Chemical Contaminants In Water Research Articles

Detection of Chemical Contaminants in Water for Irrigation Systems: A Systematic Review

Water pollution is a detrimental issue that occurs when there are bad changes in water quality parameters. It directly disrupts water usage and poses a danger to society, environment, economy, and agriculture. Water quality should be monitored to alert authorities on water pollution, so that action can be taken quickly. Improper water management pollutes rivers and lakes in Malaysia such as Klang River, Semenyih River, Kim Kim River, Slim River, and others. Various techniques are introduced to detect contaminants in water such as electronic sensors, biosensor approaches, laboratory analysis, and optical techniques. The functionality tool varies depending on the specific contaminants or parameters that are targeted, and the resources allocated. Several common contaminant types are found in polluted water including heavy metals, organic and inorganic chemicals, industrial pollutants, suspended solids, and others. The objective of the review is to study various non-optical and optical contaminant detection methods in water to identify the strengths and weaknesses of the methods. In this review, water pollution problems mainly due to the agricultural sector in several countries are discussed. Besides, conventional, and modern methods are compared in terms of parameters, complexity, and reliability. We believe that conventional methods are costly and complex, whereas modern methods are also expensive but simpler with real-time detection. Recent contaminant detection methods in water are also reviewed to study any loopholes in the latest methods. We found that the spectroscopy method based on light propagation theory is suitable and one of the promising methods for chemical contaminants detection for water quality analysis. This method offers fast analysis time, high sensitivity detection, non-invasive analysis, provides reliable data, and others. Undoubtedly, some contaminants in water can be challenging to be identified rapidly and confidently even though there are numerous tools and techniques available for water quality analysis. Thus, the review is important to compare previous methods and to improve current chemical contaminants detection analysis in terms of reliability with a minimum operating system and cost effectiveness.

Assessment of the impact of chemical pollution on endangered migratory fish in two major rivers of France, including spawning grounds

Water pollution is a one of the most contributors to aquatic biodiversity decline. Consequently, ecological risk assessment methods have been developed to investigate the effects of existing stresses on the environment, including the toxic effects of chemicals. One of the existing approaches to quantify toxic risks is called “Potentially Affected Fraction of species” (PAF), which estimates the potential loss of species within a group of species studied. In this study, the PAF method was applied to the Garonne catchment (southwest France) due to the limited information available on the involvement of water pollution in the decline of diadromous fish populations. This approach was used to quantify the potential toxic risk associated with chemical contamination of water for fish species. The objectives were to quantify this risk (1) in the Garonne and Dordogne rivers and (2) in the spawning grounds of two endangered anadromous fish species: the allis shad and the European sturgeon during the development period of their early life stages. Environmental pollution data was provided for 21 sites within the Garonne catchment between 2007 and 2022, and toxicity data was obtained specifically from freshwater toxicity tests on fish species. Then, for each site and each year, the potential toxic risk for a single substance (ssPAF) and for a mixture of substances (msPAF) was calculated and classified as high (>5 %), moderate (>1 % and < 5 %) or low (<1 %). Potential toxic risks were mostly moderate and mainly associated with: metals > other industrial pollutants and hygiene and care products > agrochemicals. In summary, this study highlights the probable involvement of water contamination on the decline, fate and restoration of diadromous fish populations in the Garonne catchment, focusing notably on the toxic effects on early life stages, a previously understudied topic.

Pollution and endometriosis: A deep dive into the environmental impacts on women's health.

The interaction between pollution and endometriosis is a pressing issue that demands immediate attention. The impact of pollution, particularly air and water pollution, or occupational hazards, on hormonal disruption and the initiation of endometriosis remains a major issue. This narrative review aims to delve into the intricate connection between pollution and endometriosis, shedding light on how environmental factors contribute to the onset and severity of this disease and, thus, the possible public health policy implications. Endocrine-disrupting chemicals (EDCs) in pollutants dysregulate the hormonal balance, contributing to the progression of this major gynaecological disorder. Air pollution, specifically PM2.5 and PAHs, has been associated with an increased risk of endometriosis by enhancing chronic inflammation, oxidative stress, and hormonal imbalances. Chemical contaminants in water and work exposures, including heavy metals, dioxins, and PCBs, disrupt the hormonal regulation and potentially contribute to endometriosis. Mitigating the environmental impact of pollution is required to safeguard women's reproductive health. This requires a comprehensive approach involving stringent environmental regulations, sustainable practices, responsible waste management, research and innovation, public awareness, and collaboration among stakeholders. Public health policies have a major role in addressing the interaction between pollution and endometriosis in a long-term commitment.

Reactivity of Dissolved Organic Matter with the Hydrated Electron: Implications for Treatment of Chemical Contaminants in Water with Advanced Reduction Processes.

Advanced reduction processes (ARP) have garnered increasing attention for the treatment of recalcitrant chemical contaminants, most notably per- and polyfluoroalkyl substances (PFAS). However, the impact of dissolved organic matter (DOM) on the availability of the hydrated electron (eaq-), the key reactive species formed in ARP, is not completely understood. Using electron pulse radiolysis and transient absorption spectroscopy, we measured bimolecular reaction rates constant for eaq- reaction with eight aquatic and terrestrial humic substance and natural organic matter isolates ( kDOM,eaq-), with the resulting values ranging from (0.51 ± 0.01) to (2.11 ± 0.04) × 108 MC-1 s-1. kDOM,eaq- measurements at varying temperature, pH, and ionic strength indicate that activation energies for diverse DOM isolates are ≈18 kJ mol-1 and that kDOM,eaq- could be expected to vary by less than a factor of 1.5 between pH 5 and 9 or from an ionic strength of 0.02 to 0.12 M. kDOM,eaq- exhibited a significant, positive correlation to % carbonyl carbon for the isolates studied, but relationships to other DOM physicochemical properties were surprisingly more scattered. A 24 h UV/sulfite experiment employing chloroacetate as an eaq- probe revealed that continued eaq- exposure abates DOM chromophores and eaq- scavenging capacity over a several hour time scale. Overall, these results indicate that DOM is an important eaq- scavenger that will reduce the rate of target contaminant degradation in ARP. These impacts are likely greater in waste streams like membrane concentrates, spent ion exchange resins, or regeneration brines that have elevated DOM concentrations.

Dual-Functional Solar-to-Steam Generation and SERS Detection Substrate Based on Plasmonic Nanostructure.

Solar-to-steam (STS) generation based on plasmonic materials has attracted significant attention as a green method for producing fresh water. Herein, a simple in situ method is introduced to fabricate Au nanoparticles (AuNPs) on cellulose filter papers as dual-functional substrates for STS generation and surface-enhanced Raman spectroscopy (SERS) sensing. The substrates exhibit 90% of broadband solar absorption between 350 and 1800 nm and achieve an evaporation rate of 0.96 kg·m-2·h-1 under 1-sun illumination, room temperature of 20 °C, and relative humidity of 40%. The STS generation of the substrate is stable during 30 h continuous operation. Enriched SERS hotspots between AuNPs endow the substrates with the ability to detect chemical contamination in water with ppb limits of detection for rhodamine 6G dye and melamine. To demonstrate dual-functional properties, the contaminated water was analyzed with SERS and purified by STS. The purified water was then analyzed with SERS to confirm its purity. The developed substrate can be an improved and suitable candidate for fresh water production and qualification.

Sensors for Chemical Contaminants in Water

Long-term exposure to chemical contaminants in our drinking water can have adverse effects on human health. Such exposure has been linked to cancers, neurological diseases, and cardiovascular diseases. Examples of chemical contaminants found in our water systems include nitrates, heavy metals such as lead, and disinfectant by-products. These contaminants are not visible to the human eye; therefore, it is essential to test the water sample to determine their presence. This work presents an electrochemical sensing platform to detect chemical contaminants in water. This sensing platform has advantages over traditional lab based methods as it eliminates the need to transport samples to a lab by giving at-source, real-time analysis. The sensing component used consisted of two combs of electrodes that were sandwiched together with ultra-small gaps between the opposing combs. This configuration notably enabled the reduction of the sensor footprint by ?6,000 times compared to previous designs. The significance of this reduction in size means these sensors are lower in cost to produce and require less power to operate. Another benefit of interdigitated electrodes investigated was the ability to use them for in-situ pH control. In situ pH control was successfully demonstrated using lead. Lead requires acidic conditions for analysis and therefore pH adjusting buffers are typically required for the analysis of lead in tap water which is normally a neutral pH between pH 6 to 8. The ability to electrochemically control the pH of the water sample allowed detection of lead as low as 10 ppb without the need for any additional buffers.

Use of Water in Animal Production, Slaughter, and Processing

Water is an essential part of food animal processing, and current processing practices use large volumes of water. Due to climate change, the food industry's access to clean and inexpensive water is increasingly a challenge. The Food Safety and Inspection Service (FSIS) seeks evaluation by the National Advisory Committee on Microbiological Criteria for Food (NACMCF) to facilitate the safe reuse of sources of water in order to reduce water consumption. There should be more collaborations among stakeholders (e.g., industry, academia, government) to collect missing information on water usage and opportunities for reuse. A complete understanding of energy use and plant infrastructure limitations is necessary to effectively understand all opportunities for water conservation and recycling. Characterization of microbial and chemical contaminants in water is a very large topic that requires extensive work. There are quality standards for potable water but not for the recycled water from different processing states, and different water treatment systems. A uniform standard for, and federal regulation of, the quality of reused/recycled water in FSIS-regulated facilities is needed. Standard water analysis methods are available, well-developed, and reliable. Initial monitoring of alternatively sourced water should be extensive, while ongoing performance monitoring should be in real-time and focus on measuring indicators (refer to Glossary). Water for non-food contact uses will require monitoring of fewer parameters. Some water conservation strategies have been published for fish processing establishments; however, economic and other incentives to incorporate conservation practices or recycling technologies do not exist. Companies should develop emergency programs to manage natural disasters, such as flooding.

Integral assessment of the drinking water quality in the Omsk region

Introduction. To analyze the likelihood of occurrence of adverse effects associated with human exposure to chemicals in drinking water, it is recommended to conduct an integral assessment. The purpose of the study was to assess the drinking water quality in rural areas of the Omsk region in accordance with modern methods. Materials and methods. The results of social and hygienic monitoring for drinking water quality in the Omsk region over 2018-2021 were used. Statistical processing of the results was carried out, the calculation of the values of carcinogenic, non-carcinogenic risk, the risk of olfactory-reflex effects, integral indicators. The percentile method was used to classify risk levels. Results. Typical polluting chemicals in the water sources in the Omsk region are resistatnt to oxidation organic substances, ammonium nitrogen, iron, aluminum, manganese, phenols, oil products. The aggregated individual carcinogenic health risk due to exposure drinking water chemical contamination in 2018-2020 amounted to 1.70E-04, which is rated as alarming. The average multi-year growth rate over the three-year period was +17.1%, and in rural areas the average growth rate of carcinogenic risk is even higher (+27.7%). The greatest contribution to the value of the aggregated carcinogenic risk is made by arsenic and organochlorine compounds. Integral indicators (II) of drinking water ranged from 0.82 to 125.88. The group with a very high II includes settlements supplied from surface water sources (the Irtysh River, the Om River). Carcinogenic risk affects the resulting value of II to a greater extent than other components (risks). Limitations. The results of monitor ikilodrinking water production monitoring in the Omsk region were not taken into account during integral assessment in terms of chemical safety. This is due to the difficulties of collecting information, its standardization and analysis. Conclusion. Integral indicators were calculated, and the levels of the integral indicator of water in settlements in rural areas of the Omsk region were classified. Despite the advantages of the method of the assessment of II of drinking water quality, some caution is needed when using II. The reason is possible loss of information or distortion of the dynamics of concentrations of individual substances, including the most toxic and dangerous.

Monitoring of natural water pollution by fluorescence spectroscopy

Introduction. Environmental monitoring of the state of water bodies is an important component of environmental protection. A promising direction for assessing the quality of water bodies is to determine their generalized indicators. Fluorescence spectroscopy can serve as a source of important information about the state of water bodies and sources of their pollution. Purpose of the study - to assess the water pollution of the Moskva River and its tributaries using the fluorescence spectroscopy method. To reveal the influence of oil products on the fluorescence spectra of river water. Materials and methods. The object of the study was water from the Moskva River and its tributaries: Pakhra, Kotlovka, Setun. Water samples from the Moskva River were taken in different parts of the city, which are characterized by varying degrees of pollution. Water fluorescence spectra were measured with SM2203 spectrofluorimeter (ZAO Solar, Belarus), total organic and inorganic carbon, on a TOC-VCHP total carbon analyzer (Shimadzu, Japan). Results. The nature of the fluorescence spectra of the Moskva River and its tributaries in the absence of significant anthropogenic pollution are characterized by relative constancy. Bacterial pollution and pollution with aromatic compounds of anthropogenic origin, including oil products, leads to an increase in the fluorescence intensity in the short-wavelength part of the spectrum. The correlation coefficient between the optical density at a wavelength of 254 nm and the content of dissolved organic carbon (DOC) for the studied samples was 0.66, and between the fluorescence intensity at a wavelength of 400 nm and DOC was 0.74. Limitations. The method cannot be used for the quantitative determination of individual substances; it is intended for a semi-quantitative assessment of water pollution. Conclusion. Measurement of fluorescence spectra and total organic carbon makes it possible to give a general assessment of the contamination of a water body (which is especially important for a sample of unknown composition) and to choose the optimal scheme for its targeted analysis. High dissolved organic carbon (DOC) values and high fluorescence intensity at 320 nm are highly likely to indicate chemical contamination of water, while DOC values characteristic of a water body and high fluorescence intensity at 320 nm indicate bacterial contamination.

Differential expression of genes in C. elegans reveals transcriptional responses to indirect-acting xenobiotic compounds and insensitivity to 2,3,7,8-tetrachlorodibenzodioxin

Caenorhabditis elegans is a well-established model organism for toxicity testing of chemical substances. We recently demonstrated its potential for bioanalysis of the toxic potency of chemical contaminants in water. While many detoxification genes are homologues to those in mammalians, C. elegans is reported to be deficient in cytochrome CYP1-like P450 metabolism and that its aryl hydrocarbon receptor (AhR) homolog encoded by ahr-1 purportedly does not interact with dioxins or any other known xenobiotic ligand. This suggests that C. elegans is insensitive for compounds that require bioactivation (indirectly acting compounds) and for dioxins or dioxin-like compounds. This study analysed genome-wide gene expression of the nematode in response to 30 μM of aflatoxin B1 (AFB1), benzo(a)pyrene (B(a)P), Aroclor 1254 (PCB1254), and 10 μM of 2,3,7,8-tetrachlorodibenzodioxin (TCDD). After 24 h of exposure in the early L4 larval stage, microarray analysis revealed 182, 86, and 321 differentially expressed genes in the nematodes treated with 30 μM of AFB1, B(a)P, and PCB1254, respectively. Among these genes, many encode xenobiotic-metabolizing enzymes, and their transcription levels were among the highest-ranked fold-changed genes. Interestingly, only one gene (F59B1.8) was upregulated in the nematodes exposed to 10 μM TCDD. Genes related to metabolic processes and catalytic activity were the most induced by exposure to 30 μM of AFB1, B(a)P, and PCB1254. Despite the genotoxic nature of AFB1 and B(a)P, no differential expression was found in the genes encoding DNA repair and cell cycle checkpoint proteins. Analysis of concentration–response curves was performed to determine the Lowest Observed Transcriptomic Effect Levels (LOTEL) of AFB1, B(a)P, and PCB1254. The obtained LOTEL values showed that gene expression changes in C. elegans are more sensitive to toxicants than reproductive effects. Overall, transcriptional responses of metabolic enzymes suggest that the nematode does metabolize AFB1, B(a)P, and PCB1254. Our findings also support the assumption that the transcription factor AhR homolog in C. elegans does not bind typical xenobiotic ligands, rendering the nematode transcriptionally insensitive to TCDD effects.

Critical Review of UV-Advanced Reduction Processes for the Treatment of Chemical Contaminants in Water.

UV-advanced reduction processes (UV-ARP) are an advanced water treatment technology characterized by the reductive transformation of chemical contaminants. Contaminant abatement in UV-ARP is most often accomplished through reaction with hydrated electrons (eaq -) produced from UV photolysis of chemical sensitizers (e.g., sulfite). In this Review, we evaluate the photochemical kinetics, substrate scope, and optimization of UV-ARP. We find that quantities typically reported in photochemical studies of natural and engineered systems are under-reported in the UV-ARP literature, especially the formation rates, scavenging capacities, and concentrations of key reactive species like eaq -. The absence of these quantities has made it difficult to fully evaluate the impact of operating conditions and the role of water matrix components on the efficiencies of UV-ARP. The UV-ARP substrate scope is weighted heavily toward contaminant classes that are resistant to degradation by advanced oxidation processes, like oxyanions and per- and polyfluoroalkyl substances. Some studies have sought to optimize the UV-ARP treatment of these contaminants; however, a thorough evaluation of the impact of water matrix components like dissolved organic matter on these optimization strategies is needed. Overall, the data compilation, analysis, and research recommendations provided in this Review will assist the UV-ARP research community in future efforts toward optimizing UV-ARP systems, modeling the eaq --based chemical transformation kinetics, and developing new UV-ARP systems.

ROSALIND: Rapid Detection of Chemical Contaminants with In Vitro Transcription Factor-Based Biosensors.

ROSALIND (RNA Output Sensors Activated by Ligand Induction) is an in vitro biosensing system that detects small molecules using regulated transcription reactions. It consists of three key components: (1) RNA polymerases, (2) allosteric protein transcription factors, and (3) synthetic DNA transcription templates that together regulate the synthesis of a fluorescence-activating RNA aptamer. The system can detect a wide range of chemicals including antibiotics, small molecules, and metal ions. We have demonstrated that ROSALIND can be lyophilized and transported at ambient conditions for water testing on-site. Here, we describe how to set up a ROSALIND reaction for detecting various chemical contaminants in water using a model transcription factor as well as how to build a new ROSALIND sensor.

Intelligent water treatment management system for swimming pools

The article presents the assessment methodology for anthropogenic water pollution in swimming pools, based on intelligent video monitoring of people physical activity, as well as a model for correlation data analysis and a regression model for the main parameters of chemical water contamination and doses of introduced reagents. The ultimate goal of the project is to create an intelligent water treatment management system for swimming pools. It is planned to use YOLOv4 neural networks to implement an intelligent pattern recognition module (swimmers in the pool) in the data stream coming from video cameras in real time. This innovative system will make it possible to automatically make managerial and technical decisions to determine the required amount of introduced reagents at various time intervals depending on the actual amount of organic contaminants, as well as other factors determined by the results of the correlation-regression analysis of the data. A review of information resources has shown that such a methodology does not exist both in Russia and abroad.

Spatial and temporal distribution of surface water contaminants in the Houston Ship Channel after the Intercontinental Terminal Company Fire.

Background:The fire at the Intercontinental Terminals Company (ITC, Deer Park, La Porte, TX, USA) from March 17-20, 2019 resulted in substantial releases of chemical contaminants to the environment, including the surface waters of the Houston Ship Channel.Objective:To characterize spatial and temporal trends, as well as potential human health risks, from these releases.Methods:Out of 433 substances with available data, seven were selected for analysis: benzene, toluene, ethylbenzene, xylenes, oil & grease, suspended solids, and total petroleum hydrocarbons. Spatial and temporal concentration trends were characterized, and hazard quotients and cancer risks were calculated to estimate the potential for human health impacts from these contaminants.Results:Temporal analysis showed presence of these chemical contaminants in water immediately after the event; their concentrations dissipated substantially within 4 weeks. The spatial distribution of contaminants indicated the highest concentrations in the waterways within about 1km of the ITC. The greatest potential human health risks stemmed from presence of benzene.Significance:A short-term but substantial spike in the concentrations of a number of hazardous contaminants occurred near the incident, with concentrations returning to apparent baseline levels within one month likely due to a combination of volatization, dilution and degradation.

Aqueous‐Phase Photocatalytic Degradation of Emerging Forever Chemical Contaminants

AbstractHeterogeneous photocatalysis is an emerging area of catalysis increasingly fraught with pains caused by the battle between hype and real‐ world application. Inspired by abundant yet diffuse solar energy and applications such as clean water and energy, ample motivation has provided the background for this situation. However, substantial fundamental (e. g., charge transfer, recombination), engineering (e. g., observed rates, photon management), and practical barriers (e. g., use of precious metals, competing technologies) have limited implementation. In this review, these are all outlined, in conjunction with typical strategies for improvements, with an emphasis on the use of semiconductor photocatalysts for the degradation of emerging forever chemical contaminants in water. The selected classes of forever chemical contaminants are (micro)‐plastics, per‐ and polyfluoroalkyl substances (PFAs), siloxanes, and dioxanes. Each has been identified as a key or emerging contaminant and often travel widely while accumulating in the atmosphere due to the lack of natural remediation processes. Recommendations to the field and opportunities for contributions are highlighted throughout and as part of the outlook to the future.

Digital colorimetric analysis for estimation of iron in water with smartphone-assisted microfluidic paper-based analytical devices

ABSTRACT Microfluidic paper-based analytical devices are emerging as promising options for on-the-spot detection of chemical contaminants in water. The coupling of these devices with digital imaging technology has attracted immense interest in developing portable sensor applications. However, the potential of digital techniques still remains to be fully explored. In this work, we integrate digital imaging with microfluidic paper-based analytical devices to develop a portable colorimetric assay for iron. The experimental conditions are optimised using image analysis and the effects of imaging equipment and colorimetric analysis methods on the readout of devices are studied using numerical, graphical and statistical techniques. The experimental results are obtained for the estimation of iron contamination in water samples using a colorimetric assay based on iron (III)-thiocyanate reaction. The digital image acquisition approach using smartphone as imaging equipment is adopted for on-the-spot colorimetric data collection. Image processing techniques are employed to estimate the iron concentration in water from digital images. Greyscale colour intensity obtained from a digital image is identified as a readout of the analytical device and employed for quantitative assessment. The limit of detection for iron is estimated to be 0.26 ppm. The microfluidic approach offers good recovery and repeatability with relative standard deviation of 1.4%. The maximum percentage difference for intensities between the image analysis methods is 4.94% and that between the imaging equipment is 9.96%. The gradients of regression lines for pairwise equipment and method outputs with zero intercept range from 0.9931 to 1.0162 with high values of coefficients of determination. The correlation coefficient values for various paired comparisons (>0.99) suggest strong agreement. Statistical test results suggest no significant differences between methods and between imaging equipment (significance level 0.05). The findings suggest the efficacy of digital imaging and colorimetric analysis for paper-based analytical devices.

Effects of organic mercury on Mytilus galloprovincialis hemocyte function and morphology

Filter-feeding organisms accumulate xenobiotics and other substances in their tissues. They can be useful as sentinel organisms in biomonitoring of the marine compartment. Bivalve cellular immunity is ensured by phagocytosis and cytotoxic reactions carried out by hemocytes in a network with humoral responses. These can be affected by chemical contaminants in water that can be immunosuppressors also at a low concentration increasing the sensibility to pathogens. This work is an attempt to individuate cellular markers for pollution detection, investigating the effect of methylmercury (CH3HgCl) at different concentrations on the activity and hemocyte morphology of the Mediterranean mussel, Mytilus galloprovincialis. We assessed the effect of three sub-lethal concentrations of the organometal on the cellular morphology, the efficacy of phagocytosis toward yeast cells, the alteration of the lysosomal membrane and the ability to release cytotoxic molecules. The results provide information on the alteration of hemocyte viability, modification of the morphological and cytoskeletal features and besides the cellular spreading, intrinsic ability of motile cells was used as a complementary investigation method. Exposure to the contaminant affected the percentage of phagocytosis and the phagocytosis index. Moreover, morphological and cytoskeleton alteration, caused by the pollutant, leads to reduced ability to incorporate the target and adhere to the substrate and the low ability of cells to retain neutral red could depend on the effects of methylmercury on membrane permeability. These results reinforce the use of the Mediterranean mussel as model for the evaluation of environmental quality in aquatic ecosystems integrating the novel information about hemocyte functions and morphology sensibility to organic mercury.Graphic abstract

Photocatalytic Degradation of Dyes by TiO2 Process in Batch Photoreactor

Chemical contamination in water caused by pollutants is becoming a severe environmental problem. The combination of photocatalysis and solar technologies are a valuable method for water pollution reduction caused by dyeing composites. Therefore, this study aims to determine the effects of operating parameters on the dyes photocatalytic degradation using titanium dioxide (TiO2)-based photocatalyst. Different types of dyes were used in this study, such as methylene blue, congo red, and methyl orange. The different weights of TiO2 were mixed respectively in 500 ml of 10 mg/L dye solutions, which was set up in the photoreactor priorly. Later, the sample extractions were carried and analyzed using a UV-Vis spectrophotometer. The dye removal efficiency was investigated by changing conditions (catalyst dosage, light sources, and aeration). The results showed methylene blue photocatalytic degradation was best with 0.0547 min-1 degradation rate at conditions of 3.0 g/L of TiO2, presence of UVC lamp, and aeration. Congo red photocatalytic degradation was best with 0.0254 min-1 degradation rate at conditions of 1.0 g/L of TiO2, presence of sunlight, and aeration. Methyl orange photocatalytic degradation was best with 0.0094 min-1 degradation rate using 1g/L of TiO2, presence of UVC lamp, and aeration. These findings can be used as an effective option in industrial wastewater treatment.

Interaction of Metal Ions with Mono- and Polysaccharides for Wastewater Treatment: A Review

Chemical contamination of water from a wide range of toxic compounds, especially heavy metals, is a critical environmental problem due to their potential human toxicity. Therefore, development of technologies that allow the removal of toxic pollutants from wastewater is a need. Among all the common heavy metals treatment processes, biosorption is one of the more popular and efficient processes. The important number of publications concerning adsorption and remediation of metal ions from aqueous solution by natural and modified polysaccharides shows an increasing interest in biopolymer uses for environment preservation. The present review describes recent developments on biosorption processes using agricultural by-products, mainly mono- and polysaccharides extracted from natural resources. General considerations on metal ions complexation mechanism and interactions between metals and saccharides are first described. Then, a review on metal ions biosorption processes and recent development of new polysaccharide-based materials is carried out and shows their high adsorption capacities and their attractive character. Finally, advantages and possible limitations of using such biosorbents for metal ions adsorption process are discussed.

Wildfire caused widespread drinking water distribution network contamination

AbstractThe Tubbs Fire (2017) and Camp Fire (2018) are the first known wildfires where widespread drinking water chemical contamination was discovered in the water distribution network and not in the source water after the fire. In both disasters, drinking water exceeded state and federal government‐defined exposure limits for several volatile organic compound (VOC) contaminants (e.g., benzene at 40,000 µg/L [Tubbs] and &gt;2,217 µg/L [Camp]). This work outlines factors that influence wildfire‐induced drinking water quality threats based on the findings from these two fires and explores related scientific and policy issues. For example, certain plastics in the network may serve as a primary VOC source through in situ plastic pyrolysis. Depressurization of the distribution network likely transported contaminated water that subsequently contaminated undamaged infrastructure. As wildfires at the wildland–urban interface are likely to occur more frequently, greater scientific evidence is needed to guide agency responses that will better protect public health.