Occupational safety and health, green chemistry, and sustainability: a review of areas of convergence

Safety profiling of technical lignins originating from various bioresources and conversion processes

In this work, a set of eight technical lignin samples from various botanical origins and production processes were characterized for their chemical composition, higher heating value, size distribution, dust explosion sensitivity and severity, thermal hazard characteristics and biodegradability, in further support of their sustainable use. More specifically, safety-focused parameters have been assessed in terms of consistency with relating physico-chemical properties determined for the whole set of technical lignins. The results emphasized the heterogeneity and variability of technical lignins and the subsequent need for a comprehensive characterization of new lignin feedstocks arising from novel biorefineries. Indeed, significant differences were revealed between the samples in terms of hazards sensitivity. This first comparative physico-chemical safety profiling of technical lignins could be useful for the hazard analysis and the safe design of the facilities associated with large scale valorisation of biomass residues such as lignins, targeting "zero waste" sustainable conversion of bioresources.

Strategies for Considering Environmental Justice in the Early-Stage Development of Circular Economy Technologies

The circular economy could transform how industry and society approach resources and waste, resulting in significant environmental justice (EJ) implications. However, there are few resources for analyzing the EJ impacts of new circular economy technologies before they are deployed. This work presents an EJ framework tailored for early stage circular economy technologies and showcases its capabilities through a case study on enzymatic plastic recycling. By providing concise, actionable, and accessible guidelines based on technology readiness levels and a series of 20 questions, the framework empowers both experts and nonexperts to evaluate the justice implications of circular economy solutions. Preliminary user feedback highlights the approachability of the framework and its corresponding interactive worksheet, as well as their potential to stimulate innovative thinking toward a more just and sustainable future.

Green Chemistry Teacher Professional Development in New York State High Schools: A Model for Advancing Green Chemistry

Teaching green chemistry within the K-12 classroom has a positive impact on attitudes and perceptions of chemistry in society for future scientists and professionals, resulting in safer, less hazardous chemistry experiments and demonstrations. The state of New York has taken advantage of the benefits that green chemistry provide in the classroom and is a leader in professional development for high school teachers throughout the state. Between 2011 and 2016, Beyond Benign and Siena College implemented 14 workshops across the state as part of New York's Department of Environmental Conservation goal of reducing hazardous chemicals in schools. At these workshops, 224 teachers were introduced to green chemistry principles and practices and provided resources for replacing traditional laboratory experiments with alternatives that used safer materials. Two professional development models were implemented, a one-day introductory workshop and a three-day train-the-trainer style in-depth workshop, using collaborative, hands-on, intensive, and peer-learning techniques. In response to a 2021 follow-up survey, participants shared that they continue to use skills from the professional development they received and reported sharing about green chemistry with peers, parents, and administrators. The long-term engagement of the participants indicates that successful models were implemented to provide a path to develop teacher leaders. Professional development models are presented herein for sharing best practices and approaches for training high school teachers on green chemistry, providing numerous benefits to both teachers and students in high school classrooms.

AI4Green: An Open-Source ELN for Green and Sustainable Chemistry

An Electronic Laboratory Notebook (ELN) combining features, including data archival, collaboration tools, and green and sustainability metrics for organic chemistry, is presented. AI4Green is a web-based application, available as open-source code and free to use. It offers the core functionality of an ELN, namely, the ability to store reactions securely and share them among different members of a research team. As users plan their reactions and record them in the ELN, green and sustainable chemistry is encouraged by automatically calculating green metrics and color-coding hazards, solvents, and reaction conditions. The interface links a database constructed from data extracted from PubChem, enabling the automatic collation of information for reactions. The application's design facilitates the development of auxiliary sustainability applications, such as our Solvent Guide. As more reaction data are captured, subsequent work will include providing "intelligent" sustainability suggestions to the user.

Recent Advances in Biological Recycling of Polyethylene Terephthalate (PET) Plastic Wastes

Polyethylene terephthalate (PET) is one of the most commonly used polyester plastics worldwide but is extremely difficult to be hydrolyzed in a natural environment. PET plastic is an inexpensive, lightweight, and durable material, which can readily be molded into an assortment of products that are used in a broad range of applications. Most PET is used for single-use packaging materials, such as disposable consumer items and packaging. Although PET plastics are a valuable resource in many aspects, the proliferation of plastic products in the last several decades have resulted in a negative environmental footprint. The long-term risk of released PET waste in the environment poses a serious threat to ecosystems, food safety, and even human health in modern society. Recycling is one of the most important actions currently available to reduce these impacts. Current clean-up strategies have attempted to alleviate the adverse impacts of PET pollution but are unable to compete with the increasing quantities of PET waste exposed to the environment. In this review paper, current PET recycling methods to improve life cycle and waste management are discussed, which can be further implemented to reduce plastics pollution and its impacts on health and environment. Compared with conventional mechanical and chemical recycling processes, the biotechnological recycling of PET involves enzymatic degradation of the waste PET and the followed bioconversion of degraded PET monomers into value-added chemicals. This approach creates a circular PET economy by recycling waste PET or upcycling it into more valuable products with minimal environmental footprint.

Occupational Health and Safety Scope Significance in Achieving Sustainability

A safe and healthy working environment is vital for overall sustainability, due to the fact that it affects opportunities of economic and social development. However, according to the International Labour Organization (ILO), despite the international commitment to Occupational Health and Safety (OSH) via the 2030’s Agenda Sustainable Development Goals (SDGs), work-related accidents are still far too common. Work-related mortality accounts for 5% of all deaths worldwide; a toll which has increased dramatically due to the COVID-19 pandemic. Yet, in the context of COVID-19, new demands on the labour market, such as teleworking, adequate protective measures, and proper use of personal protective equipment when physical presence cannot be avoided, are necessitating new approaches to ensure health and safety. Arguably, education can be viewed as a cross-cutting strategy in advance of a culture of safety for future generations, through strengthening skills and broadening knowledge. Indeed, even though education cannot be considered a panacea, related to SDG 4, which seeks to ensure inclusive and equitable quality education and promote lifelong learning opportunities for all, it can be considered a critical component to deal with OSH issues using a preventive, rather than a reactive, approach. Given this fact, European Agency for Safety and Health at Work (EU-OSHA) has stressed the prevention approach through mainstreaming OSH in education at all levels, and in all fields of vocational and academic training. Aware of the potential of universities to provide graduates the broad-based knowledge to produce labour-market skills including OSH, the aim of this study is to contribute to the discussion on mainstreaming OSH into Greek university education, using Harokopio University (HUA) as a case study. For this purpose, a web-based survey was conducted to address HUA’s students, faculty members, and staff OSH knowledge, risks awareness, and attitudes, as well as their perceptions, opinions, and beliefs about the role of OSH for academia. A statistical analysis depicted respondents’ high level of willingness to contribute to the promotion of OSH, while additional evidence suggests a considerable commitment of the respondents to participate in HUA’s OSH-related training and education.

"Turning the dials": controlling synthesis, structure, composition, and surface chemistry to tailor silicon nanoparticle properties

Silicon nanoparticles (SiNPs) can be challenging to prepare with defined size, crystallinity, composition, and surface chemistry. As is the case for any nanomaterial, controlling these parameters is essential if SiNPs are to realize their full potential in areas such as alternative energy generation and storage, sensors, and medical imaging. Numerous teams have explored and established innovative synthesis methods, as well as surface functionalization protocols to control these factors. Furthermore, substantial effort has been expended to understand how the abovementioned parameters influence material properties. In the present review we provide a commentary highlighting the benefits and limitations of available methods for preparing silicon nanoparticles as well as demonstrations of tailoring optical and electronic properties through definition of structure (i.e., crystalline vs. amorphous), composition and surface chemistry. Finally, we highlight potential opportunities for future SiNP studies.

Speaking Up about Workplace Safety: An Experimental Study on Safety Leadership

In this study, we test whether different types of safety leadership styles predict different employees’ change-oriented discretionary communications about safety (i.e., safety voice) after controlling for proactive personality disposition to improve organizational sustainability. Building upon a multidimensional model of safety voice, which attempts to conceptualize different ways in which employees make suggestions about safety procedures, we developed four realistic scenarios in which we manipulated the supervisor’s safety leadership style, including: (1) transformational safety leadership, (2) transactional safety leadership, (3) passive safety leadership, and (4) control group (i.e., no leadership at all). We randomly assigned 103 participants to two of four scenarios and measured four facets of safety voice and proactive personality dispositions. The findings showed that after controlling for the respondents’ proactive personality, transformative safety leadership predicted promotive safety voice, transactional safety leadership predicted preventive safety voice, and passive safety leadership predicted hostile safety voice. These findings have a number of implications for our understanding of safety leadership and employees’ safety communications.

Development of BIM-Based Risk Rating Estimation Automation and a Design-for-Safety Review System

Various laws and guidelines on designing for safety have been developed world-wide, and these were used to identify risks at construction sites in advance through qualitative and quantitative safe management. In other words, attention is being paid to safe management based on design drawings and models rather than field visits. It was predicted that the introduction of the concept of design-for-safety would minimize risk at construction sites through safe management in the design phase. This is because the efficiency and reliability of such a strategy has been demonstrated in various cases abroad. However, domestic design-for-safety suggests a very limited range of evaluation items, so there is a limit to using such strategies in construction sites. Building information modeling (BIM) technology is attracting attention in situations when safe management must also be based on design proposals. Although previous studies on the identification of falling disasters and automatic identification of hazards have been conducted, these studies only deal with a limited range of items for identifying risk items. For example, BIM-based risk extraction, which is limited to falling disasters, is only at the level of risk recognition that can be derived based on the process table, and evaluation is not made accordingly. It is difficult to assess the overall disaster risk in many of the items required for risk rating estimation. In this paper, we solve the above problems by deriving a BIM-based risk rating estimation scenario based on the disaster scenario for automating BIM-based risk rating estimation, and we developed an evaluation system using this method. The BIM-based risk rating estimation methodology was presented through BIM-based hazard extraction, evaluation of requirement information, evaluation item selection, and using the evaluation system in a design-for-safety review.

Making natural products from renewable feedstocks: back to the roots?

This review highlights the utilization of biomass-derived building blocks in the total synthesis of natural products.

Guiding the development of sustainable nano-enabled products for the conservation of works of art: proposal for a framework implementing the Safe by Design concept

Nanotechnology provides innovative and promising solutions for the conservation of cultural heritage, but the development and application of new nano-enabled products pose concerns regarding their human health and environmental risks. To address these issues, we propose a sustainability framework implementing the Safe by Design concept to support product developers in the early steps of product development, with the aim to provide safer nano-formulations for conservation, while retaining their functionality. In addition, this framework can support the assessment of sustainability of new products and their comparison to their conventional chemical counterparts if any. The goal is to promote the selection and use of safer and more sustainable nano-based products in different conservation contexts. The application of the proposed framework is illustrated through a hypothetical case which provides a realistic example of the methodological steps to be followed, tailored and iterated along the decision-making process.

Green Nanotechnology: Advancement in Phytoformulation Research

The ultimate goal of any scientific development is to increase well-being and human health. Novel strategies are required for the achievement of safe and effective therapeutic treatments beyond the conventional ones, and society needs new requirements for new technologies, moving towards clean and green technology development. Green nanotechnology is a branch of green technology that utilizes the concepts of green chemistry and green engineering. It reduces the use of energy and fuel by using less material and renewable inputs wherever possible. Green nanotechnology, in phytoformulations, significantly contributes to environmental sustainability through the production of nanomaterials and nanoproducts, without causing harm to human health or the environment. The rationale behind the utilization of plants in nanoparticle formulations is that they are easily available and possess a broad variability of metabolites, such as vitamins, antioxidants, and nucleotides. For instance, gold (Au) nanoparticles have attracted substantial attention for their controllable size, shape, and surface properties. A variety of copper (Cu) and copper oxide (CuO) nanoparticles have also been synthesized from plant extracts. Titanium dioxide and zinc oxide nanoparticles are also important metal oxide nanomaterials that have been synthesized from a number of plant extracts. International and domestic laws, government and private-party programs, regulations and policies are being carefully reviewed and revised to increase their utility and nurture these nanoscale materials for commercialization. Inspiring debates and government initiatives are required to promote the sustainable use of nanoscale products. In this review, we will discuss the potential of the utilization of plant extracts in the advancement of nanotechnology.

WEPA: a bio-derived medium for added base, π-acid and ligand free Ullmann coupling of aryl halides using Pd(OAc)2

A bio-derived sustainable medium based on water extract of pomegranate ash (WEPA) has, for the first time, been developed for the homocoupling of aryl halides under palladium-assistance. Avoiding the requirement of an external base, ligand and π-acid, the use of the proposed renewable medium offers remarkable attributes like wide substrate scope, good to nearly quantitative yields of biphenyls with exceptional chemoselectivity and scale up viability.

Research on Occupational Safety, Health Management and Risk Control Technology in Coal Mines

This paper studies the occupational safety and health management methods as well as risk control technology associated with the coal mining industry, including daily management of occupational safety and health, identification and assessment of risks, early warning and dynamic monitoring of risks, etc.; also, a B/S mode software (Geting Coal Mine, Jining, Shandong, China), i.e., Coal Mine Occupational Safety and Health Management and Risk Control System, is developed to attain the aforementioned objectives, namely promoting the coal mine occupational safety and health management based on early warning and dynamic monitoring of risks. Furthermore, the practical effectiveness and the associated pattern for applying this software package to coal mining is analyzed. The study indicates that the presently developed coal mine occupational safety and health management and risk control technology and the associated software can support the occupational safety and health management efforts in coal mines in a standardized and effective manner. It can also control the accident risks scientifically and effectively; its effective implementation can further improve the coal mine occupational safety and health management mechanism, and further enhance the risk management approaches. Besides, its implementation indicates that the occupational safety and health management and risk control technology has been established based on a benign cycle involving dynamic feedback and scientific development, which can provide a reliable assurance to the safe operation of coal mines.

Nanotechnology in agriculture: Opportunities, toxicological implications, and occupational risks

Nanotechnology has the potential to make a beneficial impact on several agricultural, forestry, and environmental challenges, such as urbanization, energy constraints, and sustainable use of resources. However, new environmental and human health hazards may emerge from nano-enhanced applications. This raises concerns for agricultural workers who may become primarily exposed to such xenobiotics during their job tasks. The aim of this review is to discuss promising solutions that nanotechnology may provide in agricultural activities, with a specific focus on critical aspects, challenging issues, and research needs for occupational risk assessment and management in this emerging field. Eco-toxicological aspects were not the focus of the review. Nano-fertilizers, (nano-sized nutrients, nano-coated fertilizers, or engineered metal-oxide or carbon-based nanomaterials per se), and nano-pesticides, (nano-formulations of traditional active ingredients or inorganic nanomaterials), may provide a targeted/controlled release of agrochemicals, aimed to obtain their fullest biological efficacy without over-dosage. Nano-sensors and nano-remediation methods may detect and remove environmental contaminants. However, limited knowledge concerning nanomaterial biosafety, adverse effects, fate, and acquired biological reactivity once dispersed into the environment, requires further scientific efforts to assess possible nano-agricultural risks. In this perspective, toxicological research should be aimed to define nanomaterial hazards and levels of exposure along the life-cycle of nano-enabled products, and to assess those physico-chemical features affecting nanomaterial toxicity, possible interactions with agro-system co-formulants, and stressors. Overall, this review highlights the importance to define adequate risk management strategies for workers, occupational safety practices and policies, as well as to develop a responsible regulatory consensus on nanotechnology in agriculture.

Chemical and Physical Exposures in the Emerging US Green-Collar Workforce

OBJECTIVE

"Green collar" workers serve in occupations that directly improve environmental quality and sustainability. This study estimates and compares the prevalence of select physical and chemical exposures among green versus non-green U.S. workers.

METHODS

Data from the U.S. 2010 National Health Interview Survey (NHIS) Occupational Health Supplement were linked to the Occupational Information Network (ONET) Database. We examined four main exposures: 1) vapors, gas, dust, fumes (VGDF); 2) secondhand tobacco smoke; 3) skin hazards; 4) outdoor work.

RESULTS

Green-collar workers were significantly more likely to report exposure to VGDF and outdoor work than nongreen-collar workers [adjusted odds ratio (AOR) = 1.25; 95% CI = 1.11 to 1.40; AOR = 1.44 (1.26 to 1.63), respectively]. Green-collar workers were less likely to be exposed to chemicals (AOR = 0.80; 0.69 to 0.92).

CONCLUSIONS

Green-collar workers appear to be at a greater risk for select workplace exposures. As the green industry continues to grow, it is important to identify these occupational hazards in order to maximize worker health.

Green Collar Workers: An Emerging Workforce in the Environmental Sector

OBJECTIVE

We describe the socio-demographic, occupational, and health characteristics of "green collar" workers, a vital and emerging workforce in energy-efficiency and sustainability.

METHODS

We linked data from the 2004 to 2012 National Health Interview Surveys (NHIS) and US Occupational Information Network (O*NET). Descriptive and logistic regression analyses were conducted using green collar worker status as the outcome (n = 143,346).

RESULTS

Green collar workers are more likely than non-green workers to be men, age 25 to 64 years, obese, and with less than or equal to high school (HS) education. They are less likely to be racial/ethnic minorities and employed in small companies or government jobs.

CONCLUSIONS

Green collar workers have a distinct socio-demographic and occupational profile, and this workforce deserves active surveillance to protect its workers' safety. The NHIS-O*NET linkage represents a valuable resource to further identify the unique exposures and characteristics of this occupational sector.

Chemical toxicity prediction for major classes of industrial chemicals: Is it possible to develop universal models covering cosmetics, drugs, and pesticides?

Computational models have earned broad acceptance for assessing chemical toxicity during early stages of drug discovery or environmental safety assessment. The majority of publicly available QSAR toxicity models have been developed for datasets including mostly drugs or drug-like compounds. We have evaluated and compared chemical spaces occupied by cosmetics, drugs, and pesticides, and explored whether current computational models of toxicity endpoints can be universally applied to all these chemicals. Our analysis of the chemical space overlap and applicability domain (AD) of models built previously for twenty different toxicity endpoints showed that most of these models afforded high coverage (>90%) for all three classes of compounds analyzed herein. Only T. pyriformis models demonstrated lower coverage for drugs and pesticides (38% and 54%, respectively). These results show that, for the most part, historical QSAR models built with data available for different toxicity endpoints can be used for toxicity assessment of novel chemicals irrespective of the intended commercial use; however, the AD restriction is necessary to assure the expected prediction accuracy. Local models may need to be developed to capture chemicals that appear as outliers with respect to global models.

Dioscorea spp. (A Wild Edible Tuber): A Study on Its Ethnopharmacological Potential and Traditional Use by the Local People of Similipal Biosphere Reserve, India

A number of wild crops remain unexplored in this world and among them some have excellent medicinal and nutritional properties. India is a harbor of biodiversity in general and phytodiversity in particular. The plant diversity is distributed from the Western Ghats to Eastern Ghats, along with the North-Eastern region and from the Greater Himalayas to the plain of Ganga. Among these distributed floral regions of the country, the Eastern Ghats are important due to their rich floral diversity. The forests of Odisha form a major part of Eastern Ghats in general and the Similipal Biosphere Reserve (SBR) in particular. The SBR is inhabited by many local communities. The food and medicinal habits of these communities are not fully explored even today. They are dependent on the forests of SBR for their food and medicine. Among their collections from forests, root and tuberous plants play a significant role. The local communities of SBR use about 89 types of tuberous plants for various purposes. Dioscorea is one such tuber, having maximum use among the local of SBR. However, less documentation and no specific reports are available on the food and medicinal values of the species available in this part of the World. Dioscorea species, popularly known as Yam worldwide and as Ban Aalu in Odisha, India, is a prime staple medicinal-food substitute for the majority of rural and local people of the state of India. Of the 13 Dioscorea species available in SBR, 10 species are known to be bitter in taste and unpalatable when taken raw. Since less documentation is available on the Dioscorea species of SBR and their traditional uses, the present study was focused on the ethnobotany, nutritional and pharmacological values of these species along its nutraceutical importance.

QSAR models of human data can enrich or replace LLNA testing for human skin sensitization

Skin sensitization is a major environmental and occupational health hazard. Although many chemicals have been evaluated in humans, there have been no efforts to model these data to date. We have compiled, curated, analyzed, and compared the available human and LLNA data. Using these data, we have developed reliable computational models and applied them for virtual screening of chemical libraries to identify putative skin sensitizers. The overall concordance between murine LLNA and human skin sensitization responses for a set of 135 unique chemicals was low (R = 28-43%), although several chemical classes had high concordance. We have succeeded to develop predictive QSAR models of all available human data with the external correct classification rate of 71%. A consensus model integrating concordant QSAR predictions and LLNA results afforded a higher CCR of 82% but at the expense of the reduced external dataset coverage (52%). We used the developed QSAR models for virtual screening of CosIng database and identified 1061 putative skin sensitizers; for seventeen of these compounds, we found published evidence of their skin sensitization effects. Models reported herein provide more accurate alternative to LLNA testing for human skin sensitization assessment across diverse chemical data. In addition, they can also be used to guide the structural optimization of toxic compounds to reduce their skin sensitization potential.

Alarms about structural alerts

Structural alerts are widely accepted in chemical toxicology and regulatory decision support as a simple and transparent means to flag potential chemical hazards or group compounds into categories for read-across. However, there has been a growing concern that alerts disproportionally flag too many chemicals as toxic, which questions their reliability as toxicity markers. Conversely, the rigorously developed and properly validated statistical QSAR models can accurately and reliably predict the toxicity of a chemical; however, their use in regulatory toxicology has been hampered by the lack of transparency and interpretability. We demonstrate that contrary to the common perception of QSAR models as "black boxes" they can be used to identify statistically significant chemical substructures (QSAR-based alerts) that influence toxicity. We show through several case studies, however, that the mere presence of structural alerts in a chemical, irrespective of the derivation method (expert-based or QSAR-based), should be perceived only as hypotheses of possible toxicological effect. We propose a new approach that synergistically integrates structural alerts and rigorously validated QSAR models for a more transparent and accurate safety assessment of new chemicals.

Green Jobs: Definition and Method of Appraisal of Chemical and Biological Risks

In the wake of sustainable development, green jobs are developing rapidly, changing the work environment. However a green job is not automatically a safe job. The aim of the study was to define green jobs, and to establish a preliminary risk assessment of chemical substances and biological agents for workers in Quebec. An operational definition was developed, along with criteria and sustainable development principles to discriminate green jobs from regular jobs. The potential toxicity or hazard associated with their chemical and biological exposures was assessed, and the workers' exposure appraised using an expert assessment method. A control banding approach was then used to assess risks for workers in selected green jobs. A double entry model allowed us to set priorities in terms of chemical or biological risk. Among jobs that present the highest risk potential, several are related to waste management. The developed method is flexible and could be adapted to better appraise the risks that workers are facing or to propose control measures.

Planetary boundaries: Guiding human development on a changing planet

The planetary boundary (PB) concept, introduced in 2009, aimed to define the environmental limits within which humanity can safely operate. This approach has proved influential in global sustainability policy development. Steffen et al. provide an updated and extended analysis of the PB framework. Of the original nine proposed boundaries, they identify three (including climate change) that might push the Earth system into a new state if crossed and that also have a pervasive influence on the remaining boundaries. They also develop the PB framework so that it can be applied usefully in a regional context.

Science , this issue 10.1126/science.1259855

Aggregate Exposure and Cumulative Risk Assessment--Integrating Occupational and Non-occupational Risk Factors

Occupational exposure limits have traditionally focused on preventing morbidity and mortality arising from inhalation exposures to individual chemical stressors in the workplace. While central to occupational risk assessment, occupational exposure limits have limited application as a refined disease prevention tool because they do not account for all of the complexities of the work and non-occupational environments and are based on varying health endpoints. To be of greater utility, occupational exposure limits and other risk management tools could integrate broader consideration of risks from multiple exposure pathways and routes (aggregate risk) as well as the combined risk from exposure to both chemical and non-chemical stressors, within and beyond the workplace, including the possibility that such exposures may cause interactions or modify the toxic effects observed (cumulative risk). Although still at a rudimentary stage in many cases, a variety of methods and tools have been developed or are being used in allied risk assessment fields to incorporate such considerations in the risk assessment process. These approaches, which are collectively referred to as cumulative risk assessment, have potential to be adapted or modified for occupational scenarios and provide a tangible path forward for occupational risk assessment. Accounting for complex exposures in the workplace and the broader risks faced by the individual also requires a more complete consideration of the composite effects of occupational and non-occupational risk factors to fully assess and manage worker health problems. Barriers to integrating these different factors remain, but new and ongoing community-based and worker health-related initiatives may provide mechanisms for identifying and integrating risk from aggregate exposures and cumulative risks from all relevant sources, be they occupational or non-occupational.

Chemical Recycling of PET Wastes with Different Catalysts

Chemical recycling of polyethylene terephthalate, known as PET, has been the subject of increased interest as a valuable feedstock for different chemical processes. In this work, glycolysis of PET waste granules was carried out using excess ethylene glycol in the presence of different simple chemicals acting as catalysts, which are, namely, categorized in ionic liquids, metal salts, hydrotalcites, and enzymes. From every category, some materials as a sample were used, and the one which is going to bring the best result is noted. The effect of some parameters such as temperature, pressure, amount of sample, material ratio, and stirring rate was investigated. As a result we compared the best of each category with the others and final result is shown.

The photovoltaic industry on the path to a sustainable future--environmental and occupational health issues

As it supplies solar power, a priori considered harmless for the environment and human health compared with fossil fuels, the photovoltaic (PV) industry seems to contribute optimally to reduce greenhouse gas emissions and, overall, to sustainable development. However, considering the forecast for rapid growth, its use of potentially toxic substances and manufacturing processes presenting health and safety problems may jeopardize its benefits. This paper aims to establish a profile of the PV industry in order to determine current and emerging environmental and health concerns. A review of PV system life cycle assessments, in light of the current state of the industry and its developmental prospects, reveals information deficits concerning some sensitive life cycle indicators and environmental impacts, together with incomplete information on toxicological data and studies of workers' exposure to different chemical and physical hazards. Although solar panel installation is generally considered relatively safe, the occupational health concerns related to the growing number of hazardous materials handled in the PV industry warrants an all-inclusive occupational health and safety approach in order to achieve an optimal equilibrium with sustainability. To prevent eco-health problems from offsetting the benefits currently offered by the PV industry, manufacturers should cooperate actively with workers, researchers and government agencies toward improved and more transparent research, the adoption of specific and stricter regulations, the implementation of preventive risk management of occupational health and safety and, lastly, greater responsibilization toward PV systems from their design until their end of life.

Opportunities and challenges of nanotechnology in the green economy

In a world of finite resources and ecosystem capacity, the prevailing model of economic growth, founded on ever-increasing consumption of resources and emission pollutants, cannot be sustained any longer. In this context, the "green economy" concept has offered the opportunity to change the way that society manages the interaction of the environmental and economic domains. To enable society to build and sustain a green economy, the associated concept of "green nanotechnology" aims to exploit nano-innovations in materials science and engineering to generate products and processes that are energy efficient as well as economically and environmentally sustainable. These applications are expected to impact a large range of economic sectors, such as energy production and storage, clean up-technologies, as well as construction and related infrastructure industries. These solutions may offer the opportunities to reduce pressure on raw materials trading on renewable energy, to improve power delivery systems to be more reliable, efficient and safe as well as to use unconventional water sources or nano-enabled construction products therefore providing better ecosystem and livelihood conditions.However, the benefits of incorporating nanomaterials in green products and processes may bring challenges with them for environmental, health and safety risks, ethical and social issues, as well as uncertainty concerning market and consumer acceptance. Therefore, our aim is to examine the relationships among guiding principles for a green economy and opportunities for introducing nano-applications in this field as well as to critically analyze their practical challenges, especially related to the impact that they may have on the health and safety of workers involved in this innovative sector. These are principally due to the not fully known nanomaterial hazardous properties, as well as to the difficulties in characterizing exposure and defining emerging risks for the workforce. Interestingly, this review proposes action strategies for the assessment, management and communication of risks aimed to precautionary adopt preventive measures including formation and training of employees, collective and personal protective equipment, health surveillance programs to protect the health and safety of nano-workers. It finally underlines the importance that occupational health considerations will have on achieving an effectively sustainable development of nanotechnology.