Antimony (Sb) toxicity is a significant threat to crop production and humans. Its concentration is increasing in soil and water due to human activities which needs dire attention to address this challenge. Biochar is a promising amendment to remediate polluted soils, however, its role in mitigating the toxic impacts of Sb on plants is still unclear. Seaweed-based fertilizer (SBF) has shown appreciable results in improving plant performance, however, its role against metal/metalloids toxicity has not been studied yet. Therefore, this study tested the impacts of BC and SBF in mitigating the harmful effects of Sb on rice. The study was carried out with the following treatments; control, Sb stress (600 mg kg(-1)), Sb stress + biochar (2%), Sb stress + seaweed-based fertilizer (SBF: 2%), and Sb stress + BC (1%) and SBF (1%). The results showed that Sb toxicity adversely affected rice growth and productivity by impeding photosynthetic pigments, leaf relative water contents, increasing production of oxidative stress biomarkers (electrolyte leakage: EL, hydrogen peroxide: H2O2, malondialdehyde: MDA), and accumulation of Sb in plant parts. Contrarily, BC and SBF blends mitigated Sb-induced growth and yield damages in rice by improving photosynthetic efficiency, osmolyte synthesis, nutrient uptake, soil enzymatic activity, and antioxidant activities. Moreover, BC and SBF blend also reduced the bio-accessible Sb concentration (95.63%), bio-accessibility of Sb (25.40%), Sb transport coefficient (35.70%) and soil Sb antimony concentration (52.74%). Given these findings, the co-application of BC and SBF showed a profound improvement in rice yield by regulating photosynthetic performance, antioxidant activities, oxidative stress markers, antioxidant activities, and soil properties.

Arsenic is a well-known toxic substance, widely distributed, whereas vanadium is a pollutant of emerging interest. Both have been found to correlate positively in groundwaters, thus concern arises on the effect of these pollutants on crops, if such waters are used for irrigation. We conducted a study on the effect of aging with a typical crop soil mimicking soils initially irrigated with water containing As and V. Afterwards, the soil was subjected to wet/dry cycles. The fractionation of both elements at different times from the addition (onset of the experiment) was determined by a modified European Community Bureau of Reference (BCR) method. It is found that the greater part of V is located in the most stable fraction from the onset of the experiment. This is attributed to interaction with amorphous and clay minerals and the precipitation of Ca(VO3)2, which is predicted by speciation modeling. The remaining fractions show the expected behavior: the most labile fraction decreases over time, that associated to oxidizable increases with time, whereas the fraction associated to reducible components stays approximately constant. Arsenic shows a lower proportion in the most stable fraction compared with V, and a higher proportion in the most labile, but otherwise shows similar tendencies. The results suggest a low availability of V and a higher one of As. No competence was observed between As and V in the experimental conditions.

Sewage sludge requires effective dewatering and high nutrients retention before disposal for agricultural application. Pressurized electro-osmotic dewatering (PEOD) process with low energy consumption can effectively remove water from sludge, but the influences of PEOD process on nutrients for agricultural application still lacks in-depth research. In this study, the influences of PEOD process on nutrients for agricultural application were investigated, including organic matter, nitrogen, phosphorus, potassium and silicon contents. Layered experiments were conducted to investigate the layered variation of nutrients in sludge and to understand the potential change mechanisms. The experimental results showed that PEOD process caused small losses (<10%) of organic matter and total phosphorus (TP) in sludge, but caused 11.2-18.4% loss of total nitrogen (TN). PEOD process also caused 18.6-27.0% loss of total potassium (TK) and over 80% loss of available potassium in sludge, and could weaken the potential salt damage during the agricultural application of sludge. Furthermore, the available phosphorus content of sludge in the anode area increased significantly after the PEOD process, indicating that PEOD process could enhance the phosphorus bioavailability of sludge in the anode area. Besides, PEOD process caused a slight loss of silicon components in sludge, but improved the long-term silicon dissolution and release ability of sludge. This work could expand the knowledge about the influences of PEOD process on sludge nutrients and provide scientific guidance for the agricultural application of PEOD sludge.

Mercury (Hg) is one of the most toxic global pollutants of continuing concern, posing a severe threat to human health and wildlife. Due to its mobility, Hg is easily transported through the atmosphere and directly deposited onto water, sediments and soils or incorporated in biota. In groundwater, Hg concentrations can be influenced by either geogenic or anthropogenic sources, causing critical health effects such as damage to the respiratory and nervous systems. The geogenic sources of Hg include rocks and minerals containing Hg (cinnabar, organic-rich shales, and sulfide-rich volcanic) and geothermal fluids. The anthropogenic Hg sources include the combustion of fossil fuels, gold mining, chemical discharges from dental preparation, laboratory activities and legacy sites. In groundwater, the average background concentration of Hg is < 0.01 mu g/L. Mercury can be mobilized into groundwater from geogenic or anthropogenic sources due to changes in redox potential (Eh), with concentrations reaching above the WHO drinking water standard of 1 mu g/L. Under reducing conditions, microbial activity facilitates the reductive dissolution of FeOOH, causing the release of sorbed Hg2+ into groundwater. The released Hg2+ may be reduced to Hg-0 by either dissolved organic matter or Fe2+. The stability of Hg species (Hg-0, Hg-2(2+), Hg2+, MeHg) in groundwater is controlled by Eh and pH. While high Eh and low pH conditions can mobilize Hg from the solid into aqueous phases, the soil binding ability can sequestrate the mobilized Hg via adsorption of Hg2+ by goethite, hematite, manganese oxides, hydrous ferric oxides, or organic matter restricting it from leaching into groundwater. During groundwater contamination, remediation using nanomaterials such as pumice-supported nanocomposite zero-valent iron, brass shavings, polyaniline-Fe3O4-silver diethyldithiocarbamate, and CoMoO/gamma-Al2O3 has been documented. These promising emerging technologies utilize the principle of adsorption to remove up to 99.98 % of Hg from highly contaminated groundwater. This study presents an overview of groundwater contamination, remediation, complex biogeochemical processes, and a hydrogeochemical conceptual model concerning Hg's mobility, fate, and transport.

Mining activities are among the main sources of heavy metal contamination in the environment. The damage caused to land by mining has become an increasingly important problem in some countries. A pot experiment was conducted to evaluate the effects of two application rates (1% and 5% w/w) of rice straw biochars, as prepared at 420 degree celsius and 640 degree celsius(B1420 and B640), and several inorganic amendments (pumice, leca, zeolite and bentonite) on Cd and Pb bioavailability and speciation in soil and their accumulation in maize (Zea mays L.) as an indicator plant. Furthermore, the amelioration effects of the applied amendments on the potential environmental risk of the heavy metals were assessed. The amendments resulted in a considerable reduction of the Cd and Pb contents in the shoots, which was by 28.83-70.72% and 21.78-64.02%, respectively, as compared to the control. Amendments also decreased the DTPA-extractable Pb and Cd in the soil, particularly at the 5% application rate, as compared to those in the un-amended soil. Furthermore, in comparison to the control, the transfer factors of heavy metals were reduced when the amendments were applied. Amendments also decreased the exchangeable portion of Cd and Pb by 10.43-52.11% and by 6.43-55.43%, respectively; most of these were converted into oxides and more stable forms exhibiting the lower risk assessment code (RAC) and the potential ecological risk index (PERI). These results indicate that zeolite and BI420 have a high potential to decrease the uptake of Cd and Pb in the shoots and roots of maize, respectively. Biochar and zeolite, as cost-effective and safe adsorbents, performed the best in immobilizing Pb and Cd in the studied calcareous soil.

Thallium (Tl) is a highly toxic element and can accumulate in human body through food, water, or air and cause damage to multiple organs. In this study, the nonthermal plasma (NTP) was employed to irradiate the potassium dihydrogen phosphate (KH2PO4) and sodium diethyldithiocarbamate trihydrate (SDDC) to solve the issues brought by their poor stability and insufficient chelation capabilities in soils to intensify their performance on immobilizing monovalent Tl contaminants in soils. Both an orthogonal design (OD) and a central composite design (CCD) were adopted to arrange the multi-parametrical modification and stabilization experiments. The leaching toxicities ranging from 5.11 to 52.37 mu g/L of Tl+ ions were obtained in the OD experiments. The changes in both NTP time and the molar ratios of KH2PO4 to SDDC had a significant effect on the activation procedure. The leaching concentration ranging from 0.37 to 7.34 mu g/L was achieved in the CCD stabilization experiments. NTP activation and the rearrangement of the stabilization conditions both were beneficial to the transformation of physicochemical states of Tl pollutants in soils, which proved the existence of chemical immobilization brought by the irradiated stabilizers (NTP-PK-SDDCs) to the Tl contaminants. The stabilization process was targeted between only Tl contaminants and NTP-PK-SDDCs in soils. The NTP irradiation enhanced the physicochemical characteristics of stabilizers, further intensifying the immobilization of Tl species in the soils. The enhancement mechanism was attributed to the free radicals-induced doping, oxidation, and polycondensation and the bombards of electrons, which strengthened the electrostation and chemisorption of NTPPK-SDDCs towards Tl ions. The potential impact of this study includes the development of more effective and sustainable remediation methods for Tl-contaminated soils, contributing to environmental protection and human health.

Because an element's chemical species affects toxicity, environmental mobility, and bioavailability, speciation analysis is vital in contemporary analytical chemistry. In recent years, attempts have been undertaken to identify not just components but also their species. This review highlights the latest methodologies and techniques in environmental analytical chemistry to address this tendency. Different sample treatment processes are introduced and explained, with an emphasis on employing modern nanomaterials and novel solvents in the solid phase and liquid-liquid microextraction, and on speciation analysis. An in-depth examination of experimental methods for separating and quantifying metal and metalloid species, from chromatography to electrochemistry, is also offered. This research emphasizes the greenness of these achievements, analyzing their green chemistry and environmental effects. Identifying and quantifying an element's chemistry is called element speciation. Because an element's toxicity depends on its chemical form, specification analysis is a popular issue in environmental research. Trace element levels in environmental samples have been heavily studied. Total elemental composition no longer indicates toxicity in risk assessment. Speciation analysis measures the relative concentrations of an element's physicochemical forms in a sample. Physicochemical forms include gaseous, solid, and liquid substances. It's frequently required to specialize when studying the damaging and life-saving effects of trace elements. (c) 2024 L&H Scientific Publishing, LLC. All rights reserved.

Strengthening the research of riverine mercury (Hg) export is of great significance for understanding the regional and global Hg cycle, especially for the data lacking trans-Himalayan rivers. In this study, three systematic sampling campaigns were conducted in the Koshi River Basin (KRB) during the post-monsoon, pre-monsoon and monsoon seasons. Hg speciation and distribution of river water were analyzed among the different seasons for a total of 88 water samples. The total Hg (THg) concentration of surface water in the KRB ranged from 0.64 to 32.96 ng.L-1 with an average of 5.83 +/- 6.19 ng.L-1 and decreased in the order of post-monsoon (8.79 +/- 7.32 ng.L-1) > monsoon (6.68 +/- 6.12 ng.L-1) > pre-monsoon (2.18 +/- 1.29 ng.L-1). Particulate Hg (PHg) accounted for 63% of THg on average and had a positive correlation with THg among all the three sampling seasons, indicating that the differences in PHg concentration were likely one of the main factors leading to the seasonal and spatial variations in THg in the KRB surface water. The annual Hg exports and fluxes were estimated to be 339.04 kg and 3.88 mu g.m(-2).yr(-1), respectively. Furthermore, Hg export from the KRB had significant seasonal variation and decreased in the order of monsoon (259.47 kg) > post-monsoon (61.18 kg) > winter (9.31 kg) > pre-monsoon (9.08 kg), and this pattern was mainly related to seasonal changes in river runoff. The annual Hg export is projected to increase in the future, especially in the post-monsoon season. Therefore, more attention should be paid to river runoff observations and riverine Hg research for water resources management in the Himalaya. (C) 2020 Elsevier B.V. All rights reserved.