A comprehensive review of domestic-open waste burning: recent trends, methodology comparison, and factors assessment

Polymer waste and pollution in oral healthcare clinics: a systematic review

BACKGROUND

Modern oral healthcare extensively uses polymer items and devices derived from various monomeric compounds. These materials are essential for personal protective equipment, infection barriers, packaging, and intraoral devices. The COVID-19 pandemic has led to an increased reliance on single-use polymer items, causing supply chain disruptions and higher costs. This systematic review explores the extent of polymer waste and pollution generated in oral healthcare clinics.

MATERIALS AND METHODS

A systematic review protocol was registered with PROSPERO and was formatted according to PRISMA guidelines and SWiM recommendations. Eligibility criteria included studies that provided quantified estimates of polymer waste or pollution in air or wastewater from oral healthcare clinics. Comprehensive electronic searches were conducted across several bibliometric databases, followed by data extraction and risk of bias assessments performed by two independent reviewers.

RESULTS

A total of thirty studies were included in the review. Sixteen papers reported on waste audits that detailed polymer waste data, while eight studies focused on pollution caused by polymer nano- and microparticles in clinical settings. Additionally, six experimental studies investigated potential leakage of monomeric eluates or polymer particles from landfill waste. There was significant variation in the amount of polymer waste generated per patient, ranging from 81 to 384 g per operatory room per day. On-site sampling revealed the presence of polymer nano- and microparticles in the clinic air, which was influenced by dental procedures and the equipment used.

CONCLUSIONS

This review highlights critical knowledge gaps about polymer waste and pollution in oral healthcare clinics. The variability of study designs limited the feasibility of meta-analysis. Current evidence indicates substantial polymer waste generation, particularly from single-use items, as well as potential environmental impacts from monomeric eluates and polymer microparticles. Future research should focus on sustainable polymer waste management solutions to reduce environmental pollution in oral healthcare settings.

Potential exposure to metals-bound particulate during open burning of different waste materials

Smoke caused by open waste burning (OWB) contains metal-bound particulates that can harm human health. This study aimed to understand the differences in the exposure of particulate matter 10 and 2.5 µm (PM10 and PM2.5) concentrations in several distances and investigated potential health impacts of metal-bound particulates. Observations were made based on laboratory and field studies consisting of multiple open burning practices, PM capture, and inductively coupled plasma optical emission spectrometry (ICP-OES) analysis. Moreover, the potential health risks in terms of respiratory deposition dose (RDD), carcinogenic risk (CR), and non-carcinogenic risks were determined. The results showed that the exposure levels in the distance range of 1 - 5 m were not significantly different (0.419 - 0.607 mg/m3 for PM10 and 0.289 - 0.399 mg/m3 for PM2.5). During the day, RDD values were higher for adults (2.58 - 5.79 µg/min), with adults facing greater short-term exposure risk (2.45 - 5.79 µg/min) than children (2.22 - 3.90 µg/min). It was found that the highest CR from the ingestion pathway was caused by arsenic (As) from textile burning (1.41 × 10-6), and that caused by chromium (Cr) through the inhalation pathway from backyard waste burning (7.43 × 10-9). However, the CR values for both the pathways were below the acceptable threshold. In addition, the hazard index (HI), for both adults and children were less than 1 for all metal concentrations in all types of waste burning. The higher HI value in children indicates that they are most vulnerable to long-term exposure to OWB. Preventive actions to reduce OWB activity are necessary to reduce the adverse health effects.

Evaluation of heavy metal pollution and ecological risk of surface sediments in a tropical mountainous River-Estuary-Shelf Continuum system: A case study of the Selangor River, Malaysia

As human activities continue to increase, the global production of pollutants has increased significantly, with the majority of pollutants being transported to the ocean via rivers, resulting in intensified pollution in estuaries and coastal areas. To maintain a healthy marine ecological environment, it is necessary to consider rivers, estuaries, and coastal seas as integrated systems and implement pollution management based on the concept of land-ocean integration. In this study, heavy metal elements in the surface sediments of Selangor River-Estuary-Coastal Shelf Continuum were collected and analysed to assess their pollution levels and potential ecological risks. The results show that the heavy metal content is high in the downstream and estuarine regions, with a general decreasing trend observed from nearshore to offshore in the coastal shelf area. The heavy metal pollution assessment indicates that the surface sediments of the Selangor River-Estuary-Coastal Shelf continuum were contaminated, with the most severe pollution occurring downstream and within the estuary. The pollution levels gradually decrease after exiting the estuary. The ecological risk associated with heavy metal pollution in rivers, estuaries, and southeastern coastal areas was classified as moderate to serious, whereas other areas exhibited only slight ecological risks. Specifically, As causes serious pollution in the river and estuary, with moderate-to-serious pollution in the coastal shelf area and moderate-to-serious ecological risks, mainly originating from mining within the river basin. Pb causes moderate pollution in the river, estuary, and coastal areas, with slight ecological risks due to mining within the river basin and inputs from nearby rivers, ports, and industrial activities. Other heavy metals cause minor pollution and pose minimal ecological risks.

Waste to energy, indispensable cornerstone for circular economy: A mini-review

This mini-review aims at proving that waste-to-energy (WtE) is an essential cornerstone for circular economy (CE). Based on literature, the history of thermal waste treatment over the last 150 years is investigated, from open burning to WtE with resource recovery and final sink function. The results show that in the past incineration solved the issues it was designed for but often created new and sometimes even worse problems: The introduction of incineration in the 19th century improved urban sanitation, decreased waste volume and prolonged operational life of landfills. But it also polluted the environment, triggering an unprecedented scientific and engineering effort of all stakeholders. Today, WtE is one of the best investigated and optimized technologies in waste management. It enables the recovery of energy as heat and electric power and facilitates the 'cleaning' of cycles by the destruction of hazardous organic substances. Recent developments in resource recovery from WtE residues allow to recycle metals and, in the case of sewage sludge, even phosphorus by thermal recycling. Combined with carbon capture and storage technology, WtE stands for a quantifiable contribution to greenhouse gas reduction. Today, WtE is indispensable to reach the goals of CE, namely recycling of energy and materials, supplying safe final sinks for persistent organic substances and minimizing the need for sinks for hazardous inorganic substances.

Utilizing machine learning to classify persistent organic pollutants in the serum of pregnant women: a predictive modeling approach

Polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), and per- and poly-fluoroalkyl substances (PFAS) are persistent organic pollutants (POPs) that remain detrimental to critical subpopulations, namely pregnant women. Required tests for biomonitoring are quite expensive. Moreover, statistical models aiming to discover the relationships between pollutants levels and human characteristics have their limitations. Therefore, the objective of this study is to use machine learning predictive models to further examine the pollutants' predictors, while comparing them. Levels of 33 congeners were measured in the serum of 269 pregnant women, from whom data was collected regarding sociodemographic, dietary, environmental, and anthropometric characteristics. Several machine learning algorithms were compared using "Python" for each pollutant: support vector machine (SVM), random forest, XGBoost, and neural networks. The aforementioned characteristics were included in the model as features. Prediction, accuracy, precision, recall, F1-score, area under the ROC curve (AUC), sensitivity, and specificity were retrieved to compare the models between them and among pollutants. The highest performing model for all pollutants was Random Forest. Results showed a moderate to acceptable performance and discriminative power among all POPs, with OCPs' model performing slightly better than all other models. Top related features for each model were also presented using SHAP analysis, detailing the predictors' negative or positive impact on the model. In conclusion, developing such a tool is of major importance in a context of limited financial and research resources. Nevertheless, machine learning models should always be interpreted with caution by exploring all evaluation metrics.

Estimating personal exposures to household air pollution and plastic garbage burning among adolescent girls in Jalapa, Guatemala

Waste collection services are uncommon in rural areas of low-resource countries, causing waste accumulation and subsequent dumping and burning of garbage. Air pollution from household garbage burning, including plastics, has been observed in Jalapa, Guatemala in addition to household air pollution (HAP) from cooking. Adolescent girls often help with these cooking and household tasks, but little is known about their exposures. We characterized 24-h exposures to HAP and household garbage burning in adolescent girls by measuring fine particulate matter (PM2.5), black carbon (BC), urinary biomarkers of polycyclic aromatic hydrocarbons (PAHs), bisphenol A (BPA), and phthalates. We recruited 60 girls between 13 and 17 years of age who helped with cooking activities and lived with participants of the Household Air Pollution Intervention Network (HAPIN) trial. We recruited n = 30 girls each from the control (wood-burning stove) and intervention (liquefied petroleum gas stove) arms. We also measured real-time kitchen concentrations of BC in 20 homes (33%). PM2.5 and BC were measured in n = 21 control and n = 20 intervention participants. Median concentrations of personal PM2.5 and BC and kitchen BC were lower (p < 0.05) in the intervention arm by 87%, 80%, and 85%, respectively. PAH metabolite concentrations were lower (p < 0.001) for all nine metabolites in intervention (n = 26) compared to control participants (n = 29). Urinary BPA concentrations were 66% higher in participants who reported using cosmetics (p = 0.02), and phthalate concentrations were 63% higher in participants who had reported using hair products during the sample period (p = 0.05). Our results suggest that gas stoves can reduce HAP exposures among adolescents who are not primary cooks at home. Biomarkers of plastic exposure were not associated with intervention status, but some were elevated compared to age- and sex-matched participants of the National Health and Nutrition Examination Survey (NHANES).

Learning from the past to plan for the future: An historical review of the evolution of waste and resource management 1970-2020 and reflections on priorities 2020-2030 - The perspective of an involved witness

Improving waste and resource management (WaRM) around the world can halve the weight of plastics entering the oceans, significantly mitigate global heating and contribute directly to 12 of 17 sustainable development goals (SDGs). Achieving such results demands understanding and learning from historical evolution of WaRM. The baseline is 1970, prior to environmental legislation. Early steps in the Global North focused on the 'technical fix' within strictly enforced legal frameworks, first bringing hazardous wastes and municipal solid wastes (MSW) under control, then gradually ramping up environmental standards. Using modern technologies to the Global South often failed due to institutional and financial constraints. From 1990, focus switched to integrating technical and governance aspects: local institutional coherence, financial sustainability, provider inclusivity, user inclusivity, national legislative and policy framework. The Global North rediscovered recycling, using policy measures to promote segregation at source; this relied on new markets in emerging economies, which had largely disappeared by 2020. The Global South is making progress on bringing wastes under control, but around 2.7 billion people lack access to waste collection, while ~40% of collected MSW is open dumped or burned - a continuing global waste emergency. So, much remains to be done to move further towards a circular economy. Three policy priorities are critical for all countries: access to sustainable financing, rethinking sustainable recycling and worldwide extended producer responsibility with teeth. Extending services to unserved communities (SDG11.6.1) requires a people-centred approach, working with communities to provide both quality services and decent livelihoods for collection and recycling workers.

U.S. plastic waste exports: A state-by-state analysis pre- and post-China import ban

This study analyzes the regional implications of China's 2017 import ban on plastic waste by examining U.S. census data. A statistically significant decrease in total U.S. plastic waste exports was found, dropping from about 1.4 million tons to 0.6 million tons in the post-ban period. California remained the top exporter, throughout both pre- and post-ban periods, while South Carolina exhibited the highest per capita exports. Malaysia emerged as the largest importer of U.S. plastic waste, followed by Vietnam, Indonesia, and Thailand. The ban also led to a change in the composition of the exported plastic waste. Ethylene polymers increased from 32.6% of total exports in the pre-ban period to 46.9% in the post-ban period. Other plastics (vinyl chloride polymers, styrene polymers, and for plastics not elsewhere specified or included) decreased from 67.4% of total exports in the pre-ban period to 53.1% in the post-ban period. Moreover, we found that exporting plastic waste has significant environmental and human health impacts. For example, the Global Warming Potential (GWP) decreased from 20 million tons CO2-eq in the scenario where 100% of plastics are exported, or 25 million tons exported from the U.S. since 2002, to -11.1 million tons CO2-eq in the scenario where 100% of plastics are treated domestically. Transportation exacerbates these impacts for exported waste scenarios, increasing to 5.4 million tons CO2-eq when plastics are exported by ship while decreasing to 0.9 million tons CO2-eq for domestic treatment. Although exporting plastic waste is initially cost-effective, our study highlights that investing in domestic waste management can yield significant long-term benefits, considering the environmental and public health impacts. Therefore, it is crucial to prioritize context-specific solutions to address the challenges of the evolving global plastic waste landscape.

Health Impact of Household Waste Burning in Khartoum State, Sudan

Background

Waste disposal and management is a global concern affecting both high- and low-income countries. This research assessed the health impact of burning household waste in Khartoum State, Sudan.

Methods

An online community-based cross-sectional study was implemented on a sample of 844 participants selected through a stratified random sampling technique across Khartoum State. The data were collected through a standardized pre tested online questionnaire. The data file was georeferenced through Google Earth Pro and analysed with SPSS 23 and ArcGIS 10.3. The data were summarized numerically and graphically. The appropriate frequency tables were used in ArcGIS to generate geographical distribution maps of household waste burning and predictive health risk maps of waste burning in Khartoum State. Statistical tests performed for association carried out were Chi-square and ANOVA. A binary regression analysis established the relationship between burning of household waste and its associated factors. All statistical tests were considered significant when p < 0.05.

Results

The practice of burning household waste was performed by 74.5% (619/831) of the participants with 50.8% (311/612) who reported burning the waste weekly. The health conditions related to household waste burning were predominately asthma (57.0%) and respiratory manifestations (38.0%). Of the ten contributing factors of health risks related to burning household waste, the two statistically significant were the frequency of waste collection (OR = 0.720, 95% [CI: 0.593-0.875], p = 0.001) and the place of waste disposal (OR = 0.791, 95% [CI: 0.651-0.961], p = 0.018).

Conclusion

The practice of burning household waste in Khartoum State was a public health concern. Sociodemographic and managerial factors exposing residents to health risks appeal political, health authorities and communities to establish a partnership to manage household waste for public safety and good quality of life.

Ecotoxicity of PM10 emissions generated during controlled burning of waste PET

Domestic waste is often burned either as fuel for winter heating or in open areas, simply to get rid of waste. Polyethylene terephthalate (PET) represents an important component of plastics usage as well as of plastic waste produced. While most studies attempt to characterize environmental risk of open burning of mixed household waste, present work evaluates chemical and ecotoxicological parameters of particulate matter (PM) produced during controlled burning of PET samples. In the PM₁₀ samples, polycyclic aromatic hydrocarbon and heavy metal concentrations were measured, ecotoxicity was evaluated using the kinetic Vibrio fischeri bioassay. Both chemical composition and ecotoxicity of the 4 samples showed significant correlation, regardless of the colored or colorless nature of the original PET sample. Antimony was found in considerable concentrations, in the range of 6.93-16.9 mg/kg. PAHs profiles of the samples were very similar, showing the dominance of 4-and 5-ring PAHs, including carcinogenic benzo(a)pyrene.

Plant-based coagulants/flocculants: characteristics, mechanisms, and possible utilization in treating aquaculture effluent and benefiting from the recovered nutrients

The increasing intensification of the aquaculture industry requires the development of new strategies to reduce the negative impacts of wastewater on the environment. Plant-based coagulants/flocculants, regarded as one of the environmentally friendly technologies for wastewater treatment, show good performance in the removal of suspended solids from wastewater. The aforementioned technology involves the utilization of plants as coagulants/flocculants in the treatment process and produces nontoxic sludge as treatment by-products. The produced sludge could be converted into valuable compounds used in agriculture. This review summarizes coagulation-flocculation by using plant-based coagulants/flocculants, its mechanisms, operational factors that control the treatment process, and its application in the treatment of wastewater, especially aquaculture effluent. Moreover, this work discusses the potential utilization of aquaculture sludge as a valuable compound used in agriculture. The presented review aims to emphasize the potential of using plant-based coagulants/flocculants in the treatment of aquaculture effluent and explore the potential of using the produced sludge as fertilizer for plants to solve problems related to sludge handling and the toxicity of inorganic coagulants in a recirculating aquaculture system. This paper concluded that utilization of recovered nutrients in the form of solids is feasible for agricultural purposes, while a hydroponic system can be used to reclaim the nutrients in the form of solution.