The use of artificial intelligence algorithms to detect macroplastics in aquatic environments: A critical review.

The presence of macroplastic (MP) is having serious consequences on natural ecosystems, directly affecting biota and human wellbeing. Given this scenario, estimating MPs' abundance is crucial for assessing the issue and formulating effective waste management strategies. In this context, the main objective of this critical review is to analyze the use of machine learning (ML) techniques, with a particular interest in deep learning (DL) approaches, to detect, classify and quantify MPs in aquatic environments, supported by datasets such as satellite or aerial images and video recordings taken by unmanned aerial vehicles. This article provides a concise overview of artificial intelligence concepts, followed by a bibliometric analysis and a critical review. The search methodology aimed to categorize the scientific contributions through temporal and spatial criteria for bibliometric analysis, whereas the critical review was based on generating homogeneous groups according to the complexity of ML and DL methods, as well as the type of dataset. In light of the review carried out, classical ML techniques, such as random forest or support vector machines, showed robustness in MPs detection. However, it seems that achieving optimal efficiencies in multiclass classification is a limitation for these methods. Consequently, more advanced techniques such as DL approaches are taking the lead for the detection and multiclass classification of MPs. A series of architectures based on convolutional neural networks, and the use of complex pre-trained models through the transfer learning, are currently being explored (e.g., VGG16 and YOLO models), although currently the computational expense is high due to the need for processing large volumes of data. Additionally, there seems to be a trend towards detecting smaller plastic, which need higher resolution images. Finally, it is important to stress that since 2020 there has been a significant increase in scientific research focusing on transformer-based architectures for object detection. Although this can be considered the current state of the art, no studies have been identified that utilize these architectures for MP detection.

A multi-criteria decision framework for circular wastewater systems in emerging megacities of the Global South.

Lima faces increasing water stress due to demographic growth, climate change and outdated water management infrastructure. Moreover, its highly centralized wastewater management system is currently unable to recover water or other resources. Hence, the primary aim of this study is to identify suitable wastewater treatment alternatives for both eutrophication mitigation and indirect potable reuse (IPR). For eutrophication mitigation, we examined MLE, Bardenpho, Step-feed, HF-MBR, and FS-MBR. For IPR, we considered secondary treatment+UF + RO + AOP or MBR + RO + AOP. These alternatives form part of a WWTP network at a district level, aiding Lima's pursuit of a circular economy approach. This perspective allows reducing environmental impacts through resource recovery, making the system more resilient to disasters and future water shortages. The methods used to assess these scenarios were Life Cycle Assessment for the environmental dimension; Life Cycle Costing for the economic perspective; and Multi-Criteria Decision Analysis to integrate both the quantitative tools aforementioned and qualitative criteria for social and techno-operational dimensions, which combined, strengthen the decision-making process. The decision-making steered towards Bardenpho for eutrophication abatement when environmental and economic criteria were prioritized or when the four criteria were equally weighted, while HF-MBR was the preferred option when techno-operational and social aspects were emphasized. In this scenario, global warming (GW) impacts ranged from 0.23 to 0.27 kg CO2eq, eutrophication mitigation varied from 6.44 to 7.29 g PO4- equivalent, and costs ranged between 0.12 and 0.17 €/m3. Conversely, HF-MBR + RO + AOP showed the best performance when IPR was sought from the outset. In the IPR scenario, GW impacts were significantly higher, at 0.46-0.51 kg CO2eq, eutrophication abatement was above 98 % and costs increased to ca. 0.44 €/m3.

Ocean-based sources of plastic pollution: An overview of the main marine activities in the Peruvian EEZ.

Marine-based activities are a critical source of plastic waste into the ocean. This is particularly important in countries with a competitive fishing industry, such as Peru. Thus, this study aimed to identify and quantify the major flows of plastic waste accumulating in the ocean from ocean-based sources within the Peruvian Economic Exclusive Zone. A material flow analysis was elaborated to analyze the stock of plastic and its release to the ocean by a set of Peruvian fleets, including the fishing industry, merchant vessels, cruises, and boating vessels. Results show that in 2018 between 2715 and 5584 metric tons of plastic waste entered the ocean. The fishing fleet was the most pollutant, representing approximately 97 % of the total. Moreover, fishing gear loss represented the highest single-activity contribution, although other sources, such as plastic packaging and antifouling emissions, have the potential to become vast sources of marine plastic pollution.

Climate change mitigation potential of transitioning from open dumpsters in Peru: Evaluation of mitigation strategies in critical dumpsites.

Waste management is a critical policy towards the reduction of environmental impacts to air, soil and water. Many Latin American countries, however, lack a correct waste management system in many cities and rural areas, leading to the accumulation of unmanaged waste in illegal or unregulated dumpsites. The case of Peru is of interest, as it hosts 5 of the 50 largest dumpsites in the world. An erratic waste management compromises climate actions for Peru to commit with the Paris Agreement, as no correct closure systems are established for these dumpsites. Therefore, the main objective of this study is to assess the contribution of the past and present biodegradable waste produced and disposed of in the most critical open dumpsters to the overall annual greenhouse gas (GHG) emissions of Peru using the IPCC model. Thereafter, the climate change mitigation potential of possible dumpsite closure strategies based on a selection of technologies, including economic feasibility, were estimated. Results show that cumulative GHG emissions in 2018 for the 24 critical dumpsites evaluated added up to 704 kt CO2 eq. and a cumulative value of 4.4 Mt CO2 eq. in the period 2019-2028, representing over 40 % of solid waste emissions expected by 2030. Mitigation potentials for these emissions tanged from 91 to 970 kt CO2 eq. in the ten-year period depending on the mitigation strategies adopted. The costs of these strategies are also discussed and are expected to be of utility to complement Peru's waste management commitments in the frame of the Paris Agreement.

Introducing environmental decision-making criteria to foster Green Public Procurement in Peru.

Governments in the Global South have recently started to align their public procurement regulations considering Green Public Procurement (GPP) guidelines to achieve Sustainable Development Goal 12. In this context, it is important to establish environmental criteria to help decision making after analyzing the variety of options available in the market. Thus, using as examples two of the most acquired products in public procurement in Peru: Medium-density particleboard melamine furniture and paper offset, the aim of this paper is to determine the main environmental hotspots and therefore show the path to foster GPP in Peru. To achieve this goal, a Life Cycle Assessment was carried out considering it is a suitable environmental management tool to quantify environmental impacts. For this, a set of scenarios were modeled and compared for each of the two products selected, covering different geographical and technological options that are currently purchased by the Peruvian government. Results demonstrated that it is possible to attain considerable reductions in the environmental impact of the products analyzed if the main critical stages throughout their life cycle are identified and adequate solutions are applied to avoid burden shifting. Moreover, we argue that it is important for developing countries to carry out case-specific life-cycle inventories as they provide higher-quality information based on the particular characteristics of regional or local industries, allowing the determination of more realistic environmental impact mitigation benchmarks. Nevertheless, the inclusion of lifecycle-based criteria in GPP must be performed cautiously, avoiding command and control regulations, as numerous challenges remain in terms of capacity building, environmental awareness, and environmental information, and transparency in emerging and developing economies. Integr Environ Assess Manag 2022;18:1206-1220. © 2021 SETAC.

Wastewater treatment decentralization: Is this the right direction for megacities in the Global South?

The centralization-decentralization dichotomy in wastewater treatment management has been a recurrent topic of discussion in the urban context. The escalation of environmental hazards linked to increasing mismanaged wastewater flows in emerging or developing cities has vivified this conundrum. It is argued that there is a wide range of parameters to identify the optimal level of centralization-decentralization that must be implemented. In many cases, this prevents decision-makers from having a clear picture of the most appropriate management choices that must be undertaken. Hence, the main objective of the current discussion consists of an in-depth comparison between centralized wastewater treatment systems and decentralized systems with source separation in urban environments of the Global South. Moreover, a set of actions that should be considered in order to upgrade wastewater treatment systems amidst the existence of numerous economic, social and environmental constraints are analyzed. Considering the constraints of megacentralization as a preferred option, we argue that decision-makers should restrain from entering a centralization-decentralization dichotomy, seeing the process as a gradient between the two concepts. In fact, we advocate combining the benefits of each of the two perspectives to generate an adaptive management, site-specific solution for urban environments. For this, the inclusion of quantitative management tools, such as life-cycle environmental or cost management methodologies, in multi-objective optimization models, constitutes an interesting path forward towards fostering comprehensive policy support.

Life cycle assessment of bagasse fiber reinforced biocomposites.

This study aims to evaluate the life cycle environmental implications of producing fiber-reinforced biocomposite pellets, compared with sugarcane- and petroleum-based polyethylene (PE) pellets. Life Cycle Assessment (LCA) methodology is used to evaluate the production of four types of pellets. LCA allows the evaluation of the benefits of improving the production of biobased materials by replacing part of the sugarcane bioPE with bagasse fibers. The functional unit selected was the production of 1 kg of plastic pellets. Primary data were collected from laboratory tests designed to obtain pulp fibers from bagasse and mix them with sugarcane bioPE. Two processes were studied to obtain fibers from bagasse: soda fractionation and hot water-soda fractionation. The results from the LCA show environmental improvements when reducing the amount of bioPE by replacing it with bagasse fibers in the categories of global warming, ozone formation, terrestrial acidification and fossil resource scarcity, when comparing to 100% sugarcane bioPE, and a reduction in global warming and fossil resource scarcity when compared to fossil-based PE. In contrast, results also indicate that there could be higher impacts in terms of ozone formation, freshwater eutrophication, and terrestrial acidification. Even though biocomposites result as a preferred option to bioPE, several challenges need to be overcome before a final recommendation is placed. The sensitivity analysis showed the importance of the energy source on the impacts of the processing of fibers. Thus, using clean energy to produce biobased materials may reduce the impacts related to the production stage. These results are intended to increase the attention of the revalorization of these residues and their application to generate more advanced materials. Further outlook should also consider a deeper evaluation of the impacts during the production of a plastic object and possible effects of the biobased materials during final disposal.

Enhancing waste management strategies in Latin America under a holistic environmental assessment perspective: A review for policy support.

Waste remains a serious environmental and human health hazard in developing nations, including those in Latin America and the Caribbean (LA&C). Despite important breakthroughs in waste management in LA&C, the region still faces many challenges that require special attention, such as the existence of uncontrolled open dumpsters (33%) or the low recovery rates of waste fractions (below 4%). Moreover, the adoption of sophisticated waste management technologies, such as incineration or anaerobic digestion, is still lagging. This review paper provides environmentally-sound and relevant policy support for municipal solid waste management stakeholders through a critical review of the current situation of the waste management sector in LA&C from an environmental perspective. Thereafter, Life Cycle Assessment (LCA) bibliography linked to waste management, namely collection, sorting, recycling and landfilling applications and technologies worldwide, is used in order to understand potential alternative waste management strategies in LA&C, as well as the potential environmental benefits that could be attained. Finally, based on the holistic review and analysis, the adoption of more sophisticated technologies in landfill sites (e.g. landfill gas flaring), waste-to-energy, as well as higher recycling rates, would enhance waste management in the region and mitigate environmental impacts. A holistic view to support policy formulations, including climate action, for the adoption of integrated waste management strategies in LA&C is imperative.

Environmental impacts of the life cycle of alluvial gold mining in the Peruvian Amazon rainforest.

Alluvial gold mining activities in the Peruvian Amazon rainforest are responsible for mercury emissions and deforestation. To understand related environmental impacts, specifically toxicity and climate change, this study uses Life Cycle Assessment methodology. Four predominant extraction systems were selected and modelled and three scenarios that reflect currently available gold recovery systems were modelled: amalgamation, amalgamation with mercury recovery through retort system and gravimetric tables. The USEtox and IPCC life cycle impact assessment methods were used to assess the environmental impacts in term of human toxicity, freshwater ecotoxicity and climate change. Results show that for all systems, human toxicity values are governed by mercury emissions in gold recovery activities (ca. 80%). However, the use of retort significantly lowers these impacts (ca. 90%). Machines and diesel use for ore extraction and freighting activities drive freshwater ecotoxicity. Moreover, deforestation has a major contribution on the environmental impacts related to climate change. However, these impacts are dependent on the type of extraction system. Although human toxicity, freshwater ecotoxicity and climate change are frequently studied separately, a direct relationship between them has been identified in this system. Finally, beyond the environmental burdens related to alluvial gold mining, there are impacts affecting the social, cultural, and economic dimensions that will need to be analyzed to ensure a comprehensive understanding of the system.

Peru's road to climate action: Are we on the right path? The role of life cycle methods to improve Peruvian national contributions.

Most developing nations have had to perform a swift transition from the voluntary greenhouse gas (GHG) emissions mitigation actions engaged in the Copenhagen Accord, to the relatively ambitious mitigations signed in the frame of the Paris Agreement. Consequently, Peru is currently creating its national structure to combat climate change through mitigation and adaptation actions. Nationally-determined contributions (NDCs) are the planned interventions that nations report for intended reductions in GHG emissions. In fact, Peru has now committed to reduce its annual GHG emissions by 30% in 2030 with respect to a business-as-usual estimation for that same year. The 76 NDCs have been divided into six main sectors: energy, transport, industrial processes, agriculture, forestry and waste. In this context, the main goal of this study is to provide a critical review of the validity and effectiveness of current mitigation NDCs proposed by the Peruvian government to comply with the Paris Agreement. Moreover, the analysis is accompanied by a discussion on how the use of life-cycle methods, namely Life Cycle Assessment, can be of utility in terms of policy support to evaluate the mitigation potential of these NDCs, as well as in the identification of additional contributions in sectors where the mitigation potential has been obviated. The expansion of system boundaries beyond the national context to account for the globalized nature of current market flows or the modelling of indirect impacts of a particular policy appear as relevant advantages of including life-cycle methods in public climate policy. The analysis, which is intended to be of utility to policy-makers in Peru and in other developing and emerging economies across the world, suggests that life-cycle methods arise as adequate tools to monitor the environmental appropriateness of adopting or adapting low-carbon technology to the local context.

Natural disasters and climate change call for the urgent decentralization of urban water systems.

Lima is gradually upgrading its urban water cycle to comply with improved sanitation standards, with the aim of treating the entire flow of water and wastewater that it creates. However, this paper examines the basic characteristics of the main treatment systems that are currently in operation in the Peruvian capital, highlighting the myopic and inefficient nature of these investments. It digs deep in the debate between centralized and decentralized water management systems in a city that is exposed to numerous hydro-meteorological and geological hazards. Previous errors that have occurred in the developed world throughout the evolution process of the urban water cycle should be taken into consideration prior to any infrastructure development in emerging countries. For the particular case of Lima, special emphasis should be given to the resilience of its urban water system in order to guarantee rapid recovery after disaster events.

Assessing the magnitude of potential environmental impacts related to water and toxicity in the Peruvian hyper-arid coast: A case study for the cultivation of grapes for pisco production.

The environmental sustainability of the cultivation of grapes for the production of alcoholic beverages has been extensively analyzed in the literature from a Life Cycle Assessment perspective, although certain impact categories have been repeatedly neglected despite their importance, such as toxic emissions or the depletion of freshwater resources. Hence, the current study provides a detailed assessment of water footprint-related impact categories, including toxicity, for the cultivation of grapes for pisco production, an alcoholic beverage produced in coastal Peru in hyper-arid areas that suffer high levels of water scarcity. Characterization factors at a sub-watershed level were used to calculate water consumption impact assessment of grape production using the AWARE method. Site-specific toxic emissions were modelled using the PestLCI model, considering primary climate and soil data. The USEtox assessment method was then used to compute freshwater eco-toxicity with these data. Results demonstrate the high water footprint of irrigating vineyards in coastal Peru, especially considering the inefficient flooding irrigation process. In terms of water consumption, despite the high variability shown between sub-watersheds, the shift to other irrigation technologies must be analyzed with care due to the high competition for water existing in the area. Eutrophication potential showed particularly high values compared to the literature, whereas freshwater eco-toxicity impacts were relatively low due to the high volatilization of pesticides to air. Nevertheless, the lack of an adequate wastewater management system implies that the estimated potential toxic and eutrophying emissions may constitute a further environmental threat to water bodies.

Energy potential from rice husk through direct combustion and fast pyrolysis: A review.

Rapid population growth and consumption of goods and services imply that demand for energy and resources increases continuously. Energy consumption linked to non-renewable resources contributes to greenhouse gas emissions and enhances resource depletion. In this context, the use of agricultural solid residues such as rice husk, coffee husk, wheat straw, sugar cane bagasse, among others, has been widely studied as an alternative energy source in order to decrease the use of fossil fuels. However, rice husk is among those agricultural residues that are least used to obtain energy in developing countries. Approximately 134 million tonnes of rice husk are produced annually in the world, of which over 90% are burned in open air or discharged into rivers and oceans in order to dispose of them. This review examines the energetic potential of agricultural residues, focused on rice husk. The review describes direct combustion and fast pyrolysis technologies to transform rice husk into energy considering its physical and chemical properties. In addition, a review of existing studies analyzing these technologies from an environmental life cycle thinking perspective, contributing to their sustainable use, is performed.

Quantifying Domestic Used Electronics Flows using a Combination of Material Flow Methodologies: A US Case Study.

This paper describes the scope, methods, data, and results of a comprehensive quantitative analysis of generation, stock, and collection of used computers and monitors in the United States , specifically desktops, laptops, CRT monitors, and flat panel monitors in the decade leading up to 2010. Generation refers to used electronics coming directly out of use or postuse storage destined for disposal or collection, which encompasses a variety of organizations gathering used electronics for recycling or reuse. Given the lack of actual statistics on flows of used electronics, two separate approaches, the sales obsolescence method (SOM) and the survey scale-up method (SSUM), were used in order to compare the results attained and provide a range for estimated quantities. This study intentionally sought to capture the uncertainty in the estimates. To do so, uncertainty in each data set was incorporated at each stage using Monte Carlo simulations for SOM and establishing scenarios for SSUM. Considering the average results across both methods, we estimate that in 2010 the U.S. generated 130-164 thousand metric tons of used computers and 128-153 thousand tons of used monitors, of which 110-116 thousand tons of used computers and 105-106 thousand tons of used monitors were collected for further reuse, recycling, or export. While each approach has its strengths and weaknesses, both the SOM and the SSUM appear to be capable of producing reasonable ranges of estimates for the generation and collection of used electronics.

Institutional disposition and management of end-of-life electronics.

Institutions both public and private face a challenge to develop policies to manage purchase, use, and disposal of electronics. Environmental considerations play an increasing role in addition to traditional factors of cost, performance and security. Characterizing current disposition practices for end-of-life electronics is a key step in developing policies that prevent negative environmental and health impacts while maximizing potential for positive social and economic benefits though reuse. To provide a baseline, we develop the first characterization of quantity, value, disposition, and flows of end-of-life electronics at a major U.S. educational institution. Results of the empirical study indicate that most end-of-first-life electronics were resold through public auction to individuals and small companies who refurbish working equipment for resale or sell unusable products for reclamation of scrap metal. Desktop and laptop computers sold for refurbishing and resale averaged U.S. $20-100 per unit, with computers sold directly to individuals for reuse reaching $250-350 per unit. This detailed assessment was coupled with a benchmarking survey of end-of-life electronics management practices at other U.S. universities. Survey results indicate that while auctions are still commonplace, an increasing number of institutions are responding to environmental concerns by creating partnerships with local recycling and resale entities and mandating domestic recycling. We use the analyses of current disposition practices as input to discuss institutional strategies for managing electronics. One key issue is the tension between benefits of used equipment sales, in terms of income for the institution and increased reuse for society, and the environmental risks because of unknown downstream practices.

Product or waste? Importation and end-of-life processing of computers in Peru.

This paper considers the importation of used personal computers (PCs) in Peru and domestic practices in their production, reuse, and end-of-life processing. The empirical pillars of this study are analysis of government data describing trade in used and new computers and surveys and interviews of computer sellers, refurbishers, and recyclers. The United States is the primary source of used PCs imported to Peru. Analysis of shipment value (as measured by trade statistics) shows that 87-88% of imported used computers had a price higher than the ideal recycle value of constituent materials. The official trade in end-of-life computers is thus driven by reuse as opposed to recycling. The domestic reverse supply chain of PCs is well developed with extensive collection, reuse, and recycling. Environmental problems identified include open burning of copper-bearing wires to remove insulation and landfilling of CRT glass. Distinct from informal recycling in China and India, printed circuit boards are usually not recycled domestically but exported to Europe for advanced recycling or to China for (presumably) informal recycling. It is notable that purely economic considerations lead to circuit boards being exported to Europe where environmental standards are stringent, presumably due to higher recovery of precious metals.

Evolution of product lifespan and implications for environmental assessment and management: a case study of personal computers in higher education.

Product lifespan is a fundamental variable in understanding the environmental impacts associated with the life cycle of products. Existing life cycle and materials flow studies of products, almost without exception, consider lifespan to be constant over time. To determine the validity of this assumption, this study provides an empirical documentation of the long-term evolution of personal computer lifespan, using a major U.S. university as a case study. Results indicate that over the period 1985-2000, computer lifespan (purchase to "disposal") decreased steadily from a mean of 10.7 years in 1985 to 5.5 years in 2000. The distribution of lifespan also evolved, becoming narrower over time. Overall, however, lifespan distribution was broader than normally considered in life cycle assessments or materials flow forecasts of electronic waste management for policy. We argue that these results suggest that at least for computers, the assumption of constant lifespan is problematic and that it is important to work toward understanding the dynamics of use patterns. We modify an age-structured model of population dynamics from biology as a modeling approach to describe product life cycles. Lastly, the purchase share and generation of obsolete computers from the higher education sector is estimated using different scenarios for the dynamics of product lifespan.

A dynamic agent-based analysis for the environmental impacts of conventional and novel book retailing.

The dynamics of an e-commerce market and the associated environmental impacts from a bottom-up perspective using an agent-based model is explored. A conceptual meta-theory from psychology is adopted to form the behavioral rules of artificial consumers choosing different methods of buying a book, including conventional bookstores, e-commerce, and a proposed self-pick-up option. Given the energy and emissions savings that result from a shift to e-commerce from bookstore purchase, it appears that reductions in environmental impacts are relatively probable. Additionally, our results suggest that the shift to e-commerce is mainly due to the growth of Internet users, which ties energy and emissions savings to Internet penetration. Moreover, under any scenario, the energy and emissions savings will be provided by the introduction of the proposed self-pick-up option. Our model thus provides insights into market behaviors and related environmental impacts of the growing use of e-commerce systems at the retail level, and provides a basis for the development and implementation of more sustainable policies and practices.

Designing and assessing a sustainable networked delivery (SND) system: hybrid business-to-consumer book delivery case study.

We attempted to design and assess an example of a sustainable networked delivery (SND) system: a hybrid business-to-consumer book delivery system. This system is intended to reduce costs, achieve significant reductions in energy consumption, and reduce environmental emissions of critical local pollutants and greenhouse gases. The energy consumption and concomitant emissions of this delivery system compared with existing alternative delivery systems were estimated. We found that regarding energy consumption, an emerging hybrid delivery system which is a sustainable networked delivery system (SND) would consume 47 and 7 times less than the traditional networked delivery system (TND) and e-commerce networked delivery system (END). Regarding concomitant emissions, in the case of CO2, the SND system produced 32 and 7 times fewer emissions than the TND and END systems. Also the SND system offer meaningful economic benefit such as the costs of delivery and packaging, to the online retailer, grocery, and consumer. Our research results show that the SND system has a lot of possibilities to save local transportation energy consumption and delivery costs, and reduce environmental emissions in delivery system.