Current Pollution Reports最新文献

Carbon dots (CDs) or carbon quantum dots (CQDs) have emerged as rising stars in the carbon family due to their diverse applications in various fields. CDs are spherical particles with a well-distributed size of less than 10 nm. Functional CDs are promising nanomaterials with low toxicity, low cost, and enormous applications in the field of bioimaging, optoelectronics, photocatalysis, and sensing. Plastic is non-biodegradable and hazardous to the environment, however extremely durable and used in abundance. During the COVID-19 pandemic, the use of plastic waste, particularly masks, goggles, face shields, and shoe cover, has increased tremendously. It needs to be recycled in a productive way as plastic wastes take hundreds or thousands of years to degrade naturally. The conversion of plastic waste into magnificent CDs has been reported as one of the key alternatives for environmental sustainability and socio-economic benefits. In this review, synthetic routes for the conversion of plastic wastes into CDs utilizing hydrothermal, solvothermal, pyrolysis, flash joule heating, and characterization of these CDs using different techniques, such as Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and transmission electron microscope, have been discussed. Furthermore, potential applications of these plastic-derived CDs in sensing, catalysis, agronomics, and LED lights are summarized herein.

Purpose of Review

Annually, huge amounts of microplastics (MPs) are added to farmlands through sewage sludge (SS)/biosolid applications as a fertilizer. Most research emphasizes the enormity of the problem and demonstrates the fate, impacts, and toxicity of MPs during SS treatment processes and land applications. None has addressed the management strategies. To address the gaps, the current review evaluates the performance analysis of conventional and advanced sludge treatment methods in eliminating MPs from sludge.

Recent Findings

The review uncovers that the occurrence and characteristics of MPs in SS are highly governed by factors such as population density, speed and level of urbanization, citizens’ daily habits, and treatment units in wastewater treatment plants (WWTPs). Furthermore, conventional sludge treatment processes are ineffective in eliminating MPs from SS and are accountable for the increased small-sized MPs or micro(nano)plastics (MNPs) along with altered surface morphology facilitating more co-contaminant adsorption. Simultaneously, MPs can influence the operation of these treatment processes depending on their size, type, shape, and concentration. The review reveals that research to develop advanced technology to remove MPs efficiently from SS is still at a nascent stage.

Summary

This review provides a comprehensive analysis of MPs in the SS, by corroborating state-of-the-knowledge, on different aspects, including the global occurrence of MPs in WWTP sludge, impacts of different conventional sludge treatment processes on MPs and vice versa, and efficiency of advanced sludge treatment and upcycling technologies to eliminate MPs, which will facilitate the development of mitigation measures from the systematic and holistic level.

Graphical Abstract

Purpose of Review

Neonicotinoids are synthetic insecticides, and among all agrochemicals, they rank second in consumption. The unparalleled use of neonicotinoids in various sectors including agriculture has currently reintroduced them as emerging pollutants/hazards due to their endocrine-disrupting nature. High water solubility, low volatility, and persistent nature have resulted in their accumulation in the environment. Thus, investigating efficient and sustainable methods for the remediation of contaminated environments due to this pollutant is imperative.

Recent Findings.

Bioremediation provides a cost-effective and environment-friendly option over conventional physicochemical techniques that produce toxic byproducts. The microbial route for degradation has the potential to completely mineralize neonicotinoids by virtue of their adaptive and diverse metabolic machinery. Potent microbes such as Ensifer, Phanerochaete, Bacillus, Ochrobactrum, Trametes, Rhodococcus, Sphingobacterium, and Pseudomonas have been isolated and screened for their immense degradation potential, and the metabolites, degradative enzymes, and transformation pathways have been elucidated. The incorporation of modern tools/techniques such as metabolic engineering, microbial biotechnology, omics-based database approaches or systems biology, artificial intelligence, and machine learning can fasten and give better bioremediation results.

Summary

This study has aimed to summarize the processes employed to date to degrade neonicotinoids and present a comprehensive report reflecting past efforts, advances, and future prospects. Therefore, this report will be beneficial in strengthening the understanding of the extent of efforts made for neonicotinoid degradation and how conventional approaches such as bioaugmentation, biostimulation, and biofiltration can be accelerated by advanced technologies viz., omics and machine learning.

Purpose of Review

Microalgae-based photosynthetic algal biofuel cells (PAMFCs) are effective devices for purifying wastewater and fixing carbon, nitrogen, and phosphorus, converting light energy into electricity for integrated bioelectricity, biodiesel feedstock, and more. This paper reviewed the great potential of PAMFC for wastewater treatment and energy utilization, providing new ideas for wastewater treatment and green energy development.

Recent Findings

The concept of the PAMFC is to convert pollutants into bioelectricity by using the metabolic activity of microbial populations in the wastewater, and the microalgae at the cathode make it possible to convert solar energy into green energy. The construction and type of PAMFC, biotic and abiotic factors all have an impact on its wastewater treatment and energy production. Considering the above facts, the drawbacks of PAMFC were summarized and the future development for its application in wastewater treatment and energy use was prospected.

Summary

This paper reviewed the use of PAMFC systems to recover resources in the form of nutrients, bioelectricity, and biodiesel feedstock in wastewater treatment. The selection of reactor configuration, cathode and anode materials, electrogenic microorganisms, and system optimization conditions were analyzed. The limitations of PAMFC in terms of reactor performance and scale in practical production applications were discussed and future directions for PAMFC were proposed.

Purpose of Review

This review article focuses to fulfill the gaps in the available literature on cancer incidence, antineoplastic drug consumption, environmental persistence, and toxicity assessment and provides a better understanding of the evaluation of the risk and difficulties resulting from the emergence of anticancer medications.

Recent Findings

Large amounts of antineoplastic drugs present in water bodies have adverse effects on the environment and human health. As the number of cancer patients continues to grow exponentially, the prevalence of antineoplastic chemicals in aquatic environments is steadily increasing worldwide. The oncology wards at hospitals, pharmaceutical firms, and municipal garbage (from outpatients) are the biggest contributors to the presence of antineoplastic drugs in aquatic environments. When released into the environment, the unmetabolized fraction/derivatives and free radicals of these medicines are more toxic.

Summary

It is evident from the review that the ecotoxicity, mutagenicity, and cytotoxicity are a result of the persistence of antineoplastic drug residual in water bodies. Thus, the presence of such substances in water bodies is detrimental to the health of both aquatic species and humans. The fate of antineoplastic drugs in the environment will also cause an adverse effect on agricultural crops and the soil microflora if the treated wastewater would be used for irrigation purposes.

Purpose of Review

This study was aimed at identifying the differences in the levels of 17 metals and elements (MEs) between fish species (Capoeta tinca and Squalius pursakensis) and fish tissues (muscle, gills, and liver), at identifying the effect of fish gender and fish size (length and weight) on bioaccumulation of MEs in tissues, at assessing both health risks and benefits of MEs in fish muscle, and at defining safe fish consumption quantities for consumers.

Recent Findings

The levels of most MEs in tissues did not differ significantly between both fish species. The gills had higher levels of most MEs than the liver and muscle. Only a few MEs in the tissues of both fish species demonstrated significant associations with fish length or weight. There were no significant differences between male and female fish in terms of the levels of most metals in tissues. The estimated daily intake (EDI) values of metals were below the reference doses. Target hazard quotient (THQ) and hazard index (HI) values were less than 1. Carcinogenic risk (CR) values were within or below the acceptable range. Also, maximum safe fish consumption quantities (MSCQs) were established for consumers.

Summary

Because both fish species were collected from the same water body and had the same habitat preferences, the levels of most MEs did not differ significantly in the tissues of both fish species. Because the gills and liver are metabolically active organs, they had higher levels of MEs than the muscle. The relationships between the levels of MEs in the tissues and fish size were both unclear and inconsistent. The results indicated that ME accumulation in tissues of individuals within the same species was not significantly influenced by gender. The THQ, HI, CR, and EDI values indicated that no adverse health consequences are expected for consumers. It was established that daily consumption of less than 50 g of C. tinca or 80 g of S. pursakensis would not be harmful to consumers’ health. Nutritional evaluation results indicated that both fish species are good sources of essential MEs. Therefore, consumption of the fish species would bring tremendous health benefits.

Purpose of Review

As the initial acceptor of terrigenous microplastics and the primary transporter of marine microplastics, the migration and degradation characteristics of microplastics in surface water need to be better understood. This review aims to summarize the migration and accumulation rules of microplastics in different types of surface water; analyze typical microplastic degradation pathways, and discuss the potential synergistic degradation mechanisms of microplastics in surface water.

Recent Findings

Microplastics was detected in almost all of the surface water. Some significant accumulation of microplastics occurred in local reaches of rivers, lakes, and reservoirs, which was influenced by different environment factors. Though petroleum-based plastics were defined as non-degradable plastics, physical, chemical, and biological degradation pathways of microplastics were constantly verified to occur widely in surface waters. More and more microplastics-degrading microbes, including bacteria, fungi, and even virus, were identified or speculated to directly or indirectly take part in the biodegradation of microplastics. Synergistic degradation processes of microplastics were continuously found in some natural waters, and the mechanisms were explored.

Summary

Multiple sinks of microplastics occurred in the sediments of surface water, such as urban rivers, the mouth of the lake, and reservoirs. The diversity of microplastics-degrading microbes may be much more than what we know previously. This review highlights that there are two scales of synergistic degradation of microplastics, which couple different microbes in the plastispheres and couple biophysical chemical actions in surface water separately. In all, the true degradation potential of microplastics needs to be deeply explored in surface water.

Graphical Abstract

Title: Migration, distribution, and synergistic degradation of microplastics in surface water.

Description: After entering the surface water, microplastics produced by human activities accumulate in different areas through longitudinal, lateral, and vertical migration. At the same time, the synergistic degradation of physical, chemical, and biological microplastics is also taking place, which affects the occurrence of microplastics.

Purpose of Review

The biochar-supported zero valent iron (ZVI-BC) can effectively prevent oxidation and agglomeration of ZVI, and improve the utilization rate of ZVI. Recent reviews of ZVI-BC mainly focus on the preparation methods, characterization techniques, and reaction mechanism with pollutants. Since the structural characteristics of biochar have a great impact on Fe⁰ loading, a comprehensive review of the structural characteristics of biochar is needed to explain its influence on ZVI formation during preparation. And in application of ZVI-BC, the environmental effects on organisms need to be considered. This review of recent research results provides a perspective for understanding the structural characteristics, preparation factors, and ecotoxicity of ZVI-BC.

Recent Findings

The adsorption capacity of ZVI-BC prepared by conventional methods still needs to be improved. The surface-area-normalized reaction rate constant (k_SA) of ZVI-BC can be increased to about 180 times by surface modification, adding a stabilizer, element doping, and other modification methods. Recent research on ecotoxicity has shown mostly positive effects of ZVI-BC on microorganisms, animals, and plants during environmental remediation.

Summary

This work reviews the effect of biochar as a support matrix on Fe⁰ production. The pollutant removal performance is summarized considering the elemental composition, phase components, and surface chemical properties. Also, we discuss the effect of ZVI-BC preparation on contaminant removal and propose methods to optimize the performance of ZVI-BC. The k_SA was used to conduct a meta-analysis of kinetic data to illustrate the properties of ZVI-BC. In addition, we evaluate the ecotoxicity of using ZVI-BC in environmental remediation.

Graphical Abstract

Purpose of Review

The purpose of this review is to summarize the current interactions between functional materials and microalgae, bacteria, and algal-bacterial symbioses in the environment, to analyze the mechanism of interaction between materials and the three, and to explore the development potential of functional materials in the application of algal-bacterial symbioses for better pollutant removal.

Recent Findings

Algal-bacterial symbioses were a more promising means of wastewater treatment, but the efficiency of the treatment needed to be enhanced. Pollutant removal relies mainly on oxidative decomposition nutrient uptake by algal-bacterial symbioses. Some functional materials enhanced the biomass of microalgae by supplementing them with trace elements for growth, regulating their photosynthesis (material conversion spectrum, light capture, and carbon sequestration), stimulating their metabolism, enhancing pigment accumulation, and lipid accumulation, thus indirectly removing pollutants. In addition, the hybrids formed by bacteria and light-absorbing materials were used in the algal-bacterial symbioses via performing artificial photosynthesis for indirect pollutant removal. Thus, the combination of materials with microalgae and bacteria has broader application prospects.

Summary

The introduction of functional materials increased the efficiency of algal-bacterial symbioses in treating pollutants, which was mainly facilitated by increasing microalgal biomass to convert pollutants to algal-bacterial symbioses. This paper reviewed the research process of algal-bacterial symbioses for pollutants treatment and investigated the reaction mechanism of materials with microalgae, bacteria, and algal-bacterial symbioses, respectively. Overall, this review focuses on the development trend of functional materials in algal-bacterial symbioses and provides a reference for their application in algal-bacterial symbiotic system for wastewater treatment.

Socio-economic and environmental factors have led scientific community to find alternative approaches for management of agro-industrial wastes. An integrated approach, i.e., clean biotechnology, could be used for the conversion of agro-industrial wastes into industrial important and less toxic end products. Bacterial cellulose (BC) is an incredibly multifaceted biomaterial with desirable attributes including biodegradability, biocompatibility, great tensile strength, cellulose purity, and porosity. An economical BC production is difficult to owing to the cost of expensive synthetic media. By utilizing processed agro-industrial wastes as media substrate, a sustainable large-scale BC production can be achieved along with an effective waste management strategy. Various types of industrial wastes including crop residues, food industry by-products, distillery effluents, and kitchen wastes are used to produce BC. This review is centered on various aspects of cost-effective BC production using industrial wastes and a wide range of probable substrates with alternative methods for enhanced BC production. Novel applications involving BC in the field of environment, wound healing, drug delivery, dental treatment, etc., with an emphasis on new economic opportunities are also discussed. Overall, this study suggests that integrating different methods and techno-economic analysis would be advantageous to researchers in finding way for sustainable production of BC with reduced environmental pollution for diverse applications.