Environments, Volume 9, Issue 11 (November 2022) – 13 articles

Many nations struggle with the collection, separation, and disposal of medical waste. However, extra caution is required to avoid the risk of injury, cross-contamination, and infection; thus, healthcare workers and individuals responsible for waste management must follow the mandatory safety procedures. In this review, a classification of the various types and categories of medical waste and its treatment methods are discussed. Due to the fact that medical waste can be contaminated and hazardous, it must be managed and processed using complex steps and procedures. In many countries, the primary medical/hospital waste treatment method is incineration, which is regarded as a highly polluting process that emits numerous pollutants that degrade air quality and pose a threat to human health and the environment. As case studies, medical waste treatment and disposal practices in Germany, China, USA, and Egypt were compared, and the legislations and laws enacted to regulate medical waste in each of these countries are reviewed and discussed. Full article

This research investigates the impact of controlling pandemic measures on the characteristics of atmospheric particulate matter (PM), with specific concern to its toxicity, measured by its oxidative properties. The investigated PM₁₀ samples were collected in the metropolitan area of Milan during the epidemic lockdown, and their oxidative potential (OP) was assessed using ascorbic acid (AA) and dithiothreitol (DTT) acellular assays. During the full lockdown, we estimated reductions to 46% and 60% for nitrogen dioxide (NO₂) and black carbon (BC) concentrations, respectively, based on the aggregated 2018–2019 data of NO₂ and BC levels, used as baseline conditions. To quantify the impact of lockdown restrictions on PM oxidative activity, we studied the OP data measured in our laboratory on PM₁₀ filters and directly compared the results from 15–30 April 2020 with those from the same time span in 2019. The OP^AA values dropped to nearly 50%, similar to the concentration decrease in Elemental Carbon (EC) and traffic related metals, as well as to the variation in NO₂ level. Otherwise, the OP^DTT responses decreased to nearly 75%, as described by the corresponding reduction in Organic Carbon (OC) concentration and BC level. Full article

Environmental pollution by lost fishing tackle is hardly considered in freshwater management. We collected and classified lost angling tackle during the dewatering of Lake Eixendorf, Germany. Based on the results, 1 item per 100 m² lake area was found, resulting in 5442 items, with an overall weight of more than 65 kg. This included more than 5 km of braided and monofilament fishing lines of various diameters. Lures used for active fishing methods such as stickbaits (shads and twister), metal spoons, spinners, and hard plastic baits had the greatest weight contribution (53.4%). Tackle lost from passive fishing methods (45.1%) mostly comprised groundbaiting feeder baskets and classical lead sinkers. Concerning the chemical composition, most lost items contained a composite mix of different materials. Lead was most abundant (45 kg), followed by plastics (13 kg) and steel (6 kg). Other materials such as copper, aluminum, brass (altogether 376 g), and chemicals from glow sticks (25 g) were less frequently found. Environmental pollution by lost fishing tackle deserves attention and, due to its potential environmental consequences, needs to be integrated into the pollution management of aquatic ecosystems, e.g., by identifying the most problematic items and by regulating the production and use of gear containing hazardous substances. Full article

Agriculture is the main source of income in India, with most farmers being smallholders and facing multiple challenges, such as climate change and land degradation. For the sustainable implementation of alternative circular approaches, it is important that agriculture benefits. To assess this, the impact of using co-compost (organic waste and black water consisting of feces and urine) was evaluated through surveys of 120 smallholder farmers in two case studies in South India. All 149 questions related to the overarching research question: what is the impact of using co-compost on closing loops in smallholder agriculture in terms of resource management and resilience. Secondary smallholder resources were found to be well managed and local networks and economies proved to be particularly effective in pandemics, reinforcing the potential for nutrient sources from urban areas. For most farmers, using co-compost improved yields (90%), soil (80%), plant health (93%) and, consequently, profits (67%), as well as water management (53%). Water management was significantly less of a problem for co-compost users (15%) than non-users (42%). In addition, the users of co-compost were able to save resources. Chemical fertilizer use was significantly reduced from 1.42 ± 2.1 to 0.9 ± 1.35 t (acre∙year)⁻¹, with total savings ranging from 37 to 44%. Overall, 67% were able to reduce chemical fertilizer use and 25% were able to reduce chemical spray use. Additionally, 53% reduced water consumption by 30.3% ± 19.92%. The visible benefits could motivate others to try co-composting. The reservations of non-users were due to personal or societal aspects (25%). In addition, the desire of farmers to convert to organic farming and try alternative farming methods, such as using smart technologies, vermicomposting or co-compost, was high (43%) and was positively influenced by the profitable use of alternative circular concepts. Information dissemination was mainly promoted by advertising (60%) and demonstrations (27%), which influenced openness to alternative circular concepts and products. In conclusion, co-composting and co-recycling approaches have a positive impact on the resource management and resilience of smallholder agriculture and thus, contribute to achieving sustainability goals. Full article

Phytoplankton community composition has been utilized for water quality assessments of various freshwater sources, but studies are lacking on agricultural irrigation ponds. This work evaluated the performance of the random forest algorithm in estimating phytoplankton community structure from in situ water quality measurements at two agricultural ponds. Sampling was performed between 2017 and 2019 and measurements of three phytoplankton groups (green algae, diatoms, and cyanobacteria) and three sets of water quality parameters (physicochemical, organic constituents, and nutrients) were obtained to train and test mathematical models. Models predicting green algae populations had superior performance to the diatom and cyanobacteria models. Spatial models revealed that water in the ponds’ interior sections had lower root mean square errors (RMSEs) compared to nearshore waters. Furthermore, model performance did not change when input datasets were compounded. Models based on physicochemical parameters, which can be obtained in real time, outperformed models based on organic constituent and nutrient parameters. However, the use of nutrient parameters improved model performance when examining cyanobacteria data at the ordinal level. Overall, the random forest algorithm was useful for predicting major phytoplankton taxonomic groups in agricultural irrigation ponds, and this may help resource managers mitigate the use of cyanobacteria bloom-laden waters in agricultural applications. Full article

Freshwater is in limited supply, and the growing population further contributes to its scarcity. The effective treatment of wastewater is essential now more than ever, because waterborne infections significantly contribute to global deaths, and millions of people are deprived of safe drinking water. Current wastewater treatment technologies include preliminary, primary, secondary, and tertiary treatments, which are effective in removing several contaminants; however, contaminants in the nanoscale range are often difficult to eliminate using these steps. Some of these include organic and inorganic pollutants, pharmaceuticals, pathogens and contaminants of emerging concern. The use of nanomaterials is a promising solution to this problem. Nanoparticles have unique properties allowing them to efficiently remove residual contaminants while being cost-effective and environmentally friendly. In this review, the need for novel developments in nanotechnology for wastewater treatment is discussed, as well as key nanomaterials and their corresponding target contaminants, which they are effective against. The nanomaterials of focus in this review are carbon nanotubes, graphene-based nanosheets, fullerenes, silver nanoparticles, copper nanoparticles and iron nanoparticles. Finally, the challenges and prospects of nanoparticle utilisation in the context of wastewater treatment are presented. Full article

Microplastics are major pollutants in the environment, and it is currently established that microplastics have already entered human food chains and been incorporated into the human body through ingestion and inhalation. Several works in animal models have already reported the adverse effect of microplastic exposure on biological systems; however, the effect of microplastic contamination on human health is still far from understood. In previous work, we reported microplastic contamination in the digestive tract of the Indonesian coastal and highland population. Using the same stool samples, we extended our previous work by investigating gut microbial composition in samples with and without microplastic contamination using next-generation sequencing. We found that microplastic contamination does not affect overall gut microbial composition and the abundance of gut-health-related genes. However, we found a negative and positive correlation between specific types of microplastics with certain bacterial taxa, especially from the genera Roseburia, Clostridium, and Prevotella. Despite the lack of a profound effect on the gut microbiome, we detected for the first time the presence of genes encoding plastic-degrading enzymes in the human gut microbiome, suggesting an adaptation of gut microbiome to microplastic contamination. Full article

Many agricultural areas are contaminated by heavy metals to such a level that the growth of plants is drastically reduced. Based on the site’s specific characteristics, feasibility studies were carried out to choose the most effective technologies. Feasibility tests showed that soil washing and phytoremediation technologies could be used at the agricultural site under study. The efficiency of the technologies is highly dependent on soil characteristics, which determine the chemical form of the metals. The results indicate that water-based soil washing can be successfully used with the possibility of reaching the remediation objectives quickly. However, the technology in the first step essentially breaks down the soil. Moreover, phytoremediation cannot be used directly to overcome the toxicity derived from the very high bioavailability of the heavy metals. Still, there is the need to use “assisted” phytoremediation by adding compost that reduces metal bioavailability, allowing phytoextraction. In this case, a longer time is needed to reach the remediation target. The results provide a preliminary scenario for decision-makers and stakeholders to assess possible technologies applicable and a possible scheme to be applied in similar cases of polluted agricultural areas. Full article

Biochar production and incorporation into soil is gaining momentum as a sustainable strategy for climate change mitigation, supported by ever increasing reports of significant carbon (C) sequestration in soil and reduction in greenhouse gas (GHG) emissions from the amended soils. With the progression in biochar testing and use, there is also emerging evidence that biochar induces C sequestration in soil, and that it may not be solely caused by its inherent chemical stability, but also by the complex microbially driven processes and an increase in C use efficiency (CUE) through soil microbial metabolism. This evidence contradicts the current paradigm that sees the microbial CUE decrease during the degradation of recalcitrant material due to thermodynamic constraints, as observed only in several short-term and pilot-scale trials. As the CUE in soil results from interactions between several abiotic and biotic factors, in this paper we examine the link between the biochar properties, soil physico-chemical properties and microbial physiology to explain the CUE increase reported for biochar-amended soils. Based on the large body of physico-chemical literature, and on the high functional diversity and metabolic flexibility of soil microbial communities, we hypothesize that the long-term stabilization of biochar-borne C in the soil systems is not only controlled by its inherent recalcitrance, but also by the cooperative actions of improved soil status and increased microbial CUE. Given that the current knowledge on this specific aspect is still poor, in this feature paper we summarize the state of knowledge and examine the potential impact of biochar on some factors contributing to the whole-soil CUE. We conclude that, beside its inherent recalcitrance, biochar weathering and oxidation in soil create physical and chemical conditions that can potentially increase the microbial CUE. While these processes stabilize the microbial processed C in soil and increase soil fertility, more data from long-term field trials are needed to model the relationship between the CUE and the MRT of biochar-borne C. Based on our hypotheses and relying upon analysis of the available literature, we also suggest possible research approaches that may contribute to filling the gaps in the current knowledge on the topic. Full article

COVID-19 has affected the entire existence of humans. Despite the mass vaccination programs globally deployed, some governments are still struggling to minimize human losses, high rates of virus transmission, and the socio-economic shock the entire planet has being gone through. COVID-19 has seriously affected all global socio-economic sectors. In this direction, agriculture, food-security and the environment could not be outside of the high-scale negative impacts, especially during the first year of the imposed lockdowns on both national and global scales. The present study provides information on the impact of COVID-19 and the lockdowns imposed, having as its study area the Republic of Cyprus. The study focuses on potato cultivation and production, and on which level entire agricultural procedures were affected during the examined period of the lockdown. A survey methodology study was done with questionnaires distributed to local potato farmers across the country to quantify and identify the link between the pandemic and the potato sector of the island. It was revealed that manpower was limited due to the lockdowns, the distribution of crops to markets disrupted, long delays in transactions in the agricultural sector were experienced, and economic uncertainty, in general, in Cyprus was experienced, among other impacts. Results of the study indicated that—since COVID-19 is not going to be the last disease—a global transition towards a more resilient and spatially localised food network is required. Full article

The recent sequential appearance of infectious pathogens has caused ongoing social and economic damage. Despite the very high potential for pathogen transmission within indoor multi-use facilities, there are insufficient measures for the systematic analysis, diagnosis, and reduction in such transmission. Although real-time environmental information is available for pollutants such as particulate matter, carbon dioxide, and nitrogen dioxide in South Korea, an automatic network for the real-time measurements of harmful microorganisms has not yet been established. Therefore, in this study, we analyzed the concentrations of bacteria and fungi in different types of multiple-use facilities in Bucheon, South Korea, using the analytic hierarchy process (AHP) method. All multi-use facilities in the region were classified into six types: facilities for pollution-sensitive groups (e.g., children or the elderly) and transportation-related, public transportation, temperature-controlled, food preparation, and other facilities. Next, the importance of each facility type in terms of bacterial and fungal abundance was evaluated using the AHP method, according to criteria selected using the AHP method. The highest importance was assigned to multi-use facilities for air-pollution-sensitive groups, which were associated with higher user density and more confirmed cases of COVID-19; the second-highest importance was assigned to public-transportation facilities. Bacteria detected at representative multi-use facilities were identified using 16S rRNA sequencing and included the human pathogens Bacillus anthracis, Bacillus cereus, Pseudomonas fluorescens, Erwinia billingiae, and Enterobacter cloacae. This study is the first to measure monthly and seasonal concentrations of bacteria and fungi at 30 multi-use facilities in Bucheon. The results of this study will be useful for designing systematic measures for the control of infectious bacteria and fungi in various types of multi-use facilities, according to their specific characteristics. Full article

The complex composition of natural organic matter (NOM) can affect drinking water treatment processes, leading to perceptible and undesired taste, color and odor, and bacterial growth. Further, current treatments tackling NOM can generate carcinogenic by-products. In contrast, promising substitutes such as electrochemical methods including electrooxidation (EO) have shown safer humic acid and algae degradation, but a formal comparison between EO methods has been lacking. In this study, we compared the Boron-doped diamond (BDD) electrode electrolysis performance for Suwannee River NOM degradation using mixed-metal oxide (MMO) anodes under different pH (6.5 and 8.5) representative of the high and low ranges for acidity and alkalinity in wastewater and applied two different current densities (10 and 20 mA cm⁻²). BDD anodes were combined with either BDD cathodes or stainless steel (SS) cathodes. To characterize NOM, we used (a) total organic compound (TOC), (b) chemical oxygen demand (COD), (c) specific ultraviolet absorbance (SUVA), and (d) specific energy consumption. We observed that NOM degradation differed upon operative parameters on these two electrodes. BDD electrodes performed better than MMO under stronger current density and higher pH and proved to be more cost-effective. BDD-SS electrodes showed the lowest energy consumption at 4.4 × 10³ kWh kg COD⁻¹. while obtaining a TOC removal of 40.2%, COD of 75.4% and SUVA of 3.4 at higher pH and current. On the contrary, MMO produced lower TOC, COD and SUVA at the lower pH. BDD electrodes can be used in surface water as a pre-treatment in combination with some other purification technologies to remove organic contaminants. Full article

The weathering of plastics is always accompanied by a change in surface properties, especially wettability in the case of water. For plastics weathering in an aquatic environment, wettability plays an important role in transport, sedimentation, and dispersion in the water body. To quantify wettability, contact angle measurement is a fast and convenient method that requires little experimental effort. This technique was used with the aim of systematically discussing how measured values of contact angles can contribute to the assessment of the weathering state. Using polyethylene terephthalate (PET), wetting was analyzed on samples from artificial weathering and from controlled, natural weathering. Surface analytical methods were used (Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), ultraviolet and visible light spectroscopy (UV/VIS)) to analyze the parameters affecting the contact angle: (i) chemical bond breaking and formation, (ii) eco-corona formation and biofilm growth, and (iii) change in surface structure and roughness. It was found that wettability with water increased during weathering in all cases. The reasons for this varied and depended on the method of weathering. The improved wettability during artificial weathering was due to changes in the polymer surface chemistry. In natural weathering, however, the formation of eco-corona and biofilm was responsible for the changes. Full article