Residual Contamination Research Articles

Removal of Residual Contaminants by Minute-level Washing Facilitates the Direct Regeneration of Spent Cathode from Retired EV Li-ion Batteries

Removal of Residual Contaminants by Minute-level Washing Facilitates the Direct Regeneration of Spent Cathode from Retired EV Li-ion Batteries

Toxicological aspects of wastewater

‘Alea iacta est', the die is cast, said the Roman general Gaius Julius Caesar the moment he and his troops crossed the Rubicon River. This phrase refers to a state where everything has already been decided and this decision cannot be taken back. It is at this borderline that humanity now finds itself; its survival is at stake. The basic biogenic components of the environment, such as water, air, and soil, are coming under the pressure of the modern industrial revolution. The products of this anthropogenic activity significantly affect the environment. We live in a time of rapid climate change, melting of glaciers, devastation of nature, mass extermination, or loss of animal and plant species in order to increase human living standards. Man has caused all this in one stage of human life, a generation. Humanity mismanages natural resources and clings to a lifestyle that is vain. It destroys the natural environment on which it is dependent simultaneously. An environmental disaster is coming. Will our blue planet still be livable for future generations? The study deals with one of the components of the environmental environment, not an insignificant one, that is, water. For the moment, recycled water is a neglected and underappreciated resource from the point of view of the Czech Republic and its state authorities. The cleaning process may be inadequate or unreliable, and residual biological and chemical contaminants may pose a risk to human health. This work focuses on the use of purified wastewater mainly for firefighting unit activities in relation to a possible health risk. The result of the study is a clear possible recommendation for the use of recycled wastewater from a technical, technological, and logistical point of view, but taking into account the precautionary principle.

Removal of metal impurities from diamond wire saw silicon powder by vacuum electromagnetic directional solidification

The utilization of high-purity silicon (∼99.9999 %) is prevalent in the solar photovoltaic sector, and achieving a reduction in its cost has emerged as a pivotal engineering objective within the silicon solar industry. Recycling silicon from diamond wire saw silicon powder (DWSSP) is a promising solution to fulfill the continuously expanding of high purity silicon demand. Vacuum directional solidification technology using high-frequency electromagnetic induction heating was proposed to purify DWSSP for the first time efficiently. The silicon melt and gas interface reaction, as well as metal impurities’ microsegregation in silicon ingot were observed. The effects of vacuum level and electromagnetic force on the separation of silicon and metal impurities were investigated using thermodynamics and electromagnetic mechanics. Results indicate that the content of oxygen in the silicon reduced from 30.91 wt% to 5.08 wt%, and the actual sample composition including for uptake of residual gas contamination steadily declined as the vacuum level increased from 600 Pa to 10 Pa. Vacuum electromagnetic directional solidification reduced the content of metal impurities from 641 ppmw to 29.80 ppmw, increases the proportion of crystalline silicon area, and makes the silicon lattice arrangement more regular.

Effect of Structure to Promote Organic Residue Removal during Cu Post-Chemical Mechanical Planarization (p-CMP) Cleaning

The extension of Moore’s law remains a focal point as semiconductor manufacturers drive to advance Integrated Circuit (IC) technology by implementing new materials. Chemical Mechanical Planarization (CMP) has emerged as a critical processing step in device fabrication to keep up with these demands. However, one drawback to this process is the generation of killer defects that result from residual contamination (i.e., organic residues, abrasive particles, pad remnants, etc.) that are reliant on post-CMP (p-CMP) cleaning methods. Current Cu p-CMP cleaning methods implement the use of an industry standard polymer brush coupled with cleaning chemistries to remove residual contamination. It has been well established that shear and compressive forces coupled with surface active cleaning chemistries have proven to be efficient albeit with the potential for secondary defectivity (i.e., pitting, etching, scratching). Additionally, current cleaning formulations rely on additives that promote aggressive redox conditions to remove residues through an undercutting mechanism, which leads to the propagation of the aforementioned defect modes. This work focuses on the development of a “softer” approach to Cu p-CMP cleaning by surveying various additives (i.e., -unsaturated carboxylic acids, carboxylic acids, and unsaturated benzaldehydes) to exploit an “overcutting” mode of organic residue removal. By implementing additional modes of interaction (i.e., p-stacking, H-bonding, conformational relationships, etc.), the mode of residue removal can be finely tuned to achieve desired surface-active conditions. This work employs a suite of techniques (i.e., Tafel analysis, OCP vs. time, time-resolved contact angle, shear force analysis) to correlate structure-activity to organic residue removal efficiency and the effects on the coefficient of friction (COF), particle removal efficiency, and the generation of secondary defectivity. Initial results have shown that implementing an “overcutting” mechanism will decrease the overall shear force and significantly reduce the proliferation of p-CMP cleaning defects. Furthermore, adding ancillary structure activity aids in additional modes of residue interaction to alter removal at the liquid-brush interface. Additionally, increased structure-activity has promoted residue-chemistry interactions to form a second passivation layer. Moreover, conformational changes that result in limited accessibility to the a,b-unsaturated double bond promote an “undercutting” mode of removal to become the predominant mode of organic residue mediation.

Engineered Electrochemiluminescence Biosensors for Monitoring Heavy Metal Ions: Current Status and Prospects.

Metal ion contamination has serious impacts on environmental and biological health, so it is crucial to effectively monitor the levels of these metal ions. With the continuous progression of optoelectronic nanotechnology and biometrics, the emerging electrochemiluminescence (ECL) biosensing technology has not only proven its simplicity, but also showcased its utility and remarkable sensitivity in engineered monitoring of residual heavy metal contaminants. This comprehensive review begins by introducing the composition, advantages, and detection principles of ECL biosensors, and delving into the engineered aspects. Furthermore, it explores two signal amplification methods: biometric element-based strategies (e.g., HCR, RCA, EDC, and CRISPR/Cas) and nanomaterial (NM)-based amplification, including quantum dots, metal nanoclusters, carbon-based nanomaterials, and porous nanomaterials. Ultimately, this review envisions future research trends and engineered technological enhancements of ECL biosensors to meet the surging demand for metal ion monitoring.

The efficient abatement of contaminants of emerging concern by LED-UV275nm/electrochemical chlorine for wastewater reuse: kinetics, degradation pathways, and cytotoxicity

Treating wastewater to augment surface water can be a practicable solution to water scarcity, while the residual contaminants of emerging concern (CECs) and inorganic ions put forward new requirements to the treatment methods. Electrochemical chlorine process (EC/Cl2) utilizes the remaining Cl− in wastewater to generate free chlorine and radicals, which could be further improved in conjunction with LED UV275nm irradiation (UV-EC/Cl2). Compared to UV only and EC/Cl2, UV-EC/Cl2 could effectively decompose the selected CECs at higher rates due to the much higher yield of reactive chlorine species (Cl•, ClO•, and Cl2•−). A MATLAB R2021a programming method was developed to estimate the order of magnitude of these radicals, and Cl2•− was the most abundant radical. In the UV-EC/Cl2 system, CECs with phenolic or aniline moieties were mainly degraded by electrochemical oxidation (EC), ClO•, and Cl2•−; and the CECs with weakly electron-donating moieties were predominately decomposed by EC, •OH, and Cl•. The degradation pathways of levofloxacin, diclofenac, carbamazepine (CBZ), and ibuprofen were proposed according to the transformation products (TPs) detected by LC/Q-TOF-MS. Moreover, the cytotoxicity of spiked CBZ in real water samples, that were discharged to surface water, was significantly reduced by UV-EC/Cl2. Interestingly, the electrical energy per order (EE/O) for CBZ decomposition by LED UV275nm-EC/Cl2 (1.46 kWh m−3 order−1) is lower than that by UV/Cl2, EC/Cl2, and UV254nm-EC/Cl2. The results indicate that UV-EC/Cl2 could be used as a promising method to remediate CECs during the tertiary treatment and reuse of wastewater for augmenting surface water.

Biodegradation of Imazethapyr by Bacterial Strain IM9601 Isolated from Agricultural Soil

The widespread utilization of the herbicide imazethapyr presents significant challenges to crop rotation and results in detrimental soil degradation issues. Bacterial biodegradation has emerged as a promising and eco-friendly approach for mitigating pesticide residues contamination in the environment. In this study, a novel bacterium, identified as Brevibacterium sp. IM9601, was isolated and characterized based on morphological, physiological, and biochemical characteristics, as well as 16S rRNA gene sequence. This strain exhibited the ability to utilize imazethapyr as its sole carbon source for growth. Response surface methodology (RSM) was applied to optimize the degradation conditions. The most favorable conditions were determined to be a temperature of 27 °C, pH of 6.0, and an initial inoculum with a final OD600 of 0.15. Under these optimized condition, bacterial strain IM9601 exhibited substantial imazethapyr degradation, with removal rates of 90.08 and 87.05% for initial imazethapyr concentrations of 50 and 100 mg L−1, respectively, achieved within a 5-day incubation period. This investigation highlights imazethapyr-degrading capabilities of the Brevibacterium genus bacterial strain IM9601, marking it as a potentially novel and effective solution for addressing the environmental pollution resulting from the usage of imazethapyr. The study contributes to the growing body of research on bioremediation approaches, offering a sustainable and environmentally friendly method for mitigating the adverse impacts of herbicide contamination in agricultural settings.

Contaminants of Concern and Spatiotemporal Metabolomic Changes in Quagga Mussels (Dreissena bugensis rostriformis) from the Milwaukee Estuary (Wisconsin, USA).

Environmental metabolomics has emerged as a promising technique in the field of biomonitoring and as an indicator of aquatic ecosystem health. In the Milwaukee Estuary (Wisconsin, USA), previous studies have used a nontargeted metabolomic approach to distinguish between zebra mussels (Dreissena polymorpha) collected from sites of varying contamination. To further elucidate the potential effects of contaminants on bivalve health in the Milwaukee Estuary, the present study adopted a caging approach to study the metabolome of quagga mussels (Dreissena bugensis rostriformis) deployed in six sites of varying contamination for 2, 5, or 55 days. Caged mussels were co-deployed with two types of passive sampler (polar organic chemical integrative samplers and semipermeable membrane devices) and data loggers. In conjunction, in situ quagga mussels were collected from the four sites studied previously and analyzed for residues of contaminants and metabolomics using a targeted approach. For the caging study, temporal differences in the metabolomic response were observed with few significant changes observed after 2 and 5 days, but larger differences (up to 97 significantly different metabolites) to the metabolome in all sites after 55 days. A suite of metabolic pathways were altered, including biosynthesis and metabolism of amino acids, and upmodulation of phospholipids at all sites, suggesting a potential biological influence such as gametogenesis. In the caging study, average temperatures appeared to have a greater effect on the metabolome than contaminants, despite a large concentration gradient in polycyclic aromatic hydrocarbons residues measured in passive samplers and mussel tissue. Conversely, significant differences between the metabolome of mussels collected in situ from all three contaminated sites and the offshore reference site were observed. Overall, these findings highlight the importance of contextualizing the effects of environmental conditions and reproductive processes on the metabolome of model organisms to facilitate the wider use of this technique for biomonitoring and environmental health assessments. Environ Toxicol Chem 2024;43:307-323. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Residual contamination and biofilm formation by opportunistic pathogens Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa in poultry houses isolated from drinking water systems, fans, and floors.

Residual contamination and biofilm formation by opportunistic pathogens Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa in poultry houses isolated from drinking water systems, fans, and floors.

Organophosphorus pesticide contaminants in fruits and vegetables: A meta-analysis

The worldwide demand for organophosphorus pesticides (OPs) in food production has raised concerns about pesticide residues. Meta-analysis, proven effective in assessing contaminants like aflatoxins and organotin compounds, is applied here to comprehensively study OP contamination in fresh fruits and vegetables. Employing Comprehensive Meta-Analysis V3.0 software, we meticulously examined 24 relevant articles encompassing 69,467 data points. Our findings revealed that while the residual concentrations of OPs (such as chlorpyrifos and profenofos) in most fruits and vegetables have typically met international or national safety standards, including Codex Alimentarius Commission, European Union, British, and Chinese standards, there are some instances in which the maximum residue limits have been exceeded, posing safety risks. Therefore, significant efforts are required to maintain residual OP contamination at safe concentrations.

Banana Peel Derived Chitosan-Grafted Biocomposite for Recovery of NH4+ and PO43.

Biomass-derived adsorbents afford accessible and inexpensive harvesting of nitrogen and phosphorus from wastewater sources. Human urine is widely accepted as a rich source of nitrogen and phosphorus. However, direct use of urine in agriculture is untenable because of its unpleasant smell, pathogen contamination, and pharmaceutical residues. In this work, we have grafted chitosan onto dried and crushed banana peel (DCBP) to generate the biocomposite DCBP/Ch. A combination of FTIR, TGA, XRD, FESEM, EDX, and NMR analyses were used to characterize DCBP/Ch and reveal condensation-aided covalent conjugation between O-H functionalities of DCBP and chitosan. The adsorption performance of DCBP/Ch toward NH4+ and PO43- is in sync with its attractive surface porosity, elevated crystallinity, and thermostability. The maximum adsorption capacity of DCBP/Ch toward NH4+/PO43- was estimated as 42.16/15.91 mg g-1 at an operating pH of 7/4, respectively, and ranks highly when compared to previously reported bioadsorbents. DCBP/Ch performs admirably when tested on artificial urine. While nitrogen and phosphorus harvesting from human urine using single techniques has been reported previously, this is the first report of a single adsorbent for recovery of NH4+ and PO43-. The environmental compatibility, ease of preparation, and economic viability of DCBP/Ch present it as an attractive candidate for deployment in waste channels.

ВЗАИМОСВЯЗЬ КАЧЕСТВА ТРИЕРНОЙ ОЧИСТКИ ЗЕРНА С РЕЖИМАМИ РАБОТЫ И НАСТРОЕЧНЫМИ ПАРАМЕТРАМИ

The possibilities of reducing residual grain contamination and technological losses were investigated. The relationships between the qualitative indicators of the trier's operation and the speed of rotation of the cylinder, the parameters of the circulating segment and the setting of the output tray during the experiment with interval evaluation were established. The studies were carried out using a cyclic stand, which ensures the replacement of the traditional spatial physical model with a temporary one and a radical increase in the effectiveness of the experiment. The nature of the change in the process over time and the length of the cellular cylinder, which can be divided into three characteristic sections, has been established. In the first section, the intensity of the release of grains of the main crop increases linearly for all values of the mass of the circulating segment. It was found that the higher the mass of the circulating segment, the lower the initial value of the intensity of the release of grains of the main crop due to the predominance of the dynamic “eating” effect, and the period of stabilization of the process is longer. In the second section, the maximum value of the intensity of the release of grains of the main crop is achieved with circulation in the segment of 4 - 5 layers of grain and the predominance of the effect of inertial retention of the contacting layer. In the third section, the intensity of the release of grains of the main crop decreases parabolically identically for all mass values of the circulating segment at a given rotation frequency of the mesh cylinder and the angular position of the output tray. It has been established that when the rotation speed increases to 35 rpm, the initial contamination of the grain mixture has virtually no effect on the degree of release. The regulated level of technological losses of less than 5% at a tray installation angle of 40° is ensured by a high-speed operating mode of 40 rpm. The intensity of the emission of impurity particles into the output tray is proportional to the initial contamination of the grain mixture and the time of movement of the segment along the mesh cylinder. With an increase in the installation angle of the output tray in the range of 20° - 40°, the intensity of the emission of impurity particles decreases by 3.8 - 5.0 times.

Non-touch treatment to solve the persistent contamination of culture plates with Aspergillus niger in a clinical microbiology laboratory of Spain.

A pseudo-outbreak of Aspergillus caused by false positive cultures can have a high sanitary impact. We determined the effectiveness (fungal load elimination) of a non-touch disinfection system, vs conventional disinfection methods, to solve steady contamination of culture plates with Aspergillus niger at a clinical microbiology laboratory. Routine cleaning-disinfection (RCD), intensive cleaning-disinfection (ICD), and terminal airborne disinfection (TAD) were employed in stages. Air sampling was carried out before and after each procedure. The effectiveness of TAD on contact surfaces was tested by surface sampling. After RCD, ICD, and TAD, there was a mean decrease of 5.4 (95% CI = 1.8-9.0), 19.2 (95% CI = 12.4-26.0), and 4.4 (95% CI = 2.5-6.3) CFU per tested area, and 46.2%, 21.7%, and 95.5% of contaminated areas became sterile, respectively. There was a mean decrease of 30.6CFU per tested surface (p < 0.0007) and 50% of tested surfaces became sterile. Global effectiveness of RCD, ICD, and TAD was 68.8% (95% CI = 68.5-69.1), 82.2% (95% CI = 82.1-82.3), and 99.0% (95% CI = 98.8-99.2), respectively. The effectiveness was higher with TAD (4.1CFU/cm2 less than with ICD; p = 0.0290). No further contamination has occurred since then. When construction and renovation activities are discarded and RCD and ICD practices are insufficient, non-touch disinfection remove residual dust contamination and avoid recurrence.

An improved Compton parameter map of thermal Sunyaev–Zeldovich effect from Planck PR4 data

ABSTRACT Taking advantage of the reduced levels of noise and systematics in the data of the latest Planck release (PR4, also known as NPIPE), we construct a new all-sky Compton-y parameter map (hereafter, y-map) of the thermal Sunyaev–Zeldovich (SZ) effect from the Planck PR4 data. A tailored Needlet Internal Linear Combination (NILC) pipeline, first validated on detailed sky simulations, is applied to the nine single-frequency Planck PR4 sky maps, ranging from 30 to 857 GHz, to produce the PR4 y-map over 98 per cent of the sky. Using map comparisons, angular power spectra, and one-point statistics, we show that the PR4 NILC y-map is of improved quality compared to that of the previous PR2 release. The new y-map shows reduced levels of large-scale striations associated with 1/f noise in the scan direction. Regions near the Galactic plane also show lower residual contamination by Galactic thermal dust emission. At small angular scales, the residual contamination by thermal noise and cosmic infrared background (CIB) emission is found to be reduced by around 7 and 34 per cent, respectively, in the PR4 y-map. The PR4 NILC y-map is made publicly available for astrophysical and cosmological analyses of the thermal SZ effect.

Surveillance of veterinary drug residues in food commonly consumed in Singapore and assessment of dietary exposure

Non-judicious and indiscriminate use of veterinary drugs in animal husbandry may result in accumulation of residues in animal tissues, and consequently in food for human consumption. The abuse of veterinary drugs presents a potential risk to consumer health, especially if the residue level is higher than the health-based guidance value (HBGV) such as the acceptable daily intake (ADI). Contamination of drug residues in food also promotes the emergence of antimicrobial resistance (AMR) which poses a serious threat to public health globally. There has been limited information on the occurrence and dietary exposure to veterinary drug residues in Singapore to date. In this study, the occurrence of four classes of veterinary drugs, namely beta-agonists, coccidiostats, fluoroquinolones and macrolides, were determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in food widely consumed by Singapore residents. The magnitude of dietary exposure was assessed based on the consumption profile of Singapore population. Out of 216 food samples, 9.72 % were detected positive with veterinary drug residues, where majority of the positive samples were poultry and its derived products, followed by eggs and egg products. 7 veterinary drugs, specifically ciprofloxacin, enrofloxacin, clopidol, diclazuril, lasalocid, nicarbazin and tilmicosin, were detected in the samples, with clopidol and enrofloxacin being the most frequently detected drugs. Dietary exposure was evaluated using the estimated daily intake (EDI) of the detected drugs and benchmarked against the corresponding acceptable daily intake (ADI). All the %ADI values were far less than 100 in both the average and high consumer scenarios, indicating that the health risk associated with dietary exposure to these drugs in Singapore is low.

Efficient treatment of recalcitrant biologically treated coking wastewater using Cu-doped LaFeO3/peroxymonosulfate activator: Performance evaluation and response surface methodology modeling

Biologically treated coking wastewater (BTCW) frequently contains many kinds of refractory and toxic organic pollutants, which is far from meeting the discharge standard of GB16171–2012. In the present work, the peroxymonosulfate (PMS) activation processes via Cu-doped LaFeO3 (LFC) prepared with Bis (hexamethylene triaminepenta(methylenephosphonic acid) (BHMTMP) as the complexing agent was first utilized to degrade BTCW. The degradation reaction rate constant (kobs) of LaFe0.5Cu0.5O3 (LFC5)/PMS for CODCr and NH3-N was 3.65 times and 3.63 times for LFO (LaFeO3)/PMS. Moreover, the kobs of LFC5/PMS system prepared using BHMTMP as the complexing agent surpassed that of the LFCC/PMS system prepared with citric acid (CA) as the complexing agent, and the former was 2.3 times and 1.8 times greater than that of the latter for the removal of CODCr and NH3-N, respectively. The leaching of Cu and Fe of LFC5 was much less than that of LFCC, the strong chelation performance of BHMTMP with various metal ions can greatly reduce the leaching of metal ions and improve the stability of the catalyst. Hydroxyl radicals, sulfate radicals, and singlet oxygen were generated in the LFC5/PMS system, with singlet oxygen playing a dominant role. HPLC, UV absorption spectra, and 3D-EEM fluorescence spectra were used to analyze pollutant components in BTCW before and after degradation, demonstrating the effective removal of certain residual contaminants. In addition, the degradation process of BTCW was modeled using a 3-factor-3-level Response Surface Methodology (RSM) model. RSM model fitted the true experimental results well. This research offers a new approach for the comprehensive treatment of BTCW to meet standard discharge requirements and promote a more cost-effective operating process.

Dietary risk assessment of pesticide residues in cowpeas from Hainan province of China

This study aims to provide insights into the current status of pesticide residue contamination in Hainan province and to develop food safety regulations for controlling the excessive use of pesticides on cowpea. First, to assess the dietary exposure risks of pesticide residues in Hainan cowpea, more than 340 pesticides in 80 different fresh cowpea samples were investigated by HPLC-Q-TOF/MS/MS. Further, to indicate the health hazards of pesticide residues on consumers, the index of food safety (IFS) and risk coefficient (R) that stand for cumulative and simultaneous effects of different pesticides were calculated. A total of 56 kinds of pesticides were found in all 80 cowpea samples, and the positive rate was as high as 71 % in all samples. The results showed that the detectable rate of pesticide residues in cowpea samples were 100 % (80/80), and over 56 pesticides were detected to exceed the detection limits. In terms of IFS (<1), the safety risk of Hainan cowpeas is acceptable, but the R values of carbendazim and other 11 kinds of pesticide residues is much higher than safety level (R>1.5). These findings indicate a potential high risk of pesticide residues in Hainan cowpea, which reflect the importance of continuous monitoring and daily supervision of cowpea in Hainan.

A smartphone-integrated nanosensor based on N, P co-doped graphene quantum dots for fluorescence detection of acid red 18 in food

Exploring graphene quantum dots (GQDs) that can be done to contaminant residue detection has been widely concerned. Herein, we develop nitrogen and phosphorus co-doped graphene quantum dots (N, P-GQDs) with a strong green emission (quantum yield: 0.582) by using the resorcinol and phosphonitrilic chloride trimer as precursors via the one-step hydrothermal method. The synthesized N, P-GQDs exhibit excellent photostability and excitation-independent characteristic. Meaningfully, N, P-GQDs exhibit good fluorescence response to acid red 18 (AR18) and possess a good linear relationship over the range of 0–50 μM (the detection limit: 27 nM). Meanwhile, the fluorescence resonance energy transfer is considered as the possible sensing mechanism. Furthermore, a smartphone-assisted sensing platform is designed for the detection of AR18, which can realize on-site quantitative analysis and exhibit excellent on-site detection capability (the detection limit: 43 nM). Therefore, the present strategy has a prospective value for the application in the on-site monitoring of AR18.

Herbicide exposure alters the effect of the enthomopathogen Beauveria bassiana on immune gene expression in mealworm beetles

Concerns have grown worldwide about the potentially far-reaching effects of herbicides on functional biodiversity in agroecosystems. Repeated applications over time can lead to accumulation of residues in soil, water, and food and may have negative impacts on non-target organisms. However, the effects of herbicide residues on interspecific relationships, such as host-pathogen interactions, are poorly studied. In this study, we evaluated the effects of two different concentrations of a commercial pendimethalin-based formulation (PND), the residual contamination (S, 13 ppm) in treated soils and the maximum residue level allowed by the European Commission in cereals (EU, 0.05 ppm). We tested the effect of PND on the biological interaction between the mealworm beetle Tenebrio molitor Linnaeus, 1758 and the entomopathogenic fungus Beauveria bassiana Vuillemin, 1912 (Bb, strain KVL 03–144) at two concentrations (LC50 5 × 105 conidia mL−1 and LC100 1 × 107 conidia mL−1). We checked the survival of beetles exposed to PND or/and inoculated with B. bassiana, the expression of four antimicrobial peptides (AMPs), and finally how PND affects in vitro germination of fungus. The exposure to PND had no significant effects on the survival of either control or Bb-exposed beetles. In the mealworm beetle, upregulation of gene expression of the inducible AMPs Tenecin 1, 2, and 4 was observed in PND-treated beetles after inoculation with Bb, while the levels of the non-inducible AMP Tenecin 3 were similar between treatments. In conclusion, our findings demonstrate that admitted residual doses of currently used herbicides modify an important component of the inducible immune response of an insect. This did not translate into an effect on the survival to B. bassiana in our system. However, residual doses of the herbicide at 13 ppm may temporarily affect fungal germination. These results raise questions about the compatibility of bioinsecticides with synthetic pesticides and the effects of herbicide residues on host-pathogen interactions.

BIODEGRADATION OF GLYPHOSATE CONTAINING HERBICIDE BY SOIL FUNGI

Ten fungal isolates were isolated from two herbicide-contaminated soil farms obtained from Amoyo and the University of Ilorin environment in Kwara State after enrichment with mineral salt medium (MSM) supplemented with glyphosate-containing herbicide. The growth of fungal isolates was efficiently stimulated by the organophosphorus herbicide. Fungi isolated were subjected to screening by varying the herbicide concentrations from 0.1 to 3%, which is prepared with MSM. This screening showed that all the fungal isolates had the ability to act in the biodegradation process. However, varying degradative potentials were observed, as some had heavy growth while others had only slight or no growth as the concentrations of the herbicide increased. The ten fungal isolates were characterized and identified as Aspergillus niger, Penicillum spinulosum, Aspergillus terrus, Aspergillus flavus, Fusarium oxysporum, Mucor spp., Aspergillus oryzae, Aspergillus tamari, Rhizopus stolonifer, and Trichoderma koningii, and these were reduced to six after screening with 3% concentration of the herbicide. Four isolates (A. niger, F. oxysporum, Mucor spp., and A. flavus) were selected based on their growth ability on the medium during screening and were used in the biodegradation study. However, there is an increase in fungal dry weights ranging from 8.60 to 18% for 12 days. This shows that these fungi can be employed in the biodegradation of herbicides since they are potentially effective species and are environmentally safer alternative to protect the soil from the contamination of glyphosate-containing herbicide residues.