Electron Mass Research Articles

Determination of the Seebeck Coefficient and Other Thermoelectric Parametersusing Specific Resistivity and Concentration of Charge Carriers of N-Si0.96Ge0.04 Alloy Irradiated by 60Co γ-photons

The thermoelectric alloy N-Si0.96Ge0.04-P irradiated by 60Co gamma-photons is been studied. The temperature dependences of the Seebeck coefficient, power and electronic quality factors, as well as the universal electrical conductivity and effective masses of electrons in the interval (250400)°C are calculated. All these dependences are different from the results previously obtained for SixGe1-x with other compositions (except for effective mass). This should be associated with a significant difference in specific resistivities and concentrations of charge carriers.

Theoretical study of susceptibility and effective mass in semiconductor quantum well-wires

The susceptibility and effective mass of electrons and hole vary as functions of carrier density and temperature in parabolic lateral barrier quantum-well wires (QWWRs). To investigate these properties, we utilize the leading-order dynamically screened Coulomb interaction, wherein the electron self-energy is calculated within the plasmon-pole approximation (PPA). All findings for GaAs QWWRs reveal a substantial difference between susceptibility and effective mass at low and high temperatures for varying carrier densities. These results contribute to illuminate of how Coulomb interactions and exchange–correlation energies influence the susceptibility and effective mass of GaAs semiconductors across a broad range of temperature and carrier density conditions.

Design and performance of GaSb-based quantum cascade detectors.

InAs/AlSb quantum cascade detectors (QCDs) grown strain-balanced on GaSb substrates are presented. This material system offers intrinsic performance-improving properties, like a low effective electron mass of the well material of 0.026 m 0, enhancing the optical transition strength, and a high conduction band offset of 2.28 eV, reducing the noise and allowing for high optical transition energies. InAs and AlSb strain balance each other on GaSb with an InAs:AlSb ratio of 0.96:1. To regain the freedom of a lattice-matched material system regarding the optimization of a QCD design, submonolayer InSb layers are introduced. With strain engineering, four different active regions between 3.65 and 5.5 µm were designed with InAs:AlSb thickness ratios of up to 2.8:1, and subsequently grown and characterized. This includes an optimized QCD design at 4.3 µm, with a room-temperature peak responsivity of 26.12 mA/W and a detectivity of 1.41 × 108 Jones. Additionally, all QCD designs exhibit higher-energy interband signals in the mid- to near-infrared, stemming from the InAs/AlSb type-II alignment and the narrow InAs band gap.

Analisis Pesan Moral Pada Film Bayi Ajaib Tahun 2023

Mass communication broadly is an activity carried out between one or more people to convey messages through print, electronic or digital mass media with the expectation of reciprocity. One of the media used to convey messages is film. Film is a mass media that is considered effective in conveying messages compared to other communication media. Film is a new means used to disseminate entertainment that has become a previous habit, as well as presenting stories, events, music, drama, comedy and other technical presentations to the general public. Films not only serve entertainment functions, but also contain informative, educative and even persuasive functions. In the current era, there are many types of films that educate film lovers, especially in Indonesia. There are various types of films including drama, romance, comedy, action and horror, such as the film Miracle Baby 2023. The film Miracle Baby 2023 is one of the Indonesian horror films which will be shown in Indonesian cinemas in January 2023, which tells the story of two young people. -sama wants to become rich, but in the wrong way. This magical baby film also contains many moral messages. Moral messages are statements that convey instructions, regulations, or invitations regarding societal conventions, morality, and culture so that humans can live better and as material for self-evaluation in actions. The moral messages contained in the 2023 Magic Baby Film are: 1) moral messages in the category of human relationships with God , 2) moral messages in the category of human relationships messages in the category of human relationships with themselves, and 3) moral messages in the category of human relationships with other humans.

Tunable electronic and optical properties of h-BP/MoS2 van der Waals heterostructures toward optoelectronic applications

The integration of two-dimensional materials (2D) into van der Waals heterostructures (vdWHs) is widely recognized as an effective strategy for the development of multifunctional devices. This study aims to construct stable ultrathin 2D vdWHs using h-BP and MoS2 monolayers, and analyze the impact of strain on the electronic properties of h-BP/MoS2 vdWHs, with a specific focus on the mechanism of biaxial strain regulation. The h-BP/MoS2 vdWHs demonstrate the type II band alignment and possess direct bandgap, which can be effectively controlled through appropriate application of biaxial strain. The power conversion efficiency (PCE) can reach 21.85 % achieved suggests that the material under consideration has potential as a suitable candidate for 2D excitonic solar cells. The observed decrease in effective mass for both electrons and holes implies an enhanced carrier mobility, thereby facilitating the utilization of h-BP/MoS2 vdWHs in the development of high-efficiency excitonic solar cells. These findings indicate that the h-BP/MoS2 vdWHs possess the capability to serve as a reconfigurable system in the construction of highly efficient solar cells.

In-situ electrochemical self-reconstruction of permeable Ni(OH)2/Pt hybrid for accelerating alkaline hydrogen evolution

Pt-based hybrid materials are demonstrated to be the most effective catalysts for alkaline hydrogen evolution reactions (HER) due to the synergy effect of heterogeneous interfaces. However, the heterogeneous interfaces are often constructed at the sacrifice of the electrochemical active surface area to cause relatively lower HER activity than expected. Herein, a permeable Ni(OH)2 layer and strained Pt atoms heterogeneous interface with enhanced electrocatalytic activity and minimal loss of active surface sites have been created by using an in-situ electrochemical self-reconstruction strategy. The permeable Ni(OH)2 layer promotes H2O dissociation without blocking proton contact with the active Pt sites. This unique design creates a favorable local acid-like environment that results in an ultra-high mass activity of 17.8 A mgPt−1 at an overpotential of 70 mV, which is 20.5 times superior to that of the commercial Pt/C catalyst and higher than those of the previously reported Pt-based catalysts. Meanwhile, the HER overpotential displays as low as 15 mV at 10 mA cm−2, showing superior HER efficiency and representing one of the optimal Pt-based HER catalysts in alkaline solution. In-situ Raman spectroscopy and DFT calculations prove that the interfacial synergistic interaction between permeable Ni(OH)2 layer and strained Pt atoms can significantly promote the H2O dissociation and the H2 formation. This electrochemical self-reconstruction method provides an effective and facile strategy for optimizing the electronic structure, electrocatalytic activity, and mass activity of active Pt atoms to develop efficient Pt-based heterostructure electrocatalysts.

Field-mediated neural transmission within an Ag[formula omitted]S gap-type atomic switch

Unlike conventional synaptic transmission, biological field-mediated neural transmissions solely due to extracellular field effects are hardly emphasized in artificial synapse systems. Using an Ag2S gap-type atomic switch, we demonstrate the field-mediated transmission for low bias stimulations which is capable of generating measurable current due to pre-conditioning of the junction by a change in the electrochemical potential of ions prior to any precipitation. The observed current–voltage (I−V) characteristics for V<100 mV are in good agreement with Simmon’s tunneling model for asymmetric barrier (ϕ) in the range 0<V<ϕ. For more than 100 consecutive voltage sweep cycles, an increase in hysteresis corresponding to an input energy of 10−1000 pJ was observed. The average barrier height was lowered from 1 eV to 0.125 eV and the effective mass of carrier electrons increased from 0.25 me to 2.5 me until the actual precipitation began. These results are of practical importance in developing artificial neural networks capable of mimicking field-mediated communications found in the cerebellum, heart, retina, and olfactory systems.

Theory of electronic structure and effective masses of ultra-wide bandgap wurtzite aluminum nitride

I develop a theory of electronic structure for wurtzite(W)-Aluminium Nitride, based on the three uppermost valence bands and the lowest conduction band at the Γ-point. As distinguished from the Chuang-Chang approach [9], where the Hamiltonian is diagonalised considering all the bands, through an matrix, I follow a different procedure. In my approach, initially I follow a two-band approximation for the matrix, where the Hamiltonian is diagonalised by treating the conduction band and each of the valence bands separately. Thus, I diagonalise three different matrices, for obtaining the dispersions of the valence bands. The conduction band energy is obtained from the first diagonalization, involving band edge states. Effect of other two valence bands on a given valence band is considered through second order perturbation theory. Details of this procedure are outlined in Appendix A. It gives analytic expressions for the dispersion of the bands. I compare the results obtained for W-AlN with recent calculations and note satisfactory agreements. I also calculate the effective masses of holes in the valence bands both at the Γ-point and also as functions of the wavevector. My results agree fairly well with a recent calculation [3]. The hole effective masses for all the bands show large anisotropy. The effective mass of the electron in the conduction band does not show appreciable anisotropy.

Enhanced Thermoelectric Properties in Highly Co-Doped Bi2Se3 by Density-of-State Effective Mass Increase

Bi2Se3 alloys are promising thermoelectric materials for use at near room temperature. In this study, we investigated the thermoelectric transport properties of Co-doped Bi2Se3, Bi2−xCoxSe3 (x=0, 0.03, 0.06, 0.09, and 0.12) polycrystalline alloys. The electrical conductivity of Bi2Se3 increased with Co doping as the electron concentration increased. The power factor increased by 83% (1.17 mW/mK2) with the Co doping compared with 0.64 mW/mK2 for pristine Bi2Se3 at room temperature. The density-of-states effective mass significantly increased to 0.30 m0 (free electron mass) by high Co doping of x =0.12 compared to 0.14 m0 for pristine Bi2Se3. The total thermal conductivity of the Co-doped samples increased owing to the increase in electronic thermal conductivity, despite the systematic decrease in the lattice thermal conductivity caused by Co doping due to additional phonon scattering. Nevertheless, an enhancement in zT was observed for all the Co-doped samples. The maximum zT value of 0.39 in highly Co-doped Bi1.88Co0.12Se3 is observed at 520K, which is 18% higher than that of pristine Bi2Se3. The zT value of the Co-doped sample could be further increased with the decrease in carrier concentration, which could be attained with the decrease in total thermal conductivity owing to the decreased electronic thermal conductivity while maintaining a high power factor originating from the increased effective mass.

Covalent functionalization of germanene employing computational simulations.

Computational simulations through density functional theory in conjunction with M06-L and HSE functional have been carried out to investigate the chemical reactivity of the germanene monolayer. It is exceptionally reactive, with an average reaction energy of -60.4 kcal mol-1 for the nineteen functional groups considered: H, F, Cl, Br, O, S, Se, Ge, OH, SH, CH3, CF3, NH, NH2, C6H5, C6H4, CCl2, CBr2, and the azomethine ylide. The results indicate that oxygen is the most reactive reagent (-96.9 kcal mol-1), followed by fluorine (-83.1 kcal mol-1). Germanene presents a rich organic chemistry, and functionalization with azomethine ylides, benzynes, and carbenes can be easily accomplished as indicated by the reaction energies computed, which lie between -45 and -65 kcal mol-1. Furthermore, germanene is significantly more reactive than graphene and hexagonal boron nitride monolayers since the reaction energy for germanene is more than 40 kcal mol-1 lower. Although, in general, germanene is slightly more reactive than black and blue phosphorene and less prone to oxidation, but its oxidation when exposed to air occurs spontaneously. The addition of functional groups works cooperatively. The reaction energies become lower as the number of functional groups increases, thus favouring the agglomeration of functional groups attached unless the steric effect alters this pattern. Finally, we analyzed the electronic properties of functionalized germanene. It is possible to fine-tune the band gap of germanene from 0.1 to 2 eV using different functional groups and coverages. For O-50% and S-50% functionalized germanene, we found that carrier recombination is the most difficult due to the considerable differences between the effective masses of holes and electrons, which is promising for optical applications.

Realizing ampere-level CO2 electrolysis at low voltage over a woven network of few-atom-layer ultralong silverene nanobelts with ultrahigh aspect ratio by pairing with formaldehyde oxidation.

The development of advanced multi-functional electrocatalysts and their industrial operation on paired electrocatalysis systems presents a promising avenue for the gradual penetration of renewable energy into practical production. Herein, a self-supported conductive network of silverene nanobelts (Ag-ene NBs) was delicately assembled (Ag-NB-NWs), in which ultralong and few-atom-layer Ag-ene NBs with a high edge-to-facet ratio were interconnected, serving as "superreactors" for electron transfer and mass transport during the reaction. Such superstructures as electrocatalysts delivered an unparalleled performance toward the CO2-to-CO conversion with exclusively high faradaic efficiency (FE) and partial current densities of up to 1 A cm-2. Remarkably, the membrane electrode assembly (MEA) cell with Ag-NB-NWs as the cathode was capable of ultrastable and continuous operation for over 240 h at 0.4 A with ∼100% selectivity. More importantly, by further using Ag-NB-NWs as a bifunctional electrocatalyst, a record-low voltage overall CO2 electrolysis system coupling cathodic CO2 reduction with anodic formaldehyde oxidation in MEA cell was performed to achieve concurrent feed gas generation and formate production, substantially improving electrochemical techno-economic feasibility.

Novel electrochemical strategies for the microbial conversion of CO2 into biomass and volatile fatty acids using a fluid-like bed electrode in a three-phase reactor.

Microbial electrosynthesis (MES) constitutes a bioelectrochemical process where bacteria uptake electrons extracellularly from a polarized electrode to incorporate them into their anabolic metabolism. However, the efficiency of current MES reactor designs can be lower than expected due to limitations regarding electron transfer and mass transport. One of the most promising bioreactor configurations to overcome these bottlenecks is the Microbial Electrochemical Fluidized Bed Reactor (ME-FBR). In this study, microbial CO2 fixation is investigated for the first time in a ME-FBR operated as a 3-phase reactor (solid-liquid-gas). An electroconductive carbon bed, acting as a working electrode, was fluidized with gas and polarized at different potentials (-0.6, -0.8 and -1 V vs. Ag/AgCl) so it could act as an electron donor (biocathode). Under these potentials, CO2 fixation and electron transfer were evaluated. Autotrophic electroactive microorganisms from anaerobic wastewater were enriched in a ME-FBR in the presence of 2-bromoethanosulfonic acid (BES) to inhibit the growth of methanogens. Cyclic voltammetry analysis revealed interaction between the microorganisms and the cathode. Furthermore, volatile fatty acids like propionate, formate and acetate were detected in the culture supernatant. Acetate production had a maximum rate of ca. 1 g L-1 day-1 . Planktonic cell biomass was produced under continuous culture at values as high as ca. 0.7 g L-1 dry weight. Overall, this study demonstrates the feasibility of employing a fluidized electrode with gaseous substrates and electricity as the energy source for generating biomass and carboxylic acids.

SYNTHESIS, CHARACTERIZATION OF 2-[(Z)-{[6-AMINO-2-(4- CHLOROPHENYL) PYRIMIDIN-4-YL] IMINO} METHYL]-4- NITROPHENOL SCHIFF BASE WITH Mn (II), Co (II), Ni (II), Cu (II), Zn (II), Pt (II) FOR THEIR NANOPARTICLE AND ANTIBACTERIAL STUDIES

The green synthesis of novel 2-[(Z)-{[6-amino-2-(4-chlorophenyl) pyrimidin-4-yl] imino} methyl]-4- nitrophenol Schiff base complexes with Mn 2+ , Co2+, Ni2+, Cu2+, Zn2+ and Pt2+ was successfully synthesized. These synthesized materials underwent thorough characterization using various analytical and physicochemical techniques, including elemental analysis, molar conductivity, magnetic susceptibility, Fourier transform infrared (FTIR) spectroscopy, Electron spin resonance (ESR), Electronic spectra, Thermogravimetric analysis (TGA), Mass spectrometry, and X-ray powder diffraction. The results show that the Pt2+ and Ni2+ complexes exhibit octahedral geometry, while all other complexes adopt a square planar geometry. The ESR spectral data provided insights into their structures and the degree of covalency. Additionally, SEM and TEM studies showed that the synthesized nanoparticles have sizes ranging from 19-32 nm, with spherical granules. Furthermore, Schiff base and their metal ion complexes were tested for their anti-microbial activities.

Design of back-contact interface of Cu(In,Ga)Se&lt;sub&gt;2&lt;/sub&gt; solar cells by single-target magnetron sputtering

Thin-film solar cells provide an opportunity to reduce the cost of converting solar energy into electricity by replacing expensive and thick silicon wafers, which account for more than 50% of the total cost of photovoltaic (PV) modules. However, many thin-film solar cell materials result in low PV performance due to enhanced recombination through defect states. Cu(In,Ga)Se&lt;sub&gt;2&lt;/sub&gt; (CIGS) is a promising thin-film solar cell material due to its direct tunable bandgap, high absorption coefficient, low effective electron and hole mass, and abundant constituent elements. Among them, magnetron sputtering or selenization technology is widely used to catch up with the development of preparing large-area CIGS thin-film solar cells because of its uniform film composition and simple process. However, the use of toxic gases such as H&lt;sub&gt;2&lt;/sub&gt;Se and H&lt;sub&gt;2&lt;/sub&gt;S and the difficulty in forming gradient bandgaps limit their development. In this work, the “V” Ga gradient classification of the absorbing layer of CIGS solar cells is realized by sputtering CuGaSe&lt;sub&gt;2&lt;/sub&gt; (CGS) thin layers of different thickness values in the room temperature layer by sputtering and selenium-free methods of quaternary target sputtering. Firstly, the microstructure of the film is characterized by scanning electron microscope, X-ray diffraction, Raman and X-ray photoelectron spectroscopy, and when the CGS layer is located in the middle of the low-temperature layer, the grain size of the film is the largest, the crystallinity is the best, forming a “V-shaped” structure of CGI on the back of the absorbing layer. Subsequently, IV and external quantum efficiency (EQE) tests show that the optimized cell efficiency is as high as 15.04%, and the light response intensity is enhanced in the 300 －1200 nm band. Finally, the admittance spectrum(AS) test shows that the defect energy level of the solar cell changes from In&lt;sub&gt;Ga&lt;/sub&gt; defect to &lt;i&gt;V&lt;/i&gt;&lt;sub&gt;Cu&lt;/sub&gt; defect of lower energy level, and the defect density decreases from 7.04×10&lt;sup&gt;15&lt;/sup&gt; cm&lt;sup&gt;–3&lt;/sup&gt; to 5.51×10&lt;sup&gt;15&lt;/sup&gt; cm&lt;sup&gt;–3&lt;/sup&gt;. This is comparable to the recording efficiency of the current single-target magnetron sputtering CIGS solar cells, demonstrating good application prospects.

Easily constructed porous silver films for efficient catalytic CO2 reduction and Zn-CO2 batteries.

For the electroreduction of carbon dioxide into high value-added chemicals, highly active and selective catalysts are crucial, and metallic silver is one of the most intriguing candidate materials available at a reasonable cost. Herein, through a novel two-step operation of Ag paste/SBA-15 coating and HF etching, porous silver films on a commercial carbon paper with a waterproofer (p-Ag/CP) could be easily fabricated on a large scale as highly efficient carbon dioxide reduction reaction (CO2RR) electrocatalysts with a CO Faraday efficiency (FECO) as high as 96.7% at -1.0 V vs. the reversible hydrogen electrode (RHE), and it still reaches up to 90% FECO over applied potentials ranging from -0.8 to -1.1 V vs. the RHE. Meanwhile, the membrane electrode assembly (MEA) utilizing the p-Ag/CP catalyst has achieved a current density, FECO, and stability of ∼60 mA cm-2, >91%, and 11 h, respectively. Furthermore, the assembled aqueous Zn-CO2 battery using p-Ag/CP cathode yielded a peak power density of 0.34 mW cm-2, 75 charge-discharge cycles for 25 h, and 64% FECO at 2.5 mA cm-2. Compared with flat Ag/CP, the significant enhancement in the CO2RR activity of p-Ag/CP was mainly attributed to the distinctive porous structure and an improved three-phase boundary, which is capable of inducing the stabilization of *COOH intermediates, increased active specific surface areas, fast electron transfer kinetic and mass transportation. Further, theoretical calculations revealed that p-Ag/CP possessed an optimized energy barrier for *COOH intermediates.

Carrier transport in bulk and two-dimensional Zn2(V,Nb,Ta)N3 ternary nitrides.

Density functional theory-based simulations are applied to study the electronic structures, carrier masses, carrier mobility and carrier relaxation times in bulk and two-dimensional (2D) Zn2(V,Nb,Ta)N3 ternary nitrides. Bulk Zn2(V,Nb,Ta)N3 possess moderate band gap sizes of 2.17 eV, 3.11 eV, and 3.40 eV, respectively. Two-dimensional Zn2(V,Nb,Ta)N3 have slightly higher band gap sizes of 2.77 eV, 3.33 eV, and 3.23 eV, respectively. Carrier mass, carrier mobility and carrier relaxation time are found to be anisotropic in all the studied structures. Bulk and 2D samples show an order of magnitude higher electron mobility compared to hole mobility. The highest electron mobility in bulk Zn2NbN3 and Zn2TaN3 is about ∼103 cm2 V-1 s-1. Importantly, for 2D Zn2NbN3, an abnormally high electron mobility of 1.67 × 104 cm2 V-1 s-1 is observed, which is not inferior to the highest known electron mobility values in 2D materials. Such a high electron mobility in 2D Zn2NbN3 can be attributed to a strong delocalization of the conduction band minimum, which is responsible for electron transport. Therefore, this work opens up new materials for high performance nanodevices, such as tandem solar cells and field-effect transistors. This study also provides deep physical insights into the nature of carrier transport mechanisms in bulk and 2D Zn2(V,Nb,Ta)N3 ternary nitrides.

Application of GaS nanotubes as efficient catalysts in photocatalytic hydrolysis: a first principles study.

Photocatalytic hydrogen production is a promising and sustainable technology that converts solar energy into hydrogen energy with the assistance of semiconductor photocatalysts. Herein, we investigated the geometric structure and electronic and photocatalytic properties of single-walled GaS nanotubes under the framework of density functional theory with HSE06 as an exchange-correlation function. This paper presents the first study on the geometric structure, electron, and photocatalytic properties of single-walled GaS nanotubes. The results show that the strain energy and formation energy of GaS nanotubes decrease, while the structure is more stable, with increasing radius. Our study shows that after rolling from the slab, the nanotubes undergo a transition from an indirect band gap to a direct band gap and have appropriate band gaps for absorbing visible light. Moreover, it is speculated that the large disparity between the effective mass of electrons and holes can reduce charge carrier recombination. Among them, the nanotube with a diameter larger than (35, 0) showed promising band edge positions for photocatalytic hydrolysis redox potential with pH values between 0 and 7. Based on these properties, we believe that GaS nanotubes will be promising in photocatalytic hydrolysis.

Optimization of effective electron mass in strained silicon nanosheets

This work investigated the effective mass of electrons in silicon nanosheets confined in the [001] and [1̄10] directions and having thicknesses of several nanometers with uniaxial tensile stress in the [110] direction, using density functional theory. The results show that the confinement along [1̄10] substantially reduces the effective mass in the [110] direction even in the absence of stress—a phenomenon not observed under [100] confinement. Our theoretical analysis reveals that confinement in the [110] direction acts as an effective shear strain. Furthermore, our study identifies an optimal stress that minimizes the effective mass in the transport direction, m110, thereby improving the nanosheet’s transport properties.

A METHOD FOR EMPIRICAL ESTIMATION OF PLANCK’S LENGTH, MASS, AND TIME THROUGH THE CHARACTERISTICS OF AN ELECTRON. IMPROVING THE ACCURACY OF SOME PHYSICAL CONSTANTS

A method for empirical estimation of Planck's length, mass, and time is proposed, which is based on the characteristics of the electron, Avogadro, and Euler numbers, and the fine structure constant. Basic physical constants can be expressed in terms of Planck's length, mass, and time. The disadvantage of this method is that Planck's elementary particle does not exist in nature. Planck's particle is presented in a hypothetical, virtual form, its characteristics are theoretically calculated through the reduced Planck's constant, Newton's gravitation constant, and the constant speed of light in a vacuum, and the accuracy of these characteristics is low. This is due to the low accuracy of the Newtonian constant of gravity. This shortcoming can be eliminated if the characteristics of the hypothetical Planck particle are associated with a real elementary particle, for example, with an electron, and through its characteristics with the characteristics of leptons and baryons. Since the characteristics of leptons and baryons are determined experimentally and are among the most accurate, for example, for a proton now is 11 decimal places, establishing a connection with them of a hypothetical Planck particle will increase the accuracy of the values: of Planck's length, mass and time, of Planck constant, of elementary electric charge, of the Newtonian gravitational constant, of electron mass, of Planck temperature up to the accuracy level of a proton. As is known, the 26th General Conference on Weights and Measures decided to define one of the basic SI units of measurement through physical constants. In particular, with this solution, the kilogram is now defined in terms of Planck's constant, and the ampere is now determined in terms of the value of the elementary electric charge. Accordingly, with increasing accuracy of the values of Planck's constant and elementary electric charge, the accuracy of the values of a kilogram and Ampere will increase.

Assessment of Pesticide Residues in Vegetables Commonly Consumed in The Democratic Republic of Congo (DRC): Inadequate Agricultural Practices and Potential Impacts for Public Health

Pesticides residues in food pose a serious risk to children and adults consuming pesticide-contaminated food. The aim of present study was to assess pesticide residues in vegetables in the Kinshasa and Lubumbashi cities of the Democratic Republic of Congo (DRC). The levels of three pesticide residues were determined by gas chromatography coupled with electron capture detector (ECD) or mass spectrometer-time of flight detector (GC–ECD or GC-MS-TOF) in 96 samples of four vegetables amaranth, spinach, sorrel and sweet potato-leaves purchased from wholesale markets. The Dichlorodiphenyltrichloroethane with its metabolites (3-DDTs), endosulfan and malathion residues were found in 100% of the vegetable samples from Lubumbashi and in 62.5% to 87.5% of all vegetable samples from Kinshasa. Risks were mainly associated with the residues of DDTs pesticides in vegetables. The HQ and HI estimations revealed a serious potential risk to consumers, children particularly. Due to multiple pesticide residues exceeding the MRLs for single residue levels, the consumers are exposed to pesticides, heavily in Lubumbashi. Due to increasing trend in pesticide use, continuous monitoring of pesticide residues in vegetables and other food is recommended in order to develop the base line data on which pesticide regulations could be enhanced in DRC.