Current Pollution Reports最新文献

Purpose of Review

This review aims to analyze the effects of the pandemic on the world’s sound environment.

Recent Findings

The confinements associated with the pandemic led to a reduction in sound levels worldwide and a change in the perception of soundscapes in the absence of traffic noise and human-generated noise.

Summary

In response to the COVID-19 pandemic, many countries and regions around the world adopted a series of interventions in 2020 that have been referred to as “lockdown” or “confinement.” These sets of restrictions had a clear and obvious consequence derived from the absence of people in the streets and the reduction of daily activity and commuting, which caused an unprecedented silencing on a large scale. Along with the silence that ensued, the pandemic and the confinements affected acoustics and our relationship with sounds on different scales. In the cities, this phenomenon had a strong reduction in acoustic intensity due to the absence of vehicles on the streets. Perhaps this was more perceptible in our neighborhoods, with notable changes in their soundscapes, first due to the absence of people in the streets and later due to more outdoor activity derived from the fear of the spread of the virus in indoor spaces. The longer periods of time spent in our homes during the lockdowns also highlighted the importance of sound insulation in buildings and the acoustic conditioning of our schools or homes.

Biochar is a stable carbonaceous material obtained on pyrolysing biomass. Although it possesses crucial properties of high surface area, porosity, surface functionality, and sorption capacity, there is immense scope to augment these properties for effective contaminant sorption. Physical and chemical modifications enhance surface area, porosity, and contents of oxygen-containing functional groups. While acidic modifications augment surface functional groups and cation exchange capacity, alkaline modifications increase aromaticity, hydrophobicity, and π-π interactions. Impregnation with metals amplifies magnetic properties, availability of active sites, chemisorption, electrostatic attraction, and complexation. These modifications assist in sorption of cationic and anionic contaminants. Accordingly, the present study reviews modified biochars which promote eco-friendly contaminant removal. Moreover, various biomass and modification methods utilised for modified biochar production have been elaborated along with the changes in physico-chemical properties. Importantly, mechanistic insights into the functional role of modified biochars for removal of contaminants have been provided. Further, the impact of ageing on modified biochars and their contaminant adsorption performance have been discussed. Lastly, the feasibility and limitations of various biochar modification methods in addition to different research gaps have been presented to create a road map for future investigations. Waste management and contaminant remediation are the need of the hour for planet survivability, which could be achieved by precise biochar modification.

Graphical abstract

Purpose of Review

In recent years, anthropogenic activities have caused metal pollution in the sediments of stagnant water bodies, and thus threatening aquatic ecosystems and human health. Therefore, determining the potential ecological risks, contamination degree, and possible sources of metals in sediment of stagnant water bodies is essential for effective management of metal pollution. In this study, we used contamination and risk assessment indices together with multivariate statistics to determine ecological risks and contamination degree of 14 metals in sediments of three important stagnant water bodies (Ladik Lake and Yedikır and Değirmendere dam lakes) in northern Turkey. In addition, the effects of organic matter (OM) and pH on metal accumulation in the sediments were also investigated.

Recent Findings

The mean contents of Al, V, Mn, Fe, Cu, Zn, and Pb did not differ significantly among the water bodies studied (p > 0.05). The Ladik Lake sediments had significantly lower pH level and higher OM content (p < 0.05). Contamination indices indicated that there was no significant metal contamination in the sediments of all water bodies. Similarly, ecological risk indices indicated that metals posed low ecological risks in the water bodies. According to the sediment quality guidelines, metals would not cause harm to benthic organisms. The accumulation of most metals in the Yedikır Dam Lake was controlled by OM, while the distribution of some metals was affected by both OM and pH in the Değirmendere Dam Lake. According to the factor analysis, all metals in the sediments of the water bodies studied mainly originated from natural sources.

Summary

The results of this study revealed that sediment contamination indices, ecological risk assessment methods, sediment quality guidelines, and multivariate statistics can be used as effective approaches in determining the environmental and ecological risks and pollution sources of metals in the sediments of stagnant water bodies. Thus, this study can provide important information for the ecological risk assessment and management of metals in the sediments of stagnant water bodies.

Purpose of Review

Estimating the associations between health effects and source-specific particulate matter (PM) exposure is critical to understand how PM exposure impacts health and to develop effective policies in protecting public health against PM pollution. In this paper, global studies in the past 6 years (07/27/2016 to 06/30/2022) on the associations between source-specific PM exposure and health effects were reviewed to understand the development of source apportionment (SA) technology in the epidemiological studies on PM and health effects. We searched the PubMed database and finally obtained 51 articles.

Recent Findings

The combinations of SA models and epidemiological models were conducted in these studies to address the source-specific health effects. A systematic review of these studies revealed that PM emitted from different sources contributed to those health effects, and these effects varied greatly with regions. Moreover, we discussed the effects of secondary aerosols on health outcomes, the consistency of source and its marker constituents in the effects on health outcomes, exposure error and spatial misclassification of the source exposure, and future applications of the SA technologies in epidemiological studies.

Summary

More studies in the different regions on health effects associated with source-specific PM are required to determine how source-specific exposure impacts health.

Purpose of Review

The increasing use of engineered nanoparticles (ENPs) has led to growing concerns about their environmental impacts. It has become a focus for researchers to explore their detection, quantification, as well as their fate and transport, and hence their ecotoxicity. A review of recent findings sets a basis for current knowledge of ENP levels in the surface water environment and provides a perspective to understand their toxicity.

Recent Findings

Among the various mechanisms of toxicity that have been evidenced by recent research, an important mechanism that is shared by multiple ENPs is the generation of reactive oxygen species (ROS) and subsequent oxidative stress. Another common toxic effect is cell membrane damage from physical encounters or ENPs adsorbing onto the membrane. The ecotoxicity of ENPs is dependent on many factors; however, the ENP’s physiochemical characteristics and functional behavior are two main groups. Additionally, the chemical composition and charge of ENPs are greatly influencing their toxicity.

Summary

A critical overview of updated knowledge on the regulatory standards, environmental detection, and aquatic fate and ecotoxicity of ENPs with a special focus on the most environmentally affluent nanosized titanium dioxide (n-TiO₂), cerium dioxide (n-CeO₂), zinc oxide (n-ZnO), silicon dioxide (SiO₂), silver (n-Ag), and carbon nanotubes (CNTs) is presented in this article. Among the ENPs reviewed, n-Ag and n-TiO₂ are more studied and the most ecotoxic; n-Ag dissociates into cations (Ag +) causing significant harm to organisms and cells, while light and pH notably influence the toxicity of n-TiO₂.

Road traffic noise is one of the major environmental pollutants in cities around the world that continues to increase over the years despite the implementation of regulatory policies. The lack of engagement of national governments, the use of different or inadequate methodologies and the absence of implementation of measures to control road traffic noise are some of the causes why the population exposed to noise has not been reduced. There are a large number of recommendations, methodologies and procedures for adequate road traffic noise analysis and management in the scientific literature. The aim of this paper is to analyse the main findings of recent years with the objective of highlighting the current acoustic situation and to provide tools that can reverse it. Development of accurate noise analysis methods is close to reality. However, greater engagement and control by the authorities is needed for the implementation and efficiency of noise measures.

Purpose of Review

Digested manure effluent is a potential resource for the production of liquid organic fertilizer and reused water. The purpose of this review is to provide a comprehensive understanding on the advances and challenges to high-value processing and utilization for digested manure effluent treatment.

Recent Findings

The main problem that restricts the utilization of digested manure effluent is that there is not enough land for consumption. Reasonable and efficient treatment of digested manure effluent is the key to promoting healthy development and sustainable operation. Digested manure effluent can increase yield, improve quality, and enhance the stress resistance of crops. In addition, digested manure effluent can also be used in seed soaking and feed applications. Membrane treatment techniques for the concentration of digested manure effluent can recover water and produce liquid fertilizer. It mainly includes pressure-driven membrane, osmotic-driven membrane, membrane distillation, and their combined technologies. However, membrane concentration of digested manure effluent still has challenges such as high cost and membrane fouling that restrict development. Thus, several potential approaches have been proposed to address these challenges. These approaches can be largely classified as pretreatment, process optimization, and government-guided source control.

Summary

In this paper, we critically reviewed the properties and utilization of digested manure effluent. Meanwhile, the performance of different membrane concentration processes was provided. Furthermore, key technical challenges of high-value processing and their potential countermeasures were delineated.

Purpose of Review

Home composting is an effective way to treat household waste, but global uptake remains low because of insufficient recognition and technical limits. This review aims to promote the understanding, popularization, and application of home composting by summarizing the facilities, process performance, and product quality, and to sum up the crucial technical limits and potential solve methods.

Recent Findings

Home composting studies are carried out in 20–1200 L composters for 3–12 months with kitchen and garden feedstocks. During the process, emission amounts of methane (CH₄), nitrous oxide (N₂O), and ammonia (NH₃) are 0.002–2185 kg/Mg FW, 0.004–454 kg/Mg FW, and 0.025–972 kg/Mg FW, respectively. The thermophilic stage in home composting is insufficient for harmless requirement, while the home composting products could meet the standards for the use of organic fertilizer when the basic physical and chemical indicators, biological indicators, spectral indicators, and other indices are carried out in lab. Home composting products are non-toxic to plants and can promote plant growth. The crucial technical limits are caused by slow degradation of organic matter (OM), emission of greenhouse gases (GHGs) and a lack of maturity evaluation standard and directive for subsequent product utilization.

Summary

Suitable technology and evaluation standard could reduce gas emissions and improve maturity of home composting, which would provide an additional method for existing municipal waste management, therefore reducing the transportation and collection cost of household waste, and realizing the reduction, harmless, and resource recovery.

Purpose of Review

The concern of mercury pollution and the impact that it poses on the marine environment were studied heavily since the case of the poison from Minamata bay in the 1960s. The present study provides an insight into the cycle of mercury and methylmercury in the marine environment and the bioindicators that reflect the exposure levels. The paper also used the driving forces, pressures, states, impacts, and responses (DPSIR) analysis to evaluate the global mercury and methylmercury contamination problem.

Recent Findings

The high global budgets of atmospheric total mercury influence the ocean surface water. Therefore, the aquatic environment contamination level is in turn affected by the surrounding emission sources such as industrial and petroleum activities in addition to the transport and fate of mercury across the environmental compartments. This will increase the mercury levels in fish species and will cause an adverse risk to human health through biomagnification.

Summary

This review presents a thorough description of mercury sources and emissions and their fate and transport across the different environmental compartments, despite the fact that serious mitigation measures were taken and guidelines were applied. The risk from fish consumption is still a serious concern as a result of the current mercury emissions and stability and persistent characteristics.

Purpose of Review

This review aims to summarize the occurrence of Cryptosporidium spp. and Giardia spp. in the reclaimed water and their risks in different reuse scenarios, analyze the drawbacks of protozoa detection methods, compare the removal efficiencies of different water treatment technologies, and propose potential management measures.

Recent Findings

Cryptosporidium spp. and Giardia spp. are widely present in the wastewater in the last decade, and the reclaimed water is usually used in agricultural irrigation, recreational activities, and urban reuse. The risks of protozoa infection are generally higher than the WHO defined 10⁻⁴ threshold in agriculture and recreational reuse and partial urban practices. The direct potable reuse with multiple advanced treatments has relatively low risk, while the indirect potable reuse is more risky due to the low removal efficiency of traditional drinking water treatment process. The newest protozoa detection standard applies a cheap way to measure (oo)cysts in high-turbidity water. But it still cannot distinguish live and dead (oo)cysts, and cannot identify pathogenic species. These defects result in the overestimation of the health risks. Potential solutions with fluorescence dye and molecular tools are proposed. About 4-log reduction is needed for agriculture and recreational scenarios with advanced treatments. While for urban reuse, lower log reduction might be achieved by secondary treatment with disinfection.

Summary

This review highlights the potential biorisks of Cryptosporidium spp. and Giardia spp. of the reclaimed water in various reuse scenarios and possible countermeasures to improve the safety issue. Suggestions for more accurate risk assessment and management strategies of protozoa control are proposed.