Journal of hazardous materials letters最新文献

Ingested Microplastic (MP) particles can harm the human body. Estimations of the total mass of ingested MP particles correspond to 50 plastic bags per year (Bai et al., 2022), one credit card per week (Gruber et al., 2022), or a median value of 4.1 μg/week for adults (Mohamed Nor et al., 2021). The first two estimations are based on an analysis (Senathirajah et al., 2021) that predicts a total ingested mass of MP particles m_i,MP of 0.1–5 g/week. This work revisits and evaluates this calculation and compares its results and methods to Mohamed Nor et al. (2021). Senathirajah combines data of averaged MP particle masses ${\overline{m}}_{\mathrm{MP}}$ from papers that reported MP particle sizes and MP particle counts n_MP in shellfish, salt, beer, and water based on other papers that detected MP particles. Combined with the estimated weekly consumption of those consumables, they compute m_i,MP. This work raises some serious issues of Senathirajah in the way they combine data and they obtained particle sizes. It concludes that Senathirajah overestimates m_i,MP by several orders of magnitude and that m_i,MP can be considered as a rather irrelevant factor for the toxic effects of MP particles on the human body.

Heavy metals (HM) toxicity is becoming a major threat to living organisms in recent years due to the increase in population and anthropogenic activities. Lead (Pb) shares about 10% of total pollution produced by heavy metals. The uptake of lead by the primary producers (plants) is found to affect their metabolic functions, growth, and photosynthetic activity. The accumulation of lead in excess can cause up to a 42% reduction in the growth of the roots. The current review addresses the global status of lead contamination in soil, potential lead sources, and the mechanism of lead uptake by the plants. This article also provides information about the lead concentration in plants in polluted and non-polluted areas. Humans are directly or indirectly dependent on plants to meet their daily requirements. So, it becomes necessary to review the problems associated with lead pollution in plants and its mode of action affecting the plant system. Factors like bioaccumulation, bioavailability, bioconcentration, transfer factor, and the role of Casparian strips as a natural physical barrier are discussed. Further, the updated literature survey about the various bioremediation strategies utilized for its elimination is also presented. The current study suggests that more attention needs to be focused on evaluating the effectiveness of bioremediation methods.

Tellurium (Te) is a Critical Element that is toxic to microorganisms and humans alike, most notably in its soluble oxyanionic forms. To date, the biogeochemical behaviour of Te in Earth’s surface environment is largely unknown. Here, we report the discovery of elemental Te nanoparticles (Te NPs) in regolith samples using Single-Particle Inductively Coupled Plasma Mass Spectroscopy. Tellurium NPs were detected in both proximal and distal locations (bulk concentrations >4 ppm) relative to weathering Te ores. Synchrotron X-ray Fluorescence Mapping and X-ray Absorption Spectroscopy showed that bulk Te in the regolith is generally associated with Fe (oxyhydr)oxides and clay minerals, and mostly found in the oxidation states +IV and +VI. Although Te NPs account for less than 2 mol‰ of Te in our samples, their detection provides evidence for the active biogeochemical cycling of Te in surface environments. Te NPs are reactive and are likely to have formed in situ in distal samples, most likely via microbially-mediated reduction. Hence, the presence of Te NPs indicates the potential for release of toxic soluble forms of Te even in environments where most Te is “fixed” in forms such as Fe (oxyhydr)oxides that have low solubility and poor bioavailability.

Stormwater biofilters naturally experience dry-wet and freeze-thaw cycles, which could remobilize deposited particulate pollutants including microplastics. Yet, the effect of these natural weathering conditions on the mobility of deposited microplastics has not been evaluated. We deposited microplastics on columns packed with sand or a mixture of sand with soil (25% by volume) to simulate biofilter media, subjected them to intermittent infiltration events punctuated by either freeze-thaw cycles or drying cycles. Comparing the vertical distribution of microplastics in biofilters after both treatments, we showed that more than 90% of microplastics were retained within the first 3 cm of filter media, but the distribution in deeper layers varied with media type and treatment conditions. Freeze-thaw cycles were more effective than dry-wet cycles in increasing the downward mobility of deposited microplastics. We attributed these results to the disruption of filter media by expanding ice crystals, which could release deposited colloids and associated microplastics. An increase in natural colloid concentration in the effluent following freeze-thaw treatments confirmed the hypothesis. The results are useful in predicting microplastic transport in the root zone in stormwater biofilters or contaminated land experiencing natural freeze-thaw cycles.

While it is thought that some per- and polyfluoroalkyl substances (PFAS) may volatilize from aqueous solutions, experimentally measured Henry’s Law constants (k_H, synonymous with air : water partition coefficient) are scarce. This leads to a lack of understanding of the partitioning of PFAS and an inability to predict concentrations above contaminated groundwater (e.g., vapor intrusion). We measured k_H for 27 PFAS via headspace analysis and manipulations of the gas to liquid phase ratio. Fifteen PFAS produced mass spectrometry signals suitable for k_H measurements. At 25 °C the experimentally measured dimensionless k_H were: 0.31 – 2.82 for four fluorotelomer alcohols (FTOHs), 0.09 – 0.18 for three fluorotelomer sulfonates (FTSs), 0.30 – 1.01 for three iodinated PFAS, 0.43 – 0.92 for two sulfonamides, 3.86 for 6:2 fluorotelomer olefin, 0.69 for 8:2 fluorotelomer carboxylic acid, and 0.32 for 8:2 fluorotelomer acrylate. Longer fluoroalkyl chain length resulted in increased k_H for FTOHs and FTSs, the only two groups in which chain length was studied. Perfluorinated sulfonates and carboxylates were generally not volatile enough to be measured, even at pH as low as 1, although fluorotelomers of both functional groups were measurably volatile. Temperature effects were well described by the van’t Hoff equation. k_H was not significantly different in various environmentally relevant matrices demonstrating the broad applicability of the produced constants.

Targeted analysis for 24 Per- and Polyfluoroalkyl Substances (PFAS) was conducted on 10 insecticide formulations used on a United States Department of Agriculture crop research field. Perfluorooctane sulfonic acid (PFOS) was found in 6 of the 10 formulations with concentrations ranging from 3.92 to 19.2 mg/kg. Further analysis of soil and plant samples collected at the site found several additional PFAS, with PFOS being the most prominent. Suspect screening was then conducted on the formulations and provided several suspected PFAS in addition to the 24 targeted analyzed PFAS in 7 of the 10 samples, one of which showed no PFAS during targeted analysis. PFAS-precursor oxidation was then conducted on the two insecticide formulations with the greatest lists of suspected PFAS as validation of potential unknown PFAS in the formulations. This study revealed a previously unknown potential PFAS contamination source for rural and agricultural environments.

Facing the ongoing coronavirus infectious disease-2019 (COVID-19) pandemic, many studies focus on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in indoor environment, on solid surface or in wastewater. It remains unclear whether SARS-CoV-2 can spill over into outdoor environments and impose transmission risks to surrounding people and communities. In this study, we investigated the presence of SARS-CoV-2 by measuring viral RNA in 118 samples from outdoor environment of three hospitals in Wuhan. We detected SARS-CoV-2 in soils (205–550 copies/g), aerosols (285−1,130 copies/m³) and wastewaters (255−18,744 copies/L) in locations close to hospital departments receiving COVID-19 patients or in wastewater treatment sectors. These findings revealed a significant viral spillover in hospital outdoor environments that was possibly caused by respiratory droplets from patients or aerosolized particles from wastewater containing SARS-CoV-2. In contrast, SARS-CoV-2 was not detected in other areas or on surfaces with regular implemented disinfection. Soils may behave as viral warehouse through deposition and serve as a secondary source spreading SARS-CoV-2 for a prolonged time. For the first time, our findings demonstrate that there are high-risk areas out of expectation in hospital outdoor environments to spread SARS-CoV-2, calling for sealing of wastewater treatment unit and complete sanitation to prevent COVID-19 transmission risks.

With the decommissioning of nuclear facilities, an increasing amount of radioactive graphite needs to be treated safely and effectively. In this work, microwave sintering technology was initially applied to treat simulated graphite waste. The effects of microwaves on the phase composition and microstructure of graphite were investigated. Combined with the mass loss results and fitting results of the phase, the mechanism for simulated graphite waste treatment via microwave sintering was obtained. According to the results, there are three stages regarding the effect of microwave sintering on the microstructure of graphite waste. This work reveals the potential application of microwave sintering technology in the treatment of graphite waste and its treatment mechanism.

This study, which investigated the sonodegradation of selected pharmaceutical active compounds (PhACs) (amitriptyline (AMT) and ibuprofen (IBP)) with MXene, was carried out in an aqueous solution. To investigate the practicality of the degradation process, the experiments were conducted in various water quality conditions, including pH, temperature, natural organic matter, and ionic strength. Based on the experimental results, the produced hydrogen peroxide, which could be a representative of the produced OH radicals, was a vital factor that affected the degradation performance of both PhACs. To confirm the importance of OH radicals, the effect of a OH radical promoter (H₂O₂) and scavenger (t-BuOH) was also studied. In addition, the synergism between ultrasonication (US) and MXene was evaluated with the rate constants of US only, MXene only, and a US/MXene combined system. Mineralization of the PhACs was also investigated, and removal of AMT was higher than that of IBP, which could be attributed to the physicochemical properties of the compounds and enhanced adsorption by the well-dispersed MXene. Overall, utilization of MXene by means of ultrasonication could enhance the removal performance of PhACs in water.