and structurally similar chemicals should fully consider potential androgenic disrupting effects and the influences on the activity of CYP450s.

Pesticides generate transformation products (TPs) when they are released into the environment. These TPs may be of ecotoxicological importance. Past studies have demonstrated how difficult it is to predict the occurrence of pesticide TPs and their environmental risk. The monitoring approaches mostly used in current regulatory frameworks target only known ecotoxicologically relevant TPs. Here, we present a novel combined approach which identifies and categorizes known and unknown pesticide TPs in soil by combining suspect screening time-of-flight mass spectrometry with in silico molecular typology. We used an empirical and theoretical pesticide TP library for compound identification by both non-target and target time-of-flight (tandem) mass spectrometry, followed by structural proposition through a molecular structure correlation program. In silico molecular typology was then used to group TPs according to common molecular descriptors and to indirectly elucidate their environmental parameters by analogy to known pesticide compounds with similar molecular descriptors. This approach was evaluated via the identification of TPs of the triazole fungicide tebuconazole occurring in soil during a field dissipation study. Overall, 22 empirical and 12 yet unknown TPs were detected, and categorized into three groups with defined environmental properties. This approach combining suspect screening time-of-flight mass spectrometry with molecular typology could be extended to other organic pollutants and used to rationalize the choice of TPs to be investigated towards a more comprehensive environmental risk assessment scheme.