Heavy Metal Accumulation in Water, Soil, and Plants of Municipal Solid Waste Landfill in Vientiane, Laos

Metal(loid)s in urban soil from historical municipal solid waste landfill: Geochemistry, source apportionment, bioaccessibility testing and human health risks

Landfills, especially those poorly managed, can negatively affect the environment and human beings through chemical contamination of soils and waters. This study investigates the soils of a historical municipal solid waste (MSW) landfill situated in the heart of a residential zone in the capital of Slovakia, Bratislava, with an emphasis on metal (loid) contamination and its consequences. Regardless of the depth, many of the soils exhibited high metal (loid) concentrations, mainly Cd, Cu, Pb, Sb, Sn and Zn (up to 24, 2620, 2420, 134, 811 and 6220 mg/kg, respectively), classifying them as extremely contaminated based on the geo-accumulation index (Igeo >5). The stable lead isotopic ratios of the landfill topsoil varied widely (1.1679-1.2074 for 206Pb/207Pb and 2.0573-2.1111 for 208Pb/206Pb) and indicated that Pb contained a natural component and an anthropogenic component, likely municipal solid waste incineration (MSWI) ash and construction waste. Oral bioaccessibility of metal (loid)s in the topsoil was variable with Cd (73.2-106%) and Fe (0.98-2.10%) being the most and least bioaccessible, respectively. The variation of metal (loid) bioaccessibility among the soils could be explained by differences in their geochemical fractionation as shown by positive correlations of bioaccessibility values with the first two fractions of BCR (Community Bureau of Reference) sequential extraction for As, Cd, Mn, Ni, Pb, Sn and Zn. The results of geochemical fractionation coupled with the mineralogical characterisation of topsoil showed that the reservoir of bioaccessible metal (loid)s was calcite and Fe (hydr)oxides. Based on aqua regia metal (loid) concentrations, a non-carcinogenic risk was demonstrated for children (HI = 1.59) but no risk taking into account their bioaccessible concentrations (HI = 0.65). This study emphasises the need for detailed research of the geochemistry of wastes deposited in urban soils to assess the potentially hazardous sources and determine the actual bioaccessibility and human health risks of the accumulated metal (loid)s.

Copper, Iron, Cadmium, and Arsenic, All Generated in the Universe: Elucidating Their Environmental Impact Risk on Human Health Including Clinical Liver Injury

Humans are continuously exposed to various heavy metals including copper, iron, cadmium, and arsenic, which were specifically selected for the current analysis because they are among the most frequently encountered environmental mankind and industrial pollutants potentially causing human health hazards and liver injury. So far, these issues were poorly assessed and remained a matter of debate, also due to inconsistent results. The aim of the actual report is to thoroughly analyze the positive as well as negative effects of these four heavy metals on human health. Copper and iron are correctly viewed as pollutant elements essential for maintaining human health because they are part of important enzymes and metabolic pathways. Healthy individuals are prepared through various genetically based mechanisms to maintain cellular copper and iron homeostasis, thereby circumventing or reducing hazardous liver and organ injury due to excessive amounts of these metals continuously entering the human body. In a few humans with gene aberration, however, liver and organ injury may develop because excessively accumulated copper can lead to Wilson disease and substantial iron deposition to hemochromatosis. At the molecular level, toxicities of some heavy metals are traced back to the Haber Weiss and Fenton reactions involving reactive oxygen species formed in the course of oxidative stress. On the other hand, cellular homeostasis for cadmium and arsenic cannot be provided, causing their life-long excessive deposition in the liver and other organs. Consequently, cadmium and arsenic represent health hazards leading to higher disability-adjusted life years and increased mortality rates due to cancer and non-cancer diseases. For unknown reasons, however, liver injury in humans exposed to cadmium and arsenic is rarely observed. In sum, copper and iron are good for the human health of most individuals except for those with Wilson disease or hemochromatosis at risk of liver injury through radical formation, while cadmium and arsenic lack any beneficial effects but rather are potentially hazardous to human health with a focus on increased disability potential and risk for cancer. Primary efforts should focus on reducing the industrial emission of hazardous heavy metals.

Toxic heavy metals in a landfill environment (Vientiane, Laos): Fish species and associated health risk assessment

Leachates from municipal landfills introduce toxic heavy metals into water, causing bioaccumulation. This study assesses metal levels and potential human health risks associated with consuming Anabas testudineus and Channa striata. Inductively coupled plasma mass spectrometry detected Cd, Cu, Cr, Ni, Pb, and Zn in both fish species. Leachate metal concentrations meet international discharge standards, Cd, Cr, and Pb in the fish exceed the international accepted values. Gastrointestinal tract+liver samples show significant variation between species, particularly in Cd and Pb. EDI, THQ/HI, and TR for the both species fall below TDIs, lower than the limit of 1, and within the acceptable range of the US-EPA permissible limit, respectively. Fish consumption appears safe regarding carcinogenic risk, but exceeding metal limits could impact heavy metals accumulation in the local food chain. Raising public awareness is crucial, and governmental agencies and environmental organizations should enhance waste treatment technologies and enact relevant health legislation.

Ecotoxicological impacts of landfill sites: Towards risk assessment, mitigation policies and the role of artificial intelligence

Waste disposal in landfills remains a global concern. Despite technological developments, landfill leachate poses a hazard to ecosystems and human health since it acts as a secondary reservoir for legacy and emerging pollutants. This study provides a systematic and scientometric review of the nature and toxicity of pollutants generated by landfills and means of assessing their potential risks. Regarding human health, unregulated waste disposal and pathogens in leachate are the leading causes of diseases reported in local populations. Both in vitro and in vivo approaches have been employed in the ecotoxicological risk assessment of landfill leachate, with model organisms ranging from bacteria to birds. These studies demonstrate a wide range of toxic effects that reflect the complex composition of leachate and geographical variations in climate, resource availability and management practices. Based on bioassay (and other) evidence, categories of persistent chemicals of most concern include brominated flame retardants, per- and polyfluorinated chemicals, pharmaceuticals and alkyl phenol ethoxylates. However, the emerging and more general literature on microplastic toxicity suggests that these particles might also be problematic in leachate. Various mitigation strategies have been identified, with most focussing on improving landfill design or leachate treatment, developing alternative disposal methods and reducing waste volume through recycling or using more sustainable materials. The success of these efforts will rely on policies and practices and their enforcement, which is seen as a particular challenge in developing nations and at the international (and transboundary) level. Artificial intelligence and machine learning afford a wide range of options for evaluating and reducing the risks associated with leachates and gaseous emissions from landfills, and various approaches tested or having potential are discussed. However, addressing the limitations in data collection, model accuracy, real-time monitoring and our understanding of environmental impacts will be critical for realising this potential.

Landfill leachate a potential challenge towards sustainable environmental management

The increasing amount of waste globally has led to a rise in the use of landfills, causing more pollutants to be released through landfill leachate. This leachate is a harmful mix formed from various types of waste at a specific site, and careful disposal is crucial to prevent harm to the environment. Understanding the physical and chemical properties, age differences, and types of landfills is essential to grasp how landfill leachate behaves in the environment. The use of Sustainable Development Goals (SDGs) in managing leachate is noticeable, as applying these goals directly is crucial in reducing the negative effects of landfill leachate. This detailed review explores the origin of landfill leachate, its characteristics, global classification by age, composition analysis, consequences of mismanagement, and the important role of SDGs in achieving sustainable landfill leachate management. The aim is to provide a perspective on the various aspects of landfill leachate, covering its origin, key features, global distribution, environmental impacts from poor management, and importance of SDGs which can guide for sustainable mitigation within a concise framework.

Consumer knowledge, attitudes, and behaviour regarding food safety - A perspective from Laos

Primary research data on food chain safety at consumer level is needed to help policymakers to decrease the risk of foodborne infections in the Lao People's Democratic Republic. Therefore, the objectives of this study are to 1) determine Lao people's food safety knowledge, attitudes, and intentions and identify the most influential factors that shape their food safety behaviour, and 2) to support the government in the development of more efficient risk communication programmes. A paper-based consumer survey was implemented to collect quantitative data on the selected topics about Laotian consumers, as well as on the equipment of households regarding the conditions and tools necessary for safe food preparation and storage. A model was developed based on the extended Theory of Planned Behaviour (TPB), and partial least squares structural equation modelling (PLS-SEM) was applied to analyse the factors that affect food safety behaviour. The elements of Knowledge and Perceived Behavioural Control positively influence behaviours, such as using separate chopping boards for raw and ready-to-eat foods. According to the model, only 10 % of the Intentions would be translated into Behaviours, which gap can be explained by the lack of a hygienic environment. Although the survey indicated that Laotian people intend to follow food safety guidelines, participants felt they lacked sufficient knowledge. This perception was validated by the knowledge test and behavioural part of the study. In the light of these findings, it is essential to raise awareness and promote food safety knowledge and interventions, such as enhancing food safety education in childhood. This would help to facilitate and encourage adopting safe practices to improve overall food safety at the consumer level, delivering positive impacts also to the food business sector.

Emerging environmental contaminants: Sources, effects on biodiversity and humans, remediation, and conservation implications

Ecosystems, biodiversity, and the human population all depend on a quality or uncontaminated environment. Quality environment provides people and wildlife access to nutrition, medications, dietary supplements, and other ecosystem services. The conservation of biodiversity-that is, species richness, abundance, heredities, and diversity-as well as the control of climate change are facilitated by such an uncontaminated environment. However, these advantages are jeopardized by newly emerging environmental chemical contaminants (EECCs) brought on by increased industrialization and urbanization. In developing countries, inadequate or poor environmental policies, infrastructure, and national standards concerning the usage, recycling, remediation, control, and management of EECCs hasten their effects. EECCs in these countries negatively affect biodiversity, ecological services and functions, and human health. This review reveals that the most deprived or vulnerable local communities in developing countries are those residing near mining or industrial areas and cultivating their crops and vegetables on contaminated soils, as is wildlife that forages or drinks in EECC-contaminated water bodies. Yet, people in these countries have limited knowledge about EECCs, their threats to human well-being, ecosystem safety, and the environment, as well as remediation technologies. Besides, efforts to efficiently control, combat, regulate, and monitor EECCs are limited. Thus, the review aims to increase public knowledge concerning EECCs in developing countries and present a comprehensive overview of the current status of EECCs. It also explores the sources and advancements in remediation techniques and the threats of EECCs to humans, ecosystems, and biodiversity.

Performance evaluation of Anaerobic-Aerobic Hybrid Baffled Reactor Coupled with an Anaerobic Filter treating Landfill Leachate

The Anaerobic Baffled Reactor (ABR) is an effective solution for landfill leachate treatment using an anaerobic fermentation process, which helps to reduce operating costs and sludge volume. To better understand the biological, chemical, and physical processes involved, especially when combining the ABR with an aerobic component, the study aimed to investigate the performance of an Anaerobic-Aerobic Hybrid Baffled Reactor (AABR) that includes an Anaerobic Filter (AF) for treating landfill leachate. This research utilized two glass reactors. The first reactor, designated as AABR-AF, consisted of six independent rectangular glass chambers arranged side by side. The third and sixth chamber designed for aerobic treatment and AF, respectively. The second reactor was used as a control reactor and did not include any aerobic chamber. The highest Removal Efficiencies (REs) for turbidity, COD, BOD, TP, TKN, nitrate, TOC, and TSS in the AABR-AF and ABR-AF were found to be (65.4% and 56.3%), (98.3% and 94.1%), (98.1% and 93.2%), (86.4% and 65%), (89.2% and 76.7%), (81.2% and 64.4%), (88.2% and 79.4%), and (72.4% and 68.5%), respectively. These optimal REs were achieved at an HRT of 48 h and an OLR of 10 kg/m3.d. Also, the highest and the lowest REs in Heavy Metals (HMs) were 89.57% for manganese in AABR-AF and 6.59% for nickel in ABR-AF, in an OLR of 10 kg/m3.d, respectively. The effective removal of Organic Matters (OMs) from landfill leachate using the AABR-AF and ABR-AF was found to be strongly influenced by HRT and OLR. The AABR-AF configuration, featuring a single aerobic chamber in the reactor, exhibited a higher efficiency in removing OMs compared to the ABR-AF configuration.

Global perspective of municipal solid waste and landfill leachate: generation, composition, eco-toxicity, and sustainable management strategies

Globally, more than 2 billion tonnes of municipal solid waste (MSW) are generated each year, with that amount anticipated to reach around 3.5 billion tonnes by 2050. On a worldwide scale, food and green waste contribute the major proportion of MSW, which accounts for 44% of global waste, followed by recycling waste (38%), which includes plastic, glass, cardboard, and paper, and 18% of other materials. Population growth, urbanization, and industrial expansion are the principal drivers of the ever-increasing production of MSW across the world. Among the different practices employed for the management of waste, landfill disposal has been the most popular and easiest method across the world. Waste management practices differ significantly depending on the income level. In high-income nations, only 2% of waste is dumped, whereas in low-income nations, approximately 93% of waste is burned or dumped. However, the unscientific disposal of waste in landfills causes the generation of gases, heat, and leachate and results in a variety of ecotoxicological problems, including global warming, water pollution, fire hazards, and health effects that are hazardous to both the environment and public health. Therefore, sustainable management of MSW and landfill leachate is critical, necessitating the use of more advanced techniques to lessen waste production and maximize recycling to assure environmental sustainability. The present review provides an updated overview of the global perspective of municipal waste generation, composition, landfill heat and leachate formation, and ecotoxicological effects, and also discusses integrated-waste management approaches for the sustainable management of municipal waste and landfill leachate.

Toxic heavy metal ions contamination in water and their sustainable reduction by eco-friendly methods: isotherms, thermodynamics and kinetics study

Heavy metal ions can be introduced into the water through several point and non-point sources including leather industry, coal mining, agriculture activity and domestic waste. Regrettably, these toxic heavy metals may pose a threat to both humans and animals, particularly when they infiltrate water and soil. Heavy metal poisoning can lead to many health complications, such as liver and renal dysfunction, dermatological difficulties, and potentially even malignancies. To mitigate the risk of heavy metal ion exposure to humans and animals, it is imperative to extract them from places that have been polluted. Several conventional methods such as ion exchange, reverse osmosis, ultrafiltration, membrane filtration and chemical precipitation have been used for the removal of heavy metal ions. However, these methods have high operation costs and generate secondary pollutants during water treatment. Biosorption is an alternative approach to eliminating heavy metals from water that involves employing eco-friendly and cost-effective biomass. This review is focused on the heavy metal ions contamination in the water, biosorption methods for heavy metal removal and mathematical modeling to explain the behaviour of heavy metal adsorption. This review can be helpful to the researchers to design wastewater treatment plants for sustainable wastewater treatment.

Heavy metals mitigation and growth promoting effect of endophytic Agrococcus terreus (MW 979614) in maize plants under zinc and nickel contaminated soil

Introduction

Heavy metals such as iron, copper, manganese, cobalt, silver, zinc, nickel, and arsenic have accumulated in soils for a long time due to the dumping of industrial waste and sewage. Various techniques have been adapted to overcome metal toxicity in agricultural land but utilizing a biological application using potential microorganisms in heavy metals contaminated soil may be a successful approach to decontaminate heavy metals soil. Therefore, the current study aimed to isolate endophytic bacteria from a medicinal plant (Viburnum grandiflorum) and to investigate the growth-promoting and heavy metal detoxification potential of the isolated endophytic bacteria Agrococus tereus (GenBank accession number MW 979614) under nickel and zinc contamination.

Methods

Zinc sulfate and nickel sulfate solutions were prepared at the rate of 100 mg/kg and 50 mg/kg in sterilized distilled water. The experiment was conducted using a completely random design (CRD) with three replicates for each treatment.

Results and Discussion

Inoculation of seeds with A. tereus significantly increased the plant growth, nutrient uptake, and defense system. Treatment T4 (inoculated seeds), T5 (inoculated seeds + Zn100 mg/kg), and T6 (inoculated seeds + Ni 100 mg/kg) were effective, but T5 (inoculated seeds + Zn100 mg/kg) was the most pronounced and increased shoot length, root length, leaf width, plant height, fresh weight, moisture content, and proline by 49%, 38%, 89%, 31%, 113%, and 146%, respectively. Moreover the antioxidant enzymes peroxidase and super oxidase dismutase were accelerated by 211 and 68% in contaminated soil when plants were inoculated by A. tereus respectively. Similarly the inoculation of A. tereus also enhanced maize plants' absorption of Cu, Mn, Ni, Na, Cr, Fe, Ca, Mg, and K significantly. Results of the findings concluded that 100 mg/kg of Zn and Ni were toxic to maize growth, but seed inoculation with A. tereus helped the plants significantly in reducing zinc and nickel stress. The A. tereus strain may be employed as a potential strain for the detoxification of heavy metals.

Industrial wastewater irrigation increased higher heavy metals uptake and expansins, metacaspases, and cystatin genes expression in Parthenium and maize

Industrial wastewater irrigation of agricultural crops can cause a lot of environmental and health problems in developing countries due to heavy metals deposition in agricultural soils as well as edible plant consumption by human beings. Therefore, this study was conducted to find out the heavy metals concentration in industrial wastewater and soil irrigated with that wastewater. In addition, the aim was to determine the impact of industrial wastewater irrigation on Parthenium hysterophorus and Zea mays genes involved in growth improvement and inhibition. For this purpose, plant samples from agriculture fields irrigated with wastewater from Hattar Industrial Estate (HIE) of Haripur, Pakistan, and control plants from non-contaminated soil irrigated with tape water were collected after 15 and 45 days of germination. Heavy metals concentration in the collected plant samples, wastewater, and soil was determined. The results revealed that the soil of the sample collection site was predominantly contaminated with Cr, Pb, Ni, Cu, Co, Zn, and Cd up to the concentrations of 38.98, 21.14, 46.01, 155.73, 12.50, 68.50, and 7.01 mg/kg, respectively. The concentrations of these heavy metals were found to surpass the permissible limit in normal agricultural soil. Expansins, cystatins (plant growth enhancers), and metacaspases (plant growth inhibitor) gene expression were studied through reverse transcription polymerase chain reaction. The results showed that the expression of these genes was higher in samples collected from wastewater-irrigated soils as compared to control. The expression of these genes was observed in 45 days old samples, 15 days old samples, and control. Taken together, this study suggests the use of Parthenium and maize for phytoremediation and that they should not be used for eating purposes if irrigated with industrial wastewater.

Conversion of solid wastes and natural biomass for deciphering the valorization of biochar in pollution abatement: A review on the thermo-chemical processes

This overview addresses the formation of solid trash and the various forms of waste from a variety of industries, which environmentalists have embraced. The paper investigates the negative effects on the environment caused by unsustainable management of municipal solid trash as well as the opportunities presented by the formal system. This examination looks at the origins of solid waste as well as the typical treatment methods. Pyrolysis methods, feedstock pyrolysis, and lignocellulosic biomass pyrolysis were highlighted. Explain in detail the various thermochemical processes that take place during the pyrolysis of biomass. Due to its carbon content, low cost, accessibility, ubiquitousness, renewable nature, and environmental friendliness, biomass waste is a unique biochar precursor. This study looks at the different types of biomass waste that are available for treating wastewater. This study discussed a wide variety of reactors. Adsorption is the standard method that is used the most frequently to remove hazardous organic, dye, and inorganic pollutants from wastewater. These pollutants cause damage to the environment and water supplies, thus it is important to remove them. Adsorption is both simple and inexpensive to utilize. Temperature-dependent conversions explain the kinetic theories of biomaterial biochemical degradation. This article presents a review that explains how pyrolytic breakdown char materials can be used to reduce pollution and improve environmental management.

Mercury May Pose Higher Ecological and Human Health Risks than Lead in Vegetables Cultivated on Solid Wastes Dumpsites Soils

Vegetable cultivation on solid wastes dumpsites (SWD) soils is very common in developing countries though unsafe due to heavy metals pollution. In order to evaluate the ecological and human health risks of this practice, Talium triangulare and Lycopersicon esculentum were grown in a greenhouse on soils from two abandoned and active SWD, and control site. The SWD soils were acidic (pH 6.4-6.8), rich in organic matter (10.15%-15.35%) and the heavy metals content patterned Zn > Mn > Hg > Cu > Pb > Ni > Cd. Ecological risk was very high ([Formula: see text] = 396.40; RI = 400) for waterworks dumpsite (WWD) and was > 99% attributable to Hg. Pb was not accumulated in either vegetable but Hg levels exceeded FAO/WHO limits. HQ was mostly < 1 except for Hg (0.47-3.42) and Co (0-1.33) while THQ > 1 for T. triangulare and cancer risks exceeded 10-6-10-4 acceptable limits. Regular monitoring and outlawing of vegetable cultivation on SWD is advocated to avert Hg toxicity.

The highly diverse plasmid population found in Escherichia coli colonizing travellers to Laos and its role in antimicrobial resistance gene carriage

Increased colonization by antimicrobial-resistant organisms is closely associated with international travel. This study investigated the diversity of mobile genetic elements involved with antimicrobial resistance (AMR) gene carriage in extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli that colonized travellers to Laos. Long-read sequencing was used to reconstruct complete plasmid sequences from 48 isolates obtained from the daily stool samples of 23 travellers over a 3 week period. This method revealed a collection of 105 distinct plasmids, 38.1 % (n=40) of which carried AMR genes. The plasmids in this population were diverse, mostly unreported and included 38 replicon types, with F-type plasmids (n=23) the most prevalent amongst those carrying AMR genes. Fine-scale analysis of all plasmids identified numerous AMR gene contexts and emphasized the importance of IS elements, specifically members of the IS6/IS26 family, in the evolution of complex multidrug resistance regions. We found a concerning convergence of ESBL and colistin resistance determinants, with three plasmids from two different F-type lineages carrying bla CTX-M and mcr genes. The extensive diversity seen here highlights the worrying probability that stable new vehicles for AMR will evolve in E. coli populations that can disseminate internationally through travel networks.

Heavy metal remediation using chelator-enhanced washing of municipal solid waste compost based on spectroscopic characterization

Due to high metal toxicity, mixed municipal solid waste (MSW) compost is difficult to use. This study detected the presence of heavy metals (Cd, Cu, Pb, Ni, and Zn) in MSW compost through mineralogical analysis using X-ray diffraction (XRD) and performed topographical imaging and elemental mapping using a scanning electron microscope and energy dispersive X-ray analysis (SEM-EDX). Ethylenediaminetetraacetic acid (EDTA), a typical chelator, is tested to remove heavy metals from Indian MSW compost (New Delhi and Mumbai). It deals with two novel aspects, viz., (i) investigating the influence of EDTA-washing conditions, molarity, dosage, MSW compost-sample size, speed, and contact time, on their metal removal efficiencies, and (ii) maximizing the percentage removal of heavy metals by determining the optimal process control process parameters. These parameters were optimized in a batch reactor utilizing Taguchi orthogonal (L₂₅) array. The optimization showed that the removal efficiencies were 96.71%, 47.37%, and 49.94% for Cd, Pb, and Zn in Delhi samples, whereas 45.55%, 79.52%, 59.63%, 82.31%, and 88.40% for Cd, Cu, Pb, Ni, and Zn in Mumbai samples. Results indicate that the removal efficiency of heavy metals was greatly influenced by EDTA-molarity. Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of hydroxyl group, which aids heavy metal chelation. The results reveal the possibility of EDTA to reduce the hazardous properties of MSW compost.

Concentration of heavy metals in leachate, soil, and plants in Tehran's landfill: Investigation of the effect of landfill age on the intensity of pollution

Heavy metals are one of the important pollutants in landfill leachate. Plants and soil near the landfill may be contaminated by leachate. In this study, by evaluating the heavy metals in the leachate of two landfills and the soil and plants near them, the amount of pollution caused by the leachate in the environment around the landfills in Tehran was investigated. This study was conducted in three stations, soil and plant samples were prepared according to a specific protocol. Also, three indexes including PI, PI_Nemerow, and BF were used to interpret the results. The results showed that the concentration of total metals in the old landfill leachate and new landfill leachate was only 12% different and was 24.13 mg/L on average. In the new landfill leachate, iron had the highest concentration among metals, which was 22.94 and 17.01 mg/L in two samples. In the old landfill leachate, the concentration of manganese was 15.71 mg/L, which was the highest among the studied metals. The concentration of heavy metals in the soil of the old landfill was 24.6% lower than the concentration of metals in the soil of the new landfill. In all samples, the highest metal concentration in the soil was related to manganese, which was 33.65-34.14 mg/L. Cadmium had the lowest concentration in soil compared to other metals. The concentration of total metals in the studied plants was 29-60 ppm. The PInemerow for studied stations was 0.1711, 0.1708, and 0.1463. The highest PI in the case of lead was observed at the second station equal to 0.54. The highest BF in case of Atriplex Undulata was more than 6 and related to cadmium, while the highest BF in case of Atriplex Cinearea was more than 3.5 related to cadmium. This study showed that the soil and plants of the landfill were contaminated with heavy metals under the influence of leachate, and the ability of plants to uptake and accumulate metals can be used to manage soil pollution near the landfill.

Heavy metal pollution in leachates and its impacts on the quality of groundwater resources around Iringa municipal solid waste dumpsite

Heavy metal pollution in groundwater due to leachates leaking from the Iringa municipal dumpsite was investigated. The pollution was studied by analyzing pH, electrical conductivity (EC), total dissolved solids (TDS), and heavy metals (Fe, Pb, Cr, Cd, Cu, Ni, Mn, and Zn) in leachates collected within the dumpsite and groundwater samples from residential wells close to the dumpsite. The pH of the leachate samples varied from 7.40 to 9.10, implying alkaline behavior and the methanogenic phase of solid waste deposits. The levels of EC, TDS, and heavy metals (Fe, Pb, Cr, Cu, Ni, Mn, and Zn) in leachates were above the national and/or international standards. On other hand, groundwater samples presented pH values ranging from 7.15 to 7.60 which were within the World Health Organization acceptable limit. The concentrations of EC, TDS, Fe, Pb, Ni, Mn, and Zn in most groundwater samples exceeded the national and/or international permissible limits for drinking water. In addition, the water quality indices (WQI) of groundwater samples ranged between 8.30 and 17.90, which implied the excellent quality of groundwater sources. However, the presence of high levels of heavy metals above the permissible limits in both leachate and groundwater samples signified potential risks to the environment and public health. Therefore, the present study calls for proper management of municipal solid waste to reduce the potential risks of further contamination on the groundwater resources and environment around the Iringa municipal dumpsite.

A Future Perspective on Waste Management of Lithium-Ion Batteries for Electric Vehicles in Lao PDR: Current Status and Challenges

Lithium-ion batteries (LIBs) have become a hot topic worldwide because they are not only the best alternative for energy storage systems but also have the potential for developing electric vehicles (EVs) that support greenhouse gas (GHG) emissions reduction and pollution prevention in the transport sector. However, the recent increase in EVs has brought about a rise in demand for LIBs, resulting in a substantial number of used LIBs. The end-of-life (EoL) of batteries is related to issues including, for example, direct disposal of toxic pollutants into the air, water, and soil, which threatens organisms in nature and human health. Currently, there is various research on spent LIB recycling and disposal, but there are no international or united standards for LIB waste management. Most countries have used a single or combination methodology of practices; for instance, pyrometallurgy, hydrometallurgy, direct recycling, full or partial combined recycling, and lastly, landfilling for unnecessary waste. However, EoL LIB recycling is not always easy for developing countries due to multiple limitations, which have been problems and challenges from the beginning and may reach into the future. Laos is one such country that might face those challenges and issues in the future due to the increasing trend of EVs. Therefore, this paper intends to provide a future perspective on EoL LIB management from EVs in Laos PDR, and to point out the best approaches for management mechanisms and sustainability without affecting the environment and human health. Significantly, this review compares the current EV LIB management between Laos, neighboring countries, and some developed countries, thereby suggesting appropriate solutions for the future sustainability of spent LIB management in the nation. The Laos government and domestic stakeholders should focus urgently on specific policies and regulations by including the extended producer responsibility (EPR) scheme in enforcement.

Citizens' perception towards landfill exposure and its associated health effects: a PLS-SEM based modeling approach

Around 90% of municipal solid waste in India is treated improperly at open dumps and landfills, posing a severe threat to public health. Landfills are an annoyance whose presence causes uncertainty, stress, and dissatisfaction in neighboring residential areas. This research investigates the perceived impact of exposure to landfills on health in terms of environmental quality, general living status, and defensiveness. To meet the current study's objective, "Case of exposed population" to landfill, i.e., 384 participants dwelling near 1 km of the dump site in Siliguri municipality, West Bengal, India, were considered using a purposive sample approach. The present study adopted Partial Least Square-Structural Equation Modeling (PLS-SEM) approach to prove the hypothesis related to the residential perception of landfills and their impact on health. The findings reveal that all three constructs, namely environmental quality (β = .997, t = 19.607, and ρ < 0.001), general life status (β = .116, t = 2.475 and ρ < 0.05), and people's defensive attitude (β = .150, t = 2.526 and ρ < 0.001), significantly affect the health condition of those exposed to a landfill site. The results suggest that by understanding the impact of landfills on resident health, policymakers and bureaucrats can promote reliable and effective measures linked to sustainable solid waste disposal facilities. The administration must create a policy to protect citizens who live near landfills by improving the ambient environment, establishing health management facilities, and raising awareness through public participation.

Evaluation and environmental risk assessment of heavy metals in the soil released from e-waste management activities in Lahore, Pakistan

In developing regions, electronic waste either gets recycled by using crude and primitive techniques in recycling centers or dumped in dumping grounds that result in the leaching of heavy metals into the ambient environment. The objective of this study is to determine the concentration of heavy metals (Cu, Pb, Zn, Cd, Mn, and Fe) in the surface soil of recycling centers and dumping sites in Lahore, Pakistan, and to quantify and compare the environmental risk. The mean concentration (mg/kg) of Cu, Pb, Zn, and Cd was 722.96, 446.81, 378.76, and 4.11, respectively in the surface soil of recycling centers, and only the mean concentration of Cu (214.09 mg/kg) from dumping sites were above permissible limits of World Health Organization. Results of the geo-accumulation index (Igeo) and contamination factor (Cf) revealed that the surface soil is highly contaminated with Cu, Pb, and Cd. The Cd content (701.24) caused a very high potential ecological risk (Er) (> 320) to nearby biological communities. The noncarcinogenic risk was only expected from Pb to children (1.70) living near recycling centers, whereas no risk was observed for adults living either near recycling centers (0.23) or dumping sites (0.01). There is a high probability of carcinogenic health risks to children (1.085 × 10^-2) and adults (1.195 × 10^-3) from Cu. Hence, all the results suggest that e-waste recycling and dumping activities were a significant source of heavy metals to the surrounding environment, children, and adults, so it is strongly recommended to take action for sustainable management of e-waste.

Assessment of pollution levels and ecological potential risk of the soil influenced by landfilling in a Vietnamese Mekong Delta province

The study was conducted to assess the impacts of Cai Dau and An Cu landfills in An Giang province, Vietnam on soil quality using relative soil quality index (RSQI), potential ecological risk index (PERI), and multivariable statistical methods and associated health risks. Forty-eight soil samples were collected in two layers: A (0-20 cm) and B (60-80 cm) and analyzed for five physiochemical soil parameters and eight heavy metals during the rainy and dry seasons. The results showed that pH fluctuated from weak acid to neutral, and organic matters and nutrients in soil were from poor to moderate. Heavy metal concentrations were within the Vietnamese standards. The concentrations of the soil quality parameters tended to be higher during the rainy season at the Cai Dau landfill, but lower at the An Cu landfill. The RSQI was rated as bad to good and hazardous to bad at the Cai Dau and An Cu landfills, respectively. The principal component analysis (PCA) and absolute principal component score-multiple linear regression analysis demonstrated the contribution of landfill and agricultural impacts to soil quality variability, accounting for 81.38-90.64 %. Landfills contributed greater 35 % and 50 % to heavy metal contents at Cai Dau and An Cu, respectively. The heavy metal accumulation at Cai Dau landfill was in the decreasing order of Ni > Cr > As, but that was not found at An Cu landfill. The pollution load index (PLI) indicated medium and low risks of heavy metal contamination at the Cai Dau and An Cu landfills, respectively, thus posing low potential ecological risk. The non-cancer and cancer risks of heavy metals-contaminated soil were at acceptable level. Monitoring of heavy metals in the environments surrounding landfills is needed due to its accumulative characteristics.

Engineered microbes as effective tools for the remediation of polyaromatic aromatic hydrocarbons and heavy metals

Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) have become a major concern to human health and the environment due to rapid industrialization and urbanization. Traditional treatment measures for removing toxic substances from the environment have largely failed, and thus development and advancement in newer remediation techniques are of utmost importance. Rising environmental pollution with HMs and PAHs prompted the research on microbes and the development of genetically engineered microbes (GEMs) for reducing pollution via the bioremediation process. The enzymes produced from a variety of microbes can effectively treat a range of pollutants, but evolutionary trends revealed that various emerging pollutants are resistant to microbial or enzymatic degradation. Naturally, existing microbes can be engineered using various techniques including, gene engineering, directed evolution, protein engineering, media engineering, strain engineering, cell wall modifications, rationale hybrid design, and encapsulation or immobilization process. The immobilization of microbes and enzymes using a variety of nanomaterials, membranes, and supports with high specificity toward the emerging pollutants is also an effective strategy to capture and treat the pollutants. The current review focuses on successful bioremediation techniques and approaches that make use of GEMs or engineered enzymes. Such engineered microbes are more potent than natural strains and have greater degradative capacities, as well as rapid adaptation to various pollutants as substrates or co-metabolizers. The future for the implementation of genetic engineering to produce such organisms for the benefit of the environment andpublic health is indeed long and valuable.

Human Health Risk Assessment Is Associated with the Consumption of Metal-Contaminated Groundwater around the Marituba Landfill, Amazonia, Brazil

Groundwater is present in its purest form beneath the earth's surface. However, metal contamination is potentially a problem faced by many countries. For this reason, the present study aims to make an assessment of the risks associated with groundwater consumption around the Marituba landfill in an Amazon region. The present study was characterized as transversal with the use of primary data. The sampling occurred in a stratified random way, performed in two radii of action being the 1st radius of 2.5 km away from the landfill and the 2nd radius of 3.5 km away from the landfill to the neighborhoods. A total of 184 points were collected. In all communities the average daily dose (ADD) was higher than the reference oral dose (Rfd), for the metals As, Pb and Mn the risk quotient (HQ) was greater than 1 (one) in all neighborhoods, the concentration of Mn in the least exposed neighborhood was greater than 10 µg.L^-1, even at a distance of 3.5 km from the landfill. The average concentrations for As and Pb did not exceed the recommended, however, they were more significant for the Beira Rio neighborhood, respectively 1.47 µg.L^-1 and 1.9 µg.L^-1. And the average concentration for Cu was more significant for the Uriboca neighborhood 18.20 µg.L^-1, but within the recommended. The average of the general concentration of Heavy Metals Pollution Index (HPI) of the water consumed was 80.03, indicating that the water consumed by the population is contaminated by metals.

Quantifying the effect of waste on soil health in European Union: what are the roles of technology, natural capital, and institutional quality?

With a surge in both hazardous and non-hazardous waste in recent decades, European Union countries are losing their soil quality which in turn affects the agricultural production of their economies. Taking this into account, this study presents the effect of hazardous and non-hazardous waste, plastic waste, and electronic waste on soil health for 24 European Union (EU) countries during 2004-2018 period. The impacts of several other variables such as technological innovation, ICT, natural capital, fossil fuel energy consumption, and institutional quality on soil health are also examined. To achieve the above objectives, we employ Driscoll-Kraay technique as the main methodology as well as panel spatial correlation consistent (PSCC) standard errors and quantile estimation at median. The results demonstrate that electronic waste has a negative effect on soil health while the effect of total hazardous and non-hazardous waste and plastic waste on soil health remains insignificant. Technological innovation, ICT, and institutional quality, as well as fossil fuel energy consumption, have positive impacts on soil health. Furthermore, natural capital moderates the effect of plastic and electronic waste on soil health. The study finally provides precise policy recommendations for the EU countries such as proper handling of wastes, promoting strong institutional quality as well as use of technology to enrich the soil nutrient balance.

Qualitative and Quantitative Characterization of Municipal Waste in Uncontrolled Dumpsites and Landfills Using Integrated Remote Sensing, Geological and Geophysical Data: A Case Study

The conducted research offers an environmental assessment of municipal waste (MW) using remote sensing (RS), geological, and geophysical datasets. As a test site, the present study aims to characterize one of the largest uncontrolled dumpsites in Egypt. RS data analysis indicates that high temperature values are concentrated at the MW and landfill site allocations as a result of the decomposition process, leading to fire risks. Moreover, the geological and structural data draw attention to the structural-controlled old topography role on MW distributions. Consequently, the dumpsite MW has larger surface quantities near the downthrows of the mapped faults. For MW characterization, geophysical data are acquired to produce2D/3D resistivity models. Because MW has the ability to become soft clay, the municipal organic waste and landfill leachate resistivities are lower than that of municipal solid waste and sandy soils. The geophysical inversion results indicate that the maximum thickness of MW calibrating with the drilled borehole data is 60 m. Furthermore, the estimated MW dumpsite volume is about 42.32 MCM. Accordingly, the MW can be characterized in an accurate qualitative and quantitative manner. Our findings, therefore, help the efforts of uncontrolled dumpsite development and thus contribute to sustainability plans.

Plant-Mycorrhizal Fungi Interactions in Phytoremediation of Geogenic Contaminated Soils

Soil contamination by geogenic contaminants (GCs) represents an imperative environmental problem. Various soil remediation methods have been successfully employed to ameliorate the health risks associated with GCs. Phytoremediation is considered as an eco-friendly and economical approach to revegetate GC-contaminated soils. However, it is a very slow process, as plants take a considerable amount of time to gain biomass. Also, the process is limited only to the depth and surface area of the root. Inoculation of arbuscular mycorrhizal fungi (AMF) with remediating plants has been found to accelerate the phytoremediation process by enhancing plant biomass and their metal accumulation potential while improving the soil physicochemical and biological characteristics. Progress in the field application is hindered by a lack of understanding of complex interactions between host plant and AMF that contribute to metal detoxification/(im)mobilization/accumulation/translocation. Thus, this review is an attempt to reveal the underlying mechanisms of plant-AMF interactions in phytoremediation.

A review on the applications of microbially induced calcium carbonate precipitation in solid waste treatment and soil remediation

Improper disposal and accumulation of solid waste can cause a number of environmental problems, such as the heavy metal contamination of soil. Microbially induced calcium carbonate precipitation (MICP) is considered as a promising technology to solve many environmental problems. Calcium-based solid waste can be utilized as an alternative source of calcium for the MICP process, and carbonate-based biominerals can be used for soil remediation, solid waste treatment, remediation of construction concrete, and generation of bioconcrete. This paper describes the metabolic pathways and mechanisms of microbially induced calcium carbonate precipitation and highlights the value of MICP for solid waste treatment and soil remediation applications. The factors affecting the effectiveness of MICP are discussed and analyzed through an overview of recent studies on the application of MICP in environmental engineering. The paper also summarizes the current challenges for the large-scale application of this innovative technology. In prospective study, MICP can be an effective alternative to conventional technologies in solid waste treatment, soil remediation and CO₂ sequestration, as it can reduce negative environmental impacts and provide long-term economic benefits.

Carcinogenic Risk of Pb, Cd, Ni, and Cr and Critical Ecological Risk of Cd and Cu in Soil and Groundwater around the Municipal Solid Waste Open Dump in Central Thailand

Several consequences of health effects from municipal solid waste caused by carcinogenic and noncarcinogenic metals have been recognized. The water quality index ( $\text{WQI}$ ) in the groundwater around this landfill is 2945.58, which is unacceptable for consumption. The contaminated groundwater mainly appears within a 1 km radius around the landfill. The metal pollution levels in the soil in descending order were Cu > Cd > Zn=Cr > Pb > Ni. The pollution degree (ER) of Cd was 2898.88, and the potential ecological risk index (RI) was 2945.58, indicating that the risk level was very high. Surprisingly, the hazard index (HI) of Pb (2.05) and Fe (1.59) in children was higher than 1. This indicated that the chronic risk and cancer risk caused by Pb and Fe for children were at a medium level. Carcinogenic risk by oral (CR oral) consumption of Ni, Cd, and Cr in children was 1.4E − 04, 2.5E − 04, and 1.8E − 04, respectively, while the lifetime carcinogenic risk (LCR) of Ni, Cd, and Cr in children was 1.5E − 04, 2.8E − 04, and 2.0E − 04, respectively. In adults, CR oral of Ni and Cr were 1.6E − 03 and 3.0E − 04, respectively, while LCR of Ni and Cr were 1.6E − 03 and 3.4E − 04, respectively, which exceeded the carcinogenic risks limits. Our study indicated a lifetime carcinogenic risk to humans. Environmental surveillance should focus on reducing health risks such as continuous monitoring of the groundwater, soil, and leachate treatment process.

Environmental risk assessment and factors influencing heavy metal concentrations in the soil of municipal solid waste landfills

The environmental risk assessment and the factors influencing heavy metals (HM) in the soil at the municipal solid waste landfill sites (MSWLs) were studied by literature review, field survey, and statistical methods. The results indicated that the dominant HM contamination in the soil at the MSWLs was caused by chromium (Cr) with the Nemero index values (PI) from 22.7 to 44.3 and zinc (Zn) with the PI from 0.7 to 9.8. There were significant differences in the Cr, mercury (Hg), lead (Pb), Zn, and arsenic (As) concentrations between soil samples from sanitary and non-sanitary landfills (NSLs) where HM contamination (PI = 10.9) was more obvious. As (CRA_As = 2.35 × 10^-4) and cadmium (Cd) (CRA_Cd = 1.45 × 10^-4) posed potential carcinogenic health effects. The soil Cd concentration had a significant negative correlation (r = -0.476^**) with the landfill age. The soil As concentration had a significant positive correlation (r = 0.472^**) with rainfall in NSLs. There were significant differences in the As (P = 0.042) and copper (Cu) (P = 0.042) concentrations between soil samples from the surrounding areas of MSWLs and the base where soil had higher HM concentrations. For the efficient prevention of HM ecological risk, a scientific site selection, undamaged coverage and anti-seepage systems, standardized management, and ongoing monitoring are required.

Accumulation of essential (copper, iron, zinc) and non-essential (lead, cadmium) heavy metals in Caulerpa racemosa, sea water, and marine sediments of Bintan Island, Indonesia

Background: Heavy metals are materials naturally occurring in nature and increase with a rise in human activity. Ex-mining areas and domestic waste from human settlements are sources of heavy metal contamination that enter and pollute water, which then accumulates in various organisms including the  Caulerpa racemosa community. The accumulation of heavy metals in  C. racemosa has a wide impact on the food chain in aquatic ecosystems and humans because this alga is a consumptive commodity.  

Methods: Sampling of  C. racemosa was carried out at seven sites on Bintan Island, Indonesia covering the eastern (Teluk Bakau, Beralas Pasir, Malang Rapat), northern (Berakit and Pengudang), western (Sakera), and southern parts (Tg. Siambang). Sampling was carried out during different monsoons, and heavy metals in water and sediment samples were measured to determine the heavy metal concentration. Heavy metals were analyzed by a spectrophotometric method using Atomic Absorption Spectrophotometry.  

Results: The results showed that heavy metal concentrations fluctuate according to changes in the wind season, which carry currents and spread pollutants into the water. The concentration of metal in the water is also from anthropogenic activities. The heavy metal content of cadmium (Cd), lead (Pb), copper (Cu), iron (Fe), and zinc (Zn) in  C. racemosa is high in locations close to settlements. Meanwhile, in seawater samples, Fe and Zn metals have the highest concentrations compared to others. 

Conclusions: Ex-bauxite mines are a source of Fe and Zn metal contamination in the environment, especially at Tg. Siambang. The levels of these heavy metals in the sediment are also high, as surface particle deposits accumulate at the bottom of the sediment. In general, the levels of heavy metals Cd, Pb, Cu, Fe, and Zn increase in the northern monsoon because the dynamics of the water transport greater heavy metal pollution.

Detoxification of Copper and Chromium via Dark Hydrogen Fermentation of Potato Waste by Clostridium butyricum Strain 92

The accumulation of various types of waste containing both organic and inorganic metal-containing compounds is extremely hazardous for living organisms. The possibility of polymer degradation, biohydrogen synthesis, and metal detoxification via the dark fermentation of model potato waste was investigated. For this purpose, the strict anaerobic strain was isolated and identified as Clostridium butyricum. The high efficiency of dark hydrogen fermentation of potatoes with yield of hydrogen in 85.8 ± 15.3 L kg−1 VSpotato was observed. The copperand chromium salts solutions were added to the culture fluid to obtain the concentrations of 50, 100, and 200 mg L−1 Cu(II) and Cr(VI) in the active phase of growth (19 h of cultivation). Metals at a concentration of 200 mg L−1 inhibited the fermentation process the most. The hydrogen yield decreased in 7.2 and 3.6 times to 11.9 ± 2.1 and 23.8 ± 5.6 L kg−1 VSpotato in the presence of 200 mg L−1 Cu(II) and Cr(VI), respectively. The efficiencies of the chromium bioremoval in all variants of the experiment were 100%, and those of copper bioremoval were about 90%. A pure culture of strict anaerobes Clostridium butyricum strain 92 was used for the first time for the detoxification of metals. The presented results confirmed the possibility of this promising strain application for industrial H2 production and the bioremediation of contaminated sites.

An overview on metal pollution on touristic sandy beaches: Is the COVID-19 pandemic an opportunity to improve coastal management?

The worldwide spread of the SARS-CoV-2 caused an unprecedented lockdown measures in most countries with consequences on the world society, economy, and sanitary systems. This situation provided an opportunity to identify the effects of human confinement on natural environments, like touristic sandy beaches, which are stressed due to anthropogenic pressures. Based on previous articles about heavy metals sources and levels in these ecosystems, this paper discusses the dynamic of these pollutants and a regulatory scenario associated with COVID-19 sanitation policies. The main findings suggest that 39% of the studies were on Asian sandy beaches, 16% from Europe, while America and Africa with 23% each. Also Co, Cd, Cu, Cr, Zn, Pb, Ni, Fe and Mn were the most frequently analyzed metals in sediments and in several cases their concentrations exceed international guidelines assessment. Finally, even though beaches are under several metals inputs, tourism plays a key role in these ecosystems quality. After analyzing the potential indirect effect of COVID-19 measures on metals dynamics, we propose some key recommendations and management strategies to mitigate heavy metal pollution on sandy tourist beaches. These proposals are useful for decision-makers and stakeholders to improve sandy beach management, mainly those beaches not addressed from a management perspective; and their implementation should be adapted according to the regulations and legislation of each country.

Recent Advances in Aggregation-Induced Emission Active Materials for Sensing of Biologically Important Molecules and Drug Delivery System

The emergence and development of aggregation induced emission (AIE) have attracted worldwide attention due to its unique photophysical phenomenon and for removing the obstacle of aggregation-caused quenching (ACQ) which is the most detrimental process thereby making AIE an important and promising aspect in various fields of fluorescent material, sensing, bioimaging, optoelectronics, drug delivery system, and theranostics. In this review, we have discussed insights and explored recent advances that are being made in AIE active materials and their application in sensing, biological cell imaging, and drug delivery systems, and, furthermore, we explored AIE active fluorescent material as a building block in supramolecular chemistry. Herein, we focus on various AIE active molecules such as tetraphenylethylene, AIE-active polymer, quantum dots, AIE active metal-organic framework and triphenylamine, not only in terms of their synthetic routes but also we outline their applications. Finally, we summarize our view of the construction and application of AIE-active molecules, which thus inspiring young researchers to explore new ideas, innovations, and develop the field of supramolecular chemistry in years to come.

Heavy Metal Contamination and Human Health Implications in the Chan Thnal Reservoir, Cambodia

Chan Thnal reservoir, built during the Pol Pot period, is the major water source for the people in Krang Chek commune, Kampong Speu Province, Cambodia. Metal pollution caused by agricultural activities, improper wastewater treatment, and municipal waste disposal poses serious environmental health problems. In this study, the concentrations of four potential toxic metals (i.e., Cd, Cu, Pb, and Zn) from six locations across the reservoir were investigated both in the water and sediment. The results reflected progressive deterioration and indicated moderate to heavy pollution from the metals. The metal levels in the water were in the order of Zn > Cu > Pb > Cd. The statistical analysis revealed primary sources of heavy metals contamination in the water. Cd, Cu, Zn, and Pb in the water likely originate from anthropogenic activities including agricultural runoff (i.e., the use of fertilizers and pesticides) and urban runoff (i.e., improper wastewater discharge and waste disposal). Among the four metals, the Pb levels in the water significantly exceeded the guideline for drinking water in all locations. The health risk assessment revealed serious non-carcinogenic risks of Pb intake in the children at the age below 10 and infants. Appropriate control and protection strategies are urgently needed to cut off the main Pb exposure pathway in pregnant women, children, and infants.

Extraction of Value-Added Minerals from Various Agricultural, Industrial and Domestic Wastes

Environmental pollution is one of the major concerns throughout the world. The rise of industrialization has increased the generation of waste materials, causing environmental degradation and threat to the health of living beings. To overcome this problem and effectively handle waste materials, proper management skills are required. Waste as a whole is not only waste, but it also holds various valuable materials that can be used again. Such useful materials or elements need to be segregated and recovered using sustainable recovery methods. Agricultural waste, industrial waste, and household waste have the potential to generate different value-added products. More specifically, the industrial waste like fly ash, gypsum waste, and red mud can be used for the recovery of alumina, silica, and zeolites. While agricultural waste like rice husks, sugarcane bagasse, and coconut shells can be used for recovery of silica, calcium, and carbon materials. In addition, domestic waste like incense stick ash and eggshell waste that is rich in calcium can be used for the recovery of calcium-related products. In agricultural, industrial, and domestic sectors, several raw materials are used; therefore, it is of high economic interest to recover valuable minerals and to process them and convert them into merchandisable products. This will not only decrease environmental pollution, it will also provide an environmentally friendly and cost-effective approach for materials synthesis. These value-added materials can be used for medicine, cosmetics, electronics, catalysis, and environmental cleanup.

Quantitative Microbial Risk Assessment (QMRA) of Workers Exposure to Bioaerosols at MSW Open Dumpsites

The bioaerosol exposure data from the study by Akpeimeh, Fletcher, and Evans (2019) was used to compute the risk of infection from the exposure of dumpsite workers to Aspergillus fumigatus and Escherichia coli O157:H7. A stochastic (Markov Chain) model was used to model the transport of the inhaled dose though the human respiratory system and then integrated into the beta-Poisson dose-response model to estimate workers risks of respiratory and gastrointestinal (GI) infection. The infection risk was computed based on workers exposure to E. coli O157:H7 at 10-50% pathogen ingestion rate and pathogen-indicator ratio (P:I) of 1:10³ and 1:10⁴ , while exposure to A. fumigatus was based solely on the average initial exposure dose. The results showed that after 11 hours of exposure, workers engaged in scavenging, waste sorting, and site monitoring were at risk of respiratory and GI infection in the magnitude of 10^-1 . However, the risk estimates associated with specific areas of the dumpsite showed that, the risk of GI infection at the active area ranged between 3.23 × 10^-3 -1.56 × 10^-2 and 3.25 × 10^-4 -1.62 × 10^-3 ; dormant area 2.06 × 10^-3 -1.01 × 10^-2 and 2.09 × 10^-4 -1.04 × 10^-3 ; entrance 1.85 × 10^-3 -9.09 × 10^-3 and 1.87 × 10^-4 -9.27 × 10^-4 ; boundary 1.82 × 10^-3 -8.82 × 10^-3 and 2.09 × 10^-4 -8.94 × 10^-4 for P:I = 1:10³ and 1:10⁴ respectively, while the risk of respiratory infection risks were in the magnitude of 10^-1 for all four locations. The estimated risk of workers developing respiratory and gastrointestinal infections were high for all activities assessed at the dumpsite.

Metabolic Toxification of 1,2-Unsaturated Pyrrolizidine Alkaloids Causes Human Hepatic Sinusoidal Obstruction Syndrome: The Update

Saturated and unsaturated pyrrolizidine alkaloids (PAs) are present in more than 6000 plant species growing in countries all over the world. They have a typical heterocyclic structure in common, but differ in their potential toxicity, depending on the presence or absence of a double bond between C1 and C2. Fortunately, most plants contain saturated PAs without this double bond and are therefore not toxic for consumption by humans or animals. In a minority of plants, however, PAs with this double bond between C1 and C2 exhibit strong hepatotoxic, genotoxic, cytotoxic, neurotoxic, and tumorigenic potentials. If consumed in error and in large emouns, plants with 1,2-unsaturated PAs induce metabolic breaking-off of the double bonds of the unsaturated PAs, generating PA radicals that may trigger severe liver injury through a process involving microsomal P450 (CYP), with preference of its isoforms CYP 2A6, CYP 3A4, and CYP 3A5. This toxifying CYP-dependent conversion occurs primarily in the endoplasmic reticulum of the hepatocytes equivalent to the microsomal fraction. Toxified PAs injure the protein membranes of hepatocytes, and after passing their plasma membranes, more so the liver sinusoidal endothelial cells (LSECs), leading to life-threatening hepatic sinusoidal obstruction syndrome (HSOS). This injury is easily diagnosed by blood pyrrolizidine protein adducts, which are perfect diagnostic biomarkers, supporting causality evaluation using the updated RUCAM (Roussel Uclaf Causality Assessment Method). HSOS is clinically characterized by weight gain due to fluid accumulation (ascites, pleural effusion, and edema), and may lead to acute liver failure, liver transplantation, or death. In conclusion, plant-derived PAs with a double bond between C1 and C2 are potentially hepatotoxic after metabolic removal of the double bond, and may cause PA-HSOS with a potential lethal outcome, even if PA consumption is stopped.

Analysis of Generation, of Household Waste and Its Potential Utilization in Darul Imarah subdistrict - Aceh Besar District

Abstract   BACKGROUND: Darul Imarah District is one of the largest sub-districts in Aceh Besar, which is very dense and faces a waste problem. The increase in population in the Darul Imarah sub-district has resulted in waste generation.   AIM: analyzing the generation, composition of household waste and its potential use in Darul Imarah subdistrict, Aceh Besar District, Aceh Province   METHODS: This study used a cross-sectional study design by conducting an initial survey on the generationvolume and composition of waste in each house selected as a sample and continued with an experimental study. The research object is solid wastegarbage generated from daily activities in the selected sample group households in the Darul Imarah sub-district in the form of primary data from sampling, with a random sampling technique. The number of samples of 100 houses with the respondent's target is housewives. Data analysis was carried out using the T-Test difference test to compare the value before being given knowledge about household waste management after being given knowledge.   RESULTS: The study results show differences in the generation and composition of waste before and after being given knowledge about household waste management in Darul Imarah District, Kab. Aceh Besar with a significant (sig.) Of 0.000 (0.05). The total waste produced before being given knowledge about waste management was 164.6 kg. The composition of the waste consists of plastic waste (22.9 kg), wet waste (62.5 kg), dry waste (37.4 kg), and glass waste (41.8 kg). After being given knowledge about waste management, there was a reduction in the total waste produced, namely 131.8 kg. A significant reduction in the amount of waste in the volume of plastic waste (7.8 kg), wet waste (48.0 kg), dry waste (37.3 kg), and glass waste (38.8 kg). There is a difference in the volume of plastic waste in plastic waste after being given knowledge about household waste management, with the difference between the average before and after is 0.1530 and the difference is between 0.1045 - 0.2015 (95% Ci). In wet waste, there is a difference in the volume of wet waste after being given knowledge about household waste management with the difference between the before and after averages of 0.1450 and the difference between the differences is between 0.0784 - 0.2116 (95% Ci). In dry waste, there is no difference in the volume of dry waste after being given knowledge about household waste management with an average difference before and after of 0.0020, and the difference is between -, 0008 - 0.0048 (95% Ci). There is a difference in the volume of glass waste in glass waste after being given knowledge about household waste management with the difference between the before and after an average of 0.0310 and the difference between the differences between 0.0170 - 0.0450 (95% Ci). CONCLUSION:   There are differences in the generation and composition of waste before and after being given knowledge about household waste management in Darul Imarah District, Kab. Aceh Besar with a significant (sig.) of 0.000 (0.05).

Increase in SARS-CoV-2 infected biomedical waste among low middle-income countries: environmental sustainability and impact with health implications

Studies have shown that severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) is a highly infectious disease, with global deaths rising to about 360,438 as of 28 May 2020. Different countries have used various approaches such as lockdown, social distancing, maintenance of personal hygiene, and increased establishment of testing and isolation centers to manage the pandemic. Poor biomedical waste (BMW) management, treatment, and disposal techniques, especially SARS-CoV-2 infected BMW, may threaten the environmental and public health in most developing countries and, by extension, impact the economic status of individuals and the nation at large. This may increase the potential for the transmission of air/blood body fluid-borne pathogens, increase the growth of microorganisms, risk of mutagenesis, and upsurge of more virulent strain. In contrast, uncontrolled substandard burning could increase the potential spread of nosocomial infection and environmental exposure to toxic organic compounds, heavy metals, radioactive, and genotoxic bio-aerosols which might be present in the gaseous, liquid, and solid by-products. The paucity of understanding of pathophysiology and management of the SARS-CoV-2 pandemic has also necessitated the need to put in place appropriate disposal techniques to cater for the sudden increase in the global demand for personal protective equipment (PPE) and pharmaceutical drugs to manage the pandemic and to reduce the risk of preventable infection by the waste. Therefore, there is a need for adequate sensitization, awareness, and environmental monitoring of the impacts of improper handling of SARS-CoV-2 infected BMWs. Hence, this review aimed to address the issues relating to the improper management of increased SARS-CoV-2 infected BMW in low middle-income countries (LMICs).

Biochemical Responses of Medicinal Plant Tussilago farfara L. to Elevated Heavy Metal Concentrations in Soils of Urban Areas

This study was conducted in Tyumen (Russian Federation) to establish the effects of heavy metals' (Cu, Zn, Fe, Mn, Pb, and Cd) accumulation in soil and coltsfoot, as well as plants' biochemical responses to such an accumulation. The mobile and acid-soluble heavy metal fractions in soils, and the heavy metal contents in plants, were determined by atomic absorption spectrophotometry. The Cu, Zn, Fe, Mn, and Pb concentrations in soils exceeded background values. Pb content at the battery manufacturing plant was above the maximum permitted concentration. The percentages of the mobile heavy metal fractions decreased in the following order: Mn > Zn > Cu > Fe. The greatest heavy metal accumulation in soils and plants was found at the battery manufacturing and metallurgical plants examined in our study. Heavy metals' accumulation in the aboveground part of Tussilago farfara decreased in the following order: Fe > Zn > Cu > Mn > Pb > Cd. The accumulation of heavy metals stimulated the synthesis of photosynthetic pigments by 6-30%. Heavy metals provoked oxidative stress in cells, increasing the concentration of lipid peroxidation in products by up to 80%. Plant phenolics and flavonoids in the urban area of our study decreased compared to those in the control by 1.05, reaching up to 6.5 times. The change in coltsfoot catalase activity both increased and declined. Biochemical responses and heavy metal accumulation in coltsfoot from urban areas limit its use for medicinal purposes.

Monitoring and Assessment of Groundwater Quality at Landfill Sites: Selected Case Studies of Poland and the Czech Republic

In order to protect the components of natural environment, each landfill must be properly secured and the monitoring program should be adopted. This study aims to present a comparative analysis of groundwater quality at selected landfill sites in Poland and the Czech Republic, with a special attention given to the levels and temporal changes of heavy metals (HMs) concentrations measured in collected groundwater samples. A secondary objective was to detect possible leakages of pollutants from the landfill body, into the groundwater, and further into the environment. The assessment of groundwater quality was based on a comparison of HMs concentrations with standards provided by the European environmental laws. On the basis of the long-term monitoring period, it was revealed, for the Polish landfill site, that the groundwater quality is improving over time, especially due to remedial works applied. For the Czech landfill, it was observed that the quality of groundwater is not negatively affected by the operation of the landfill, but in the immediate vicinity of the landfill, the groundwater quality is significantly affected by the agricultural use of neighbouring lands, as well as by the storage of construction and demolition wastes. The results showed that the leachate did not leak outside the landfills, especially due to minimal concentrations of HMs, measured in groundwater samples, taken from the piezometers located in the outflow direction from the landfills.

Soil quality of simulated landfill exposure to plastics in context of heavy metal analysis

It is imperative to have soil guidelines that consider commodities on the market especially biodegradable plastics that are increasing in popularity nowadays. In this short communication, heavy metal in soil was investigated after degrading plastics commonly used on the market. The plastic materials included virgin linear low-density polyethylene, plastic waste of polyolefin origin, and biodegradables of oxo- and hydro-based types. Soil/water matrix that simulates arid land conditions was used. Metals including cobalt, chromium, cadmium, and nickel, among others, were studied after exposure of three continuous months. It was noted that background concentrations reduced with water indicating that leachate might contain the majority of the transferred metals from plastics. In particular, the concentration of nickel in soil was detected to be 84 ppm after exposure to type I of the oxo-biodegradable commercial plastics. Furthermore, the material of similar source started to retain nickel by day 74 of exposure. This surpasses both Canadian and Australian guidelines discussed herein. Furthermore, nickel concentrations exceeded international guidelines and point towards the need for remediation. Mean values of chromium exceeded soil control results and the USA remediation values in the case of single screw compounded plastics. It should also be noted that the work conducted points towards metal trace detection limits that are tied to waste and sludge disposal in an improper manner with time.

Distribution Characteristics, Pollution Assessment, and Source Identification of Heavy Metals in Soils Around a Landfill-Farmland Multisource Hybrid District

Heavy-metal pollution is a negative impact of municipal solid-waste landfills. The multiple pollution transport pathways (including leachate, runoff, and waste gas) and complex and co-existing potential pollution sources (such as agricultural activities) around landfills require a combination of different pollution assessment methods and source identification tools to address pollution distribution and potential risks. In this study, the distributions of eight heavy metals (chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn), arsenic (As), cadmium (Cd), and mercury (Hg)) around a landfill were analyzed using 60 topsoil samples. Ecological risk assessments indicated that there are currently no ecological risks. Based on health risk assessments, however, high concentrations of Cr and As in the soil pose a noncarcinogenic and carcinogenic risk to humans in the study area, respectively. In addition, the geoaccumulation indices for Cr, Cu, Ni, Zn, As, and Hg confirmed anthropogenic sources of accumulation of these metals in soils. Additionally, the potential ecological risk index indicated that Hg posed a considerable risk to the ecology of the area around the landfill. Sources of heavy metals in the study area were attributed to natural sources (22.10%), agricultural activities (27.65%), landfill (31.35%), and transportation (18.89%). The continuous accumulation of heavy metals and health risk for humans suggests the need to continuously monitor of heavy metal content and migration around the landfill. This study provides a reference for local authorities in the study area.

Potential Environmental and Human Health Risks Caused by Antibiotic-Resistant Bacteria (ARB), Antibiotic Resistance Genes (ARGs) and Emerging Contaminants (ECs) from Municipal Solid Waste (MSW) Landfill

The disposal of municipal solid waste (MSW) directly at landfills or open dump areas, without segregation and treatment, is a significant concern due to its hazardous contents of antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs), and metal resistance genes (MGEs). The released leachate from landfills greatly effects the soil physicochemical, biological, and groundwater properties associated with agricultural activity and human health. The abundance of ARB, ARGs, and MGEs have been reported worldwide, including MSW landfill sites, animal husbandry, wastewater, groundwater, soil, and aerosol. This review elucidates the occurrence and abundance of ARB, ARGs, and MRGs, which are regarded as emerging contaminants (ECs). Recently, ECs have received global attention because of their prevalence in leachate as a substantial threat to environmental and public health, including an economic burden for developing nations. The present review exclusively discusses the demands to develop a novel eco-friendly management strategy to combat these global issues. This review also gives an intrinsic discussion about the insights of different aspects of environmental and public health concerns caused due to massive leachate generation, the abundance of antibiotics resistance (AR), and the effects of released leachate on the various environmental reservoirs and human health. Furthermore, the current review throws light on the source and fate of different ECs of landfill leachate and their possible impact on the nearby environments (groundwater, surface water, and soil) affecting human health. The present review strongly suggests the demand for future research focuses on the advancement of the removal efficiency of contaminants with the improvement of relevant landfill management to reduce the potential effects of disposable waste. We propose the necessity of the identification and monitoring of potential environmental and human health risks associated with landfill leachate contaminants.

Environmental burden of unprocessed solid waste handling in Enugu State, Nigeria

Improper waste management has assumed a worrisome dimension in cities across many developing countries. One of its commonest features is open dumps. Open dumps in Enugu and Nsukka were investigated in this study. Waste samples were collected from ten dumps located in low-income, low-to-middle income, and high-income zones of the study area. The composition of waste was determined following standard methods and results obtained subjected to statistical analyses. Selected open dumps were subjected to detailed inspection in order to identify possible environmental impacts. Soil samples were also collected from the top soil and subsoil (15 cm) of selected dumps and analyzed for As, Cd, Cr, Cu, Hg, Mn, Pb, Ni, Cd, and Zn. The sources of contamination were determined using the principal component analysis (PCA) and cluster analysis (CA). Results of heavy metal analyses were used to determine extent of soil pollution. Food waste ranged from 29.6 to 56.5% with an average of 42.2%. Analysis along income line showed a decline in the proportion of food and rubber waste from lower to high income. The order of heavy metals concentration in waste dump soils investigated was as follows: Mn > Zn > Cu > Cr > Pb > As > Ni > Cd > Hg. The pollution indices (PI) of the dumpsites ranged from 1.87 for Ni to 1634.6 for Cu in the topsoil, and 0.62 for Ni to 1354.74 for Cu in the subsoil, indicating a severe level of pollution. Pollution load index (PLI) ranged from 25.38 to 75.07 with a mean of 60.75 for the dump surface and from 51.46 to 21.7 with a mean of 33.86 below the dump soil. Forty-three percent (43%) of the topsoil and 40% of the subsoil exhibited ecological risk index values greater than 320, indicating extreme degree of ecological risk. The first principal and second principal components with 36% and 28.2% variance respectively represent the growing impact of electronic waste disposal, specifically mobile phones, personal computers, and other potable electronic devices with short life span on waste dumps. The third principal component (10.2%) represents input from households and other forms of chemicals such as insecticides, paints, and detergents.

Cost analysis and optimization of Blockchain-based solid waste management traceability system

As global concerns over End-of-Life (EoL) wastes released to the environment is rising, the need for enhancing the transparency of recycling systems is growing. To address the waste traceability issue, technologies such as Blockchain can be instrumental in the proper disposal and handling of wastes. In this paper, we propose a Blockchain-based Solid Waste Management (SWM) model that can help municipalities enhance the efficiency of their waste management efforts. A Blockchain framework owned and controlled by a municipality is proposed in which customer companies pay to join the platform to avail services from the suppliers managed by the municipality. The cost burdens to both supplier and consumer companies have been discussed. In addition, an optimization model is developed to determine the optimal quantity of waste that can be traded between supplier and consumer companies in order to maximize their profit based on parameters such as the number of suppliers, consumer companies, and the processing capacity of customer companies and several constraints including maximum storing capacity, storage, and transportation constraints. Further, the cost aspects associated with Blockchain implementation are estimated from several use cases obtained from companies providing Blockchain solutions.

Evaluation of drinking water quality using heavy metal pollution indexing models in an agrarian, non-industrialised area of South-East Nigeria

The objectives of this study were to evaluate the physicochemical properties of drinking water sources at Ihiala, Nigeria, and to assess the water quality using the heavy metal pollution index, heavy metal evaluation index and contamination index models. Physicochemical parameters like pH, total hardness, total dissolved solids, nitrate, cyanide, residual chlorine and six metals (Al, Cd, Cr, Cu, Pb and Ni) were analyzed in the water samples, and heavy metal pollution indices computed. The spring and borehole waters had better organoleptic properties compared to stream, river and sachet waters. Total hardness, pH and nitrate were the major nonmetallic contributors to the poor water quality. The mean pollution indices were: heavy metal pollution index (HPI) 143.02 ± 71.16, heavy metal evaluation index (HEI) 7.53 ± 4.12 and contamination index (C_d) 1.53 ± 4.12. Sixty percent of the samples exceeded the critical HPI value of 100. There was significant (P < 0.01) positive correlation between HPI and C_d, HPI and HEI (r = 0.886) and HEI and C_d (r = 1.000). Lead contributed most to heavy metal pollution of water in the region. The quality of most water sources in Ihiala is not good for drinking.

Communities of arthropods associated with the composting process of the organic solid waste produced in a landfill in Brazil

Composting is a process recommended as a way to recycle the organic part of the solid waste in which several micro and macroorganisms act as decomposers of the organic matter, in a process that takes around 120 days and faces roughly three different phases. Because we do not know the community of arthropods associated with the compost produced in one of the biggest landfills placed in Brazil, here we collected and identified the community of arthropods present in each phase of the organic compost. Our hypothesis is that the abundance and diversity of arthropods are different within each phase of the compost and we hope to find particular groups of arthropods that can be used as indicator of specific phases. In total, we identified the taxa of 1204 arthropods (insects, arachnidan and diplopods). We found that diversity and abundancy of arthropods were indeed different for each maturation phase of the compost, but we did not find families that are good indicators of each phase. In addition, to be certain about the safety of the compost produced, we investigated the presence of microorganisms in the final product and we found considerable levels of Escherichia coli and Enterococcus faecalis in some samples. Finally, we argue that the presence of these macro and microorganisms during the process may be beneficial or harmful. Since their presence decreased greatly by the end of the process, we acknowledge that composting works efficiently as a way to recycle the organic part of the waste generated in Brazil.