Efficiency of Wastewater Treatment Plants (WWTPs) for Microplastic Removal: A Systematic Review

Occurrence, bioaccumulation, fate, and risk assessment of emerging pollutants in aquatic environments: A review

Significant concerns on a global scale have been raised in response to the potential adverse impacts of emerging pollutants (EPs) on aquatic creatures. We have carefully reviewed relevant research over the past 10 years. The study focuses on five typical EPs: pharmaceuticals and personal care products (PPCPs), per- and polyfluoroalkyl substances (PFASs), drinking water disinfection byproducts (DBPs), brominated flame retardants (BFRs), and microplastics (MPs). The presence of EPs in the global aquatic environment is source-dependent, with wastewater treatment plants being the main source of EPs. Multiple studies have consistently shown that the final destination of most EPs in the water environment is sludge and sediment. Simultaneously, a number of EPs, such as PFASs, MPs, and BFRs, have long-term environmental transport potential. Some EPs exhibit notable tendencies towards bioaccumulation and biomagnification, while others pose challenges in terms of their degradation within both biological and abiotic treatment processes. The results showed that, in most cases, the ecological risk of EPs in aquatic environments was low, possibly due to potential dilution and degradation. Future research topics should include adding EPs detection items for the aquatic environment, combining pollution, and updating prediction models.

Microplastic contamination in wastewater: Sources, distribution, detection and remediation through physical and chemical-biological methods

Microplastics are tiny plastic particles smaller than 5 mm. that have been widely detected in the environment, including in wastewater. They originate from various sources including breakdown of larger plastic debris, release of plastic fibres from textiles, and microbeads commonly used in personal care products. In wastewater, microplastics can pass through the treatment process and enter the environment, causing harm to biodiversity by potentially entering the food chain. Additionally, microplastics can act as a vector for harmful pollutants, increasing their transport and distribution in the environment. To address this issue, there is a growing need for effective wastewater treatment methods that can effectively remove microplastics. Currently, several physical and chemical methods are available, including filtration, sedimentation, and chemical degradation. However, these methods are costly, low efficiency and generate secondary pollutants. Furthermore, lack of standardization in the measurement and reporting of microplastics in wastewater, makes it difficult to accurately assess microplastic impact on the environment. In order to effectively manage these issues, further research and development of effective and efficient methods for removing microplastics from wastewater, as well as standardization in measurement and reporting, are necessary to effectively manage these detrimental contaminants.

Microplastic removal in managed aquifer recharge using wastewater effluent

Microplastic (MP) pollution has emerged as a pressing environmental issue, with its impacts on ecosystems and human health yet to be fully understood. This study aims to investigate the presence and distribution of MPs in the soil of a managed aquifer recharge (MAR) system, built with different reactive barriers of natural materials and irrigated with the secondary effluent of a wastewater treatment plant (WWTP). MPs were extracted from reactive barrier material following an approach based on the density separation of MPs with posterior oxidant digestion, combined with visual and chemical characterisation by Fourier-Transform Infrared Spectroscopy (FTIR). The results revealed the widespread occurrence of MPs in the MAR soil samples. MPs concentration in the different barrier materials ranged from 60 to 236 n kg-1. The most dominant morphologies were fragments (60%) and fibers (17%), and the most abundant colour was white (51%), followed by transparent MPs (20%). Polypropylene (PP) was detected in all the samples with an abundance of 47%, followed by polyethylene (PE, 34%). The interplay of barrier composition significantly influences the retention of MPs, with compost (T5) and woodchips (T4) exhibiting the most notable retention rates. Remarkably, the outer layers of the reactive barriers display superior retention compared to the deeper layers. The findings of this study demonstrate the good performance of the MAR system in retaining MPs and contribute to the growing body of knowledge on MPs pollution in freshwater systems while providing insights into the dynamics of MPs transport and accumulation in soil. Such information can inform the development of effective wastewater management strategies to mitigate the impacts of these pollutants on water resources and safeguard the environment.

Repair mechanism of Yishen Tongluo formula on mouse sperm DNA fragmentation caused by polystyrene microplastics

CONTEXT

Plastics can break down into millions of microplastic (MPs, < 5 mm) particles in the soil and ocean. These MPs can then affect the function of the reproductive system. There is currently no effective solution to this problem aside from traditional Chinese medicine. We have previously used Yishen Tongluo formula (YSTL) to treat sperm DNA damage caused by some toxic substances.

OBJECTIVE

To investigate the mechanism underlying the repair of mouse sperm DNA fragmentation caused by polystyrene microplastics by YSTL.

MATERIALS AND METHODS

An animal model of polystyrene microplastic (PS-MP)-induced sperm DNA damage was replicated by gavage of SPF ICR (CD1) mice PS-MPs at 1 mg/d and treated with YSTL at 11.89, 23.78 and 47.56 g/kg, respectively, for 60 days. The Sperm DNA fragmentation index (DFI) of each group was detected and compared. The target genes of YSTL identified by transcriptomic and proteomic analyses were validated by qRT-PCR and western blotting.

RESULTS

The DFI of the PS group (20.66%) was significantly higher than that of the control group (4.23%). The medium and high doses of the YSTL group (12.8% and 11.31%) exhibited a significant repairing effect. The most enriched pathway was PI3K/Akt. TBL1X, SPARC, hnRNP0, Map7D1, Eps8 and Mrpl27 were screened and SPARC was validated.

DISCUSSION AND CONCLUSIONS

The precise mechanism by which YSTL inhibits PD-MPs DNA damage may be associated with the PI3K/Akt pathway and SPARC. It provides a new direction for using traditional Chinese medicine to prevent and repair reproductive system injury caused by MPs.

A critical review on remediation of microplastics using microalgae from aqueous system

Microplastics (MPs) are deemed to be a global concern due to their harmful negative effects on the aquatic environment and human beings. MPs have a significant impact on both fresh and marine water ecosystems. In many countries, there is concern about the deleterious consequences of MPs on human health due to the presence of MPs in aquatic life for higher intake of marine food (fish and shellfish). Exposure to MPs causes fish to suffer from growth retardation, neurotoxicity, and behavioural abnormalities and it affects human as well. It causes oxidative stress, neurotoxicity, cytotoxicity, and immune system disruption after being ingested to these contaminated fish in human body. Due to these reasons, it has become imperative to find ways to resolve this problem. This review paper represents a pioneering endeavor by consolidating comprehensive information on microplastic-polluted Indian riverine ecosystems and effective MPs removal methods into a single, cohesive document. It meticulously evaluates the principles, removal efficiency, benefits, and drawbacks of various techniques, aiming to identify the most optimal solution. Furthermore, this paper provides a comprehensive exploration of the interesting interactions between MPs and microalgae, delving into the intricate processes of hetero-aggregation. Additionally, it shines a spotlight on the latest advancements in understanding the efficacy of microalgae in removing MPs, showcasing recent breakthroughs in this field of research. Moreover, the work goes beyond conventional assessments by elucidating the characteristics of MPs and exploring diverse influencing parameters that impact MPs removal by microalgae and also addresses the potential future aspects. This thorough investigation uncovers important factors that could significantly contribute to the development of more efficient and sustainable remediation strategies.

Microplastics (≤ 10 μm) bioaccumulation in marine sponges along the Moroccan Mediterranean coast: Insights into species-specific distribution and potential bioindication

Microplastics (MPs) are pervasive in marine environments and widely recognized as emerging environmental pollutants due to the multifaceted risks they exert on living organisms and ecosystems. Sponges (Phylum Porifera) are essential suspension-feeding organisms that may be highly susceptible to MPs uptake due to their global distribution, unique feeding behavior, and sedentary lifestyle. However, the role of sponges in MP research remains largely underexplored. In the present study, we investigate the presence and abundance of MPs (≤10 μm size) in four sponge species, namely Chondrosia reniformis, Ircinia variabilis, Petrosia ficiformis, and Sarcotragus spinosulus collected from four sites along the Mediterranean coast of Morocco, as well as their spatial distribution. MPs analysis was conducted using an innovative Italian patented extraction methodology coupled with SEM-EDX detection. Our findings reveal the presence of MPs in all collected sponge specimens, indicating a pollution rate of 100%. The abundance of MPs in the four sponge species ranged from 3.95×105 to 1.05×106 particles per gram dry weight of sponge tissue, with significant differences observed among sampling sites but no species-specific differences. These results imply that the uptake of MPs by sponges is likely influenced by aquatic environmental pollution rather than the sponge species themselves. The smallest and largest MPs were identified in C. reniformis and P. ficiformis, with median diameters of 1.84 μm and 2.57 μm, respectively. Overall, this study provides the first evidence and an important baseline for the ingestion of small MP particles in Mediterranean sponges, introducing the hypothesis that they may serve as valuable bioindicators of MP pollution in the near future.

Fate and transformation of microplastics due to electrocoagulation treatment: Impacts of polymer type and shape

The prevalence and adverse impacts of microplastics requires the identification of science-based abatement measures. Electrocoagulation treatment is a cost-effective oxidation process that removes numerous pollutants, including to some extent, microplastics. The performance of a custom-built electrocoagulation reactor was determined by calculating the removal efficiency. The effects of the oxidation process on polymer types (polyamide (PA), polyethylene (PE), polyethylene terephthalate (PET) and polypropylene (PP)) and shapes (fibres and fragments) were investigated in synthetic wastewater and laundry wastewater. The calculated removal efficiency suggested that electrocoagulation treatment was an effective technology for microplastics abatement. More fibres tended to be removed than fragments, viz. 92% fibres removed versus 88% fragments. The findings also demonstrated that specific polymers were preferentially removed, viz. PET > LDPE > PP > PA. Further analysis indicated that the electrocoagulation treatment affected microplastic polymers physically, viz. flaking and changed surface conditions, as well as chemically, viz. changes in vibrational energies of C-O-C stretching bonds, C=O stretching bonds, C-H stretching bonds and formation of reactive oxygen species (ROS). Our findings indicate that whilst seemingly effective, electrocoagulation treatment induces changes to microplastic polymers that could beneficially lead to degradation, and/or further fragmentation or breakdown and thereby potentially generating more bioavailable toxic nanoplastic byproducts.

Estimation of microplastic emission and transfer into Tokyo Bay, Japan, using material flow analysis

To reduce microplastic (MP) discharge into the aquatic environment, it is necessary to properly identify its sources and amounts. Here, specific MP sources, i.e., personal care products (PCPs), fibers from clothes, and tire-wear particles (TWPs) were focused, and MP generations from these sources in the Tokyo Bay watershed, Japan, were estimated based on statistical data on production and reported emission factors of the MP sources and executing considering uncertainty on the data. Potential annual MP emission into Tokyo Bay was estimated to be 10.2 ± 1.6, 38 ± 22, and 1500-1800 tons for PCPs, fibers, and TWPs, respectively. Emissions into Tokyo Bay by assuming MP density and diameter was estimated. For fiber, the fraction to potential emission was estimated at 1.0-2.8 %. This study contributes to determining potential discharge pathways. This will assist in the application of appropriate measures to reduce MP discharge into water bodies.

Trophic niche influences ingestion of micro- and mesoplastics in pelagic and demersal fish from the Western Mediterranean Sea

Plastic pollution has been extensively documented in the marine food web, but targeted studies focusing on the relationship between microplastic ingestion and fish trophic niches are still limited. In this study we investigated the frequency of occurrence and the abundance of micro- and mesoplastics (MMPs) in eight fish species with different feeding habits from the western Mediterranean Sea. Stable isotope analysis (δ13C and δ15N) was used to describe the trophic niche and its metrics for each species. A total of 139 plastic items were found in 98 out of the 396 fish analysed (25%). The bogue revealed the highest occurrence with 37% of individuals with MMPs in their gastrointestinal tract, followed by the European sardine (35%). We highlighted how some of the assessed trophic niche metrics seem to influence MMPs occurrence. Fish species with a wider isotopic niche and higher trophic diversity were more probable to ingest plastic particles in pelagic, benthopelagic and demersal habitats. Additionally, fish trophic habits, habitat and body condition influenced the abundance of ingested MMPs. A higher number of MMPs per individual was found in zooplanktivorous than in benthivore and piscivorous species. Similarly, our results show a higher plastic particles ingestion per individual in benthopelagic and pelagic species than in demersal species, which also resulted in lower body condition. Altogether, these results suggest that feeding habits and trophic niche descriptors can play a significant role in the ingestion of plastic particles in fish species.

Microplastics in aquatic environments: A comprehensive review of toxicity, removal, and remediation strategies

The occurrence of microplastics (MPs) in aquatic environments has been a global concern because they are toxic and persistent and may serve as a vector for many legacies and emerging pollutants. MPs are discharged to aquatic environments from different sources, especially from wastewater plants (WWPs), causing severe impacts on aquatic organisms. This study mainly aims to review the Toxicity of MPs along with plastic additives in aquatic organisms at various trophic compartments and available remediation methods/strategies for MPs in aquatic environments. Occurrences of oxidative stress, neurotoxicity, and alterations in enzyme activity, growth, and feeding performance were identical in fish due to MPs toxicity. On the other hand, growth inhibition and ROS formation were observed in most of the microalgae species. In zooplankton, potential impacts were acceleration of premature molting, growth retardation, mortality increase, feeding behaviour, lipid accumulation, and decreased reproduction activity. MPs togather with additive contaminants could also exert some toxicological impacts on polychaete, including neurotoxicity, destabilization of the cytoskeleton, reduced feeding rate, growth, survivability and burrowing ability, weight loss, and high rate of mRNA transcription. Among different chemical and biological treatments for MPs, high removal rates have been reported for coagulation and filtration (>86.5 %), electrocoagulation (>90 %), advanced oxidation process (AOPs) (30 % to 95 %), primary sedimentation/Grit chamber (16.5 % to 58.84 %), adsorption removal technique (>95 %), magnetic filtration (78 % to 93 %), oil film extraction (>95 %), and density separation (95 % to 100 %). However, desirable extraction methods are required for large-scale research in MPs removal from aquatic environments.

Estimating Microplastics related to Laundry Wash and Personal Care Products released to Wastewater in Major Estonian Cities: a comparison of calculated and measured microplastics

Microplastics (MPs) research still at the budding stage in Estonia. A theoretical model build on substance flow analysis principles was developed. The goal of this study is to broaden understanding of MPs-types in wastewater and their contribution from known sources, quantify their presence based on model prediction and in-situ measurements. The authors estimate MPs from laundry wash (LW) and personal care products (PCPs)) in wastewater in Estonia. We found out that total estimated MPs load per capita from PCPs and LW in Estonia were between 4.25 - 12 tons/year, 3.52 - 11.24 tons / year respectively, and estimated load ended up in wastewater were between 700 - 30,000 kg/yr. and 2 - 1500 kg/yr. in WWTPs influent and effluent stream respectively. Finally. We conducted a comparison between estimated MPs load and on-site sample analysis and observed a medium-high level of MPs being discharged into the environment annually. During quantification and chemical characterization using µFTIR analysis, we found that microfibers with a length of 0.2-0.6 mm accounted for over 75% of the total MPs load in the effluent samples collected from four coastal WWTPs in Estonia. The estimation avails us broader overview about the theoretical MPs load in wastewater and gain valuable insight into developing process methods that prevent MPs accumulation in sewage sludge for safe application in agriculture.

Research status and prospects of microplastic pollution in lakes

As an emerging pollutant, microplastics have attracted widespread concern around the world. Research on microplastics was first conducted in oceans, and in recent years, inland water, especially lakes, has gradually become a hot spot. This paper systematically reviews the sampling, separation, purification, and identification technologies used to assess microplastics in lakes and summarizes the occurrence of lake microplastics worldwide. The results show that microplastics are widespread in lake water and sediment. There are obvious geographical differences in the occurrence of microplastics. The abundance of microplastics in different lakes varies greatly. The forms are mostly fibrous and fragments, and the main polymers are polypropylene (PP) and polyethylene (PE). Previous papers have failed to comment in as much detail on the microplastic sampling techniques employed within lake systems. The sampling and analysis methods are critical to accurately evaluating contamination results. Due to the widespread presence of microplastics and the lack of uniform standards, there are various sampling methods. Trawls and grabs are most widely used in the sampling of lake water bodies and sediment, and sodium chloride and hydrogen peroxide are the most widely used media for flotation and digestion, respectively. In the future, it will be critical to establish unified standards for lake microplastic sampling and analysis technology, further explore the migration mechanism of microplastics in lake systems, and pay attention to the impact of microplastics on lake ecosystems.

Prevalence and implications of microplastics in potable water system: An update

Synthetic plastics, which are lightweight, durable, elastic, mouldable, cheap, and hydrophobic, were originally invented for human convenience. However, their non-biodegradability and continuous accumulation at an alarming rate as well as subsequent conversion into micro/nano plastic scale structures via mechanical and physio-chemical degradation pose significant threats to living beings, organisms, and the environment. Various minuscule forms of plastics detected in water, soil, and air are making their passage into living cells. High temperature and ambient humidity increase the degradation potential of plastic polymers photo-catalytically under sunlight or UV-B radiations. Microplastics (MPs) of polyethylene terephthalate, polyethylene, polystyrene, polypropylene, and polyvinyl chloride have been detected in bottled water. These microplastics are entering into the food chain cycle, causing serious harm to all living organisms. MPs entering into the food chain are usually inert in nature, possessing different sizes and shapes. Once they enter a cell or tissue, it causes mechanical damage, induces inflammation, disturbs metabolism, and even lead to necrosis. Various generation routes, types, impacts, identification, and treatment of microplastics entering the water bodies and getting associated with various pollutants are discussed in this review. It emphasizes potential detection techniques like pyrolysis, gas chromatography-mass spectrometry (GC-MS), micro-Raman spectroscopy, and fourier transform infrared spectroscopy (FT IR) spectroscopy for microplastics from water samples.

Environmental microplastics exposure decreases antioxidant ability, perturbs gut microbial homeostasis and metabolism in chicken

The widespread presence and accumulation of microplastics (MPs) in organisms has led to their recognition as a major global ecological issue. There is a lot of data on how MPs affect the physiology and behavior of aquatic species, but the effects of MPs on poultry are less understood. Therefore, we aimed to explore the adverse effects and mechanisms of MPs exposure to chicken health. Results indicated that MPs exposure decreased growth performance and antioxidant ability and impaired chickens' intestine, liver, kidney, and spleen. Additionally, the gut microbiota in chickens exposed to MPs showed a significant decrease in alpha diversity, accompanied by significant alternations in taxonomic compositions. Microbial taxonomic investigation indicated that exposure to MPs resulted in a significant increase in the relative proportions of 11 genera and a distinct decline in the relative percentages of 3 phyla and 52 genera. Among decreased bacterial taxa, 11 genera even couldn't be detected in the gut microbiota of chickens exposed to MPs. Metabolomics analysis indicated that 2561 (1190 up-regulated, 1371 down-regulated) differential metabolites were identified, mainly involved in 5 metabolic pathways, including D-amino acid metabolism, ABC transporters, vitamin digestion and absorption, mineral absorption, and histidine metabolism. Taken together, this study indicated that MPs exposure resulted in adverse health outcomes for chickens by disturbing gut microbial homeostasis and intestinal metabolism. This study also provided motivation for environmental agencies worldwide to regulate the application and disposal of plastic products and decrease environmental contamination.

Microplastics in sewage sludge: Distribution, toxicity, identification methods, and engineered technologies

Microplastic pollution is becoming a global challenge due to its long-term accumulation in the environment, causing adverse effects on human health and the ecosystem. Sludge discharged from wastewater treatment plants (WWTPs) plays a critical role as a carrier and primary source of environmental microplastic contamination. A significantly average microplastic variation between 1000 and 301,400 particles kg^-1 has been reported in the sludge samples. In recent years, advanced technologies have been successfully applied to address this issue, including adsorption, advanced oxidation processes (AOPs), and membrane bioreactors (MBRs). Adsorption technologies are essential to utilizing novel adsorbents (e.g., biochar, graphene, zeolites) for effectively removing MPs. Especially, the removal efficiency of polymer microspheres from an aqueous solution by Mg/Zn modified magnetic biochars (Mg/Zn-MBC) was obtained at more than 95%. Also, advanced oxidation processes (AOPs) are widely applied to degrade microplastic contaminants, in which photocatalytic by semiconductors (e.g., TiO₂ and ZnO) is a highly suitable approach to promote the degradation reactions owing to strongly hydroxyl radicals (OH*). Biological degradation-aided microorganisms (e.g., bacterial and fungal strains) have been reported to be suitable for removing microplastics. Yet, it was affected by biotic and abiotic factors of the environmental conditions (e.g., pH, light, temperature, moisture, bio-surfactants, microorganisms, enzymes) as well as their polymer characteristics, i.e., molecular weight, functional groups, and crystallinity. Notably, membrane bioreactors (MBRs) showed the highest efficiency in removing up to 99% microplastic particles and minimizing their contamination in sewage sludge. Further, MBRs illustrate the suitability for treating high-strength compounds, e.g., polymer debris and microplastic fibers from complex industrial wastewater. Finally, this study provided a comprehensive understanding of potential adverse risks, transportation pathways, and removal mechanisms of microplastic, which full-filled the knowledge gaps in this field.

A case study on small-size microplastics in water and snails in an urban river

Microplastic pollution has become pervasive in aquatic ecosystems. They readily interact with aquatic biota, potentially subjecting them to ecological and health risks. Urban rivers are also affected by microplastics due to intense anthropogenic activity. Nevertheless, relatively little is known about the physiocochemistry or ecotoxicology of microplastics in urban rivers. The present study used laser direct infrared chemical imaging to investigate microplastic pollution in a highly urbanized river in Beijing, China. Surface water was sampled at five sites along the river in March and July, and the benthic snail Bellamya aeruginosa was also collected at each location in July. Thirteen and fifteen different polymers were detected and identified in the surface water sampled in March and July, respectively. Thirteen different polymers were found and isolated in the snails. Of these, polypropylene, polyamide and polyethylene predominated in the microplastic particles. Moreover, the average abundance of the microplastic was significantly higher in the surface water sampled in July (39.55 ± 4.78 particles L^-1) than in March (22.00 ± 4.87 particles L^-1) (p < 0.05). The average microplastic abundance of snails across all sites was 28.13 ± 4.18 particles, among which the Q2 site has significantly higher microplastic abundance than station Q3-Q5 (p < 0.05). Microplastic particles 10-100 μm in size predominated in both the surface water and the snails. By contrast, the proportions of microplastic particles 200-500 μm in size were substantially smaller. The measured microplastic pollution load and microplastic pollution risk indices in the surface water indicated that the current microplastic pollution level in the Qing River was moderate from upstream to downstream. Moreover, the potential adverse effects of microplastic particles on snails remain unclear. Further research is required to elucidate small-size microplastics' environmental fate and potential ecological risks in urban rivers.

Biological Activated Sludge from Wastewater Treatment Plant before and during the COVID-19 Pandemic

The COVID-19 pandemic and the related measures brought a change in daily life that affected the characteristics of the municipal wastewater and further, of the biological activated sludge. The activated sludge process is the most widely used biological wastewater treatment process in developed areas. In this paper, we aim to show the situation of specific investigations concerning the variation of the physicochemical parameters and biological composition of the activated sludge from one conventional wastewater treatment plant from a metropolitan area. The investigations were carried out for three years: 2019, 2020 and 2021. The results showed the most representative taxa of microorganisms: Microtrix, Aspidisca cicada, Vorticella convallaria, Ciliata free of the unknown and Epistylis and Rotifers. Even if other microorganisms were found in the sludge flocs, their small presence did not influence in any way the quality of the activated sludge and of the wastewater treatment process. That is why we conclude that protozoa (especially Flagellates and Ciliates) and rotifers were the most important. Together with the values and variation of the physicochemical parameters, they indicated a good, healthy, and stable activated sludge, along with an efficient purifying treatment process, no matter the loading conditions.

In-depth characterization revealed polymer type and chemical content specific effects of microplastic on Dreissena bugensis

In aquatic ecosystems, filter feeders like mussels are particularly vulnerable to microplastics (MP). However, little is known about how the polymer type and the associated properties (like additives or remaining monomers) of MP impact organisms, as the predominant type of MP used for effect studies on the organismic level are micron grade polystyrene spheres, without considering their chemical composition. Therefore, we exposed the freshwater mussel Dreissena bugensis (D. bugensis) to in-depth characterized fragments in the same concentration and size range (20-120 µm): recycled polyethylene terephthalate from drinking bottles, polyamide, polystyrene, polylactic acid, and mussel shell fragments as natural particle control. Real-time valvometry, used to study behavioral responses via the movement of the mussels' valves, showed that mussels cannot distinguish between natural and MP particles, and therefore do not cease their filtration, as when exposed to dissolved pollutants. This unintentional ingestion led to polymer type-dependent adverse effects (activity of antioxidant enzymes and proteomic alterations), related to chemicals and residual monomers found in MP. Overall, recycled PET elicited the strongest negative effects, likely caused by anthranilamide, anthranilonitrile and butylated hydroxytoluene, contained in the fragments, which are toxic to aquatic organisms. As PET is among the most abundant MP in the environment, sublethal effects may gradually manifest at the population level, leading to irreversible ecosystem changes.

Modifications of microplastics in urban environmental management systems: A review

Microplastics (MPs) are a worldwide environmental pollution issue. Besides the natural environmental stresses, various treatments in urban environmental management systems induce modifications on MPs, further affecting their environmental behavior. Investigating these modifications and inherent mechanisms is crucial for assessing the environmental impact and risk of MPs. In this review, up-to-date knowledge regarding the modifications of MPs in urban environmental management systems was summarized. Variations of morphology, chemical composition, hydrophilicity and specific surface area of MPs were generalized. The aging and degradation of MPs during drinking water treatment, wastewater treatment, sewage sludge treatment and solid waste treatment were investigated. A high abundance of MPs occurred in sewage sludge and aging solid waste, while digestion and composting contributed to significant decomposition and reduction of MPs. These treatments have become converters for MPs before entering the environment. Several novel technologies for MPs removal were listed; However, no appropriate methods can be put into actual application by now, except the membrane separation. The corresponding effects of degradation on the behaviors of MPs, including adsorption, sinking and contaminant leakage, were discussed. Finally, three priorities for research were proposed. This critical review provides viewpoints and references for risk evaluation of MPs after treatments in urban environmental management systems.

Trace elements in the muscle tissue of Hemiculter leucisculus and Abramis brama orientalis from the Anzali International wetland, south-west of Caspian Sea: An exposure risk assessment

High levels of trace elements in aquatic environments can affect the quality of seafood. We analyzed the concentrations of As, Cd, Co, Hg, Mn, Ni and Pb, in the edible muscles of Hemiculter leucisculus and A. brama orientalis caught in four different areas of southwest of the Caspian Sea. We estimated the potential risks for human health deriving by the oral consumption of these two species, and the Target Hazard Quotient (THQ) according to the US-EPA approach. THQ by adults and children was always below 1 for all stations. The greater contribution was given by Co, followed by Cd, Hg, Pb, Ni, As and Mn. Total-THQ was 0.538 and 0.246 for children and adults, respectively. Trace elements detected by our study were not elevated, highlighting a positive picture of the studied area and a lower risk of developing chronic systemic effects deriving from the consumption of local fish products.

Identification and Quantification of Microplastics in Effluents of Wastewater Treatment Plant by Differential Scanning Calorimetry (DSC)

In this research, the presence of microplastics was detected through a differential scanning calorimetry (DSC) analysis of three wastewater treatment plants. One of these plants applied only a preliminary treatment stage while the others applied up to a secondary treatment stage to evaluate their effectiveness. The results showed the presence of polyethylene (PE), polystyrene (PS), polypropylene (PP) and polyethylene terephthalate (PET), which were classified as fragments, fibers or granules. During the evaluation of the plants, it was determined that the preliminary treatment did not remove more than 58% of the microplastics, while the plants applying up to a secondary treatment with activated sludge achieved microplastic removal effectiveness between 90% and 96.9%.

Country-Specific Environmental Risks of Fragrance Encapsulates Used in Laundry Care Products

Fragrance encapsulates (FEs) are designed to deliver fragrance components, notably in laundry care products. They are made of thermoset polymeric shells surrounding the fragrance content. These materials enter the environment mainly during laundry washing, but little is known about their distribution in and impact on the environment. The aim of the present study was to estimate the environmental concentrations of FE shells in freshwater, sediment, and soil compartments for 34 selected countries and to compare them with ecotoxicological effects. Probabilistic material flow analysis was used to estimate worst-case predicted environmental concentrations (PECs). The lowest freshwater PEC was predicted for Finland (0.00011 µg/L) and the highest for Belgium (0.13 µg/L). Accumulation of FE shells between 2010 and 2019 was considered for sediments and sludge-treated soils. The PECs in sediments ranged from 3.0 µg/kg (Finland) to 3400 µg/kg (Belgium). For sludge-treated soil, the concentration was estimated to be between 0 (Malta and Switzerland) and 3600 µg/kg (Vietnam). Ecotoxicological tests showed no effects for FE shells at any tested concentration (up to 2700 µg/L freshwater, 5400 µg/kg sediment, and 9100 µg/kg soil), thus not allowing derivation of a predicted-no-effect concentration (PNEC). Therefore, to characterize the environmental risks, the PEC values were compared with highest-observed-no-effect concentrations (HONECs) derived from ecotoxicological tests. The PEC/HONEC ratios were 9.3 × 10^-6 , 0.13, and 0.04 for surface waters, sediments, and sludge-treated soils, respectively, which are much below 1, suggesting no environmental risk. Because the PEC values constitute an upper boundary (no fate considered) and the HONEC values represent a lower boundary (actual PNEC values based on NOECs will be higher), the current risk estimation can be considered a precautionary worst-case assessment. Environ Toxicol Chem 2022;41:905-916. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Bioaccumulation and health risk assessment of exposure to potentially toxic elements by consuming agricultural products irrigated with wastewater effluents

Potentially toxic elements (PTEs) have many adverse health effects due to bioaccumulation capability and their long persistence in the environment. As a renewable water source, the effluents of municipal wastewater treatment systems have been used to irrigate agricultural products widely. However, the evidence on the bioaccumulation of PTEs in crops irrigated with these effluents is still scarce, with no available study in low and middle-income countries. Therefore, this study aimed to assess the PTEs concentration in the soil and crops irrigated with effluents of Sabzevar wastewater treatment plant and the related health risk by that. The clustered method was used to determine the soil and craps samples. Seventy cumulative samples were randomly prepared in summer and autumn 2016 and 2017 from crops, soil and effluent. Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure PTEs. The health risk of exposure to PTEs was assessed using Monte Carlo simulation technique. Kruskal Wallis test and Posthoc Tukey HSD test were used to assess the mean difference of PTEs between soil, effluent and crops as well as between crops together. The bioaccumulation factor (BAF) magnitude order in different crop samples was Cd > Sr > Cu > Pb > Zn > Co > As > Cr > Ni, respectively. The Cd accumulation in Sugar beet plant was significantly higher than in other samples. The highest hazard quotient (HQ) based on single PTEs was observed for As (mineral) (mean: 5.62 × 10^-1 and percentile 95th: 2.13) in Okra. Regarding total HQ (THQ), the highest and lowest mean (percentile 95th) values were 1.50 (3.22) and 2.40 × 10^-1 (4.01 × 10^-1) for Okra and Watermelon, respectively. The mean concentrations of Co, Cr, Ni and Zn were significantly higher in crops compared to soil and influent samples. Posthoc tests indicated that the concentration of PTEs between investigated crop samples were not statistically significant different (p > 0.05). Overall, our study suggested that irrigation with the effluent of stabilization pond wastewater treatment system exerts a potential health risk due to bioaccumulation of PTEs in crops.

Occurrence and Quantification of Natural and Microplastic Items in Urban Streams: The Case of Mugnone Creek (Florence, Italy)

The terrestrial environment is an important contributor of microplastics (MPs) to the oceans. Urban streams, strictly interwoven in the city network and to the MPs’ terrestrial source, have a relevant impact on the MP budget of large rivers and, in turn, marine areas. We investigated the fluxes (items/day) of MPs and natural fibers of Mugnone Creek, a small stream crossing the highly urbanized landscape of Florence (Italy) and ending in the Arno River (and eventually to the Tyrrhenian Sea). Measurements were done in dry and wet seasons for two years (2019–2020); stream sediments were also collected in 2019. The highest loads of anthropogenic particles were observed in the 2019 wet season (10⁹ items/day) at the creek outlet. The number of items in sediments increased from upstream (500 items/kg) to urban sites (1540 items/kg). Fibers were the dominant shape class; they were mostly cellulosic in composition. Among synthetic items, fragments of butadiene-styrene (SBR), indicative of tire wear, were observed. Domestic wastewater discharge and vehicular traffic are important sources of pollution for Mugnone Creek, especially during rain events. The study of small creeks is of pivotal importance to limit the availability of MPs in the environment.

Reuse of Water Contaminated by Microplastics, the Effectiveness of Filtration Processes: A Review

Water treatment generally does not specifically address the removal of microplastics (MPs). Nevertheless, treatment plants process water effectively, and the number of synthetic microparticles in effluents is usually very low. Still, discharge volumes from water-treatment plants are often elevated (reaching around 108 L/day), leading to the daily discharge of a substantial number of MPs and microfibers. Furthermore, MPs accumulate in the primary and secondary sludge, which in the end results in another environmental problem as they are currently used to amend soils, both for cultivation and forestry, leading to their dispersion. Something similar occurs with the treatment of water intended for human consumption, which has a much lower but still significant number of MPs. The amount of these pollutants being released into the environment depends on the processes that the water undergoes. One of the most-used treatment processes is rapid sand filtration, which is reviewed in this article. During the filtration process, MPs can break into smaller pieces, resulting in a greater number of plastic particles which mainly accumulate in sewage sludge. Thermal processes, such as incineration, carried out in facilities with the best available techniques in practice, could guarantee the safe disposal of highly MP-contaminated sewage sludges.

Microplastics in fillets of Mediterranean seafood. A risk assessment study

Microplastics (MPs) are considered as emergent threat to human health. No complete data still exists on MPs presence in fish tissue and their transmission to humans. The present study aims to detect and quantify the presence of MPs (<3 μm) in several edible seafood (Sardina pilchardus, wild and farmed Sparus aurata, Mullus surmuletus, Solea solea and musselMytilus galloprovincialis) from the south coast of Mediterranean Sea. MPs were detected through an innovative extraction method coupled to the SEM-EDX technology. The Estimated Daily Intakes (EDIs) for adults and children for each species were calculated. The higher median level (IQR) of MPs (9.09E+04) was found inM. surmuletus. Conversely, the lower median (IQR) level was observed in S. pilchardus (7.04E+04). The smallest and biggest median (IQR)diameter of MPs (1.8 and 2.5 μm) were identified in M. galloprovincialisand S. solea, respectively. The highest EDIs (25.50E+03; 48.09E+03) arefor ingestion of farmedS. auratarespectively for adults and children. Instead, the lowest EDIs (2.37E+02; 4.48E+02) are due to M. galloprovincialisingestion for adults and children, respectively. Our data should be carefully considered in view of the direct exposure of humans to plastic particles under 3 μm through seafood consumption to better manage the related risks.

Oncogenic Role of miRNA in Environmental Exposure to Plasticizers: A Systematic Review

The daily environmental exposure of humans to plasticizers may adversely affect human health, representing a global issue. The altered expression of microRNAs (miRNAs) plays an important pathogenic role in exposure to plasticizers. This systematic review summarizes recent findings showing the modified expression of miRNAs in cancer due to exposure to plasticizers. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology, we performed a systematic review of the literature published in the past 10 years, focusing on the relationship between plasticizer exposure and the expression of miRNAs related to cancer. Starting with 535 records, 17 articles were included. The results support the hypothesis that exposure to plasticizers causes changes in or the deregulation of a number of oncogenic miRNAs and show that the interaction of plasticizers with several redundant miRNAs, such as let-7f, let-7g, miR-125b, miR-134, miR-146a, miR-22, miR-192, miR-222, miR-26a, miR-26b, miR-27b, miR-296, miR-324, miR-335, miR-122, miR-23b, miR-200, miR-29a, and miR-21, might induce deep alterations. These genotoxic and oncogenic responses can eventually lead to abnormal cell signaling pathways and metabolic changes that participate in many overlapping cellular processes, and the evaluation of miRNA-level changes can be a useful target for the toxicological assessment of environmental pollutants, including plastic additives and plasticizers.

Polystyrene particles combined with di-butyl phthalate cause significant decrease in photosynthesis and red lettuce quality

Microplastics, an emerging pollutant in the environment, have attracted extensive attention in recent years for their possible negative impact on organisms. However, direct and indirect effects of polystyrene (PS) microplastics on vegetables are still not completely known. In this study, we used red lettuce (Lactuca sativa L. Red Sails) in a hydroponic system to investigate the effects of nano- and micro-sized PS and dibutyl phthalate (DBP) on the photosynthesis and red lettuce quality. The results clearly indicated that PS reduced the bioavailability of DBP while causing a decrease in the photosynthetic parameters as well as the total chorophyll content compared to DBP alone by affecting the crystalline structure of the water-soluble chlorophyll protein. Compared with DBP monotherapy, the presence of PS significantly increased hydrogen peroxide and malondialdehyde content in the lettuce treated with DBP, indicating serious oxidative damage. Furthermore, the soluble protein and sugar content in lettuce leaves decreased with higher PS concentration and smaller PS size. It may be due to PS inhibited lettuce root and ribulose-1,5-bisphosphate carboxylase/oxygenase activities. In contrast, nitrite content increased significantly with the induction of the glutathione-ascorbic acid cycle, indicating that the presence of PS reduced the quality of DBP-treated-red lettuce. Additionally, the nano-sized PS greatly inhibited lettuce growth and quality more than the micro-sized PS. This study described the interactions between microplastics and phthalates using molecular simulation and experimental validation to highlight the potential risks of microplastics on vegetable crop production.

Food Plastic Packaging Transition towards Circular Bioeconomy: A Systematic Review of Literature

Advancement in packaging technology has played an essential role in reducing food waste and losses; however, most of this technology relies mostly on the use of plastics. Thus, there is an imminent need to think seriously about the transition towards a circular bioeconomy of innovative biobased materials with biodegradability potentials. This paper examines the driving forces behind the changes in food plastic packaging regimes and specifically seeks to understand how socio-technical configurations may influence niches to transition to a circular bioeconomy, particularly biobased biodegradable plastic materials. By employing a systematic review of the literature, we find that coordination with other back-end socio-technical systems that provide valorization of packaging waste is crucial to enable the transition. The literature indicates that one possible transition path is that the biobased biodegradable materials serve as “carriers of food waste”. The paper contributes to the discussion on the dynamics of food packaging in the transition to a bioeconomy viewed through the lenses of a socio-technical system (niche–regime–landscape), which continues to reinforce future actions, leading to better management of packaging end-of-life.