Environmental Chemistry Letters最新文献

Aflatoxin B1 is a mycotoxin produced by the fungus Aspergillus that contaminates food, notably grains and peanuts. Aflatoxin B1 is hepatotoxic, causing necrosis, and cirrhosis, and is classified as an hepatocarcinogen. Traditional methods for detecting aflatoxin B1 such as thin-layer chromatography, high-performance liquid chromatography, enzyme-linked immunoassay, and liquid chromatography–tandem mass spectrometry, have limitations including high costs, complex preparation procedures, and occasionally low sensitivity. Here, we review DNA-based biosensors for aflatoxin B1 detection with emphasis on electrochemical and optical sensors. Electrochemical biosensors are based on electrochemical impedance spectroscopy, amperometry, voltammetry, and potentiometry. Optical sensors involve colorimetry, surface plasmon resonance, fluorescence, and electrochemiluminescence. Sensors combine nano and composite materials, such as gold nanoparticles, black phosphorus nanosheets, graphene oxide, niobium carbide, photonic crystals, and liquid crystals. DNA-based biosensors, such as aptamer biosensors, are efficient, rapid, sensitive, affordable, and selective to detecting contaminants and pathogens.

Phosphogypsum, a major by-product of phosphoric acid production, can be recycled. Nonetheless, phosphogypsum contains impurities such as heavy metals, fluoride, and phosphate, which can decrease the performance and contaminate the environment, calling for pretreatment or solidification methods. Here, we review phosphogypsum with emphasis on impurities and their hazards, solidification methods, and treatment methods for use in road construction. Solidification involves blending phosphogypsum with inorganic cementitious materials, adding additives, geopolymers, biological treatments, and biochar adsorption. Phosphogypsum can be blended with electrolytic manganese residues, granulated blast furnace slag, and inorganic cementitious materials. Additives comprise polymers, surface modifiers, and curing agents. We observe that solidification methods display more advantages than pretreatment methods. The combination of phosphogypsum with inorganic cementitious materials, polymer surface modifiers, curing agents, geopolymer materials, and biomass materials can effectively solidify various impurities, though the effectiveness varies across different solidification methods. There are four solidification mechanisms: physical encapsulation, chemical precipitation, ion exchange, and adsorption. When solidified in road engineering applications, phosphogypsum show reduced leaching levels of arsenic, lead, while maintaining a good road performance.

Peptide-based chemicals are promising for numerous applications including home and personal care and medical treatments. To better understand and control the environmental fate of peptide-based chemicals, in-depth knowledge on the specificity of wastewater peptidases is needed. Here, we employed multiplex substrate profiling by mass spectrometry to obtain specificity profiles of extracellular peptidases derived from influent and aeration tanks of three full-scale wastewater treatment plants. Specificities were confirmed by fluorogenic peptidase substrates. Our results revealed highly similar specificity profiles across wastewater treatment plants. We found that hydrolysis by extracellular wastewater peptidases is favored when positively charged amino acid residues surround the cleavage site and disfavored when negatively charged amino acid residues surround the cleavage site.

The coronavirus disease COVID-19 is primarily transmitted through person-to-person contact, but meteorological conditions may influence its spread and severity. High levels of indoor ozone are known to inactivate the virus, yet the impact of low-level tropospheric ozone remains unclear. We thus hypothesized that tropospheric ozone, influenced by seasonal conditions, may mitigate viral spread. We studied the influence of ozone concentration, temperature, and humidity on the COVID-19 reproduction number in three large Israeli cities during 2020–2021. The effect of these parameters was also analyzed in laboratory experiments on viral inactivation. Field results show that in winter, under low temperature and low humidity, the COVID-19 reproduction number decreases with an increase in ozone concentration. In contrast, in the summer, under high temperature and high humidity, the COVID-19 reproduction number increases weakly with an increase in ozone concentration. This seasonal variation is attributed to ozone’s dual effects. Indeed, in winter, ozone inactivates the virus, whereas in summer, ozone primarily impacts human respiratory health, which indirectly favors COVID-19 transmission. Nonetheless, experimental results did not fully align with the field survey, showing increased virus inactivation with an increase in temperature.

Global microplastic contamination of almost all biological and environmental media is an emerging threat to human health that recently fostered intense research. Here, we review polyethylene terephthalate with focus on microplastics, characteristics, uses, concentration, degradation, toxicity, and remediation. Plastic remediation can be done by landfills, incineration, pyrolysis, and biodegradation. We present microplastic occurrence in food, beverages, dust, wildlife, and human tissues. We observed inconsistencies in measurement techniques, limitations in detection reliability, and gaps in risk assessment.

Scandium has been used to distinguish between natural and anthropogenic sources of lead to the atmosphere. Here, scandium is used to estimate the natural abundance of lead in surface and groundwater. In pristine groundwater sampled at the Elmvale Groundwater Observatory in southern Ontario, the lead/scandium mass ratio (Pb/Sc) ranges from 1.1 to 1.2, similar to the ratio (1.2) most recently proposed for the Upper Continental Crust. In the Athabasca River of northern Alberta, where dissolved lead is well below the global average for uncontaminated river water, the average Pb/Sc ratio was 2.2 in 2014 and in 2015, consistent with the Pb/Sc ratio recently compiled for soil (2.3). In contrast, the average Pb/Sc ratio in the rivers and lakes of central Ontario was 6.0, reflecting the far larger cumulative inputs of anthropogenic, atmospheric lead in eastern Canada compared to western Canada. Support for this interpretation comes from contemporary snow from southern Ontario with an average Pb/Sc ratio of 400. Despite the profound differences in the geology of the study regions, and ignoring the geochemical processes affecting both elements in the watersheds, scandium appears to be a helpful, simple tool for estimating the natural abundance of lead in surface and groundwater. However, the use of the Pb/Sc ratio in this way depends critically on accurate, precise and sensitive measurements of both elements. While the problems of low level lead determinations are well known, those of scandium may have been underestimated.

Oxocarboxylic acids are produced when oil is exposed to sunlight and are photo-dissolved in the aqueous phase in oil–water systems, impacting the fate, transport, and impact of spilled oil. However, temperature effects on these reactions are unknown, thus we investigate oxocarboxylic acid photoproduction from irradiated oil–water systems. Oil samples include British Petroleum crude, Deepwater Horizon crude, Maya crude from Mexico, SRM 2717a oil from the National Institute of Standards and Technology, and an Alaskan crude. Oils were spread over water and exposed to simulated sunlight for 6 h at 12, 25, and 35 °C, followed by quantifying oxocarboxylic acid abundance and dissolved organic carbon in the water. Treatment with 2,4-dinitrophenyl hydrazine produced hydrazones, enriched using solid phase extraction and analyzed by using electrospray ionization-tandem mass spectrometry. Results show that temperature and oxocarboxylic acid photoproduction exhibit a complex relationship; however, oil behavior was similar with temperature. Dissolved organic carbon increased with irradiation temperature for photosolubilized oil. Deepwater Horizon oil showed high-temperature sensitivity with dissolved organic carbon production of 12.6 ppm at 35 °C versus 6.0 ppm at 12 °C. Low molecular weight species are easily volatilized, while larger molecules require greater photooxygenation to become substantially water soluble.

Traditional Chinese medicine has a rich history in the diagnosis and treatment of diseases, yet the disposal of medicine residues by incineration and landfilling is challenging. Here we review methods to recycle Chinese medicine residues with focus on challenges, recycling solutions, and case studies. Cases studies include extraction of bioactive compounds, use as feed additives, and biochar-based materials. We observed that residues from single-compound medicines are easier to extract and recycle into animal feed additives or adsorbents. Technical and economic analysis show that the valorisation of single-compound medicine residues is profitable. For instance, the re-extraction cost of flavonoids is 25.8–36.6% lower than the market price, and the cost as feed additives represents 14.7% of the market prices.

Carbon emissions from the water and wastewater treatment sector account for about 2% of global carbon emissions, calling for the integration of sustainable energies to decrease carbon footprints. Here we review the use of hydrovoltaic technologies in water and wastewater treatment, with emphasis on the hydrovoltaic effect, self-powered sensors, and pollutant removal. The hydrovoltaic effect can be obtained using moisture-induced hydrovoltaic generators and water evaporation-induced hydrovoltaic generators. Strain, pressure, humidity, gas, and liquid sensors can be powered by hydrovoltaic generators. Remarkably, the hydrovoltaic technology-driven liquid sensors can reach a detection limit of 1 femtomolar. The hydrovoltaic technology reduces pollution in two ways, first by generating electricity from environmental moisture and evaporation, thereby reducing fossil fuel dependency. Second, it takes advantage of the photocatalytic properties of materials to decompose organic matter during water treatment, thus minimizing the usage of chemical reagents. Applications comprise wastewater power generation, seawater desalination and organic matter degradation.

The generation of reactive species and their derivatives, whether in the human body or in the food systems, contributes to various human diseases and compromises food quality. Unfortunately, both natural and synthetic antioxidants have specific limitations. Green chemistry-derived carbon dots offer a promising solution in this regard. Here we review the antioxidant activity of green synthesized carbon dots. The review commences with an overview of carbon dots, their properties, and the top-down and bottom-up synthesis approaches, along with their merits and drawbacks. Furthermore, the importance of the green chemistry concept is highlighted. The role of different functional groups in carbon dots attributed to their antioxidant activity is emphasized. Subsequently, the review elucidates several methods commonly utilized to evaluate the antioxidant activity of carbon dots together with a discussion on various oxidative and non-oxidative stress markers. The review compiles a variety of ex vivo, in vitro, and in vivo studies underscoring the antioxidant activity of pristine and doped carbon dots. Among all studies, the hydrothermal method was observed to be a popular synthesis approach. Out of 87 studies, 38 exclusively assessed the 2,2-diphenyl-1-picrylhydrazyl-scavenging properties of pristine and doped carbon dots with half-maximum effective concentration values ranging from 2.7 to 524 μg mL⁻¹. The subsequent studies recorded the scavenging of other radicals alongside 2,2-diphenyl-1-picrylhydrazyl, with 18, 14, 10, 5, and 2 studies demonstrating the scavenging efficacy of carbon dots for hydroxyl, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), superoxide, hydrogen peroxide, and nitric oxide radicals, respectively. Furthermore, 18 studies reported the antioxidant property of carbon dots in cell, animal, and vertebrate models by modulating oxidative stress markers and upregulating the expressions of various antioxidant enzymes. The review also highlights the prooxidant nature of green carbon dots briefly. Finally, the paper delves into the practical applications of carbon dots in the food, agricultural, and environmental sectors.