Xenobiotic Contaminants Research Articles

Development of a unified method for the determination of legacy and metabolites of current pesticides in serum for exposure assessment.

The use of pesticides is often regarded as a fundamental aspect of conventional agriculture. However, these compounds have gained recognition as some of the oldest and most widely employed xenobiotic contaminants, necessitating effective strategies for human biomonitoring. In this context, a method was developed for the determination of 16 legacy organochlorine pesticides, 6 metabolites of current pesticides (2,4-D, malathion, parathion, fipronil, pyraclostrobin, cypermethrin, permethrin, cyfluthrin), and 1 triazine herbicide (atrazine) in serum. Samples were prepared with water, formic acid, acetonitrile, and ultrasound irradiation, followed by solid-phase extraction with Oasis Prime HLB. Subsequently, metabolites from current pesticides underwent derivatization using MTBSTFA with 1% TBDMSCl for analysis via gas chromatography-tandem mass spectrometry (GC-MS/MS), employing an SLB-5MS fused silica capillary column. Analytical curves were generated with limits of quantification from 0.3 to 4.0ng.mL-1. Accuracy ranged from 69 to 124%, and the coefficient of variation from 2 to 28%. Moreover, determining 1-(4-chlorophenyl)-1H-pyrazol-3-ol was suggested as a biomarker for pyraclostrobin biomonitoring. This analytical approach facilitated the determination of both legacy and metabolites of current pesticides in the same serum sample, presenting an interesting and cost-effective option for large cohorts, and multi-omics studies that evaluate time-dependent biomarkers in blood samples, thereby enabling biomonitoring within the same matrix. Furthermore, a proof-of-concept involving 10 volunteers demonstrated exposure to 9 pesticides at mean concentrations measured in ngmL-1, consistent with findings from various biomonitoring initiatives.

Electrochemical sensing of hydroquinone using green synthesized nitrogen-doped carbon dots

Xenobiotic contaminants are dreadful to the environment. Hydroquinone is one of those toxins that need to be sensed using a nonenzymatic, environmentally friendly material. This was achieved by carbon quantum dots (CQDs) synthesized using hydrothermal supported by heteroatom doping using a bare glassy carbon electrode (GCE) electrochemically. The carbon dot’s largest active surface area of 0.13 cm2, better electron transfer capability, and doping enhance the functional groups and electrostatic interaction with a Limit of Detection (LOD) of 0.112 µM.

Occurrence, analysis and removal processes of emerging pharmaceuticals from waters for the protection and preservation of a sustainable environment: A review

Pharmaceuticals are a group of man-made commercial and synthetic products and an important mainstay of modern society. However, their presence in aquatic environments is identified as a potential risk, causing harm to living things even at low concentrations ranging from ng L−1 to μg L−1. Due to their pseudo-persistence, bio-accumulation, and low elimination rate by conventional treatments, the majority of these xenobiotic contaminants and their metabolites are routinely released into the environment by sewage treatment plants and last longer in an aquatic environment. This review aims to provide an extensive report and a current state of knowledge concerning various classes of pharmaceutical compounds (PCs). It also discusses the occurrence, the analytical methods for the determination of PC micro-pollutants, and the remediation methods noted in recent literature focusing on the most recent advances. In this context, this review highlights the statistical data regarding the status of PCs in detection, analysis, and removal methods in aqueous media. In addition, this review provides an overview of the conventional and advanced technologies for the removal of PCs from water sources, offering critical comments, and discussing the challenges related to improving existing technologies for sustainable and eco-friendly management of water resources. It likewise emphasizes the importance of the combination of different treatment methods to reach up to 100% PC removal.Finally, gaps in the literature were found, and recommendations for further research were also cited in accordance with this paper. To the best of our knowledge, this review paper is among the rare works that deal with both: i) the analysis of large varieties of PCs in different water matrices, ii) the removal and identification of target analytes and their by-products generated during the elimination processes, and iii) the possible degradation pathways proposed by different studies.

Metagenome-assembled genomes from enrichment cultures grown on xenobiotic solvents.

Microbes play a significant role in the cleanup of xenobiotic contaminants. Based on metagenomes derived from long-term enrichment cultures grown on xenobiotic solvents, we report 166 metagenome-assembled genomes, of which 137 are predicted to be more than 90% complete. These genomes broaden the representation of xenobiotic degraders.

Ecological indicators and biological resources for hydrocarbon rhizoremediation in a protected area.

Spillage from oil refineries, pipelines, and service stations consistently leads to soil, food and groundwater contamination. Bacterial-assisted phytoremediation is a non-invasive and sustainable solution to eliminate or decrease the concentration of xenobiotic contaminants in the environment. In the present study, a protected area interested by a fuel discharge was considered to assess a bioremediation intervention. From the spill point, a plume of contamination flowed South-West into the aquifer, eventually reaching a wetland area. Soils, groundwaters and plants belonging to the species Scirpus sylvaticus (L.) were sampled. In the majority of the soil samples, concentrations of total petroleum hydrocarbons, both C ≤ 12 and C > 12, exceeded legal limits set forth in Directive 2000/60/EC. The analysis of diatom populations, used as ecological indicators, evidenced morphology alterations and the presence of Ulnaria ulna and Ulnaria biceps species, previously detected in hydrocarbon-polluted waters. Tests for phytotoxicity and phytodegradation, carried out in soil mesocosms, planted with Zea mays and Helianthus annuus, demonstrated that both species significantly contributed to the removal of total petroleum hydrocarbons. Removal of C ≤ 12 and C > 12 petroleum hydrocarbons was in the range of 80%-82% for Z. mays and 71%-72% for H. annuus. Microbial communities inhabiting high organic carbon and vegetated soils were more active in hydrocarbon degradation than those inhabiting subsoils, as evidenced by soil slurry experiments. The abundance of functional genes encoding toluene-benzene monooxygenase (tbmD) and alkane hydroxylase (alkB), quantified in environmental samples, confirmed that the plant rhizosphere recruited a microbial community with higher biodegradation capacity. Bacterial strains isolated from the sampling site were able to grow on model hydrocarbons (hexane, hexadecane and o-, m-, p-xylene) as sole carbon and energy sources, indicating that a natural bio-attenuation process was on-going at the site. The bacterial strains isolated from rhizosphere soil, rhizoplane and endosphere showed plant growth promoting traits according to in vitro and in vivo tests on Z. mays and Oryza sativa, allowing to forecast a possible application of bacterial assisted rhizoremediation to recover the protected area.

Eco-friendly approach developed for the microextraction of xenobiotic contaminants from tropical beverages using a camphor-based natural hydrophobic deep eutectic solvent

In this work, an innovative green strategy has been developed for the analysis of twenty-seven endocrine disruptors, including bisphenols, alkylphenols and alkylphenol ethoxylates, phthalic acid esters and one adipate in tropical beverages. For this purpose, nine natural hydrophobic deep eutectic solvents based on the terpenoids camphor, thymol and menthol at different molar ratios were investigated for the first time as extractants for the liquid-liquid microextraction of the target analytes from coconut waters and Aloe Vera drinks. A mixture of camphor:thymol at molar ratio 1:2 (n/n) was selected as extraction solvent. Determination of the target analytes was carried out by ultra-high performance liquid chromatography coupled to tandem mass spectrometry. After optimisation of the determination and extraction conditions, the methodology was validated achieving good results in terms of linearity, as well as recovery values in the range 75–111% and limits of quantification from 0.137 to 10.08 μg/L. Finally, the developed methodology was applied to the analysis of commercially available samples, finding the presence of diethyl phthalate.

Understanding the Interplay between Antimicrobial Resistance, Microplastics and Xenobiotic Contaminants: A Leap towards One Health?

According to the World Health Organization, the two major public health threats in the twenty-first century are antibiotic-resistant bacteria and antibiotic-resistant genes. The reason for the global prevalence and the constant increase of antibiotic-resistant bacteria is owed to the steady rise in overall antimicrobial consumption in several medical, domestic, agricultural, industrial, and veterinary applications, with consequent environmental release. These antibiotic residues may directly contaminate terrestrial and aquatic environments in which antibiotic-resistance genes are also present. Reports suggest that metal contamination is one of the main drivers of antimicrobial resistance (AMR). Moreover, the abundance of antibiotic-resistance genes is directly connected to the predominance of metal concentrations in the environment. In addition, microplastics have become a threat as emerging contaminants because of their ubiquitous presence, bio-inertness, toughness, danger to aquatic life, and human health implications. In the environment, microplastics and AMR are interconnected through biofilms, where genetic information (e.g., ARGs) is horizontally transferred between bacteria. From this perspective, we tried to summarize what is currently known on this topic and to propose a more effective One Health policy to tackle these threats.

Multi-omics strategies and applications for the degradation of pollutants by microbiome

<p indent="0mm">The wide distribution and metabolic flexibility of microorganisms in nature endow them with the capacity to degrade large amounts of xenobiotic substances. Human production activities release a variety of xenobiotic pollutants into the soil, water and atmosphere causing serious environmental pollution problems. Xenobiotic contaminants are partially or completely mineralized by the combination of metabolic collaboration among microbiome and environmental factors. Traditional pollutant degradation studies are based on isolation and culture of microorganisms, while high-throughput strategies such as metagenome, metatranscriptome, metaproteome and metabolome provide technical support to investigate pollutant degradation and ecological remediation by microbiome. This article mainly introduces the applications of different omics in exploring the microbiome in pollutant degradation and ecological restoration.

Decolorization of Reactive Black 5 by Immobilized Bacterial Cells

Azo dyes are xenobiotic contaminants that pose a substantial risk to environmental and human health. The study investigates biodecolorization potential of immobilized bacterial cells. Newly isolated bacterial cells were immobilized with two support matrices viz. sodium alginate and magnetite nanoparticles for the decolorization of model azo dye - reactive black 5. The bacterial cells coated with magnetic nanoparticles displayed complete decolorization of dye (100 ppm) in 16 h, while cells immobilized in sodium alginate beads required more time for complete removal of dye (24 h). Coated bacterial cells exhibited stable decolorization with repeated use for 12 cycles. However, due to destabilization of sodium alginate beads and subsequent cell leaching, stable decolorization was observed until 3rd cycle only. Nanoparticles coated bacterial cells offer the advantage of easy separation, allowing the cells to be reused for multiple cycles. Biodecolorized medium was analyzed by UV-Vis spectroscopy and FTIR techniques. The magnetic nanoparticles and coated bacterial cells were characterized through XRD and SEM, respectively. Overall results indicate that magnetite nanoparticles coated bacterial cells could be an effective tool for the decolorization of azo dyes.

Latest Advances and Developments to Detection of Micro‐ and Nanoplastics Using Surface‐Enhanced Raman Spectroscopy

AbstractThe increasing demand for single‐use plastic‐based products worldwide has generated immense waste during the last decade. This review aims to summarize the current developments of surface‐enhanced Raman spectroscopy (SERS) for detecting micro‐ and nanoplastics in a variety of samples and environments. Despite the SERS technique being very recent for this purpose, its robustness has already been discussed in a few analyses focused on well‐known pollutants such as phthalates, plasticizers, and xenobiotic contaminants from commercially available water bottles. Here, the latest advances, obstacles, and perspectives are reviewed using SERS detection as a robust alternative for analyzing complex samples containing nanoplastic particles present in daily consumer products such as wine and vegetables. Moreover, this paper describes different SERS substrates developed to overcome the limitations for identifying polymer particles at low concentrations. Factors contributing to the sensitivity of SERS substrates are discussed to show the advantages and limitations of this technique. The broader role of SERS as a tool in environmental research is currently explored from polluted air and aquatic environments, which can be relevant for other fields, such as clinical monitoring and nanotoxicology.

Analysis of alkylphenols, bisphenols and alkylphenol ethoxylates in microbial-fermented functional beverages and bottled water: Optimization of a dispersive liquid-liquid microextraction protocol based on natural hydrophobic deep eutectic solvents

In this work, the analysis of alkylphenols, bisphenols and alkylphenol ethoxylates in bottled waters, kombuchas and water kefir was performed through a vortex-assisted dispersive liquid–liquid microextraction method based on a natural hydrophobic eutectic solvent. For this purpose, mixtures of monoterpenes and fatty acids were employed. Different factors affecting extraction were optimized and the method was validated in terms of matrix effect, linearity, limits of detection and recovery. Recovery values varied between 70.0 and 124.3% (except for 4-tert-butylphenol: 67.0% and 4-n-nonylphenol: 60.8% in water kefir) and limits of detection were in the range 0.10 ng/L – 2.99 µg/L. Finally, 8 bottled waters, 8 kombuchas and 4 water kefirs were analyzed and 4-tert-octylphenol monoethoxylate was detected in water (20.28 ± 0.99 – 62.08 ± 3.63 µg/L). This is the first application analyzing xenobiotic contaminants in kombucha and water kefir and the first time in which the three types of compounds are simultaneously extracted by dispersive liquid–liquid microextraction.

Pollutant Degrading Enzyme: Catalytic Mechanisms and Their Expanded Applications.

The treatment of environmental pollution by microorganisms and their enzymes is an innovative and socially acceptable alternative to traditional remediation approaches. Microbial biodegradation is often characterized with high efficiency as this process is catalyzed via degrading enzymes. Various naturally isolated microorganisms were demonstrated to have considerable ability to mitigate many environmental pollutants without external intervention. However, only a small fraction of these strains are studied in detail to reveal the mechanisms at the enzyme level, which strictly limited the enhancement of the degradation efficiency. Accordingly, this review will comprehensively summarize the function of various degrading enzymes with an emphasis on catalytic mechanisms. We also inspect the expanded applications of these pollutant-degrading enzymes in industrial processes. An in-depth understanding of the catalytic mechanism of enzymes will be beneficial for exploring and exploiting more degrading enzyme resources and thus ameliorate concerns associated with the ineffective biodegradation of recalcitrant and xenobiotic contaminants with the help of gene-editing technology and synthetic biology.

The stress–immunity axis in shellfish

It is a difficult task to describe what constitutes a ‘healthy’ shellfish (e.g., crustacean, bivalve). Visible defects such as discolouration, missing limbs or spines, fouling, lesions, and exoskeletal fractures can be indicative of underlying issues, senescence, or a ‘stressed’ animal. The absence of such symptoms is not evidence of a disease-free or a stress-free state. Now, more than ever, aquatic invertebrates must cope with acute and chronic environmental perturbations, such as, heatwaves and cold shocks, xenobiotic contaminants, intoxication events, and promiscuous pathogens expanding their host and geographic ranges. With that in mind, how does one determine the extent to which shellfish become stressed in situ (natural) or in cultured (artificial) settings to enhance disease susceptibility? Many biomarkers – predominantly biochemical and cellular measures of shellfish blood (haemolymph) – are considered to gauge immunosuppression and immunocompetence. Such measures range from immune cell (haemocyte) counts to enzymic activities and metabolite quantitation. Stressed invertebrates often reflect degraded conditions of their ecosystems, referred to as environmental indicators.We audit briefly the broad immune functions of shellfish, how they are modulated by known and emerging stressors, and discuss these concepts with respect to neuroendocrinology and immunotoxicology. We assert that chronic stress, alone or in combination with microbial, chemical and abiotic factors, increases the risk of infectious disease in shellfish, exacerbates idiopathic morbidity, and reduces the likelihood of recovery. Acute stress events can lead to immunomodulation, but these effects are largely transient. Enhancing our understanding of shellfish health and immunity is imperative for tackling losses at each stage of the aquatic food cycle and disease outbreaks in the wild.

Xenobiotic Contamination of Water by Plastics and Pesticides Revealed through Real-Time, Ultrasensitive, and Reliable Surface-Enhanced Raman Scattering

Uncontrolled utilization and consequent ubiquitous percolation of carcinogenic and xenobiotic contaminants, such as plasticizers and pesticides, into the ecosystem have created an immediate demand for robust analytical detection techniques to identify their presence in water. Addressing this demand, we uncover the presence of xenobiotic contaminants such as bisphenol A (BPA), triclosan (TC), and dimethoate (DM) through a robust, ultrasensitive, and reliable surface-enhanced Raman scattering (SERS) platform. Thereby, conclusive real-time evidence of degradation of polyethylene terephthalate (PET) leading to the release of BPA in water is presented. Worryingly, the release of BPA occurs at ambient temperature (40 °C) and within realistic time scales (12 h) that are regularly encountered during the handling, transport, and storage of PET-based water containers. Complementary mass-spectrometric, surface-specific atomic force microscopy and surface-selective X-ray photoelectron spectroscopy confirm the nanoscale surface degradation of PET through a loss of C═O and C–O surface functionalities. Such ultrasensitive (ppm-level) spectroscopic detection is enabled by the bottom-up assemblies of metal nanoparticles (Soret colloids, SCs) acting as SERS platforms to provide high analytical enhancement factor (108) with high reliability (relative standard deviation, RSD < 5%). Effective and rapid detection (30 s) of several other potential xenobiotic contaminants such as triclosan (TC) and dimethoate (DM) over a wide range of concentrations (10–5–10–1 M) has also been demonstrated. Finally, nondestructive real-time spectroscopic “sniffing” of organophosphorous pesticides from the surface of fruits is achieved, illustrating the multiphasic versatility of this label-free, non-lithography-based SERS platform.

Decolorization of textile industry effluent using immobilized consortium cells in upflow fixed bed reactor

Textile dyes are xenobiotic contaminants which pose a potential risk on the ecosystem upon their disposal to the water bodies. This study evaluated the efficiencies of different immobilization matrices for its utilization in a reactor with continuous mode operation for decolorization of textile effluent. An effective consortium of bacteria (Brevibacillus laterosporus) and yeast (Galactomyces geotrichum) were immobilized in different support matrices including calcium alginate, polyvinyl alcohol, stainless steel sponge and polyurethane foam to investigate the decolorization of a model azo dye, Remazol red and textile industry effluent. The microbial consortia immobilized in stainless steel sponge and polyurethane foam exhibited 100% decolorization of 50 mg L−1 Remazol red in 11 and 15 h, respectively; however, calcium alginate and polyvinyl alcohol required considerably more time (20 and 24 h, respectively) for complete decolorization. Among all the matrices, The calcium alginate, stainless steel sponge and polyurethane foam showed >95% decolorization of textile industry effluent within 48 h. The calcium alginate and polyvinyl alcohol exhibited stable performance of decolorization with its repeated use for 5 cycles with >76% decolorization. An upflow fixed bed reactor (total volume- 215 mL) packed with the immobilized cells of consortium onto stainless steel sponge attained ∼90% decolorization of textile industry effluent in continuous operation at 10 mL h−1. The decolorization efficiency of the reactor was well maintained (>90%) when the reactor was used repeatedly for three cycles. The overall results indicated that immobilized mixed consortium cells can be considered as an effective tool for its potential application in removal of xenobiotic textile dyes from the textile industry wastewater with >90% of decolorization efficiency.

Sewer Sediment Bacterial Communities Suggest Potential to Transform Persistent Organic Pollutants.

Sediments of combined sewers are seeded with microbes from a variety of sources, and experience varying biogeochemical conditions. A variety of redox processes have been demonstrated to occur within sewer systems, as well as transformation of several recalcitrant xenobiotic contaminants. Illumina sequencing of the 16S ribosomal RNA gene from sediments of three combined sewer systems in the northeastern United States resulted in 10 000 to 47 000 operational taxonomic units per sample. Whereas orders Clostridiales and Bacteroidales, considered human fecal indicators, were dominant in one city's sediments; other cities had communities suggestive of diverse redox processes, including reductive dechlorination of chlorinated organic compounds. Collection systems previously associated with polychlorinated biphenyl (PCB) biotransformation, and those with elevated in situ PCB concentrations, had high abundances of Dehalococcoidetes. The results suggest that wastewater collection systems have intrinsic passive treatment capacity, reducing contaminant loads on water resource recovery facilities and, ultimately, on receiving waters.

Phytotoxicity alleviation by bacterial species isolated from polycyclic aromatic hydrocarbons (PAHs) contaminated sites

Abstract The increasing industrialization has led to a high accumulation of xenobiotic contaminants in the natural environments. Most frequently, such pollutants include petroleum hydrocarbons (PHCs), polycyclic aromatic hydrocarbons (PAHs), halogenated hydrocarbons, agrochemicals, solvents, heavy metals and salts; among all of them, PAHs are particularly hazardous for their toxicity, mutagenic and carcinogenic potential, since they also feature a very high potential of accumulation in several food chains. Although several remediation techniques based on physical and chemical processes have been developed, the biological approach seems to be the most promising, since it very often allows the complete removal of the xenobiotics from the environment. In this work, the cultivable microbial community has been isolated from PAHs polluted soils and each individual strain has been tested for its ability to grow on both naphthalene and phenanthrene. Out of forty-seven isolates, two bacterial strains able of growing on the xenobiotics were found (T1 and W1) and the 16S rDNA was sequenced. The potential ability of both T1 and W1 to alleviate phytotoxicity symptoms was assessed by running an ecotoxicity test, using Lepidium sativum as indicator plant. Interestingly, both T1 and W1 alleviated the naphthalene-induced phytotoxicity in cress plants, whilst their contributions were not effective when plants were exposed to the highest concentrations of phenanthrene. In conclusion, our data highlighted that both the plants sensitivity to PAHs and the microbial ability to degrade xenobiotics are strongly dependent on either plant or bacterial species and on the xenobiotic molecule. In addition, considering the plant growth promotion traits displayed by T1 and W1, the isolated bacterial strains might represent a promising tool to possibly enhance the plant fitness, even in xenobiotic contaminated soils.

Identification of a dioxin-responsive oxylipin signature in roots of date palm: involvement of a 9-hydroperoxide fatty acid reductase, caleosin/peroxygenase PdPXG2

Dioxins are highly hazardous pollutants that have well characterized impacts on both animal and human health. However, the biological effects of dioxins on plants have yet to be described in detail. Here we describe a dioxin-inducible caleosin/peroxygenase isoform, PdPXG2, that is mainly expressed in the apical zone of date palm roots and specifically reduces 9-hydroperoxide fatty acids. A characteristic spectrum of 18 dioxin-responsive oxylipin (DROXYL) congeners was also detected in date palm roots after exposure to dioxin. Of particular interest, six oxylipins, mostly hydroxy fatty acids, were exclusively formed in response to TCDD. The DROXYL signature was evaluated in planta and validated in vitro using a specific inhibitor of PdPXG2 in a root-protoplast system. Comparative analysis of root suberin showed that levels of certain monomers, especially the mono-epoxides and tri-hydroxides of C16:3 and C18:3, were significantly increased after exposure to TCDD. Specific inhibition of PdPXG2 activity revealed a positive linear relationship between deposition of suberin in roots and their permeability to TCDD. The results highlight the involvement of this peroxygenase in the plant response to dioxin and suggest the use of dioxin-responsive oxylipin signatures as biomarkers for plant exposure to this important class of xenobiotic contaminants.

Emerging pollutants and plants--Metabolic activation of diclofenac by peroxidases.

Human pharmaceuticals and their residues are constantly detected in our waterbodies, due to poor elimination rates, even in the most advanced waste water treatment plants. Their impact on the environment and human health still remains unclear. When phytoremediation is applied to aid water treatment, plants may transform and degrade xenobiotic contaminants through phase I and phase II metabolism to more water soluble and less toxic intermediates. In this context, peroxidases play a major role in activating compounds during phase I via oxidation. In the present work, the ability of a plant peroxidase to oxidize the human painkiller diclofenac was confirmed using stopped flow spectroscopy in combination with LC-MS analysis. Analysis of an orange colored product revealed the structure of the highly reactive Diclofenac-2,5-Iminoquinone, which may be the precursor of several biological conjugates and breakdown products in planta.

Rapid Phytotransformation of Benzotriazole Generates Synthetic Tryptophan and Auxin Analogs in Arabidopsis.

Benzotriazoles (BTs) are xenobiotic contaminants widely distributed in aquatic environments and of emerging concern due to their polarity, recalcitrance, and common use. During some water reclamation activities, such as stormwater bioretention or crop irrigation with recycled water, BTs come in contact with vegetation, presenting a potential exposure route to consumers. We discovered that BT in hydroponic systems was rapidly (approximately 1-log per day) assimilated by Arabidopsis plants and metabolized to novel BT metabolites structurally resembling tryptophan and auxin plant hormones; <1% remained as parent compound. Using LC-QTOF-MS untargeted metabolomics, we identified two major types of BT transformation products: glycosylation and incorporation into the tryptophan biosynthetic pathway. BT amino acid metabolites are structurally analogous to tryptophan and the storage forms of auxin plant hormones. Critical intermediates were synthesized (authenticated by (1)H/(13)C NMR) for product verification. In a multiple-exposure temporal mass balance, three major metabolites accounted for >60% of BT. Glycosylated BT was excreted by the plants into the hydroponic medium, a phenomenon not observed previously. The observed amino acid metabolites are likely formed when tryptophan biosynthetic enzymes substitute synthetic BT for native indolic molecules, generating potential phytohormone mimics. These results suggest that BT metabolism by plants could mask the presence of BT contamination in the environment. Furthermore, BT-derived metabolites are structurally related to plant auxin hormones and should be evaluated for undesirable biological effects.