The disposal of potentially toxic element (PTE)-loaded sludge that is produced during industrial or commercial wastewater treatments evoke concerns because of the probability of hazardous environmental consequences. In the current work, we proposed a chelant-assisted decontamination technique of the laboratory-produced PTE-loaded (As, Cd, Pb) polymeric-Fe-coated sludge and subsequent recovery of the chelants and PTEs. The chelant options include both biodegradable (EDDS, GLDA, and HIDS) and non-biodegradable (EDTA) alternatives. The washing performance was compared and discussed in terms of the solution pH and relative stabilities of the complexes of PTEs and chelants in solution. The changes in solution pH or chelants have no significant effect on the chelant-induced removal efficiency of Cd, and the same result was observed for Pb at extreme and moderate acidic pH. The As-extraction rate is also improved with chelant in the solution despite a limited interaction between the chelant and the arsenic species in the solution. The column-packed solid-phase extraction (SPE) system, which was equipped with macrocycle, chelating resin, or ion-exchange resin, was used to explore the corresponding separation performance of the PTEs and chelant. The macrocycle-equipped SPE system shows better selectivity than other SPEs in terms of extraction and recovery performance of the PTEs regardless of the chelants. Some unique points of the proposed process are minimum environmental burden due to the use of biodegradable materials in the washing solution and cost minimization by recycling the ingredients.

Seasonal variations of chloroplast thylakoids and plasma membrane ultrastructure and changes in some biochemical parameters (e.g., metal accumulation, photosynthetic pigments, carbohydrates, lipid peroxidation, and electrolyte leakage) were studied in fronds of Salvinia minima plants exposed to increasing concentrations of Cr(VI) in both winter and summer. Disorganization of stacked (grana) and unstacked (stroma lamellae) thylakoids was greater in winter chloroplasts than in summer chloroplasts. Plasma membrane was less affected than thylakoids. Photosynthetic pigments, lipid peroxidation, soluble sugars, and starch were affected differently in winter and summer. Our results suggest that much greater ultrastructural alterations and changes in metabolite levels occurring in winter fronds are produced by higher oxidative stress resulting from the interactive effect between low temperature, low solar irradiance, and Cr(VI) toxicity, rather than from metal accumulation per se. Seasonal differences occurring in chloroplast ultrastructure and metabolite concentrations were discussed in relation to metabolic implications. Evaluated parameters represent a relevant approach to enhance knowledge on performance and fitness of plants exposed to heavy metals under fluctuating environmental conditions. This work also indicates that selection of suitable macrophytes to remove Cr(VI) requires an additional analyzing focus on structural and metabolic interactions that occur in plants exposed to heavy metals in contrasting seasons.

To treat PCP-contaminated soil, abiotic methods for PCP degradation have been developed, where heme or powder hemoglobin acts as a catalyst and hydrogen peroxide as an oxidant. Degradation of PCP had the first-order kinetics, and rate coefficients, k, were 0.073 and 0.104/day for heme and hemoglobin, respectively, indicating that the hemoglobin was a more efficient catalyst than heme. Approximately 96 % of the initial PCP was degraded at day 35. Thus, hemoglobin might be recommended as the catalyst of choice, since it is much less expensive than heme.

The purpose of this review is to describe how plants take up lead and its distribution to plant parts, morphological, physiological, and biological effects of lead on plants, sequestration strategies, and tolerance mechanisms including detoxification. How lead despite its lack of essential function in plants, causes phytotoxicity by changing cell membrane permeability, by reacting with active groups of different enzymes involved in plant metabolism by reacting with the phosphate groups of adenosine diphosphate (ADP) or adenosine-5′-triphosphate (ATP). Moreover, we also address role of hyperaccumulating plants in lead absorption. How synthetic chelators such as ethylenediaminetetraacetic acid (EDTA) enhances the availability of heavy metal lead in soils and increase phytoextraction efficiency in aboveground harvestable plant parts through enhancing the metal solubility and translocation from roots to shoots, metal tolerance, and future prospectives to decrease lead pollution.

Upland swamps of the Blue Mountains are unique and legislatively protected peat swamp communities. This study investigated water chemistry of surface waters from seven Blue Mountains Upland Swamps (BMUS), four within urbanised catchments and three from naturally vegetated catchments. The purpose of the study was to investigate any ionic contamination from urban development. Water chemistry of non-urban BMUS was acidic (mean pH 4.7) and dilute (mean EC 26.6 μS/cm) and dominated by sodium and chloride ions with most other major ions at low concentrations, often below detection limits. In contrast, urban BMUS had higher pH (mean 6.6) and salinity (mean 153.9 μS/cm) and were dominated by calcium and bicarbonate ions. The results of this study support the hypothesis that urban concrete contamination is modifying the geochemistry of urban BMUS. Further research is required to investigate ecological implications of the contamination and also to explore measures to protect such sensitive wetlands of high conservation value from urban development.

Microalgae-based bioremediation processes pose dual abilities of simultaneous CO₂ fixation through photosynthesis and degradative effect on environmental pollutants. This study intends to investigate the tolerance and biodegradation capability of Spirulina maxima for removal of phenol. An assimilation study of the phenol-carbon was also conducted to elucidate if the phenol removal was dominated by physical adsorption on cell walls or through metabolic activities. S. maxima cells were found to be capable of growing on phenol up to a concentration of 400 mg l⁻¹, and they had a highest specific growth rate at a phenol concentration of 50 mg l⁻¹. The results suggested that the removal of phenol (as high as 97.5 %) was mainly due to biodegradation processes rather than a bioadsorption process. Moreover, it was evident that nearly 30 % of the ¹³C-labeled phenol content was discovered in the cellular fraction, indicating that the ¹³C-phenol-carbon was indeed assimilated to biomass followed by mineralize the carbon to CO₂.

Featured with biodegradability and biocompatibility properties, gelatin (GE) was selected as the backbone to graft poly(acrylic acid) (PAA) to fabricate a granular hydrogel at room temperature in air. Using attapulgite (APT) as an inorganic component, the resulting GE-g-PAA/APT hydrogel was characterized by means of Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and zeta potential analysis and then used as the adsorbent to be applied in a mixed dye solution containing malachite green and orange G. The addition of APT can significantly reduce the swelling degree during the adsorption process, though its influences on the adsorption capacity are not so expectable. The as-prepared hydrogel shows a wide pH-independent adsorption from 3.0 to 10.0, with the maximum adsorption capacity of 1370 mg/g for GE-g-PAA and 1190 mg/g for GE-g-PAA/APT (5 wt%). More importantly, the as-prepared hydrogel shows high adsorption selectivity for cationic dyes and the dye-loaded hydrogel can be easily regenerated and recovered for successive adsorption cycles. Graphical Abstract Gelatin-based granular hydrogel for selective removal of MG in a mixed dyes containing MG and OG-G.

The first uranium extraction mine of Brazil, nowadays found in decommissioning phase, has caused several negative environmental impacts in its area, as a result of mining, treatment, and beneficiation processes. The generation of acid mine drainage in waste rock pile 4 (WR-4) is one of the negative impacts with the most critical situation. The acidic water, product of this drainage, presents heavy metals and radioactive elements and it may be infiltrated by the basis of the impoundment basin, where this water is collected for treatment. The objective of this study was to investigate a typical tropical soil, located in the area of Ores Treatment Unit of Caldas in the southwestern state of Minas Gerais, Brazil, in order to use it as a mineral liner for a retention basin to minimize leakage of acidic water through the foundation of a containment dam. In this way, geotechnical, chemical, and mineralogical tests were performed in order to characterize a soil sample collected in the area. In addition, adsorption tests were conducted with solutions of aluminum (Al), manganese (Mn), and iron (Fe), and with and without adjustment of the initial pH (pHₜₒ) of the solutions. The results indicated a well-weathered soil composed of kaolinite, gibbsite, and iron oxides. The adsorption tests showed different behaviors for Al, Mn, and Fe considering or not the adjustment of the pHₜₒ. Aluminum showed low adsorption by soil; because of this, only the adsorption isotherms of Mn and Fe for test with adjustment of the pHₜ₀were determinate. The coefficient of distribution (KD) of Mn was 0.0364 L g⁻¹and Fe 0.0281 L g⁻¹. As for the retardation factor (Rd), its values ranged from 81 to 91 for Mn and from 61 to 79 for Fe, considering different behaviors of the adsorption isotherm models.

The potential of agricultural waste materials for the removal bisphenol A (BPA) from aqueous solution was investigated. BPA is an endocrine-disrupting compound (EDC) used mainly in the plastic manufacturing industry. It may be hazardous to humans and animals because of its estrogenic activity. Agricultural wastes are sustainable adsorbents because of their low cost and availability. Hence, this study investigated the removal of BPA from water by adsorption onto treated coir pith, coconut shell and durian peel. The adsorption of BPA from water onto adsorbent was evaluated using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET). The effects of morphology, functional groups, and surface area on adsorption before and after pretreatment with sulfuric acid and reaction were investigated, and it was found that the treated adsorbent were able to remove BPA. Carbonyl and hydroxyl groups had appear in large number in FTIR analysis. The present study indicates that coir pith had removed 72 % of BPA with adsorption capacity of 4.308 mg/g for 24 h, followed by durian peel (70 %, 4.178 mg/g) and coconut shell (69 %, 4.159 mg/g). The results proved that these modified phyto-waste were promising materials as alternative adsorbent for the removal of BPA from aqueous solution.

In this paper, we compared the costs and benefits of reducing premature mortality caused by exposure to surface ozone and particulate matter with an aerodynamic diameter <2.5 μm (PM₂.₅) in East Asia in 2020. The cost of ozone and PM₂.₅emission reduction is estimated using the Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS)-China model. The benefit of reducing premature mortality caused by exposure to corresponding ozone and PM₂.₅emission is valued by the value of statistical life (VSL). The costs and benefits are evaluated for two emission reduction policies in 2020 with varying stringency in China: Case FS (the strict policy implementation case in China) and Case FR (the less strict policy implementation case in China). For ozone, the emission reduction cost and the benefit of life saving are 33,000 and 8200, 36,600–99,700 and 22,200–60,700 (million int. $, 2005), for Case FS and Case FR, respectively. The corresponding cost and benefit for PM₂.₅are 3580 and 523, 292,000–797,000 and 194,000–530,000 (million int. $, 2005), respectively. In total (ozone and PM₂.₅), the respective values are 36,400 and 8720, 329,000–897,000 and 217,000–591,000 (million int. $, 2005). Owing to these large benefits and also relatively low PM control costs, the benefits of controlling PM₂.₅surpass control costs significantly. The benefit/cost ratio is especially high for PM₂.₅for both policies and highlight the priority of controlling aerosol emissions in East Asia.