Analysis of selected phytotoxins and mycotoxins in environmental samples

Croplands proximity is associated with amyotrophic lateral sclerosis incidence and age at onset

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease resulting from an intricate interplay between genetics and environmental factors. Many studies have explored living in rural areas as a possible risk factor for ALS, without focusing simultaneously on incidence, age at onset and phenotypic features.

OBJECTIVE

To evaluate the effect of croplands residential proximity on ALS incidence and phenotype, focusing on age of onset, site of onset and progression rate.

METHODS

The address history of ALS patients belonging to the population-based Piemonte and Valle d'Aosta registry (PARALS), diagnosed between 2007 and 2014, was obtained for the 20 years prior to the onset date. The smoothed ALS incidence per year (im) was compared with the percentage of area covered by each crop for each municipality. A proximity score was calculated for each cropland by geolocation, measuring the percentage of area surrounding patients' residence for variable radii, and was used to compare croplands exposure and phenotype.

RESULTS

We observed an increased ALS incidence in the municipalities with a higher percentage of area covered by arable crops (R = 0.191, p < 0.001). Age at onset was significantly lower in those patients who lived near arable crops, with a median anticipation ranging from 1.8 to 3.4 years; using historical data, a significant anticipation was found also for patients living near vineyards.

DISCUSSION

Our study proved a direct association between arable crops and ALS risk and an inverse association between arable crops and vineyards proximity and age at onset, suggesting the possible causative role of specific environmental contaminants.

Indole and quinolizidine alkaloids from blue lupin leach to agricultural drainage water

Phytotoxins are produced in plants including agricultural crops. Lupins and other plants of the Fabaceae family produce toxic alkaloids. These alkaloids have been studied in food and feed, however, the environmental fate of alkaloids produced by cultivated lupins is largely unknown. Therefore, we conducted an agricultural field experiment to investigate the occurrence of indole and quinolizidine alkaloids in lupin plant tissues, soil, soil pore water and in drainage water. During the field experiment, alkaloids were regularly quantified (median concentrations) in lupin (13-8.7 × 10³ ng/g dry weight (dw)), and topsoils at depth 0-5 cm (0.1-10 ng/g dw), and depth 15-30 cm (0.2-8.5 ng/g dw), soil pore water (0.2-7.5 ng/L) and drainage water samples (0.4-18 ng/L). Lupanine was the dominant alkaloid in all collected samples. Cumulative amounts of alkaloids emitted via drainage water were around 0.1-11 mg/ha for individual alkaloids over one growing season. The total cumulative amount of alkaloid in drainage water was 14 mg/ha, which is a very small amount compared to the mass of alkaloid in the lupin biomass (11 kg/ha) and soil (0.02 kg/ha). Nearly half of the alkaloids were exported in the drainage water during high flow events, indicating that alkaloids transport preferentially via macropores. These findings indicate that drainage from lupin cultivated areas contribute to surface water contamination. The environmental and ecotoxicological relevance of alkaloids as newly identified aquatic micropollutants in areas with agricultural activities have yet to be assessed.

Aquatic occurrence of phytotoxins in small streams triggered by biogeography, vegetation growth stage, and precipitation

Toxic plant secondary metabolites (PSMs), so-called phytotoxins, occur widely in plant species. Many of these phytotoxins have similar mobility, persistence, and toxicity properties in the environment as anthropogenic micropollutants, which increasingly contaminate surface waters. Although recent case studies have shown the aquatic relevance of phytotoxins, the overall exposure remains unknown. Therefore, we performed a detailed occurrence analysis covering 134 phytotoxins from 27 PSM classes. Water samples from seven small Swiss streams with catchment areas from 1.7 to 23 km² and varying land uses were gathered over several months to investigate seasonal impacts. They were complemented with samples from different biogeographical regions to cover variations in vegetation. A broad SPE-LC-HRMS/MS method was applied with limits of detection below 5 ng/L for over 80% of the 134 included phytotoxins. In total, we confirmed 39 phytotoxins belonging to 13 PSM classes, which corresponds to almost 30% of all included phytotoxins. Several alkaloids were regularly detected in the low ng/L-range, with average detection frequencies of 21%. This is consistent with the previously estimated persistence and mobility properties that indicated a high contamination potential. Coumarins were previously predicted to be unstable, however, detection frequencies were around 89%, and maximal concentrations up to 90 ng/L were measured for fraxetin produced by various trees. Overall, rainy weather conditions at full vegetation led to the highest total phytotoxin concentrations, which might potentially be most critical for aquatic organisms.

The role of soils in provision of genetic, medicinal and biochemical resources

Intact, 'healthy' soils provide indispensable ecosystem services that largely depend on the biotic activity. Soil health is connected with human health, yet, knowledge of the underlying soil functioning remains incomplete. This review highlights selected services, i.e. (i) soil as a genetic resource and hotspot of biodiversity, forming the basis for providing (ii) biochemical resources and (iii) medicinal services and goods. Soils harbour an unrivalled biodiversity of organisms, especially microorganisms. Some of the abilities of autochthonous microorganisms and their relevant enzymes serve (i) to improve natural soil functions and in particular plant growth, e.g. through beneficial plant growth-promoting, symbiotic and mycorrhizal microorganisms, (ii) to act as biopesticides, (iii) to facilitate biodegradation of pollutants for soil bioremediation and (iv) to yield enzymes or chemicals for industrial use. Soils also exert direct effects on human health. Contact with soil enriches the human microbiome, affords protection against allergies and promotes emotional well-being. Medicinally relevant are soil substrates such as loams, clays and various minerals with curative effects as well as pharmaceutically active organic chemicals like antibiotics that are formed by soil microorganisms. By contrast, irritating minerals, soil dust inhalation and misguided soil ingestion may adversely affect humans. This article is part of the theme issue 'The role of soils in delivering Nature's Contributions to People.

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.

Occurrence of pyrrolizidine alkaloids in ragwort plants, soils and surface waters at the field scale in grassland

Pyrrolizidine alkaloids (PA)s are natural toxins produced by a variety of plants including ragwort. The PAs present a serious health risk to human and livestock. Although these compounds have been extensively studied in food and feed, little is known regarding their environmental fate. To fill this data gap, we investigated the occurrence of PAs in ragwort plants, soils and surface waters at three locations where ragwort was the dominant plant species to better understand their environmental distribution. The concentrations of PAs were quantified during the full growing season (April-November) and assessed in relation to rain events. PA concentrations ranged from 3.2-6.6 g/kg dry weight (dw) in plants, 0.8-4.0 mg/kg dw in soils, and 6.0-529 μg/L in surface waters. Maximum PA concentrations in the soil (4 mg/kg) and water (529 μg/L) were in mid-May just before flowering. The average distribution of PAs in water was approximately 5 g/10,000 L, compared to the average amounts present in ragwort (506 kg/ha), and soil (1.7 kg/ha). In general, concentrations of PAs increase in the soil and surface water following rain events.

Suspect and Target Screening of Natural Toxins in the Ter River Catchment Area in NE Spain and Prioritisation by Their Toxicity

This study presents the application of a suspect screening approach to screen a wide range of natural toxins, including mycotoxins, bacterial toxins, and plant toxins, in surface waters. The method is based on a generic solid-phase extraction procedure, using three sorbent phases in two cartridges that are connected in series, hence covering a wide range of polarities, followed by liquid chromatography coupled to high-resolution mass spectrometry. The acquisition was performed in the full-scan and data-dependent modes while working under positive and negative ionisation conditions. This method was applied in order to assess the natural toxins in the Ter River water reservoirs, which are used to produce drinking water for Barcelona city (Spain). The study was carried out during a period of seven months, covering the expected prior, during, and post-peak blooming periods of the natural toxins. Fifty-three (53) compounds were tentatively identified, and nine of these were confirmed and quantified. Phytotoxins were identified as the most frequent group of natural toxins in the water, particularly the alkaloids group. Finally, the toxins identified to levels 2 and 1 were prioritised according to their bioaccumulation factor, biodegradability, frequency of detection, and toxicity. This screening and prioritisation approach resulted in different natural toxins that should be further assessed for their ecotoxicological effects and considered in future studies.

A novel model concept for modelling the leaching of natural toxins: results for the case of ptaquiloside

Phytotoxins are a large class of highly diverse emerging environmental contaminants that have been detected at high concentrations in plants, water and soils. This study presents a novel modelling approach for assessing the fate of plant toxins in the soil-plant-atmosphere continuum, developed for the specific case of ptaquiloside (PTA), a carcinogenic phytotoxin produced by Pteridium aquilinum. The mechanistic model DAISY has been adapted for reproducing phytotoxin dynamics in plants, covering processes such as toxin generation in the canopy, wash off by precipitation and toxin recovery in the canopy after depletion events. Transport of the toxin in the soil was simulated by the advection-dispersion equation assuming weak sorption and degradation for two Danish soils. The model simulates realistic toxin contents in the plant during the growing season, where the actual PTA content is dynamic and a function of the biomass. An average of 48% of the PTA produced in the canopy is washed off by precipitation, with loads in the soil often in the order of mg m^-2 and up to a maximum of 13 mg m^-2 in a single rain event. Degradation in the soil removes 99.9% of the total PTA input to the soil, while only 0.1% leaches into the soil. The median annual flux-averaged predicted environmental concentrations during single events are often in the order of μg L^-1, reaching up to 60 μg L^-1 for the worst-case scenario. The simulated results for both degradation and wash off are of the same order of magnitude as the published data. Based on the results, we conclude that DAISY, with the newly implemented processes, is a useful tool for understanding, describing and predicting the fate of PTA in the soil. Further work comparing the model results with real data is needed for the calibration and validation of the model.

Evaluation of Cytotoxicity and Mould Contamination of Selected Plants from Meadows Covered by the Agri-Environmental Program

The aim of the study was the evaluation of selected species of meadow plants obtained from the first cut from the area covered by the agri-environmental program 'Natura 2000' in terms of the presence of cytotoxic compounds detected by the MTT test and the level of fungal contamination. The research was carried out on plant species that were evaluated differently in previously used methods for quality assessment of pasture feeds according to Klapp and Filipek. Twenty-six plant species were harvested in 2014 from meadows located in the valley of the Bydgoszcz Canal. Mycological examination of meadow plant samples was carried out according to PN-ISO 7954:1999. Cytotoxicity evaluation was performed using the MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] test. Selected samples were also subjected to evaluation of the endophytes occurrence in grasses using PCR. Natural meadow positions included in the study were dominated by moulds belonging to Humicola spp., Alternaria spp., Cladosporium spp., Torula spp., Fusarium spp. and Mucor spp. The highest level of fungal contamination was observed for Carex acutiformis Ehrh. The most infested grasses were Deschampsia caespitosa (L.) P.Beauv., Festuca arundinacea Schreb. and Lolium perenne L. The MTT test showed that the most cytotoxic species were Arrhenatherum elatius (L.) P.Beauv. (IC50 1.563 mg/mL) and Ranunculus repens L. (IC50 3.125 mg/mL). Epichloë endophytes were detected in one of 13 examined grass samples. Our own research suggests that previously used feed quality assessments should be verified by introducing modern methods of molecular biology and instrumental analysis. Results of this study may broaden the knowledge of the causes of problems resulting from feeding of roughage, mainly from natural meadows, and help in creating new rankings of the feed value of meadow sward components.

Comprehensive Toxic Plants-Phytotoxins Database and Its Application in Assessing Aquatic Micropollution Potential

The production of toxic plant secondary metabolites (phytotoxins) for defense is a widespread phenomenon in the plant kingdom and is even present in agricultural crops. These phytotoxins may have similar characteristics to anthropogenic micropollutants in terms of persistence and toxicity. However, they are only rarely included in environmental risk assessments, partly because a systematic overview of phytotoxins is missing. Here, we present a newly developed, freely available database, Toxic Plants-PhytoToxins (TPPT), containing 1586 phytotoxins of potential ecotoxicological relevance in Central Europe linked to 844 plant species. Our database summarizes phytotoxin patterns in plant species and provides detailed biological and chemical information as well as in silico estimated properties. Using the database, we evaluated phytotoxins regarding occurrence, approximated from the frequencies of Swiss plant species; environmental behavior based on aquatic persistence and mobility; and toxicity. The assessment showed that over 34% of all phytotoxins are potential aquatic micropollutants and should be included in environmental investigations.

Effects of deoxynivalenol (DON) and its microbial biotransformation product deepoxy-deoxynivalenol (DOM-1) on a trout, pig, mouse, and human cell line

Deoxynivalenol (DON), a trichothecene produced by various Fusarium species, is one of the most prevalent food- and feed-associated mycotoxins. The effects of DON and deepoxy-deoxynivalenol (DOM-1) were assessed in five different cell lines from different tissues and species starting from the first line of defense, the trout gill (RTgill-W1) and pig intestinal cells (IPEC-1 and IPEC-J2) over immune cells, as second line of defense (mouse macrophages RAW 264.7) to human liver cells (HepG2). Viability was assessed with a WST-1 assay, except for RTgill-W1, where a neutral red (NR) and sulforhodamine B (SRB) assay was performed. Additionally, more sensitive parameters, such as interleukin-, nitric oxide (NO)-, and albumin-release were determined. Viability was affected by DON at concentrations starting at 10 μmol/L (RTgill-W1), 0.9 μmol/L (IPEC-1), 3.5 μmol/L (IPEC-J2), and 0.9 μmol/L (HepG2), whereas DOM-1 did not have such an effect. Additionally, NO was decreased (0.84 μmol/L DON), whereas interleukin (IL)-6 was increased (0.42 μmol/L DON) in lipopolysaccharide (LPS)-stimulated DON-, but not DOM-1-treated RAW cells. Tumor necrosis factor (TNF)-α release, however, was not affected. Interestingly, albumin secretion of HepG2 cells was decreased by both DON and DOM-1 but at a much higher concentration for DOM-1 (228 versus 0.9 μmol/L for DON). 98.9% of DOM-1 was retrieved by liquid chromatography tandem mass spectrometry at the end of the experiment, proving its stability. In this study, IL-6 was the most sensitive parameter, followed by NO and albumin release and viability for HepG2 and IPEC-1.

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.

Effects of Dietary Exposure to Zearalenone (ZEN) on Carp (Cyprinus carpio L.)

The mycotoxin zearalenone (ZEN) is frequently contaminating animal feeds including feed used in aquaculture. In the present study, the effects of dietary exposure to ZEN on carp (Cyprinus carpio L.) were investigated. ZEN at three different concentrations (low dose: 332 µg kg⁻¹, medium dose: 621 µg kg⁻¹ and high dose: 797 µg kg⁻¹ final feed, respectively) was administered to juvenile carp for four weeks. Additional groups received the mycotoxin for the same time period but were fed with the uncontaminated diet for two more weeks to examine the reversibility of the ZEN effects. No effects on growth were observed during the feeding trial, but effects on haematological parameters occurred. In addition, an influence on white blood cell counts was noted whereby granulocytes and monocytes were affected in fish treated with the medium and high dose ZEN diet. In muscle samples, marginal ZEN and α-zearalenol (α-ZEL) concentrations were detected. Furthermore, the genotoxic potential of ZEN was confirmed by analysing formation of micronuclei in erythrocytes. In contrast to previous reports on other fish species, estrogenic effects measured as vitellogenin concentrations in serum samples were not increased by dietary exposure to ZEN. This is probably due to the fact that ZEN is rapidly metabolized in carp.

Occurrence of fungal metabolites--fumonisins at the ng/L level in aqueous environmental samples

The B-series fumonisins (FBs) are some of the most prevalent mycotoxins produced as a secondary metabolite by Fusarium species growing on cereals. For decades they have been studied extensively in food and feed products, but there is no information about their occurrence in the aquatic environment or about how these mycotoxins are transported to the surface water and the groundwater. The aim of this study was to clarify the causes of fumonisin occurrence in aquatic ecosystems by examining the relation between mycotoxin contamination of crops and their levels in the aquatic environment. Water samples were collected from drainage ditches and wells or watercourses located in agricultural areas in the Wielkopolska region, Poland. Our research conducted on an annual basis showed the seasonal variability of fumonisin B1 concentration in the analyzed water samples, with the highest concentration in the post-harvest season (September to October) at 48.2 ng L(-1), and the lowest in winter and spring at 21.9 ng L(-1). Fumonisins B2 and B3 in water samples were not detected. Cereal samples were collected in the harvest season from each agricultural area close to tested water bodies. Mycotoxins were present in all cereal samples at concentrations from 43.3 to 1055.9 ng g(-1). Our results confirm that fumonisins are transported to aquatic systems by rainwater through soil. On the basis of available literature, this is the first report concerning the presence of fumonisin B1 in different aquatic environments. To date their ecotoxicological effects are largely unknown and require further investigation.

Sorption of isoflavones to river sediment and model sorbents and outcomes for larval fish exposed to contaminated sediment

Isoflavones are compounds whose presence in the aquatic environment is increasingly recognized and may be of concern due to their potential to act as endocrine disruptors. Sorption to particles may be a relevant removal mechanism for isoflavones. This work investigated the influence of pH, ionic strength, and sediment composition on sorption of genistein and daidzein, two key isoflavones, using sorption isotherms and edges. The effect of sorbed isoflavones on the survival, growth, and predator avoidance performance of larval fathead minnows (Pimephales promelas) was assessed. Sorption to goethite and kaolinite was pH-dependent, with a maximum near pH 7 for both compounds. Sorption to montmorillonite was ionic-strength dependent but largely pH-independent. Overall, sorption to sediments is likely to sequester less than 5% of isoflavones in a discharge. No statistically significant effects were observed for larvae exposed to sorbed isoflavones, suggesting that sorption to sediments reduces exposure to isoflavones.

Exposure of Aspergillus fumigatus to T-2 toxin results in a stress response associated with exacerbation of aspergillosis in poultry

Aspergillus fumigatus is a ubiquitous airborne pathogen. Saprophytic growth in the presence of environmental mycotoxins might affect its fitness and virulence. T-2 toxin (T-2) is a trichothecene mycotoxin produced by Fusarium spp. in various substrates. This study aimed to evaluate the effects of T-2 on the fitness of A. fumigatus in vitro and its virulence in experimentally inoculated chickens. We cultured A. fumigatus on agar media containing T-2, and examined the changes in viability, morphology, growth rate, proteome expression, and susceptibility to antimycotics and oxidative stress of this fungus. Results showed that exposure to 1000 ng/ml T-2 in the substrate did not reduce the viability of A. fumigatus, but its growth was inhibited, with wrinkling and depigmentation of the colonies. Proteomic analysis revealed 21 upregulated proteins and 33 downregulated proteins, including those involved in stress response, pathogenesis, metabolism, transcription. The proteome seems to have shifted to enhance the glycolysis, catabolism of lipids, and amino acid conversion. Assays on fungal susceptibility to antimycotics and oxidative stress showed that T-2 exposure did not affect the minimal inhibitory concentrations of amphotericin B, itraconazole, voriconazole and terbinafine against A. fumigatus, but increased the susceptibility of A. fumigatus to H2O2 and menadione. Experimental inoculation of chickens with A. fumigatus showed that exposure of A. fumigatus to T-2 significantly exacerbated aspergillosis in chickens exposed to dietary T-2. In conclusion, A. fumigatus is capable of surviving and growing on substrates containing levels of T-2 up to 1000 ng/ml. Growth in presence of T-2 induces a stress response in A. fumigatus, which is associated with exacerbation of aspergillosis in vivo.

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.

Unraveling the mechanisms involved in zearalenone-mediated toxicity in permanent fish cell cultures

The world-wide occurrence of zearalenone (ZEN) as a contaminant in feed for farm animals and fish requires the evaluation of toxicity mechanisms of action of ZEN. The present study investigates possible metabolization of ZEN in fish cell lines suggesting that mainly glucuronidation takes place. It demonstrates that concentrations up to 20,000 ng ml(-1) ZEN are capable of influencing cell viability in permanent fish cell cultures in a dose-response manner with different response patterns between the five tested cell lines, whereby lysosomes appeared to be the main target of ZEN. ZEN toxicity is often discussed in the context of oxidative stress. Our study shows a biphasic response of the cell lines when reactive oxygen species (ROS) production is monitored. Damage in cells was observed by measuring lipid peroxidation, DNA strand breaks, and alterations of intracellular glutathione levels. Metabolization of ZEN, especially at concentrations above 7500 ng ml(-1) ZEN, does not prevent cytotoxicity. ZEN as an estrogenic compound may involve processes mediated by binding to estrogen receptors (ER). Since one cell line showed no detectable expression of ER, an ER-mediated pathway seems to be unlikely in these cells. This confirms a lysosomal pathway as a main target of ZEN in fish cells.

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.

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

Thirty-three different mycotoxins were surveyed over nearly two years in a typical Swiss wastewater treatment plant (WWTP), as well as in Swiss midland rivers. Out of these, 3-acetyl-deoxynivalenol, deoxynivalenol (DON), nivalenol (NIV), and beauvericin (BEA), were detected. DON was quantified in all WWTP effluent grab samples with a maximum concentration of 73.4 ng/L, while the lowest concentration was observed for BEA with 1.3 ng/L. NIV was detected in about 37%, the other three compounds in 9-36% of the weekly or fortnightly integrated flow proportional river water samples. Concentrations were river discharge dependent, with higher numbers in smaller rivers, but mostly in the very low ng/L-range, with a maximum of 24.1, and 19.0 ng/L for NIV and DON, respectively. While NIV and DON prevailed in summer and autumn, BEA occurred mostly during winter. Summer and autumn seasonal load fractions were, however, not correlating with other river basin parameters indicative of the probably most obvious seasonal input source, that is, Fusarium graminearum infected wheat crop areas. Nevertheless, together with WWTP effluents, these two sources largely explained the loads of mycotoxins quantified in river waters. The ecotoxicological relevance of mycotoxins as newly identified aquatic micropollutants has yet to be assessed.

Multiclass mycotoxin analysis in food, environmental and biological matrices with chromatography/mass spectrometry

Mold metabolites that can elicit deleterious effects on other organisms are classified as mycotoxins. Human exposure to mycotoxins occurs mostly through the intake of contaminated agricultural products or residues due to carry over or metabolite products in foods of animal origin such as milk and eggs, but can also occur by dermal contact and inhalation. Mycotoxins contained in moldy foods, but also in damp interiors, can cause diseases in humans and animals. Nephropathy, various types of cancer, alimentary toxic aleukia, hepatic diseases, various hemorrhagic syndromes, and immune and neurological disorders are the most common diseases that can be related to mycotoxicosis. The absence or presence of mold infestation and its propagation are seldom correlated with mycotoxin presence. Mycotoxins must be determined directly, and suitable analytical methods are necessary. Hundreds of mycotoxins have been recognized, but only for a few of them, and in a restricted number of utilities, a maximum acceptable level has been regulated by law. However, mycotoxins seldom develop alone; more often various types and/or classes form in the same substrate. The co-occurrence might render the individual mycotoxin tolerance dose irrelevant, and therefore the mere presence of multiple mycotoxins should be considered a risk factor. The advantage of chromatography/mass spectrometry (MS) is that many compounds can be determined and confirmed in one analysis. This review illustrates the state-of-the-art of mycotoxin MS-based analytical methods for multiclass, multianalyte determination in all the matrices in which they appear. A chapter is devoted to the history of the long-standing coexistence and interaction among humans, domestic animals and mycotoxicosis, and the history of the discovery of mycotoxins. Quality assurance, although this topic relates to analytical chemistry in general, has been also examined for mycotoxin analysis as a preliminary to the systematic literature excursus. Sample handling is a crucial step to devise a multiclass analytical method; so when possible, it has been treated separately for a better comparison before tackling the instrumental part of the whole analytical method. This structure has resulted sometimes in unavoidable redundancies, because it was also important to underline the interconnection. Most reviews do not deal with all the possible mycotoxin sources, including the environmental ones. The focus of this review is the analytical methods based on MS for multimycotoxin class determination. Because the final purpose to devise multimycotoxin analysis should be the assessment of the danger to health of exposition to multitoxicants of natural origin (and possibly also the interaction with anthropogenic contaminants), therefore also the analytical methods for environmental relevant mycotoxins have been thoroughly reviewed. Finally, because the best way to shed light on actual risk assessment could be the individuation of exposure biomarkers, the review covers also the scarce literature on biological fluids.

Molecular and life-history effects of a natural toxin on herbivorous and non-target soil arthropods

Natural toxins, such as isothiocyanate (ITC), are harmful secondary metabolites produced by plants. Many natural toxins occur in commercial crops, yet their possible negative repercussions on especially non-target soil organisms are largely unknown. This study examined life-history and gene transcriptional responses to 2-phenylethyl ITC on two soil arthropod species: Folsomia candida and Protaphorura fimata. To that end the standardized ISO guideline for ecotoxicological tests and a microarray for F. candida were used. The dissipation of 2-phenylethyl ITC in natural soil was investigated using GC-MS/MS for quantification. Half-lives, tested at four concentration levels in natural soil, were on average 16 h with biodegradation as the plausible main removal process. Regardless, toxic effects on reproduction were shown for F. candida and P. fimata, with EC50 values of around 11.5 nmol/g soil illustrating the toxic character of this compound. Gene expression profiles revealed the importance of fatty acid metabolism at low exposure concentrations (EC10), which is associated with the lipophilic nature of 2-phenylethyl ITC. At higher concentrations (EC50) gene expression became more ubiquitous with over-expression of especially stress-related genes and sugar metabolism. The regulation of a gene encoding a precursor of follistatin, furthermore, implied the inhibition of reproduction and may be an important molecular target that can be linked to the observed adverse effect of life-history traits.

Occurrence and mass balance of isoflavones on an experimental grassland field

Isoflavones and coumestrol (COU) are estrogenic compounds that are naturally produced by plants (e.g., red clover, soybeans). Although these compounds have been extensively studied in food and feed, only little is known about their environmental fate. Therefore, we investigated the occurrence of isoflavones (formononetin, daidzein, equol, biochanin A, and genistein) and COU over 3.5 years in red clover, manure, and soil of a grassland field with and without manure application, as well as their emission via drainage water. Isoflavones were regularly quantified in plant (≤ 15 × 10(6) ng/g(dry weight (dw))), manure (≤ 230 × 10(3) ng/g(dw)), soil (≤ 3.4 × 10(3) ng/g(dw)), and drainage water samples (≤ 3.6 × 10(3) ng/L). In contrast, COU was observed only in manure and soil. Cumulative isoflavone loads emitted via drainage water were around 0.2 × 10(-3) kg/ha/y, which is very little compared to the amounts present in red clover (105-220 kg/ha/y), manure (0.5-1.0 kg/ha/y), and soil (0.1-5.1 kg/ha/y). Under good agricultural practice, no additional emission of isoflavones into drainage water was observed after manure application. With calculated 17β-estradiol equivalents up to 0.46 ng/L in drainage water, isoflavones can constitute a dominant and ecotoxicological relevant portion of the total estrogenicity in small rural river catchments.

Developments in mycotoxin analysis: an update for 2009-2010

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2009 and mid-2010. It covers the major mycotoxins aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. New and improved methods for mycotoxins continue to be published. Immunological-based method developments continue to be of wide interest in a broad range of formats. Multimycotoxin determination by LC-MS/MS is now being targeted at the specific ranges of mycotoxins and matrices of interest or concern to the individual laboratory. Although falling outside the main emphasis of the review, some aspects of natural occurrence have been mentioned, especially if linked to novel method developments.

Zearalenone occurrence and human exposure

Among the mycotoxins zearalenone (ZEA) is of interest because of the oestrogenic effects that it, and certain of its metabolites possess. The fungi that produce ZEA are found worldwide, particularly in cereal grains and derived products. This has prompted many surveys to detect these compounds in commodities and foods. As a result, the widespread occurrence of ZEA in foods is well documented. Previous summaries including extensive reports by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the European Commission's Scientific Cooperation on Questions Relating to Food (SCOOP), and others, have provided significant information on the occurrence of ZEA in commodities and foods. Publication of occurrence data has continued at a rapid pace, and certain of that data, as well as highlights from previous intake and exposure assessments, are summarised herein. Comparing estimates of intake (exposure) with previous estimates of tolerable daily intakes, suggests that, for many of the countries where exposure assessments have been done, the populations are exposed to levels that would be considered safe. The situation may be different in populations that consume large quantities of foods that are susceptible to contamination, or in instances where contamination is atypically high. For much of the world estimates of exposure have not been reported, meaning that for much of the world, the true extent of the relevance of ZEA to human health remains uncharacterised.

On-line preconcentration for the determination of aflatoxins in rice samples by micellar electrokinetic capillary chromatography with laser-induced fluorescence detection

MEKC coupling with LIF detection has been used for the determination of four aflatoxins (B(1), B(2), G(1) and G(2)). Separations were performed in an uncoated fused-silica capillary (70 cm x 75 microm id, 55 cm effective length), using 20 mM borate buffer with 30 mM SDS (pH 8.5) and 7% ACN. In order to increase sensitivity, an on-line preconcentration procedure was applied, based on sweeping, using the same separation buffer without SDS as solvent of the sample. The precision of the method was evaluated in terms of repeatability and intermediate precision and the results were acceptable in all cases (RSD<12%). With the on-line preconcentration LODs (obtained as 3 x S/N) were as low as 0.11, 0.52, 0.04 and 0.10 microg/L for G(2), G(1), B(2) and B(1), respectively. Recovery studies were developed with extracts of rice samples spiked with aflatoxins, being in the range between 93.0 and 105.4%. The method has also been applied to the determination of aflatoxins in rice samples, and the results compared with those obtained by a standard method, being in good agreement.

Poor elimination rates in waste water treatment plants lead to continuous emission of deoxynivalenol into the aquatic environment

Deoxynivalenol (DON) is one of the most prominent mycotoxins generated by fungi of the generus Fusarium on crops. Its presence in surface waters was recently demonstrated. Here, we elucidate the occurrence and behaviour of DON in three Swiss waste water treatment plants (WWTP) as a result of human consumption and excretion. DON was shown to be omnipresent in the primary effluent samples of these WWTP in concentrations from 32 to 118 ng/L. Corresponding loads were a factor of 1.3-2.3 higher than predicted based on human excretion data from the literature. DON elimination rates in WWTP ranged from 33 to 57%. These rather low percentages were confirmed with a further, more detailled study conducted at WWTP Kloten/Opfikon (average elimination rate 32%). The relative importance of WWTP as a source of DON in surface waters was compared with agricultural emissions due to runoff from Fusarium infected crops. Both sources seem to contribute equally to the total DON exposure of surface waters of a few ng/L, however, their input dynamics vary considerably in space and time.