Polyhalogenated carbazoles (PHCZs) are a kind of emerging contaminants with doxin-like toxicity, potential bioaccumulation capability, and persistence. Data about the risks of PHCZs on soil ecosystem are scarce to date, although PHCZs have been detected with high concentrations in the soil. The present study performed a preliminary investigation of 3,6-dibromocarbazole (36-DBCZ, a PHCZ with a high detection rate, and concentration in the environment) at concentrations of 0.1, 1.0, 10, and 100 mg/kg on the soil health, based on soil enzyme test and Biolog-ECO assay. Results showed that 36-DBCZ could inhibit the activity and diversity of soil microbes, even at the environment-relevant concentration (0.1 mg/kg). But, the inhibition lasted only about 10 days. As time passed, slight increases in microbe activity and diversity were found in 36-DBCZ-treated groups. We hypothesized that the degradation products of 36-DBCZ provided extra nutrients to the soil microbes, which required further verification. Activities of urease, β-glucosidase, and acid phosphatase were increasingly increased, in contrast to the microbial activity. The present study provides valuable data on the effects of PHCZs on the soil ecosystem, and we suggest that the degradation of PHCZs, as well as their influences on the structure and functions of the soil microbial community, should be investigated in future studies.

This study is close to an earlier urban soil survey carried out for a rapidly growing city with a high traffic density in Aurangabad city, India. Consequently, it aims to use the environmental magnetism approach to assess roadside emissions at a known polluted site. Magnetic measurements have been successfully implemented in soil studies and seem to be a suitable approach for pollution assessment in industrial and roadside areas of the study area. The present study was accomplished for magnetic susceptibility, isothermal remanent magnetization, coercivity, hysteresis measurements, thermomagnetic curves, scanning electron microscopy, and energy-dispersive spectroscopy analysis to evaluate the absolute fraction of magnetic minerals in bulk soil samples. The soils displayed variation in magnetic susceptibility values, which was influenced by concentration, domain states, and morphological characteristics of magnetic minerals. Substantial variation in the mineralogical composition of soils deriving from different industrial activities was noticed. The results indicate that industrial and roadside soil samples with mostly coarser and irregular-shaped show ferrimagnetic minerals. The presence of iron–titanium combination in most of the samples is due to titanomagnetite accompanying the titanium-bearing grains. In soils, a higher amount of ferrimagnetic minerals (magnetite, titanomagnetite, maghemite) with a minor content of antiferromagnetic minerals (hematite/goethite) was noticed. These studies reveal that magnetic and morphological characterization of soils can be used as an appropriate tracer for industrial and roadside soil pollution, which leads to new avenues for more detailed chemical mapping.

Phosphate-solubilizing bacteria (PSB) can accelerate phytoremediation, especially in those fertilized soils. However, PSB function in oligotrophic growth substrates remains poorly studied. In this study, we isolated lead (Pb)- and cadmium (Cd)-resistant PSB from contaminated sandy soil at an abandoned lubricant plant. The isolated Pantoea sp. PP4 (PP4 hereafter) can produce organic acid and IAA (Indole-3-acetic acid) and dissolve up to 238 mg/L of inorganic phosphate Ca₂(PO₄)₃, exhibiting biosorption capability for Pb and bioprecipitation for Pb and Cd. In the sand pot experiment, inoculation of PP4 increased the accumulation of Pb and Cd in Lolium multiflorum Lam. by 28.9% and 95.5%, respectively, and increased the available phosphorous in oligotrophic river sand by 30.8% (P < 0.05). Meanwhile, the growth of Lolium multiflorum Lam. was also stimulated, resulting in 89.2%, 57.1%, 184.6%, and 28.5% increase in fresh weight, dry weight, root length, and shoot length, respectively. NMDS analysis showed that the bacterial communities in river sand were more clustered after inoculation with PP4. These results indicated that the application of Pantoea sp. PP4 can facilitate the phytoremediation of Pb and Cd in oligotrophic growth substrates, forming a convergent bacterial community. Our findings highlighted the importance of identifying ideal PSB to improve phytoremediation efficiency in oligotrophic environments.

Phytoremediation is a strategy to employ plants to recover high quantities of metals in the soil into the harvestable parts such as shoots and roots. High levels of Cd and lead (Pb) in the soil cause several stress symptoms in plants including a decrease in growth, reduced root growth, and carbohydrate metabolism. In this study, Saravan and HGS-867 as local landrace and Indian guar variety were selected to investigate the effect of the application of Pb (0, 40, 150, and 200 mg/l) and the cadmium (0, 25, 50, and 100 mg/l) on phonological, yield parameters, and phytoremediation assessment. The results showed that Pb translocation factor (TF) was significant in Pb×Cd and Pb×Cd×G (genotype) at p<0.01 and in Pb×G at p<0.05. Pb bioconcentration factor (BCF) was significant (p<0.01) in all treatments except Cd and Cd×G treatments. Mean comparison of the data showed that the number of flowers, leaves, and clusters in plant decreased significantly with increasing Pb content. With increasing Cd concentration, the number of branches, height, the number of seeds, clusters, and leaves for each plant decreased significantly at the level of 1%. The maximum TF was observed in Pb at 40 mg/l in the HG-867 variety. Moreover, the Saravan landrace exposed to Cd (100 mg/l) showed the highest value of BCF (Cd). The gum percentage significantly decreased with increasing concentrations of Pb and Cd. Pearson’s correlation analysis indicated that plant height, number of pods/plant, root length, biomass, and pod length had a positive correlation with seed yield and a negative correlation with TF (Pb) and BCF (Pb). The results suggest that according to TF, BCF, and BAC, C. tetragonoloba L. can be effectively used as a good accumulator of toxic metals in contaminated soils.

Aquatic products contain both beneficial substances such as polyunsaturated fatty acids and harmful compounds such as methylmercury, and their combined health effects should be assessed at a common end point for a rational analysis. We used a risk–benefit model to assess net IQ point gain from consumption of Chinese mitten crabs (Eriocheir sinensis) from Jiangsu Province. Levels of methylmercury in the edible parts of the crabs ranged from 0.79 to 69.47 μg/kg (mean: 26.88 ± 15.09 μg/kg). Levels of methylmercury did not differ by sampling location. In aquaculture experiments, we simulated artificial pond farming using either iced trash fish or formulated feed. Crabs fed iced trash fish contained 28.72 ± 2.30 mg/g of eicosapentaenoic acid and docosahexaenoic acid and crabs fed formulated feed contained 19.64 ± 3.62 mg/g of eicosapentaenoic acid and docosahexaenoic acid. Model calculations estimated a gain of 7.52 IQ points from consumption of crabs fed formulated feed and 11.00 IQ points from consumption of crabs fed iced trash fish. They are all above the maximum theoretical IQ point gain value. Chinese mitten crab is a kind of high-quality food which is beneficial to the neural development of infants. Our findings may assist in improving crab farming methods and consumption patterns, accelerating the sustainable development of the Chinese mitten crab industry.

The present study focuses on the effect of temperature and extraction methods on the yields, chemical quality, fatty acids, and tocopherols of the oil extracted from the seeds of Opuntia ficus-indica, collected in the eastern region of Morocco. Our results revealed the effect of temperature that when we increase the temperature used, the yields also increase; the results also showed that this high temperature does not affect the physicochemical properties, fatty acids, and tocopherols. Thus, the results of this study revealed that the prickly pear is a rich source of oil; the obtained oil yields varied from 12.49%±0.09 for mechanical extraction, 11.46±0.10 for chemical extraction, and 10.52%±0.09 for maceration. The main fatty acids founded in Opuntia ficus-indica are linoleic acid 75.80%±0.10 (chemical), 74.07%±0.14 (maceration), and 71.59%±0.14 (mechanical) and palmitic acid 17.32%±0.02 (chemical), 22.419%±0.06 (maceration), and 26.58%±0.00 (mechanical); prickly pear oil could be classified as a linoleic acid. The physicochemical properties of Opuntia ficus-indica seed oils such as acid index mgKOH/g oil (4,376±0.10, 5.854±0.03, 5.667±0.07), saponification value mgKOH/g oil (181.12 ±0.18, 183.77±1.23, 179.08±3.45), and peroxide value 20milieq/Kg (5.75±0.08, 6±0.06, 5.97±0.04) for mechanical, chemical, and maceration extraction, respectively, density, and refractive index were all found to be in good accordance with quality criteria for both pure and fresh oils. Among the tocopherols found, a high value of γ-tocopherol was detected in mechanical extraction with 502.04±0.76 mg/kg, followed by chemical extraction and maceration with 430.12±0.61mg/kg and 315.47±0.96 mg/kg, respectively.

The demand of wet wipes and masks has been rising worldwide since the outbreak of global COVID-19; however, with more reports about improper handling of wipes and masks, their potential threats to the environment are gradually emerging. Wipes and masks are made of a large number of plastic fibers, which are easily broken and fragmented into microplastic fibers under the influence of environmental factors. Weathered wipes or masks can release billions of microplastic fibers, which is a great challenge to the local ecological security. Wipes and masks as new microplastic pollution sources and their potential role in the ecosystem have not been fully recognized and considered. Microplastic fiber pollution is a huge environmental issue, and how to prevent a large number of discarded wipes and masks from entering the environment and how to deal with them are an important issue for all countries and regions in the world. In the post era of global COVID-19, disposable wipes and masks, as new sources of environmental microplastic fiber pollution, should be given concern. It is urgent to recognize this potential environmental threat and prevent it from becoming the next microplastic problem.

We investigate the validity of the environmental Kuznets curve (EKC) hypothesis for the NAFTA countries. In this investigation, we approach this hypothesis from a different methodology and propose employing the ARMEY curve hypothesis since the mathematical-functional propositions of both hypotheses were constructed on the same inverted U-shaped relationships. Thus, for the first time, it can be interpreted that the EKC hypothesis is empirically tested through a transmission mechanism of the ARMEY curve hypothesis in a single composite model. Therefore, this approach makes our study different from all empirical studies in the relevant literature. We apply the Augmented Mean Group (AMG) estimator to this aim. Empirical findings indicate that the ARMEY curve hypothesis was verified only for the USA. However, this new approach proposed in this study cannot test the EKC hypothesis through the ARMEY curve model for any NAFTA country since this approach requires verification of the ARMEY curve hypothesis and a significant composite model for the same NAFTA country. If our composite model was significant, it might make it possible to numerically determine a maximum real GDP per capita level that would minimize or maximize CO₂ emission levels for the USA. Therefore, this study introduces-proposes this new methodology as an alternative way of testing the EKC hypothesis in the relevant literature for future empirical studies.

Cold recycling techniques emerged in road construction to recycle deteriorated pavements as bases and surfaces. A detailed review is carried out in the current study on the design, evaluation, performance, and advances in the emulsified asphalt-treated bases (EATB). The mix-design of EATB is a complex procedure in which the performance is based on optimizing water, additives, and emulsified asphalt contents. This paper covers the design methods, compaction characteristics, curing periods, additive contents, strength development, strength parameters, determination of the optimum emulsified asphalt content, and finally, the performance evaluation of EATB. From the detailed review, indirect tensile strength (ITS) is the most influencing parameter considered in the mix design of the EATB. Maximum dry density, Marshall Stability, and ITS are considered as primary performance indicators of the EATB. Modulus, rutting, and fatigue being consider secondary performance indicators. Overall, the recycled bases using emulsified asphalt proved sustainable and economical compared with the natural aggregates (NA).

Mineralogy was an important driver for the environmental release of heavy metals. Therefore, the present work was conducted by coupling mineral liberation analyzer (MLA) with complementary geochemical tests to evaluate the geochemical behaviors and their potential environmental risks of heavy metals in the smelter contaminated soil. MLA analysis showed that the soil contained 34.0% of quartz, 17.15% of biotite, 1.36% of metal sulfides, 19.48% of metal oxides, and 0.04% of gypsum. Moreover, As, Pb, and Zn were primarily hosted by arsenopyrite (29.29%), galena (88.41%), and limonite (24.15%), respectively. The integrated geochemical results indicated that among the studied metals, Cd, Cu, Mn, Pb, and Zn were found to be more bioavailable, bioaccessible, and mobile. Based on the combined mineralogical and geochemical results, the environmental release of smelter–driven elements such as Cd, Cu, Mn, Pb, and Zn were mainly controlled by the acidic dissolution of minerals with neutralizing potential, the reductive dissolution of Fe/Mn oxides, and the partial oxidation of metal sulfide minerals. The present study results have confirmed the great importance of mineralogy analysis and geochemical approaches to explain the contribution of smelting activities to soil pollution risks.