Low Concentrations Of Chemicals Research Articles

Role of epidemiology in the EU policy formulation of chemicals

Abstract Over the past 50 years, the European Union has built a robust legal framework for managing chemicals. This framework balances the benefits of using chemicals for societal well-being and economic prosperity with the need to protect human health and the environment from potential risks. As part of the EU’s Zero Pollution ambition in the context of the Green Deal, the European Commission adopted in 2020 the Chemicals Strategy for Sustainability, with the aim to better protect human health and the environment from harmful chemicals, while boosting innovation by promoting the use of safer and more sustainable chemicals. Assessing quantitative health impacts within the EC Better Regulation guidance typically involves indicators measuring the environmental burden of disease (EBD), providing a useful mean for legislators to evaluate the benefits of policy actions both in terms of health gains and cost. While such analyses are common in air pollution studies, challenges arise in the chemical legislation area, particularly in non-occupational settings, where the population is exposed to low concentrations of many chemicals through multiple exposure routes. In such contexts, the intrinsic complexities linked to exposure characterization and to the assessment of causality between the exposure and the health outcome may hinder the estimation of benefits of legislative actions. Debates may arise regarding the reliability of the underlying epidemiological studies, making challenging for policymakers to ascertain the robustness and generalizability of the findings of such analyses. Our work provides a summary and analysis of recent case studies in the context of chemicals. We focus on how epidemiological evidence was used in conducting EBD analyses in supporting better formulation of EU polices of chemicals. Speakers/Panelists Marleen Bekker Wageningen University & Research, Wageningen, Netherlands

Nonadditive Cytotoxicity in Select Disinfection Byproducts and Disinfected Secondary Effluents.

Toxicity studies of water disinfection byproducts (DBPs) typically assume additive interactions. Coupling results from both the bottom-up cytotoxicity interaction approach by selecting six common DBPs and the top-down cytotoxicity fractionating the disinfected secondary effluent containing a much broader DBP selection, we demonstrated a novel effect of clear, nonadditive cytotoxicity at low chemical concentrations regardless of the number of DBP types involved. We revealed that the cytotoxicity interactions were influenced by the chemical's type, concentration factor, and mixing ratio. For the bottom-up approach, the average combination indices (CIs) were 1.61 (chloracetamide + chloroacetonitrile, antagonism), 1.03 (bromoacetamide+bromoacetonitrile, near additivity), and 0.69 (iodoacetamide + iodoacetonitrile, synergism) across the DBPs' concentration range of 10-4-10-7 M. These cytotoxicity interactions also varied with the components' mixing ratios. For the top-down approach, we obtained two fractions of DBP mixtures from the disinfected secondary effluent using solvents of different polarities. The effect of the concentration on CI values was significant, with a maximum 43.1% relative deviation in CI from LC5 to LC95. The average CI values across the sample concentration range of 1-50 × (concentration factor) varied from 1.68 (antagonism) to 0.89 (slight synergism) as the ratio of mixture A increased. These results call for further research in prioritizing the forcing DBPs in mixtures.

Combining Thermal Effect and Mobility Control Mechanism to Reduce Water Cut in a Sandstone Reservoir in Kazakhstan.

The application of polymer flooding is currently under investigation to control water cut and recover residual oil from a giant sandstone reservoir in Kazakhstan, where the water cut in most producers exceeds 90%, leaving substantial untouched oil in the porous media. The primary objective of this research is to explore the feasibility of a novel approach that combines the mechanisms of mobility control by polymer injection and the thermal effects, such as oil viscosity reduction, by utilizing hot water to prepare the polymer solution. This innovative hybrid method's impact on parameters like oil recovery, resistance factor, and mobility was measured and analyzed. The research involved an oil displacement study conducted by injecting a hot polymer at a temperature of 85 °C, which is higher than the reservoir temperature. Incremental recovery achieved through hot polymer injection was then compared to the recovery by conventional polymer flooding and the conventional surfactant-polymer-enhanced oil recovery techniques. The governing mechanisms behind recovery, including reductions in oil viscosity, alterations in polymer rheology, and effective mobility control, were systematically studied to comprehend the influence of this proposed approach on sweep efficiency. Given the substantial volume of residual oil within the studied reservoir, the primary objective is to improve the sweep efficiency as much as possible. Conventional polymer flooding demonstrated a moderate incremental oil recovery rate of approximately 48%. However, with the implementation of the new hybrid method, the recovery rate increased to more than 52%, reflecting a 4% improvement. Despite the polymer's lower viscosity during hot polymer flooding, which was observed by the lower pressure drop in contrast to the conventional polymer flooding scenario, the recovery factor was higher. This discrepancy indicates that while polymer viscosity decreases, the activation of other oil displacement mechanisms contributes to higher oil production. Applying hybrid enhanced oil recovery mechanisms presents an opportunity to reduce project costs. For instance, achieving comparable results with lower chemical concentrations is of practical significance. The potential impact of this work on enhancing the profitability of chemically enhanced oil recovery within the sandstone reservoir under study is critical.

Alternative material recommendation for facade cladding: High silica-containing stonepaste ceramics

This study investigated the potential of using stonepaste ceramics, which were widely preferred as a coating and decoration material on the facades of architectural buildings in ancient times and continues to be produced on a workshop scale today as a cladding material on building facades. Stonepaste ceramics, made from a mixture prepared with a high amount of crystalline quartz as well as frit, plastic clay, and bentonite raw materials, were hand-shaped and sintered at 930 °C after glazing. The physico-mechanical properties of stonepaste ceramics, their behaviour under various environmental conditions (resistance to chemicals, frost, and thermal shock), and their microstructures have been characterized. The characterization results were compared with the properties of commonly used facade cladding materials. It was determined that stonepaste ceramics had a very low firing shrinkage value (2.84 %) compared to that of other ceramic cladding materials, a higher water absorption value (11.79 %) than that of porcelain tiles and floor tiles, and close to wall tiles, and a flexural strength value (33.64MPa) higher than wall tiles and close to porcelain tiles despite the high-water absorption value. Ten cycles of thermal shock resistance showed that the body and glaze layer of the stonepaste ceramic material are well bonded to each other, and there is no significant thermal expansion mismatch between them. One hundred cycles of freeze-thaw conditions indicated that the stonepaste ceramic had good adhesion and thermal expansion compatibility between the glaze and the body but only chipping damage under the action of tensile forces caused by the freezing of water entering the pores of the body. In terms of behaviour against various chemicals, stonepaste ceramics were found to be highly resistant to high and low concentrations of household chemicals, swimming pool salts, and alkalis but less resistant to low concentrations of HCl and citric acid and high concentrations of HCl and lactic acid compared to other chemicals. The results show that stonepaste ceramics, despite their high-water absorption potential, have properties close to those of traditional ceramic tiles and, like these materials, can serve for significant periods in various environmental conditions when used as facade cladding. Consequently, it has been revealed that stonepaste ceramics can be used as a facade cladding material in sustainable, long-lasting, contemporary architectural facades thanks to their technical and protective properties.

Anaerobic co-digestion of low Chemical oxygen demand concentration sludge mixture by different pretreatment methods

<p>Three laboratory scale systems were operated to study the anaerobic co-digestion of sewage sludge with the excess activated sludge and cattle manure which contained low COD concentration. The experiments were performed to evaluate the effects of different methods of pretreatment. Since the poor organic substrate, the organic loading rate(OLR) was designed about 1.6kg total solids(TS)(l *d)-1 and the hydraulic retention time was controlled from 78days to 53days throughout the experiment to investigate the effects of the input on overall stability. When the digesters got stabilized, the COD removal efficiencies were 61%, 89% and 54%, respectively, and the pH value fluctuated little in the three digesters. The results indicated that the treatment of 1g volatile solids(VS) of SSEASCM on semi-continuous co-digestion generated more than 200ml of biogas on average. Thus, anaerobic co-digestion of the mixed sludge provided a means for low COD waste treatment and produced renewable energy.</p>

Toxicity of Plastic Additive 1-Hydroxycyclohexyl Phenyl Ketone (1-HCHPK) to Freshwater Microcrustaceans in Natural Water

Various potentially toxic compounds associated with plastic (e.g., plastic additives) can enter the environment during plastic fragmentation and/or weathering. 1-Hydroxycyclohexyl phenyl ketone (1-HCHPK) is a widely used photoinitiator, e.g., in UV-radiation-curable technologies such as 3D-printing, plastic coatings and construction materials. 1-HCHPK may reach aquatic ecosystems via various waste-flows, including leaching from consumer goods. However, knowledge of its potential environmental hazard is scarce. In the present study, we addressed this data gap by assessing the acute and long-term toxicity of 1-HCHPK to freshwater microcrustaceans in environmentally relevant conditions using natural waters. The results showed that the acute toxicity of 1-HCHPK (L(E)C50) to pelagic Thamnocephalus platyurus and Daphnia magna and benthic Heterocypris incongruens ranged between 27 and 55 mg/L. Further, the long-term exposure of D. magna to low levels of 1-HCHPK (0.1 and 1.0 mg/L) did not affect ephippia hatching or organismal fitness, even in three successive daphnid generations. Thus, 1-HCHPK did not pose a hazard to the freshwater microcrustaceans at concentrations < 1 mg/L in the environmentally relevant conditions (i.e., multigenerational life cycle tests conducted in lake water at low chemical exposure concentrations). The tests employed in this study allowed for the environmentally relevant hazard assessment of emerging pollutants such as a plastic additive 1-HCHPK.

Applying synchrotron radiation-based attenuated total reflection-fourier transform infrared to chemically characterise organic functional groups in terrestrial soils of King George Island, Antarctica

Anthropogenic activities, especially associated with fossil fuel combustion, are raising concerns worldwide, but remote areas with extreme climate conditions, such as Antarctica, are isolated from the adverse influence of human civilisation. Antarctica is considered as the most untouched place on Earth. Such pristine areas, which have extremely low chemical pollutant concentrations owing to restricted anthropogenic impacts, exemplify plausible model environments to test the reliability and sensitivity of advanced analytical techniques employed to chemically characterise and evaluate the spatial distribution of chemical pollutants. Here, synchrotron radiation-based attenuated total reflection-Fourier transform infrared (SR-ATR-FTIR) spectroscopy was employed to evaluate the variations in the organic functional groups (OFGs) of terrestrial soils of King George Island, Antarctica. Second-derivative SR-ATR-FTIR spectroscopy coupled with several multivariate statistical techniques highlighted the influence of anthropogenic activities on the alterations of OFGs in terrestrial soils collected near airports. Moreover, the daily activities of penguins could also have caused fluctuations in some OFGs of the samples the close to the Tombolo area and Ardley Island. The findings proved the effectiveness of SR-ATR-FTIR in evaluating the potential sources of variations in the chemical constituents, especially OFGs, in Antarctic terrestrial soils.

CIL-ExPMRM: An Ultrasensitive Chemical Isotope Labeling Assisted Pseudo-MRM Platform to Accelerate Exposomic Suspect Screening.

Exposome is the future of next-generation environmental health to establish the association between environmental exposure and diseases. However, due to low concentrations of exposure chemicals, exposome has been hampered by lacking an effective analytical platform to characterize its composition. In this study, by combining the benefit of chemical isotope labeling and pseudo-multiple reaction monitoring (CIL-pseudo-MRM), we have developed one highly sensitive and high-throughput platform (CIL-ExPMRM) by isotope labeling urinary exposure biomarkers. Dansyl chloride (DnsCl), N-methylphenylethylamine (MPEA), and their isotope-labeled forms were used to derivatize polar hydroxyl and carboxyl compounds, respectively. We have programmed a series of scripts to optimize MRM transition parameters, curate the MRM database (>70,000 compounds), predict accurate retention time (RT), and automize dynamic MRMs. This was followed by an automated MRM peak assignment, peak alignment, and statistical analysis. A computational pipeline was eventually incorporated into a user-friendly website interface, named CIL-ExPMRM (http://www.exposomemrm.com/). The performance of this platform has been validated with a relatively low false positive rate (10.7%) across instrumental platforms. CIL-ExPMRM has systematically overcome key bottlenecks of exposome studies to some extent and outperforms previous methods due to its independence of MS/MS availability, accurate RT prediction, and collision energy optimization, as well as the ultrasensitivity and automated robust intensity-based quantification. Overall, CIL-ExPMRM has great potential to advance the exposomic studies based on urinary biomarkers.

Assessment of the Body Response to Snowmelt Water Consumption in Military Personnel Serving in the Arctic Based on Blood Parameters

Introduction: Stability of physicochemical parameters of body fluids reflects the degree of influence of environmental factors on the body. Objective: To assess the body response to snowmelt water consumption for drinking purposes in military personnel serving in the Arctic based on blood parameters. Material and methods: The study was conducted in summer 2022. We took snowmelt water samples for chemical analysis and venous samples from 51 servicemen for a complete blood count and electrolyte measurements. Results: Snowmelt testing showed that the levels of iron were 1.2–1.6, copper – 22.2, zinc – 52.1, sodium – 11.6 to 21.9, magnesium – 5.7 to 29.1, and calcium – 9.0 to 34.1 times lower than reference concentrations. Potassium levels were negligible. The length of service of the study subjects in the Arctic above the 76th parallel North was 5.7 ± 0.3 years. Blood test results showed low or lower normal values of erythrocyte count in 39.2 %, hematocrit – in 19.6 %, and mean hemoglobin – in 13.7 % of the military personnel. A high mean corpuscular volume was detected in 17.6 % of them. The proportion of stab neutrophils in the sample was 0.55 ± 0.04 % with the normal range of 1 to 6 %. The electrolyte imbalance was evidenced by high serum potassium levels in 21.6 %, a lack of ionized calcium and magnesium in 29.4 % and 17.6 %, respectively, and sodium, phosphorus, and chlorine levels at the lower limit of the normal range in 29.4 to 47.1 % of the examined. Conclusions: Snowmelt water contains low concentrations of inorganic chemicals. Its long-term daily consumption for drinking purposes leads to electrolyte imbalance in the body, such as hypotonic water overload, and is likely to affect nonspecific resistance.

Effect of psychoactive substances on cardiac and locomotory activity of juvenile marbled crayfish Procambarus virginalis

Pharmaceutically active compounds are common and increasing in the aquatic environment. Evidence suggests they have adverse effects on non-target organisms, and they are classified as emerging pollutants for a variety of aquatic organisms. To determine the effects of environmentally relevant levels of psychoactive compounds on non-target organisms, we analyzed cardiac and locomotory activity in early developmental stages of marbled crayfish Procambarus virginalis. Responses to sertraline, methamphetamine, and a mixture of citalopram, oxazepam, sertraline, tramadol, venlafaxine, and methamphetamine at a concentration of 1 µg L-1 of each compound were assessed. On day four of exposure, cardiac activity was recorded for 5 min, and on day eight, locomotory activity was recorded for 15 min. There was a significant increase (p < 0.01) in heart rate in methamphetamine-exposed and Mix-exposed juveniles compared to the unexposed control and there was significant difference (p < 0.01) in proportion of time (activity %) was observed with sertraline-exposed, whereas velocity, and distance moved did not significantly differ (p > 0.05) in exposed and control animals. These findings revealed that low concentrations of chemicals and their mixtures can modify the physiological state of aquatic animals without outward manifestations (activity, distance moved, and velocity). Aquatic animals can be impacted earlier than is visible, but effects can potentially lead to substantial changes in populations and in ecosystem processes. Additional research to investigate chemical combinations, exposure systems, and organism physiological and molecular responses may provide evidence of broad impact of environmental pharmaceuticals.

Changes in metabolic profiles of amphipods Allorchestes compressa after acute exposures to copper, pyrene, and their mixtures

Amphipods are ideal indicators for biomonitoring and ecotoxicological studies of environmental contaminants because they are extensively distributed in aquatic environments, are easy to collect and are important in nutrient cycling. Marine amphipods (Allorchestes compressa) were exposed to two concentrations of copper and pyrene, and their mixtures, for 24 and 48 h. Changes in polar metabolites were assessed using Gas Chromatography Mass Spectrometry (GC-MS)-based untargeted metabolomics. Generally, limited metabolite changes were observed for copper and pyrene single exposures (eight and two significant metabolites, respectively), while 28 metabolites had changed following exposures to mixtures. Furthermore, changes were mainly observed after 24 h but had seemingly returned to control levels after 48 h. Multiple types of metabolites were affected including amino acids, Tricarboxylic acid (TCA) cycle intermediates, sugars, fatty acids, and hormones. This study highlights the sensitivity of metabolomics in assessing the impacts of low concentrations of chemicals compared to traditional ecotoxicological endpoints.

Morphological and thermal stability characteristics of oil palm frond and trunk by ultrasound-low alkali-based pretreatment

Oil palm fronds and trunks leave a lot of lignocellulosic residues in the agricultural field. Due to its highly complex chemical composition, the lignocellulosic matrix is difficult to break down. This study aims to investigate the effects of chemo-physical pretreatment of oil palm fronds and trunks with ultrasound in a low alkali concentration solution. The microstructure and thermal stability of the oil palm frond and trunk were investigated using scanning electron microscopy (SEM) and a thermogravimetric (TG) method. SEM analysis proved the deterioration of the lignocellulose matrix of the ultrasound-assisted alkali pretreatment compared to raw. According to the TG results, the decomposition temperature curve of treated oil palm shifted to the right side after 50 percent mass degradation, indicating more excellent thermal stability than untreated oil palm biomass. On the other hand, at a temperature above 350 °C, the pretreated biomass has less thermal stability. It has been demonstrated that a combination of low chemical concentration and physical pretreatments can disrupt the oil palm lignocellulose microstructure and potentially shorten the time required to achieve maximum hydrolysis efficiency. Furthermore, ultrasonication power of 300 W, frequency of 40 kHz, temperature of 80 °C, and time of 30 min in combination with low alkali-based pretreatment in oil palm residue will be helpful in applications requiring greater thermal stability.

Differences in mirex [dechlorane] and dechlorane plus [syn- and anti-] concentrations observed in Canadian human milk

As part of the pan-Canadian Maternal-Infant Research on Environmental Chemicals (MIREC) study, human milk samples were collected between 2008 and 2011, and analyzed for mirex, an organochlorine insecticide and flame retardant, in addition to dechlorane plus (syn- and anti-DDC-CO), the flame retardant replacement for mirex. Mirex was analyzed separately, using a method for the analysis of existing organochlorine insecticides, while the presence of DDC-CO isomers was determined using a method developed for the detection of emerging flame retardants. Mirex was detected in all samples analyzed (n = 298), while syn- and anti-DDC-CO were present in 61.0% and 79.5% of the samples, respectively (n = 541). Mirex concentrations have declined in human milk since the 1990s. Since this is the first pan-Canadian dataset reporting DDC-CO concentrations in human milk, no temporal comparisons can be made. Maternal age was correlated with concentrations of both compounds although parity did not impact concentrations of either analyte. Given the presence of this relatively recently identified flame retardant (DDC-CO) in human milk from women across Canada, studies to identify dominant sources of this compound are critical. Despite low concentrations of environmental chemicals in human milk from Canadian women, Health Canada supports breastfeeding of infants because of the important health benefits to both the mothers and their infants.

A new targetry system for production of zirconium-89 radioisotope with Cyclone-30 cyclotron

Abstract In this study, an efficient method for targetry and production of zirconium-89 radioisotope (89Zr) with Cyclone-30 cyclotron was developed. The preparation of a highly pure compressed yttrium oxide target material and design of a target made by copper for better heat transfer was performed. Electrodeposition of target with gold was done to prevent the entry of metallic impurities (copper, zinc and other trace metal elements). Nuclear reaction cross sections for optimization of production with new target and irradiation parameters of the target were evaluated. The prepared 89Zr in the form of [89Zr] Zr-oxalate had high radionuclidic purity (&gt;99.9%) and a low chemical impurity concentration (&lt;0.1 ppm for copper and zinc elements). The yield of 89Zr radioisotope production via the reaction of 89Y(p,n)89Zr was measured to be 77 ± 9.5 MBq/μAh (time of irradiation = 3, the current 20–30 µA). [89Zr] Zr-oxalate specific-activity was in the range 2.319641 × 104–3.479443 × 104 MBq/mmol of Oxalate.

Inorganic Finishing for Textile Fabrics: Recent Advances in Wear-Resistant, UV Protection and Antimicrobial Treatments

The surface modification of textile fabrics and therefore, the development of advanced textile materials featuring specific implemented and new properties, such as improved durability and resistance, is increasingly in demand from modern society and end-users. In this regard, the sol–gel technique has shown to be an innovative and convenient synthetic route for developing functional sol–gel coatings useful for the protection of textile materials. Compared with the conventional textile finishing process, this technique is characterized by several advantages, such as the environmentally friendly approaches based on one-step applications and low concentration of non-hazardous chemicals. The sol–gel method, starting from inorganic metal alkoxides or metal salts, leads to inorganic sols containing particles that enable a chemical or physical modification of fiber surfaces, giving rise to final multifunctional properties of treated textile fabrics. This review considered the recent developments in the synthesis of inorganic nanoparticles and nanosols by sol–gel approach for improving wear and UV resistance, as well as antibacterial or antimicrobial effects for textile applications.

Application of surface-enhanced Raman scattering to qualitative and quantitative analysis of arsenic species.

Given the toxicity of arsenic, there is an urgent need for the development of efficient and reliable detection systems. Raman spectroscopy, a powerful tool for material characterization and analysis, can be used to explore the properties of a wide range of different materials. Surface-enhanced Raman spectroscopy (SERS) can detect low concentrations of chemicals. This review focuses on the progress of qualitative and quantitative studies of the adsorption processes of inorganic arsenic and organic arsenic in aqueous media using Raman spectroscopy in recent years and discusses the application of Raman spectroscopy theory simulations to arsenic adsorption processes. Sliver nanoparticles are generally used as the SERS substrate to detect arsenic. Inorganic arsenic is chemisorbed onto the silver surface by forming As-O-Ag bonds, and the Raman shift difference in the As-O stretching (∼60 cm-1) between As(V) and As(III) allows SERS to detect and distinguish between As(V) and As(III) in groundwater samples. For organic arsenicals, specific compounds can be identified based on spectral differences in the vibration modes of the chemical bonds. Under the same laser excitation, the intensity of the Raman spectra for different arsenic concentrations is linearly related to the concentration, thus allowing quantitative analysis of arsenic. Molecular modeling of adsorbed analytes via density functional theory calculation (DFT) can predict the Raman shifts of analytes in different laser wavelengths.

ODP272 ROUNDUP IS AN IMPORTANT DISRUPTOR THAT CAUSES PROLIFERATIVE EFFECTS ON NORMAL AND ON CANCER THYROID CELLS

Abstract Glyphosate has long be suspected to promote endocrine disruptive and even carcinogenic effects, but little is known about its effect at different concentrations on normal and on cancer thyroid cells. Since the endocrine system responds to low chemical concentrations and abnormal cells may have different sensitivity, it is essential to determine the effects of this compound at different levels, including the Acceptable Occupational Exposure Level (AOEL) and the Acceptable Daily Intake (IDA) doses. We used two human thyroid-derived cell lines strains, Nthy-ori 3-1 (from thyroid normal follicular cells) and TPC-1 (from papillary carcinoma) to test 15 different concentrations of Roundup® Original DI, ranging from 6.5 µg/L to 6.500 µg/L, including AOEL and IDA according to the Technical Note Process No. 25351. 056754/2013-17 of the National Health Surveillance Agency (ANVISA) in Brazil. Trypan blue assay and Cell Counting Kit – 8 (CCK-8) were employed to evaluate cell viability and cytotoxicity. Exposures were made for 24 and 48 hours in technical and biological triplicates. We observed a decrease in the number of viable cells at the 24h exposure compared to 48h in both strains. Exposure of Nthy-ori 3-1 and TPC-1 cells for 24h at the AOEL concentration (160µg/L) caused death of 52% and 58% of the cells, respectively, whereas IDA (830µg/L) resulted in 43% e 58% cell death. These data evidence an important disruptive effect of Roundup Original DI® at the acceptable concentrations. After 48h of exposure, AOEL and IDA concentrations caused a lower number of Nthy-ori 3-1 (19% e 15%) and TPC-1 (29% e 23%) dead cells, respectively, suggesting both thyroid strains have compensatory mechanisms that protect them from longer exposures to the herbicide. The CCK-8 assay, on the contrary, showed a proliferative effect on small concentrations: 6.5 µg/L increased the number of viable Nthy-ori 3-1 and TPC-1 cells to 113% and 118%, respectively, at 24h, and this stimulatory effect persisted after 48h of exposure. In contrast, AOEL and IDA concentrations produced a reduction in the number of both strains cells, likewise observed with the Trypan blue assay. Our data demonstrate that thyroid cells exposed to Roundup Original DI® present a non-monotone dose-response curve, which is a well-known characteristic of an endocrine disruptor. The proliferative effect produced on thyroid cells, especially TPC-1 mutant cells, by very low concentrations of this glyphosate-based herbicide widely used around the world, suggests that it may play a role in the increasing incidence rate of thyroid nodules and/or cancer that have been observed worldwide. Presentation: No date and time listed

Investigation of the effect of nitrification inhibition on the performance and effluent quality of aerobic sequential batch reactors.

The use of nitrification inhibition as a concentrating step for ammonium (NH4+), for the purpose of increasing the potential for simultaneous recovery of phosphate (PO43-) and NH4+ from effluent streams of an aerobic sequencing batch reactor (SBR) system, has never been investigated in the literature. Therefore, the present study aimed to determine the effect of the inhibition of nitrification on both the reactor performance and effluent quality in a laboratory scale aerobic SBR system. In order to compare the observed results, a separate reactor, where the inhibition was not applied, was operated as a control reactor (CR) under the identical operational conditions used for the inhibitory reactor (IR). Experimental results for the reactor performance showed that effluents with low total suspended solids (< 50mg/L) and chemical oxygen demand concentrations (> 90% of removal efficiency based on the influent concentration of 500mg/L) were achieved for both SBRs by obtaining an activated sludge with a sludge volume index < 60mL/g after the acclimation period. In the same period, the effluent PO43-, NH4+, and nitrate (NO3-) concentrations were found to be 17.0 ± 4.0, 1.26 ± 0.84, and 21.5 ± 39mg/L for the CR and 10.0 ± 4.4, 3.9 ± 2.4, and 9.2 ± 1.5mg/L for the IR, respectively. During this period, 94% of the removed NH4+ (NH4+rem.) was converted to NO3- in the CR, indicating almost complete nitrification occurred in the reactor. However, only 47% of the NH4+rem. was converted to NO3- in the IR as a result of the inhibition of nitrification, meaning a partial inhibition (53%) occurred due to the inhibition treatment. These results clearly demonstrated that the inhibition of nitrification allowed the effluent NH4+ concentrations to increase by suppressing the formation of NO3- ions. Based on the results, it can be concluded that inhibition of nitrification in an aerobic SBR system creates a potential for conserving the effluent NH4+ concentration and increasing consecutive recovery of PO43- together with NH4+ from the effluent discharges.

Permanganate Treatment Optimization on Tensile Properties and Water Absorption of Kenaf Fiber-Polypropylene Biocomposites

Kenaf fiber has been studied for biocomposites reinforcement due to its renewable and carbon neutrality. Meanwhile, polypropylene sheets are easily processed and considered a prospective thermoplastic matrix source for biocomposites. Hence, the combination of both materials is expected to form an attractive biocomposite. This study aimed to optimize permanganate treatment on tensile properties and water absorption of kenaf-reinforced propylene biocomposites. It thermally tested kenaf fibers and PP using differential scanning calorimetry (DSC) before performing compression molding at 185°C and 70 bars using the film stacking method. The kenaf fiber variables were untreated, alkaline pre-treated, and alkaline-permanganate treated to low concentrations of 0.01 to 0.05 wt% of KMnO4. Furthermore, this study conducted Yarn tensile test and Weibull distribution to find a strength variability statistically. Composite tensile and burn tests were performed to obtain tensile strength, constituent materials, and void volume fractions. Composites fractography was implemented to examine the effect of permanganate on composite water uptake behavior using scanning electron microscopy. This study used low concentration in permanganate treatments than several previous studies. The results showed that biocomposites have a tensile strength of 125 MPa, higher than in previous studies that found a value less than 80 MPa. This study has contributed to the green optimization treatment using lower chemical concentrations but with better results on impregnation, interfacial, water absorption, and mechanical properties of kenaf or polypropylene composites.

Detection of molecular vibrations of atrazine by accumulation of silver nanoparticles on flexible glass fiber as a surface-enhanced Raman plasmonic nanosensor

Surface-Enhanced Raman Spectroscopy (SERS) is a sensitive vibration spectroscopy method applied to analyze a variety of analytes, including toxins and pesticides. The SERS method is an accurate method for detecting significantly low concentrations of biomaterials and chemicals. In the present study, in order to detect atrazine pesticide, the glass fiber substrates coated with silver nanoparticles have been used as SERS plasmonic nanosensors. First, silver nanoparticles were prepared by applying a chemical approach named the Tollens' method, and the SERS plasmonic substrates (SPS) were fabricated by depositing the colloidal silver solution on a glass fiber substrate. The SERS plasmonic nanosensors were fabricated by self-assembling the silver nanoparticles and after functionalization of glass fiber substrate using 3-aminopropyl triethoxysilane (APTES). For this purpose, silver nanoparticles were chemically prepared, and their size distribution was determined to be 140–150 nm using dynamic light scattering (DLS). Ultraviolet–visible spectroscopy was applied for the optical characterization of colloids of silver nanoparticles and the prepared substrates. The results indicate the displacement of the plasmonic peak toward longer wavelengths after self-assembly of the nanoparticles. Field emission scanning electron microscopy images indicated the non-uniform distribution of silver nanoparticles on the surface of glass fiber substrates. Atrazine pesticide was employed as an analyte to investigate the performance of SERS plasmonic substrates (SPS). The detection limit of SPS for detecting atrazine pesticide was equal to 10−12 M, and the average relative standard deviation for ten repeated measurements was obtained to be 4.02%. With reducing the solution concentration to 10−12 M, the intensity of Raman modes decreased significantly so that only some peaks were clear. Moreover, the quantum mechanics calculation and molecular dynamics simulation were performed to clarify the molecular interactions between atrazine and silver nanoparticles. By increasing the concentration of atrazine, the Lennard-Jones potential was increased following the experimental results of Raman spectroscopy.