Market-based tools for a plastic waste reduction policy in agriculture: A case study in the south of Italy

Does forest farm carbon sink projects affect agricultural development? Evidence from a Quasi-experiment in China

Forest Farm Carbon Sink (FFCS) projects are one of the effective ways to achieve carbon neutrality and mitigate global warming. Though the existing literature has widely discussed the effect of FFCS on the allocation of agricultural factors, such as land, labor employment structure and income structure, little is known about whether FFCS projects could have an effect on agricultural development. Based on the panel data of 140 counties in Sichuan province, China, from 2002 to 2018, we examined the causal effect on agricultural total factor productivity (TFP), and revealed their dynamic effect and underlying mechanisms. Propensity score matching and the difference in difference (PSM-DID) method were used to address the endogeneity problem of FFCS implementation. Results showed that FFCS projects increased agricultural TFP by 1.7%-2.4%. Health, saving and industrial structure were the important channels through which FFCS projects affect agricultural TFP. Our findings suggest that policies promoting FFCS projects can increase agricultural TFP while achieving environmental goals-a win-win situation.

Post-consumer plastic sorting infrastructure improvements planning: Scenario-based modeling of greenhouse gas savings with sustainable costs

With the increasing share of waste material recovery, household plastic waste is one of the biggest problems. In most countries, mainly manual sorting is used. Meanwhile, new automated technologies are being developed to expand the range of classifiable types to increase material recovery. The overall automation of the sorting process can help the EU's established recycling targets to be effectively met. However, the new technologies are feasible only in the case of large-capacity centers, which must be conveniently located in the existing infrastructure. This paper presents a two-stage model aiming to modernize the current sorting infrastructure for plastic waste. The approach uses multi-criteria optimization to minimize environmental impact at a reasonable price. The result is the optimal location of new automatic sorting centers, and waste stream flows using existing manual sorting facilities. The model is applied through an initial case study inspired by the Czech Republic data. Optimization output proposes four new automatic sorting lines with a total capacity of 158 kt per year. In most cases, manual sorting is used to reduce the transported weight of plastic waste, while automatic sorting lines separate the remaining, hardly recognized part. More than 60% of separately collected plastic is sorted and determined for material recovery.

Influencing Factors on the Household-Waste-Classification Behavior of Urban Residents: A Case Study in Shanghai

As the process of urbanization in China continues to accelerate, the amount of domestic waste generated correspondingly increases and directly affects the living space of residents. This indirectly implies that to reduce the production of municipal solid waste and the need for garbage disposal and recycling, household-waste-classification activities by the residents are of great significance. Using Shanghai as a case study, this study investigated the influencing factors on residents’ household waste classification by conducting a survey. Statistical analysis was then adopted, which is specified below. First, this study proposed research hypotheses related to the influencing factors of residents’ domestic-waste-sorting behavior from three levels: government, society and individuals. Second, the study designed a questionnaire from five perspectives: individual characteristic variables, government, society, residents and classification behavior. Then, SPSS software was used to carry out descriptive statistical, reliability and validity assessments using ANOVA, correlation and regression analyses on the sample data obtained from the questionnaire. The results suggested that the research hypotheses were statistically significant: (1) females and residents with higher education were more likely to participate in domestic waste classification; (2) reward and punishment measures had the most significant impact on residents’ waste-classification behavior; and (3) publicity and education, classification standards, classification facilities, the recycling system, subjective norms, environmental knowledge and environmental attitudes all had a positive effect on residents’ household waste classification. Finally, based on the results of the empirical analysis, this paper provides reference suggestions for the further development of domestic waste classification in Shanghai.

A method for measuring the emissions of in situ agricultural plastic film microplastics by ultraviolet and mechanical abrasion

Agricultural plastic film (APF) is widely used in modern agriculture. Under natural environmental conditions, the structure, surface properties and mechanical properties of APFs change because of sunlight, wind and other factors and gradually break into debris, resulting in the generation of microplastics (MPs). Studies have reported that the MPs concentration in soil is positively correlated with the use intensity and duration of APFs. Unfortunately, to the best of our knowledge, no method to measure the emissions of in situ APFs has been developed. In this study, the effects of mechanical abrasion driven by wind on MPs fragmentation by polyethylene (PE) and polyvinyl chloride (PVC) APFs with the increase of exposure time were investigated. Meanwhile, based on the release rate model of PS fragmented MPs under natural sunlight, a modified model to quantify the effect of ultraviolet (UV) radiation exposure duration on the production of APF fragmented MPs was developed. Based on these models, the amount of MPs produced from APFs in farmland in China was estimated. The national annual MPs mass emissions from APFs in agricultural soil were approximately 5 × 10⁴ to 6.8 × 10⁴ tons in 2018 due to wind and 6.5 × 10³ tons due to sunlight, and the total emission level due to both wind and sunlight was 5.1 × 10⁴ to 7.0 × 10⁴ tons. Compared with that of wind, the contribution of UV radiation to MPs emission is smaller. Our estimates are comparable to data reported in previous studies, indicating that our models have good practical applications and are of great significance for predicting MPs production from APFs in farmland.

Tripartite Evolutionary Game Analysis for Plastic Pollution Prevention and Control under the Background of China’s Plastic Ban

Controlling plastic pollution is an important issue in the field of sustainable development and is of great concern for numerous countries’ governments. After investigating the implementation of relevant policies, this paper analyzes the tripartite mainstay under the background of China’s Plastic Ban by constructing an evolutionary game model involving governments, enterprises and the public. Through simulation modeling, the paper then investigates the possible regulatory effects of different policies at the micro level. According to the results, the government should pay more attention to how it reacts to enterprises’ compliance strategies, both for the sake of the public and itself. It is vital to increase enterprises’ compliance rewards and decrease their compliance costs through various means such as policy changes and technological innovation. The policy’s effect can be improved if supervision and regulations are both enforced.

Contribution of mulch film to microplastics in agricultural soil and surface water in China

Agricultural mulch film (AMF) is deemed an important source of microplastics (MPs) in agricultural soil (AS). However, quantitating the contribution of AMFs to MPs in farmland soil and surface water remains a considerable challenge to date. In the present study, a basic framework was developed to address these concerns. First, the concentrations of MPs in soil derived from AMF abrasion (C_MP) and the total MPs from all sources in AS (C_TMP) were measured. Then, the ratios of C_MP to C_TMP, i.e., the contribution of AMFs to MPs in AS, were calculated. The contribution of AMFs to MPs in surface water via soil erosion was calculated based on C_TMP values, the ratios of C_MP to C_TMP, soil erosion intensities (SEIs), and farmland areas. Furthermore, the potential contribution of soil erosion to MPs in the ocean was estimated. In China, the inventory of MPs in surface AS in 2018 ranged from 4.9 × 10⁶ to 1.0 × 10⁷ tons according to our results. AMFs contributed 10%-30% of the C_TMP with certainties of 60-95%. Assuming that all MPs in AS can be exhaustively transferred to surface water via soil erosion, the national mass transfer amount of MPs (MT_TMP) from AS to surface water reached 1.2 × 10⁵-2.2 × 10⁵ tons (∼2% of the inventory of MPs in the AS of China); the fluxes of MPs into the ocean from AS were 3.4 × 10⁴-6.6 × 10⁴ tons, assuming that all MPs in the AS of coastal provinces enter the ocean. It is likely that AMFs contributed 10%-30% MT_TMP and fluxes of MPs to the ocean according to the ratios of C_MP to C_TMP. Apparently, approximately 30% of the national MT_TMP (i.e., the rate of MP flux to the ocean to MT_TMP) was input to the ocean.

Bibliographic mapping of post-consumer plastic waste based on hierarchical circular principles across the system perspective

The current dominating production and consumption model is based on the linear economy (LE) model, within which raw materials are extracted-processed-consumed-discarded. A circular economy (CE) constitutes a regenerative systemic approach to economic development which views waste as a valuable resource to be reprocessed back into the economy. In order to understand the circular strategy for a systemic change from an LE to a CE as a means of resolving the issue of plastic waste, this research aims to map current circular strategy trends across the system perspective contained in the literature relating to plastic CE literature. The novelty of the research lies in the mapping and review of the distribution of comprehensive circular strategies within the 9R framework across the entire system perspective (e.g. micro-meso-macro) down to its sub-levels in the literature on a plastic CE. The bibliographic mapping and systematic literature review iindicateed that the majority of the research focused on recycle (R8), followed by refuse (R0), reuse (R3), and reduce (R2). Certain circular strategies are more appropriate to handling certain plastic materials, despite CE's favoring of prevention and recycling over incineration. Recover (R9) is often used to process mixed and contaminated plastic. Recycling (R8) is the most popular circular strategy and the most applicable to plastic material with three recycle trends, namely; mechanical recycling, chemical recycling and DRAM (Distributed-Recycling-and-Additive-Manufacturing). Prolonging the product life through refurbishing (R5) is not applicable to plastic due to its material limitations. Reduce (R2) popularity as circular strategy reflects the preference to reduce consumption, either by launching campaigns to prevent waste or increasing production efficiency. Research on Rethink (R1) has largely focused on rethinking product design, consumer and organization behavior and perceptions of CE. Refuse (R0) strategy is an adoption of bio-based plastics which have a similar function to fossil-based plastics.

Mammary microbial dysbiosis leads to the zoonosis of bovine mastitis: a One-Health perspective

Bovine mastitis is a prototypic emerging and reemerging bacterial disease that results in cut-by-cut torture to animals, public health and the global economy. Pathogenic microbes causing mastitis have overcome a series of hierarchical barriers resulting in the zoonotic transmission from bovines to humans either by proximity or remotely through milk and meat. The disease control is challenging and has been attributed to faulty surveillance systems to monitor their emergence at the human-animal interface. The complex interaction between the pathogens, the hidden pathobionts and commensals of the bovine mammary gland that create a menace during mastitis remains unexplored. Here, we review the zoonotic potential of these pathogens with a primary focus on understanding the interplay between the host immunity, mammary ecology and the shift from symbiosis to dysbiosis. We also address the pros and cons of the current management strategies and the extent of the success in implementing the One-Health approach to keep these pathogens at bay.

Microplastics in agricultural soils: Extraction and characterization after different periods of polythene film mulching in an arid region

Plastic film mulching has been extensively used in farmland, especially in arid regions, for over half-century. However, this has led to heavy pollution of soils by microplastics (MPs). Currently, efficient extraction of MPs from the organo-mineral soil matrix is a problem because microsize clay particles tightly adhere to MPs. It is therefore extremely challenging to investigate, identify, quantify, and characterize MP particles and their behavior in agricultural soils. In this study, we developed a simple and effective method of separating and extracting MPs from the soil matrix. Clean polyethylene (PE) MPs were obtained after a series of treatments including pressure leaching, flotation, electrostatic adsorption, and concentrated sulfuric acid (98% H₂SO₄) carbonization. The characteristics of MP pollutants, such as abundance, size, and morphology, in soils that have been continuously mulched with PE film for various periods of time were determined after extraction. The highest abundance of MPs (40.35 mg/kg) with sizes ranging from 0.9-2.0 mm was found in soil samples that had been continuously mulched with plastic film for 30 years. The sampled MP particles are in the microplastic size (0.8-0.3 mm) range, and the size of MPs decreases gradually as the period of mulching increased. Scanning electron microscopy analysis showed that the surface of the MP particles showed visible cracks, with round holes, and the particle surface roughened as the number of years of continuous mulching increased. Fourier-transform infrared spectroscopy results showed that the absorption peak area of hydrocarbyl (-CH₂) of PE MPs decreased significantly, and the typical oxidation characteristic peak area increased as the mulching period increased. The concentration of mesoplastics also increased, from 91.20 mg/kg to 308.50 mg/kg, when the mulching period increased from 5 to 30 years.

Plastics: physical-and-mechanical properties and biodegradable potential

Introduction. Processing agricultural waste into plant biodegradable plastics is a promising way for its recycling. This work featured the main physical-and-mechanical properties of plant plastics without adhesive substances obtained from millet husk and wheat husk and wood plastic obtained from sawdust, as well as their biodegradation potential. Study objects and methods. Objects of the study were plastics without adhesives based on wood sawdust, millet husk, and wheat husk. Results and discussion. We analyzed of the physical-and-mechanical parameters of the plant plastic based on millet husk, wheat husk, as well as wood plastic based on sawdust. The analysis showed that, in general, the strength characteristics of the wood plastics were higher than those of the plastics based on millet husk, especially flexural strength. Thus, the average value of the density of the wood plastic exceeded that of the plant plastic from millet husk by 10%, hardness by 40%, compression elasticity modulus by 50%, and flexural modulus by 3.9 times. It was found that wood and plant plastics obtained from sawdust, millet husk, and wheat husk without adhesives had a high biodegradation potential. Conclusion. The plastics obtained can be used as an insulating, building, and decorative material in the steppe regions experiencing a shortage of wood and wood powder.