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Biomass burning is a significant anthropogenic source of air pollution, including the preharvest burning of sugar cane. These burn events result in atmospheric emissions, including semivolatile organic compounds, that may have adverse impacts on air quality and human health on a local, regional, and even a global scale. Gaseous and particulate polycyclic aromatic hydrocarbon (PAH) emissions from various sugar cane burn events in the province of Kwa‐Zulu Natal in South Africa were simultaneously sampled using a portable denuder sampling technology, consisting of a quartz fiber filter sandwiched between two polydimethylsiloxane multichannel traps. Total gas and particle phase PAH concentrations ranged from 0.05 to 9.85 µg m–3 per individual burn event, and nine PAHs were quantified. Over 85% of all PAHs were found to exist in the gas phase, with smaller two‐ and three‐ring PAHs, primarily naphthalene, 1‐methyl naphthalene, and acenaphthylene, being the most dominant and causing the majority of variance between the burn sites. The PAH profiles differed between the different burn events at different sites, emphasizing the significant influence that the crop variety, prevailing weather conditions, and geographical location has on the type and number of pollutants emitted. The potential carcinogenicity of the PAH exposure was estimated based on toxic equivalency factors that showed varying risk potentials per burn event, with the highest value of 5.97 ng m–3. Environ Toxicol Chem 2023;42:778–792. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

The development of amine‐functionalized graphene quantum dots (GQDs) linked to mycolic acids (MAs) as a potential fluorescent biosensor to detect tuberculosis (TB) biomarkers is described. GQDs have attractive properties: high fluorescence, excellent biocompatibility, good water solubility, and low toxicity. MAs are lipids that are found in the cell wall of Mycobacterium tuberculosis that are antigenic, however, they are soluble only in chloroform and hexane. Chloroform‐soluble MAs were covalently linked to synthesized water‐soluble GQDs using an amide connection to create a potential fluorescent water‐soluble TB biosensor: MA‐GQDs. Fluorescence results showed that GQDs had a narrow emission spectrum with the highest emission at 440 nm, while MA‐GQDs had a broader spectrum with the highest emission at 470 nm, after exciting at 360 nm. The appearance of the peptide bond (amide linkage) in the Fourier‐transform infrared spectrum of MA‐GQDs confirmed the successful linking of MAs to GQDs. Powder X‐ray diffraction exhibited an increase in the number of peaks for MA‐GQDs relative to GQDs, suggesting that linking MAs to GQDs changed the crystal structure thereof. The linked MA‐GQDs showed good solubility in water, high fluorescence, and visual flow through a nitrocellulose membrane. These properties are promising for biomedical fluorescence sensing applications. [ABSTRACT FROM AUTHOR]

Higher-tier methods for greenhouse gas reporting require country-specific emission factors for a range of liquid and gaseous fuels for both stationary and mobile fuel combustion activities. Samples of selected liquid fuels used in South Africa were collected over the summer and winter seasons in the Gauteng, Mpumalanga, Free State, KwaZulu-Natal and Western Cape provinces of South Africa, primarily from large retail stations along major traffic routes (unleaded petrol – ULP93 and ULP95 – and diesel). Liquid fuels used in smaller volumes (bio-ethanol, paraffin, jet kerosene, aviation gasoline and heavy fuel oil) were also sampled at appropriate locations. Samples (343 in total) were analysed for carbon content using standard methods at an accredited commercial laboratory. Calorific values of the fuels were also determined, to allow for the calculation of methane and nitrous oxide emission factors. Results were statistically analysed to determine mean values and their uncertainties, to identify outliers, and to determine correlations between variables. Results for ULP93 and ULP95 were weighted by their respective 2021 annual average sales volumes to obtain an average value for all petrol of 2 263 g CO2/L. Based on sales data from the years 2018–2021, summer and winter results were equally weighted to obtain annual average emission factors for ULP93 (2255 g CO2/L), ULP95 (2 265 g CO2/L) and diesel (2 650 g CO2/L), reflecting a slight decrease from the values contained in the 2017 Department of Environmental Affairs Technical guidelines for monitoring, reporting and verification of greenhouse gas emissions by industry. A calculation-based liquefied petroleum gas emission factor, confirmed by analysis certificates from a number of local suppliers, was found to be 3002 g CO2/kg. [ABSTRACT FROM AUTHOR]

The United States Environmental Protection Agency categorized polycyclic aromatic hydrocarbons (PAHs) as hazardous to humans upon acute and/or chronic exposure. This study investigated the simultaneous adsorption of several PAHs onto graphene wool (GW), thereby providing holistic insights into the competitive adsorption of PAHs onto graphene-based materials. SEM, TEM and FTIR provided evidence for the adsorption of PAHs and successful regeneration of the adsorbent accompanied by distinct morphological changes. Isotherm experiments revealed that adsorption of PAHs was significantly influenced by hydrophobic interactions between the sorbate and hydrophobic surface of GW. The Freundlich multilayer isotherm model best fit the experimental data obtained for both multi-component PAH and single-solute experiments as indicated by the Error Sum of Squares (SSE) obtained from nonlinear regression analysis. Experiments revealed that competitive adsorption had a limiting effect on the overall adsorption capacity as qmax and Kd were higher in single-solute than multi-component PAH experiments. The results suggest that partition distribution coefficients (Kd) between the solid–liquid interphase played a significant role in the overall adsorption and a positive correlation between Kd and LogKow of PAHs was established in single-solute experiments. Sorption-desorption experiments revealed that PAHs were adsorbed with a maximum removal efficiency of 100% at an optimum GW dosage of 2 g/L. Adsorption thermodynamics revealed that PAH adsorption onto GW is spontaneous and endothermic. The adsorbent was regenerated and reused for up to six times and its efficiency remained fairly constant. [ABSTRACT FROM AUTHOR]

The sources, ecotoxicological impact, and potential remediation strategies of antiretroviral drugs (ARVDs) as emerging contaminants in surface waters are reviewed based on recent literature. The occurrence of ARVDs in water bodies raises concern because many communities in Africa depend on rivers for water resources. Southern Africa is a potential hotspot regarding ARVD contamination due to relatively high therapeutic application and detection thereof in water bodies. Efavirenz and nevirapine are the most persistent in effluents and are prevalent in surface water based on environmental concentrations. Whereas the highest concentration of efavirenz reported in Kenya was 12.4 µg L–1, concentrations as high as 119 and 140 µg L–1 have been reported in Zambia and South Africa, respectively. Concentrations of ARVDs ranging from 670 to 34 000 ng L–1 (influents) and 540 to 34 000 ng L–1 (effluents) were determined in wastewater treatment plants in South Africa, compared with Europe, where reported concentrations range from less than limit of detection (LOD) to 32 ng L–1 (influents) and less than LOD to 22 ng L–1 (effluents). The present African‐based review suggests the need for comprehensive toxicological and risk assessment of these emerging pollutants in Africa, with the intent of averting environmental hazards and the development of sustainable remediation strategies. Environ Toxicol Chem 2022;41:247–262. © 2021 SETAC [ABSTRACT FROM AUTHOR]

This work explores the potential use of cadmium‐based quantum dots (QDs) coupled to mycolic acids (MAs) as a fluorescent probe to detect anti‐MA antibodies which are biomarkers for tuberculosis (TB). The use of free MAs as antigens for the serodiagnosis of TB is known but has not been developed into a point of care test. This study focuses on the synthesis, solubility, and lateral flow of QDs coupled to MAs. Water‐soluble CdSe/ZnS QDs capped with l‐cysteine were synthesised and covalently coupled to MAs via amide linkages to form a water‐soluble fluorescent probe: MA‐CdSe/ZnS QDs. The MA‐CdSe/ZnS QDs showed broad absorption bands and coupling, confirmed by the presence of amide bonds in the Fourier‐transform infrared (FTIR) spectrum, resulting in a blue shift in fluorescence. Powder X‐ray diffraction (XRD) revealed a shift and increase in the number of peaks for MA‐CdSe/ZnS QDs relative to the L‐cys‐CdSe/ZnS QDs, suggesting that coupling changed the crystal structure. The average particle size of MA‐CdSe/ZnS QDs was ~3.0 nm. Visual paper‐based lateral flow of MA‐CdSe/ZnS QDs was achieved on strips of nitrocellulose membrane with both water and membrane blocking solution eluents. The highly fluorescent MA‐CdSe/ZnS QDs showed good water solubility and lateral flow, which are important properties for fluorescence sensing applications. [ABSTRACT FROM AUTHOR]

In the last two decades, environmental experts have focused on the development of several biological, chemical, physical, and thermal methods/technologies for remediation of PAH‐polluted water. Some of the findings have been applied to field‐scale treatment, while others have remained as prototypes and semi‐pilot studies. Existing treatment options include extraction, chemical oxidation, bioremediation, photocatalytic degradation, and adsorption (employing adsorbents such as biomass derivatives, geosorbents, zeolites, mesoporous silica, polymers, nanocomposites, and graphene‐based materials). Electrokinetic remediation, advanced phytoremediation, green nanoremediation, enhanced remediation using biocatalysts, and integrated approaches are still at the developmental stage and hold great potential. Water is an essential component of the ecosystem and highly susceptible to PAH contamination due to crude oil exploration and spillage, and improper municipal and industrial waste management, yet comprehensive reviews on PAH remediation are only available for contaminated soils, despite the several treatment methods developed for the remediation of PAH‐polluted water. This review seeks to provide a comprehensive overview of existing and emerging methods/technologies, in order to bridge information gaps toward ensuring a green and sustainable remedial approach for PAH‐contaminated aqueous systems. Practitioner points: Comprehensive review of existing and emerging technologies for remediation of PAH‐polluted water.Factors influencing efficiency of various methods, challenges and merits were discussed.Green nano‐adsorbents, nano‐oxidants and bio/phytoremediation are desirous for ecofriendly and economical PAH remediation.Adoption of an integrated approach for the efficient and sustainable remediation of PAH‐contaminated water is recommended. [ABSTRACT FROM AUTHOR]

Semi-volatile organic compounds (SVOCs), partitioned between particulates and vapours of an aerosol, require special attention. The toxicological effects caused by the inhalation of such aerosols may depend on the concentration and in which phase the organic compounds are found. A personal denuder-gas–particle separation aerosol sampler was developed to provide information about the partitioning of aerosols from organic compounds. The sampler was tested in a series of controlled laboratory experiments, which confirmed the capability and accuracy of the sampler to measure gas–particle mixtures. An average difference of 14.8 ± 4.8% was found between sampler and reference laboratory instruments. The obtained results showed that our sampler enables a more accurate measurement of the SVOC aerosols' gas–particle fractionation, compared with that of conventional samplers. [ABSTRACT FROM AUTHOR]

Unbanded crocodilian eggs do not form an opaque band around their lesser circumference, indicating fertilization failure or early embryonic death. Assuming they represent fertile eggs prior to the onset of embryonic metabolism, the concentration and content of calcium (Ca) and phosphorus (P) in each component (shell, shell membrane, yolk and albumen) of unbanded farm‐laid Nile crocodile (Crocodylus niloticus) eggs were described. The grouping effect of clutch (clutch effect) on each component's Ca and P concentration and content were assessed. Using regression models, the clutch size, clutch laying date, pond of origin, component mass and component Ca and P concentration were evaluated for an effect on each component's Ca and P content. Eggshell made by far the greatest contribution to total egg Ca whilst contributing no measurable P. Yolk contributed by far the greatest quantity of P and a significant quantity of Ca. Albumen contributed variable, but generally very low quantities of Ca and P to the egg. A strong clutch effect existed for shell Ca content and yolk Ca and P concentration and content. A very weak clutch effect existed for shell Ca concentration, and albumen Ca and P concentration. Shell membrane was an unreliable sample type in this study, likely reflecting issues with processing. Shell Ca and yolk Ca and P content were influenced primarily by component mass, and secondarily by element concentration. Albumen Ca and P content was principally influenced by element concentration. These descriptive findings will guide sample selection for future research. [ABSTRACT FROM AUTHOR]

In developing countries, household energy use is highly variable and complex, yet emissions arising from fuel combustion indoors are typically poorly quantified. Polycyclic aromatic hydrocarbons (PAHs) are emitted during the combustion of organic fuels such as charcoal and biomass. In the present study, multichannel polydimethylsiloxane rubber traps were used for gas‐phase PAH sampling and extracted using a low–solvent volume plunger‐assisted solvent extraction method. Sixteen US Environmental Protection Agency priority PAHs, primarily in the gas phase, were investigated in indoor air of rural and urban residential homes in coastal Kenya (Mombasa and Taita Taveta Counties) using typical combustion devices of each area. Average gaseous PAH concentrations per household were higher in rural (ranging 0.81–6.09 µg m–3) compared to urban (ranging 0–2.59 µg m–3) homes, although ambient PAH concentrations were higher in urban environments, likely attributable to traffic contributions. The impact of fuel choice and thereby combustion device on PAH emissions was very clear, with the highest concentrations of PAHs quantified from wood‐burning emissions from 3‐stone stoves (total PAH averages 46.23 ± 3.24 µg m–3 [n = 6]). Average benzo[a]pyrene equivalent total concentrations were evaluated for the priority PAHs and ranged from not detected to 43.31, 88.38, 309.61, and 453.88 ng m–3 for gas, kerosene, jiko, 3‐stone, and improved 3‐stone stoves, respectively. Environ Toxicol Chem 2020;39:538–547. © 2019 SETAC [ABSTRACT FROM AUTHOR]

Byline: Jonathan Okechukwu Okonkwo, Shadung John Moja, Patricia Forbes Mn in street dust and soil from selected roads was studied to assess the contribution of combustion of vehicular methylcyclopentadienyl manganese tricarbonyl (MMT) to Mn levels and distribution in Pretoria, South Africa. Total Mn concentrations ranged from (329.1-863.9 μg g−1) for dust and (215.8-450.6 μg g−1) for soil. These values were significantly higher than the mean value (278.9 μg g−1) found on soil from a rural environment in Pretoria. The lowest value for the dust sample (329.1 μg g−1) was close to the mean background level of 330 μg g−1 for Mn in soil. Mn distribution in the samples was most in the residual fraction (178.18-487.50 μg g−1) and (140.76-293.40 μg g−1) for dust and soil respectively. Mn in the other fractions were 56.45-202.60 μg g−1 oxides, 90.71-45.34 μg g−1 organic, 45.36-12.65 μg g−1 carbonates and 1.98-6.72 μg g−1 exchangeable for dust and 32.54–167.31 μg g−1 oxides, 34.23–70.45 μg g−1 organic, 10.98-30.45 μg g−1 carbonate and 1.0-4.87 μg g−1 exchangeable for soil. Major source of Mn determined was mainly from the combustion of vehicular MMT.

Atrazine is a common agricultural pesticide which has been reported to occur widely in surface drinking water, making it an environmental pollutant of concern. In the quest for developing sensitive detection methods for pesticides, the use of quantum dots (QDs) as sensitive fluorescence probes has gained momentum in recent years. QDs have attractive and unique optical properties whilst coupling of QDs to molecularly imprinted polymers (MIPs) has been shown to offer excellent selectivity. Thus, the development of QD@MIPs based fluorescence sensors could provide an alternative for monitoring herbicides like atrazine in water. In this work, highly fluorescent CdSeTe/ZnS QDs were fabricated using the conventional organometallic synthesis approach and were then encapsulated with MIPs. The CdSeTe/ZnS@MIP sensor was characterized and applied for selective detection of atrazine. The sensor showed a fast response time (5 min) upon interaction with atrazine and the fluorescence intensity was linearly quenched within the 2–20 mol L−1 atrazine range. The detection limit of 0.80 × 10−7 mol L−1 is comparable to reported environmental levels. Lastly, the sensor was applied in real water samples and showed satisfactory recoveries (92–118%) in spiked samples, hence it is a promising candidate for use in water monitoring. [ABSTRACT FROM AUTHOR]