Scaling up the electrokinetic-assisted phytoremediation of atrazine-polluted soils using reversal of electrode polarity: A mesocosm study

Progress in environmental monitoring and mitigation strategies for herbicides and insecticides: A comprehensive review

Herbicides and insecticides are pervasively applied in agricultural sector to increase the yield by controlling or eliminating bug vermin and weeds. Although, resistance development occurs, direct and indirect impact on human health and ecosystem is clearly visible. Normally, herbicides and pesticides are water soluble in nature; accordingly, it is hard to decrease their deadliness and to dis-appear them from the environment. They are profoundly specific, and considered as poisonous to various peoples in agricultural and industrial work places. In order to substantially reduce the harmful impacts, it is crucial to thoroughly examine the detection and mitigation measures for these compounds. The primary objective of this paper is to provide an overview of various herbicide and pesticide detection techniques and associated remedial techniques. A short summary on occurrence and harmful effects of herbicides/insecticides on ecosystem has been included to the study. The conventional and advanced, rapid techniques for the detection of insecticides and herbicides were described in detail. A detailed overview on several mitigation strategies including advanced oxidation, adsorption, electrochemical process, and bioremediation as well as the mechanism behind the strategic approaches to reduce the effects of growing pesticide pollution has been emphasized. Regardless of the detection techniques and mitigation strategies, the recent advances employed, obstacles, and perspectives have been discussed in detail.

Toxic effects of antimony in plants: Reasons and remediation possibilities-A review and future prospects

Antimony (Sb) is a dangerous heavy metal (HM) that poses a serious threat to the health of plants, animals, and humans. Leaching from mining wastes and weathering of sulfide ores are the major ways of introducing Sb into our soils and aquatic environments. Crops grown on Sb-contaminated soils are a major reason of Sb entry into humans by eating Sb-contaminated foods. Sb toxicity in plants reduces seed germination and root and shoot growth, and causes substantial reduction in plant growth and final productions. Moreover, Sb also induces chlorosis, causes damage to the photosynthetic apparatus, reduces membrane stability and nutrient uptake, and increases oxidative stress by increasing reactive oxygen species, thereby reducing plant growth and development. The threats induced by Sb toxicity and Sb concentration in soils are increasing day by day, which would be a major risk to crop production and human health. Additionally, the lack of appropriate measures regarding the remediation of Sb-contaminated soils will further intensify the current situation. Therefore, future research must be aimed at devising appropriate measures to mitigate the hazardous impacts of Sb toxicity on plants, humans, and the environment and to prevent the entry of Sb into our ecosystem. We have also described the various strategies to remediate Sb-contaminated soils to prevent its entry into the human food chain. Additionally, we also identified the various research gaps that must be addressed in future research programs. We believe that this review will help readers to develop the appropriate measures to minimize the toxic effects of Sb and its entry into our ecosystem. This will ensure the proper food production on Sb-contaminated soils.

Improvement of the electrokinetic fluxes by tall fescue: Alleviation of ion attenuation and maintainability of soil colloidal properties

In this study, we aimed to address the attenuation of electrokinetic fluxes that occur during plant (tall fescue)-based electrokinetic remediation of oil-contaminated soil. Following 60 days of treatment, the concentration of water-soluble cations and anions in the electrokinetics-assisted phytoremediation treatment (EK-P) were 20.03 mg/kg and 15.7 mg/kg higher than that in the electrokinetic (EK) treatment, respectively. At the electrode, plants were able to alleviate the ion aggregation effect caused by the electrokinetics, reduce the conversion of soluble ions to insoluble ones, and reduce the decay of water-soluble ions. In addition, the zeta potential of EK-P was 5.05 mV lower than that of EK. Plants maintained the stability of the soil colloid and reduced the movement of the peak of colloidal particle size from small to large particles, thereby reducing the amount of colloidal deposition. Finally, the EK-P current was 22.49% higher than that in EK while the electrokinetic effect was maintained. Meanwhile, electrokinetics increased plant biomass by 20.21%. Electrokinetics was found to create a synergy with the plants, an effect that eventually enhanced the rate of oil degradation.

Antimony contamination and its risk management in complex environmental settings: A review

Antimony (Sb) is introduced into soils, sediments, and aquatic environments from various sources such as weathering of sulfide ores, leaching of mining wastes, and anthropogenic activities. High Sb concentrations are toxic to ecosystems and potentially to public health via the accumulation in food chain. Although Sb is poisonous and carcinogenic to humans, the exact mechanisms causing toxicity still remain unclear. Most studies concerning the remediation of soils and aquatic environments contaminated with Sb have evaluated various amendments that reduce Sb bioavailability and toxicity. However, there is no comprehensive review on the biogeochemistry and transformation of Sb related to its remediation. Therefore, the present review summarizes: (1) the sources of Sb and its geochemical distribution and speciation in soils and aquatic environments, (2) the biogeochemical processes that govern Sb mobilization, bioavailability, toxicity in soils and aquatic environments, and possible threats to human and ecosystem health, and (3) the approaches used to remediate Sb-contaminated soils and water and mitigate potential environmental and health risks. Knowledge gaps and future research needs also are discussed. The review presents up-to-date knowledge about the fate of Sb in soils and aquatic environments and contributes to an important insight into the environmental hazards of Sb. The findings from the review should help to develop innovative and appropriate technologies for controlling Sb bioavailability and toxicity and sustainably managing Sb-polluted soils and water, subsequently minimizing its environmental and human health risks.

Enhancement of electrokinetic-bioremediation by ryegrass: Sustainability of electrokinetic effect and improvement of n-hexadecane degradation

Phytoremediation-assisted electrokinetic-bioremediation is a novel technology for soil remediation. We aimed to study the effects of a plant (ryegrass) on electrokinetic-bioremediation in n-hexadecane-contaminated soil. After treatment for 40 days, the n-hexadecane degradation ratio of electrokinetic-bioremediation-ryegrass (EK-Bio-RG) was 4.86% higher than that of electrokinetic-bioremediation (EK-Bio) (p < 0.05), with a maximum constant degradation rate (107.23 ± 4.62 mg kg^-1· d^-1). Owing to the improved electrical conductivity, 73.28% of the initial current was maintained on the 40th day in EK-Bio-RG, which was 1.62 times that in EK-Bio. Furthermore, ryegrass reduced the soil zeta potential, which indicated the alleviation of the soil electric double layer compression and prevention of the aggregation of small soil colloids into larger ones. The fine colloidal structure was conducive to mass transfer in electrokinetic-bioremediation. An analysis of the microbial community showed that the degradation of n-hexadecane was mainly attributable to gram-positive bacteria, and a new microbial community was gradually constructed in the rhizosphere, which still metabolized n-hexadecane. The results indicated that the sustainability of the electrokinetic effect was improved combined with ryegrass, and the harmonious micro-environment in the rhizosphere was constructed which furtherly optimized the EK-Bio technology to remediate organics-polluted soil.