Mycotoxins in the environment: II. Occurrence and origin in Swiss river waters

Ribosomal proteins mediate non-canonical regulation of gut inflammatory signature by crop contaminant deoxynivalenol

Deoxynivalenol (DON), a prevalent mycotoxin produced by Fusarium species, contaminates global agricultural products and poses significant health risks, particularly to the gastrointestinal (GI) system. DON exposure disrupts ribosomal function, inducing stress responses linked to various inflammatory diseases, including inflammatory bowel disease (IBD). In this study, we elucidate a novel regulatory mechanism involving ribosomal proteins (RPs) RPL13A and RPS3, which mediate proinflammatory chemokine production in DON-exposed gut epithelial cells. Through a combination of transcriptomic analysis and experimental models, we demonstrate that while RPL13A negatively regulates inflammation by enhancing the anti-inflammatory transcription factor ATF3, RPS3 acts as a proinflammatory driver, promoting chemokine production via activation of MAPK pathways, transcriptional upregulation of EGR-1, and stabilization of mRNA through cytosolic translocation of HuR. Our findings reveal a dynamic interplay between RPL13A and RPS3, wherein RPL13A counteracts the proinflammatory effects of RPS3, offering a finely tuned regulatory axis in the inflammatory response to environmental toxins. These insights provide potential molecular targets for therapeutic intervention in toxin-induced inflammatory diseases of the gut, highlighting the non-canonical roles of ribosomal proteins in modulating immune responses to environmental stressors.

The potential of soil microbial communities to transform deoxynivalenol in agricultural soils-a soil microcosm study

Infestation of cereal fields with toxigenic Fusarium species is identified as an environmental source for the mycotoxin deoxynivalenol (DON). During rain events, DON may be washed off from infested plants and enter the soil, where microbial transformation may occur. Although some studies showed DON transformation potential of soil microbial communities in liquid soil extracts, these findings can not be transferred to environmental conditions. Accordingly, microbial transformation of DON in soil has to be investigated under realistic conditions, e.g., microcosms mimicking field situations. In this study, we investigated the potential of soil microbial communities to transform DON in six different agricultural soils at two levels (0.5 and 5 µg g-1). The dissipation and the formation of transformation products were investigated in a period of 35 days and compared to a sterilized control. In addition, we measured soil respiration and applied the phospholipid-derived fatty acid (PLFA) analysis to assess whether soil microbial community characteristics are related to the microbial transformation potential. Dissipation of DON in non-sterilized soils was fast (50% dissipation within 0.6-3.7 days) compared to the sterile control where almost no dissipation was observed. Thus, dissipation was mainly attributed to microbial transformation. We verified that small amounts of DON are transformed to 3-keto-deoxynivalenol (3-keto-DON) and 3-epi-deoxynivalenol (3-epi-DON), which were not detectable after 16-day incubation, indicating further transformation processes. There was a trend towards faster transformation in soils with active and large microbial communities and low fungi-to-bacteria ratio.

Effect of the aflatoxins B1 and M1 on bovine oocyte developmental competence and embryo morphokinetics

Aflatoxins are considered as reproductive toxins for mammalian species. Here, we studied the effect of aflatoxin B1 (AFB1) and its metabolite aflatoxin M1 (AFM1) on the development and morphokinetics of bovine embryos. Cumulus oocyte complexes (COCs) were matured with AFB1 (0.032, 0.32, 3.2, 32 µM) or AFM1 (0.015, 0.15, 1.5, 15, 60 nM), then fertilized and the putative zygotes were cultured in an incubator equipped with a time-lapse system. Exposing COCs to 32 µM AFB1 or 60 nM AFM1 reduced the cleavage rate, whereas exposing them to 3.2 or 32 µM AFB1 further reduced the blastocyst formation. A delay was recorded for the first and second cleavages in a dose-dependent manner for both AFB1- and AFM1-treated oocytes. A delay was recorded in the third cleavage in the AFM1-treated group. To explore potential mechanisms, subgroups of COCs were examined for nuclear and cytoplasmic maturation (n = 225; DAPI and FITC-PNA, respectively), and mitochondrial function was examined in a stage-dependent manner. COCs were examined for their oxygen consumption rates (n = 875; Seahorse XFp analyzer) at the end of maturation, MII-stage oocytes were examined for their mitochondrial membrane potential (n = 407; JC1), and putative zygotes were examined using a fluorescent time-lapse system (n = 279; IncuCyte). Exposing COCs to AFB1 (3.2 or 32 µM) impaired oocyte nuclear and cytoplasmic maturation and increased mitochondrial membrane potential in the putative zygotes. These alterations were associated with changes in the expression of mt-ND2 (32 µM AFB1) and STAT3 (all AFM1 concentrations) genes in the blastocyst stage, suggesting a carryover effect from the oocyte to the developing embryos.

Xenobiotic-induced ribosomal stress compromises dysbiotic gut barrier aging: A one health perspective

Upon exposure to internal or environmental insults, ribosomes stand sentinel. In particular, stress-driven dysregulation of ribosomal homeostasis is a potent trigger of adverse outcomes in mammalians. The present study assessed whether the ribosomal insult affects the aging process via the regulation of sentinel organs such as the gut. Analyses of the human aging dataset demonstrated that elevated features of ribosomal stress are inversely linked to barrier maintenance biomarkers during the aging process. Ribosome-insulted worms displayed reduced lifespan, which was associated with the disruption of gut barriers. Mechanistically, ribosomal stress-activated Sek-1/p38 signaling, a central platform of ribosomal stress responses, counteracted the gut barrier deterioration through the maintenance of the gut barrier, which was consistent with the results in a murine insult model. However, since the gut-protective p38 signaling was attenuated with aging, the ribosomal stress-induced distress was exacerbated in the gut epithelia and mucosa of the aged animals, subsequently leading to increased bacterial exposure. Moreover, the bacterial community-based evaluation predicted concomitant increases in the abundance of mucosal sugar utilizers and mucin metabolic enzymes in response to ribosomal insult in the aged host. All of the present evidence on ribosomal insulting against the gut barrier integrity from worms to mammals provides new insights into organelle-associated translational modulation of biological longevity in a one health perspective.

Mycotoxins and Essential Oils-From a Meat Industry Hazard to a Possible Solution: A Brief Review

The preservation of food supplies has been humankind's priority since ancient times, and it is arguably more relevant today than ever before. Food sustainability and safety have been heavily prioritized by consumers, producers, and government entities alike. In this regard, filamentous fungi have always been a health hazard due to their contamination of the food substrate with mycotoxins. Additionally, mycotoxins are proven resilient to technological processing. This study aims to identify the main mycotoxins that may occur in the meat and meat products "Farm to Fork" chain, along with their effect on the consumers' health, and also to identify effective methods of prevention through the use of essential oils (EO). At the same time, the antifungal and antimycotoxigenic potential of essential oils was considered in order to provide an overview of the subject. Targeting the main ways of meat products' contamination, the use of essential oils with proven in vitro or in situ efficacy against certain fungal species can be an effective alternative if all the associated challenges are addressed (e.g., application methods, suitability for certain products, toxicity).

Sensitive, simultaneous and quantitative detection of deoxynivalenol and fumonisin B1 in the water environment using lateral flow immunoassay integrated with smartphone

Deoxynivalenol (DON) and fumonisin B₁ (FB₁), as a group of highly toxic secondary metabolites, have become a potential source of water environmental pollutants. To minimize two mycotoxins exposure to consumers, a dual lateral flow immunoassay (LFIA) integrated with the smartphone was reported for simultaneous and quantitative detection of DON and FB₁ in the water environment. The significantly improved sensitivity was contributed to a smartphone-based device with the ability to image and analyze results. Under optimized conditions, the detection limits of DON and FB₁ were calculated to be 3.46 and 2.65 ng/mL, which were approximately 25 and 10 folds lower than those of the visual detection of the LFIA. This method showed good specificity and a good dynamic linear detection for DON and FB₁. The recoveries of DON and FB₁ were evaluated by the spiked lake water, river water, and pond water, ranging from 92.47% to 106.2% with the relative standard deviation under 9.13%. Moreover, the results of the developed LFIA showed a high correlation with enzyme-linked immunosorbent assay (ELISA) results, with a correlation coefficient of 0.999 for DON and 0.996 for FB₁, respectively. To sum up, the developed LFIA provides a promising platform for sensitive, simultaneous, quantitative, and on-site detection of DON and FB₁ in the water environment.

How does multiannual plastic mulching in strawberry cultivation influence soil fungi and mycotoxin occurrence in soil?

The production of mycotoxins is often interpreted as fungal response to cope with unfavorable growth conditions induced by toxic substances, environmental and biological factors. Soil covers influence soil environment, which consequently can change the abundance and composition of microbial communities. We investigated how plastic coverage (PC) influence soil fungi and mycotoxin occurrence (deoxynivalenol, nivalenol and zearalenone) compared to the traditional straw coverage (SC) in dependence of soil depth and time in a 3-year field experiment in strawberry cultivation. In total, 300 soil samples, resulting from two treatments, three soil layers, and ten sampling dates (n = 5), were analyzed for mycotoxins and ergosterol (proxy for soil fungal biomass) with liquid chromatography high resolution mass spectrometry and high-performance liquid chromatography with UV-detection, respectively. The modified microclimate under PC had no significant influence on fungal biomass, whereas SC promoted fungal biomass in the topsoil due to C-input. Mycotoxins were detected under both cover types in concentrations between 0.3 and 21.8 µg kg⁻¹, mainly during strawberry establishment period and after fungicide application. Deoxynivalenol had the highest detection frequency with 26.3% (nivalenol: 8.3%, zearalenone: 8.7%). This study confirmed the in situ production of mycotoxins in soil, which seems mainly triggered by field treatment (fungicide application) and plant growth stage (establishment period) rather than on mulching type. Further investigations are necessary to better understand the influence of different agricultural practices and soil types on the production and fate of mycotoxins.

Fusarium Mycotoxins in Maize Field Soils: Method Validation and Implications for Sampling Strategy

While mycotoxins are generally regarded as food contamination issues, there is growing interest in mycotoxins as environmental pollutants. The main sources of trichothecene and zearalenone mycotoxins in the environment are mainly attributed to Fusarium infested fields, where mycotoxins can wash off in infested plants or harvest residues. Subsequently, mycotoxins inevitably enter the soil. In this context, investigations into the effects, fate, and transport are still needed. However, there is a lack of analytical methods used to determine Fusarium toxins in soil matrices. We aimed to validate an analytical method capable of determining the toxins nivalenol (NIV), deoxynivalenol (DON), 15-acetyl-deoxynivalenol (15-AcDON), and zearalenone (ZEN), at environmentally relevant concentrations, in five contrasting agricultural soils. Soils were spiked at three levels (3, 9 and 15 ng g-1), extracted by solid-liquid extraction assisted with ultrasonication, using a generic solvent composition of acetonitrile:water 84:16 (v:v) and measured by LC-HRMS. Method validation was successful for NIV, DON, and 15-AcDON with mean recoveries > 93% and RSDr < 10%. ZEN failed the validation criteria. The validated method was applied to eight conventionally managed maize field soils during harvest season, to provide a first insight into DON, NIV, and 15-AcDON levels. Mycotoxins were present in two out of eight sampled maize fields. Soil mycotoxin concentrations ranged from 0.53 to 19.4 ng g-1 and 0.8 to 2.2 ng g-1 for DON and NIV, respectively. Additionally, we found indication that "hot-spot" concentrations were restricted to small scales (<5 cm) with implications for field scale soil monitoring strategies.

Occurrence and distribution of estrogenic substances in the northern South China Sea

Estrogenic substances are today among the contaminants of emerging concern. Besides naturally occurring estrogens, other natural and synthetic substances can mimic a hormonal action due to their structural resemblance to hormones, possibly affecting the endocrine system of living organisms. Estrogens have been detected in inland water bodies such as influents and effluents of waste water treatment plants as well as in rivers, but data on their distribution and variability in the marine ecosystem are still limited. Surface water samples obtained during two research cruises on the northern shelf of the South China Sea (SCS) near the Pearl River Estuary, in September 2018 and in August 2019, were investigated for estrogenic substances, namely estrone (E1), 17β-estradiol (E2), 17α-ethinylestradiol (EE2), genistein (GEN), daidzein (DAI) and zearalenone (ZEN). Among the target analytes, the natural hormones E1 and E2, as well as the synthetic EE2, were the most abundant with maximum concentrations of 1.1 ng L^-1, 0.7 ng L^-1 and 0.6 ng L^-1, respectively. Of substances produced by plants and fungi, GEN, DAI and ZEN, only GEN was detected (1.2 ng L^-1). High concentrations occurred predominantly close to the coast, which was also reflected in the calculated estradiol equivalent quotients (up to 1.4 ng L^-1). In general, the distribution of estrogenic substances observed in both years shows a regional and inter-annual variability consistent with the modeled surface current data for the SCS. Regarding single estrogenic compounds and estradiol equivalents, marine organisms in the northern SCS might be exposed to high potential risk.

Multi-residue analysis of 20 mycotoxins including major metabolites and emerging mycotoxins in freshwater using UHPLC-MS/MS and application to freshwater ponds in flanders, Belgium

Mycotoxins are known for their negative impact on human and animal health as they frequently contaminate food and feed products from crop origin that are consumed by humans and animals. Furthermore, mycotoxins can leach out of plant tissue, to be transported through runoff water into nearby ponds where they can exert negative effects on aquatic organisms, such as fish, amphibians and zooplankton. The overall goal of this study was to develop a SPE-UHPLC-MS/MS method for the detection and quantification of multiple mycotoxins in amphibian breeding ponds. The method was validated and yielded acceptable within-run and between-run apparent recoveries and precision, as well as good linearity. Matrix effects (i.e. 75.7-109.6%, ≤ 17.8% RSD) were evaluated using water from 20 different ponds in Flanders, Belgium. By incorporating internal standards, overall results improved and adequate precision values (i.e. ≤ 15%) were obtained according to the EMA guideline. Additionally, extraction recovery (n = 3) was evaluated, yielding good results for all mycotoxins (i.e. 75.3-109.1%, ≤15% RSD), except for AME (i.e. 6.7 ± 0.7%), which implied the need for a matrix-matched calibration curve. Detection sensitivity was in the low nanograms per liter range. Storage stability experiments indicated that sample storage at 4 °C in amber glass bottles and analysis performed within 96 h after sampling was sufficient to avoid loss by degradation for all compounds, excluding β-ZAL and β-ZEL, for which analysis within 24 h is more indicated. The method was successfully applied to water samples originating from 18 amphibian breeding ponds situated across Flanders. Overall, enniatins B, B1 and A1 were most commonly detected at maximum concentrations of 6.9, 3.3 and 2.6 ng L^-1, respectively, followed by detection of beauvericin (1.1 ng L^-1 and < 1 ng L^-1), alternariol monomethyl ether (< 10 ng L^-1), HT2-toxin (< 40 ng L^-1), zearalenone (< 25 ng L^-1) and α-zearalanol (< 10 ng L^-1). We believe that this method will boost further research into the dynamics and ecotoxicological impact of mycotoxins in aquatic environments.

Disentangling Mechanisms in Natural Toxin Sorption to Soil Organic Carbon

Natural toxins are multifunctional, often ionizable organic compounds increasingly detected in the environment. Surprisingly little is known about their interactions with soil organic carbon, although sorption largely controls transport, bioavailability, and dissipation. For a set of 117 natural toxins from 36 compound classes the pH-dependent organic carbon-water distribution coefficient (D_oc) was quantified using a soil column chromatography approach under changing conditions with regards to pH, ionic strength, and the major inorganic cation in solution. Natural toxins could be assigned to groups with either hydrophobic partitioning or specific interactions (complexation reactions, cation exchange) as dominating sorption mechanisms. The complex interplay of interactions in the sorption of natural toxins was equally influenced by sorbate, sorbent, and solution specific characteristics. High variability in sorption was particularly observed in the presence of Ca²⁺ resulting in D_oc being enhanced by a factor of 10 when the pH was increased from 4.5 to 6. Sorbates following this trend contain either functional groups able to form ternary complexes via Ca²⁺ or aromatic moieties adjacent to protonated N presumably stabilizing cation exchange reactions. Although sorption was often stronger than predicted, investigated natural toxins were highly mobile under all considered conditions.

Environmental risks to freshwater organisms from the mycotoxins deoxynivalenol and zearalenone using Species Sensitivity Distributions

In this study, laboratory experiments have addressed the acute toxicity of two common mycotoxins, deoxynivalenol (DON) and zearalenone (ZON), in a range of freshwater organisms (including rotifers Brachionus calyciflorus, insects Chironomus riparius (larvae), crustaceans Daphnia pulex and Thamnocephalus platyurus, cnidarians Hydra vulgaris, molluscs Lymnaea stagnalis (embryos) and Protozoa Tetrahymena thermophila). Acute EC₅₀ values highlight crustaceans as the most sensitive organisms to DON, with T. platyurus having a 24 h EC₅₀ of 0.14 and D. magna having a 48 h EC₅₀ of 0.13 mg DON/L. During exposures to ZON, H. vulgaris and L. stagnalis embryos showed the highest sensitivity; mortality EC₅₀ values were 1.1 (96 h) and 0.42 mg ZON/L (7 d), respectively. Combining these novel invertebrate toxicity results, along with recent published data for freshwater plant and fish toxicity for analysis of Species Sensitivity Distributions, provides freshwater HC₅ values of 5.2 μg DON/L and 43 μg ZON/L, respectively. Using highest reported environmental concentrations and following REACH guidelines, risk ratios calculated here show the risk of ZON to freshwater organisms is low. In contrast, DON may periodically because for concern in streams subject to high agricultural run-off, likely during certain times of year where cereal crops are susceptible to higher fungal infections rates and may pose increased risks due to climate change.

Mycotoxin Occurrence, Exposure and Health Implications in Infants and Young Children in Sub-Saharan Africa: A Review

Infants and young children (IYC) remain the most vulnerable population group to environmental hazards worldwide, especially in economically developing regions such as sub-Saharan Africa (SSA). As a result, several governmental and non-governmental institutions including health, environmental and food safety networks and researchers have been proactive toward protecting this group. Mycotoxins, toxic secondary fungal metabolites, contribute largely to the health risks of this young population. In SSA, the scenario is worsened by socioeconomic status, poor agricultural and storage practices, and low level of awareness, as well as the non-establishment and lack of enforcement of regulatory limits in the region. Studies have revealed mycotoxin occurrence in breast milk and other weaning foods. Of concern is the early exposure of infants to mycotoxins through transplacental transfer and breast milk as a consequence of maternal exposure, which may result in adverse health effects. The current paper presents an overview of mycotoxin occurrence in foods intended for IYC in SSA. It discusses the imperative evidence of mycotoxin exposure of this population group in SSA, taking into account consumption data and the occurrence of mycotoxins in food, as well as biomonitoring approaches. Additionally, it discusses the health implications associated with IYC exposure to mycotoxins in SSA.

Enterocyte-Based Bioassay via Quantitative Combination of Proinflammatory Sentinels Specific to 8-keto-trichothecenes

Type B 8-keto-trichothecenes are muco-active mycotoxins that exist as inevitable contaminants in cereal-based foodstuffs. Gut-associated inflammation is an early frontline response during human and animal exposure to these mycotoxins. Despite various tools for chemical identification, optimized biomonitoring of sentinel response-associated biomarkers is required to assess the specific proinflammatory actions of 8-keto-trichothecenes in the gut epithelial barrier. In the present study, intoxication with 8-keto-trichothecenes in human intestinal epithelial cells was found to trigger early response gene 1 product (EGR-1) that plays crucial roles in proinflammatory chemokine induction. In contrast, epithelial exposure to 8-keto-trichothecenes resulted in downregulated expression of nuclear factor NF-kappa-B p65 protein, a key transcription factor, during general inflammatory responses in the gut. Based on the early molecular patterns of expression, the inflammation-inducing activity of 8-keto-trichothecenes was quantified using intestinal epithelial cells with dual reporters for EGR-1 and p65 proteins. EGR-1-responsive elements were linked to luciferase reporter while p65 promoter was bound to secretory alkaline phosphatase (SEAP) reporter. In response to conventional inflammagens such as endotoxins and cytokines such as TNF-α, both luciferase and SEAP activity were elevated in a dose-dependent manner. However, as expected from the mechanistic evaluation, 8-keto-trichothecene-exposed dual reporters of luciferase and SEAP displayed contrasting expression patterns. Furthermore, 8-keto-trichothecene-elevated EGR-1-responsive luciferase activity was improved by deficiency of PSMA3, an α-type subunit of the 20S proteasome core complex for ubiquitin-dependent EGR-1 degradation. This molecular event-based dual biomonitoring in epithelial cells is a promising supplementary tool for detecting typical molecular inflammatory pathways in response to 8-keto-trichothecenes in the food matrix.

Wastewater-based epidemiology for tracking human exposure to mycotoxins

Mycotoxins are among the compounds of most concern for human health because of their common presence in food and their proven toxicity for human health. Human biomonitoring (HBM) studies, foodstuff analysis and dietary surveys are usually used to assess human exposure, but they are costly and time-consuming. Wastewater-based epidemiology (WBE) can complement the established exposure monitoring tools. The aim of this study was to develop a new WBE application for assessing human exposure to mycotoxins by measuring specific biomarkers in raw wastewater. Eleven substances were analysed by liquid chromatography-tandem mass spectrometry in wastewater from four cities in Italy and Spain. Only deoxynivalenol (DON) and fumonisines were found, DON being the most abundant, in accordance with HBM studies. DON intake, back-calculated by WBE, was lower than the established Health-Based Guidance values, indicating moderate exposure in the population, with no risks for human health. WBE intake estimates were very close to those reported in HBM studies, validating WBE for estimating DON intake in the population. This study describes a promising WBE approach to complement HBM studies and assess the human intake of specific classes of mycotoxins, thus helping to identify risks for human health.

A Review on the Synthesis and Bioactivity Aspects of Beauvericin, a Fusarium Mycotoxin

Beauvericin (BEA) is an emerging Fusarium mycotoxin that contaminates food and feeds globally. BEA biosynthesis is rapidly catalyzed by BEA synthetase through a nonribosomal, thiol-templated mechanism. This mycotoxin has cytotoxicity and is capable of increasing oxidative stress to induce cell apoptosis. Recently, large evidence further shows that this mycotoxin has a variety of biological activities and is being considered a potential candidate for medicinal and pesticide research. It is noteworthy that BEA is a potential anticancer agent since it can increase the intracellular Ca²⁺ levels and induce the cancer cell death through oxidative stress and apoptosis. BEA has exhibited effective antibacterial activities against both pathogenic Gram-positive and Gram-negative bacteria. Importantly, BEA exhibits an effective capacity to inhibit the human immunodeficiency virus type-1 integrase. Moreover, BEA can simultaneously target drug resistance and morphogenesis which provides a promising strategy to combat life-threatening fungal infections. Thus, in this review, the synthesis and the biological activities of BEA, as well as, the underlying mechanisms, are fully analyzed. The risk assessment of BEA in food and feed are also discussed. We hope this review will help to further understand the biological activities of BEA and cast some new light on drug discovery.

Mycotoxins induce developmental toxicity and behavioural aberrations in zebrafish larvae

Mycotoxins are secondary metabolites produced by varieties of fungi that contaminate food and feed resources and are capable of inducing a wide range of toxicity. In the current study, we investigated developmental and behavioural toxicity in zebrafish larvae after exposure to six different mycotoxins; ochratoxin A (OTA), type A trichothecenes mycotoxin (T-2 toxin), type B trichothecenes mycotoxin (deoxynivalenol - DON), and zearalenone (ZEN) and its metabolites alpha-zearalenol (α-ZOL) and beta-zearalenol (β-ZOL). Developmental defects, hatching time, and survival were monitored until 96 h post fertilisation (hpf). The EC₅₀, LC₅₀, and IC₅₀ values were calculated. Subsequently, to assess behavioural toxicity, new sets of embryos were exposed to a series of non-lethal doses within the range of environmental and/or developmental concern. Results indicated that all the tested mycotoxins were toxic, they all induced developmental defects, and with the exception of OTA, all affected hatching time. Behavioural effects were only observed following exposure to OTA and ZEN and its metabolites, α ZOL and β ZOL. These results demonstrate that mycotoxins are teratogenic and can influence behaviour in a vertebrate model.

Measuring biomarkers in wastewater as a new source of epidemiological information: Current state and future perspectives

The information obtained from the chemical analysis of specific human excretion products (biomarkers) in urban wastewater can be used to estimate the exposure or consumption of the population under investigation to a defined substance. A proper biomarker can provide relevant information about lifestyle habits, health and wellbeing, but its selection is not an easy task as it should fulfil several specific requirements in order to be successfully employed. This paper aims to summarize the current knowledge related to the most relevant biomarkers used so far. In addition, some potential wastewater biomarkers that could be used for future applications were evaluated. For this purpose, representative chemical classes have been chosen and grouped in four main categories: (i) those that provide estimates of lifestyle factors and substance use, (ii) those used to estimate the exposure to toxicants present in the environment and food, (iii) those that have the potential to provide information about public health and illness and (iv) those used to estimate the population size. To facilitate the evaluation of the eligibility of a compound as a biomarker, information, when available, on stability in urine and wastewater and pharmacokinetic data (i.e. metabolism and urinary excretion profile) has been reviewed. Finally, several needs and recommendations for future research are proposed.

Photochemical transformation of zearalenone in aqueous solutions under simulated solar irradiation: Kinetics and influence of water constituents

The presence of estrogenic mycotoxins, such as zearalenone (ZEN), in surface waters is an emerging environmental issue. Little is known about its phototransformation behavior, which may influence its environmental fate. In this context, the phototransformation of ZEN was investigated in pure water, river water and estuarine water using simulated sunlight irradiation. Kinetic studies revealed that two concomitant processes contribute to the fate of ZEN under solar irradiation: photoisomerization and photodegradation. This phototransformation followed a pseudo-first order kinetics. ZEN degrades quickly in natural waters and slowly in deionized water, with half-lives (t_1/2) of 28 ± 4 min (estuarine water), 136 ± 21 min (river water) and 1777 ± 412 min (deionized water). The effects of different water constituents on the phototransformation of ZEN in aqueous solution have been assessed (NaCl, Ca²⁺, Mg²⁺, Fe³⁺, NO₃^- and oxalate ions, synthetic seawater, Fe(III)-oxalate and Mg(II)-oxalate complexes, humic acids, fulvic acids and XAD-4 fraction). In the presence of synthetic seawater salt (t_1/2 = 18 ± 5 min) and Fe(III)-oxalate complexes (t_1/2 = 61 ± 9 min), the transformation rate increased considerably in relation to other water constituents tested. The solution pH also had a considerable effect in the kinetics with maximum transformation rates occurring around pH 8.5. These results allow us to conclude that phototransformation by solar radiation can be an important degradation pathway of ZEN in natural waters.

Anthropogenic pressure in a Portuguese river: Endocrine-disrupting compounds, trace elements and nutrients

Natural organic compounds such as phytoestrogens and phytosterols found in various plants, as well as mycotoxins produced by fungi, can be found in aquatic environments. The aim of this study was to investigate the occurrence of three different classes of natural estrogenic compounds, i.e., phytoestrogens, phytosterols and mycotoxins, in estuarine water samples from the Ave River estuary. For that, water samples were collected at five sampling points distributed along the estuary at low tide, during 1 year, processed by solid-phase extraction (SPE) and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). To correlate the presence of phytoestrogens and phytosterols in the estuarine water, local flora was collected on riverside. Trace elements content and physicochemical parameters such as nutrients and dissolved oxygen were also determined seasonally at each sampling point, to give insights for the evaluation of water quality and anthropogenic pressure. Both phytoestrogens and phytosterols showed a seasonal variation, with the highest values observed in spring and summer and the lowest in winter. Daidzein (DAID) was found up to 404.0 ng L(-1) in spring and coumestrol (COUM) was found up to 165.0 ng L(-1) in summer. The mycotoxin deoxynivalenol (DON) was ubiquitously determined with values ranging from 59.5 to 642.4 ng L(-1). Nutrients and metals distribution and concentration varied among sampling stations and seasons. This study revealed for the first time the presence of mycotoxins, various classes of phytoestrogens and stigmasterol (STG) in estuarine water from the Ave River (Portugal), and the evaluation of the water quality confirmed that this estuary is still highly impacted by anthropogenic activities.

Deoxynivalenol inhibits proliferation and induces apoptosis in human umbilical vein endothelial cells

Deoxynivalenol (DON) is a stable mycotoxins found in cereals infected by certain fungal species and causes adverse health effects in animals and human such as vomiting, diarrhea and reproductive toxicity. In this study, we investigated the toxic and apoptotic effects of DON in human umbilical vein endothelial cells (HUVECs), a good model for studying inflammation. The results show that DON significantly inhibited the viability of HUVECs. DON could also inhibit the proliferation of HUVECs through G2/M phase arrest in cell cycle progression. Moreover, oxidative stress induced by DON was indicated by observations of increased levels of reactive oxygen species (ROS). In addition, DON also causes mitochondrial damage by decreasing the mitochondrial membrane potential and inducing apoptosis by up-regulation of apoptosis-related genes like caspase-3, caspase-9, and Bax genes, and down-regulation of Bcl-2 gene. These results together suggest that DON could induce cell cycle arrest, oxidative stress, and apoptosis in HUVECs.

Occurrence of Natural Contaminants of Emerging Concern in the Douro River Estuary, Portugal

Many studies demonstrated the presence of diverse environmental contaminants in the Douro River estuary, such as natural and synthetic estrogens, pharmaceuticals, industrial compounds and pesticides. This estuary is located between two densely populated cities and is highly impacted due to anthropogenic activities, such as industry and agriculture. Although the presence of mycotoxins and phytoestrogens, such as lignans and coumestrans, in the aquatic environment is reported by some authors, their occurrence in Portuguese waters was not investigated yet. To evaluate the presence of phytoestrogens, phytosterols and mycotoxins in Douro River estuary, water samples were collected seasonally at nine sampling points, preconcentrated by solid phase extraction and analysed by gas chromatography mass spectrometry. Local flora was collected on the riverside, in the same sampling points, for identification and evaluation of the possible relation to the presence of phytoestrogens and/or phytosterols in the estuarine water. Results showed the ubiquitous presence of mycotoxins, namely deoxynivalenol up to 373.5 ng L(-1). Both phytoestrogens and phytosterols showed a possible seasonal fluctuation, which is in accordance to the life cycle of the local flora and agricultural practices. Physicochemical parameters were also determined for water quality evaluation. This study revealed for the first time the presence of mycotoxins and lignans in estuarine waters from Portugal, and highlights the need to consider natural contaminants in future monitoring programs.

Effect of plastic mulching on mycotoxin occurrence and mycobiome abundance in soil samples from asparagus crops

Plastic mulching (PM) is widely used in modern agriculture because of its advantageous effects on soil temperature and water conservation, factors which strongly influence the microbiology of the soil. The aim of this study was to assess the effect of PM on mycotoxin occurrence in relation with mycobiome abundance/diversity and soil physicochemical properties. Soil samples were collected from green (GA) and white asparagus (WA) crops, the last under PM. Both crops were cultivated in a ridge-furrow-ridge system without irrigation. Samples were analyzed for mycotoxin occurrence via liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). Total colony-forming unit was indicative of mycobiome abundance, and analysis of mycobiome diversity was performed by internal transcribed spacer (ITS) sequencing. PM avoided the drop of soil temperature in winter and allowed higher soil temperature in early spring compared to non-covered soil. Moreover, the use of PM provided controlled conditions for water content in soil. This was enough to generate a dissimilar mycotoxin occurrence and mycobiome diversity/abundance in covered and non-covered soil. Mycotoxin soil contamination was confirmed for deoxynivalenol (DON), range LOD to 32.1 ng/g (LOD = 1.1 ng/g). The DON values were higher under PM (average 16.9 ± 10.1 ng/g) than in non-covered soil (9.1 ± 7.9 ng/g); however, this difference was not statically significant (p = 0.09). Mycobiome analysis showed a fungal compartment up to fivefold higher in soil under PM compared to GA. The diversity of the mycobiome varied between crops and also along the soil column, with an important dominance of Fusarium species at the root zone in covered soils.

Effect of sample dilution on matrix effects in pesticide analysis of several matrices by liquid chromatography-high-resolution mass spectrometry

This study used two LC columns of different adsorbents and liquid chromatography-electrospray ionization-high-resolution mass spectrometry to study the relationship between matrix effects (ME), the LC separations, and elution patterns of pesticides and those of matrix components. Using calibration standards of 381 pesticides at three dilution levels of 1×, 1/10×, and 1/100×, 108 samples were prepared in solvent and five different sample matrices for the study. Results obtained from principal component analysis and slope ratios of calibration curves provided measurements of the ME and showed the 1/100× sample dilution could minimize suppression ME for most pesticides analyzed. Should a pesticide coeluting with matrix components have a peak intensity of 25 times or higher, the suppression for that pesticide would persist even at 1/100× dilution. The number of pesticides had enhancement ME increased with increasing dilution from 1× to 1/100×, with those early eluting, hydrophilic pesticides affected the most.

Phytotoxins: environmental micropollutants of concern?

Natural toxins such as mycotoxins or phytotoxins (bioactive compounds from fungi and plants, respectively) have been widely studied in food and feed, where they are stated to out-compete synthetic chemicals in their overall human and animal toxicological risk. A similar perception and awareness is yet largely missing for environmental safety. This article attempts to raise concern in this regard, by providing (circumstantial) evidence that phytotoxins in particular can be emitted into the environment, where they may contribute to the complex mixture of organic micropollutants. Exposures can be orders-of-magnitude higher in anthropogenically managed/affected (agro-)ecosystems than in the pristine environment.

Mycotoxins: diffuse and point source contributions of natural contaminants of emerging concern to streams

To determine the prevalence of mycotoxins in streams, 116 water samples from 32 streams and three wastewater treatment plant effluents were collected in 2010 providing the broadest investigation on the spatial and temporal occurrence of mycotoxins in streams conducted in the United States to date. Out of the 33 target mycotoxins measured, nine were detected at least once during this study. The detections of mycotoxins were nearly ubiquitous during this study even though the basin size spanned four orders of magnitude. At least one mycotoxin was detected in 94% of the 116 samples collected. Deoxynivalenol was the most frequently detected mycotoxin (77%), followed by nivalenol (59%), beauvericin (43%), zearalenone (26%), β-zearalenol (20%), 3-acetyl-deoxynivalenol (16%), α-zearalenol (10%), diacetoxyscirpenol (5%), and verrucarin A (1%). In addition, one or more of the three known estrogenic compounds (i.e. zearalenone, α-zearalenol, and β-zearalenol) were detected in 43% of the samples, with maximum concentrations substantially higher than observed in previous research. While concentrations were generally low (i.e. < 50 ng/L) during this study, concentrations exceeding 1,000 ng/L were measured during spring snowmelt conditions in agricultural settings and in wastewater treatment plant effluent. Results of this study suggest that both diffuse (e.g. release from infected plants and manure applications from exposed livestock) and point (e.g. wastewater treatment plants and food processing plants) sources are important environmental pathways for mycotoxin transport to streams. The ecotoxicological impacts from the long-term, low-level exposures to mycotoxins alone or in combination with complex chemical mixtures are unknown.

Mycotoxins in the environment: I. Production and emission from an agricultural test field

Mycotoxins are secondary metabolites that are naturally produced by fungi which infest and contaminate agricultural crops and commodities (e.g., small grain cereals, fruits, vegetables, and organic soil material). Although these compounds have extensively been studied in food and feed, only little is known about their environmental fate. Therefore, we investigated over nearly two years the occurrence of various mycotoxins in a field cropped with winter wheat of the variety Levis, which was artificially inoculated with Fusarium spp., as well as their emission via drainage water. Mycotoxins were regularly quantified in whole wheat plants (0.1-133 mg/kg(dry weight), for deoxynivalenol), and drainage water samples (0.8 ng/L to 1.14 μg/L, for deoxynivalenol). From the mycotoxins quantified in wheat (3-acetyl-deoxynivalenol, deoxynivalenol, fusarenone-X, nivalenol, HT-2 toxin, T-2 toxin, beauvericin, and zearalenone), only the more hydrophilic ones or those prevailing at high concentrations were detected in drainage water. Of the total amounts produced in wheat plants (min: 2.3; max: 292 g/ha/y), 0.5-354 mg/ha/y, i.e. 0.002-0.12%, were emitted via drainage water. Hence, these compounds add to the complex mixture of natural and anthropogenic micropollutants particularly in small rural water bodies, receiving mainly runoff from agricultural areas.