Potential consequences for human health from toxic substances contained in e-waste plastics highlights the growing importance to avoid the open burning practices of e-waste plastics containing Hg, ...Pb, Cr and Sb that should prevent human and environmental exposures to toxic components.
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•Potential consequences for human health from toxic substances contained in e-waste plastics was conducted.•Toxic metals and organic chemicals were identified in the plastics of discarded mobile phones.•Hg contributed the largest risk for carcinogens and non-cancer diseases.
At present, waste mobile phone is considered to be one of the fastest-growing obsolete items in the stream of electronic waste (e-waste). Toxic substances such as heavy metals and brominated flame retardants (BFRs) have been widely added to plastics used in electrical and electronic equipment (EEE). The recent technological revolution in electronic appliances combined with high and growing consumption has caused a huge generation of waste electrical and electronic equipment (WEEE). Therefore, e-waste plastics are considered to be one of the fastest-growing waste streams globally. In this study, we examined the hazardous substances in the plastic components of waste mobile phones and then applied the USEtox life cycle impact assessment (LCIA) model to determine the impacts on human health. Specifically, various plastic parts separated from waste mobile phones (n = 20) were collected and then, we used standard tests to characterize the heavy metals and brominated flame retardants. The mean and range of the results are 2207.7 μg/kg (503.9–11569.9 μg/kg) for Pb, 91.6 μg/kg (8.8–464.4 μg/kg) for Cd, 13.7 μg/kg (1.6–58.9 μg/kg) for Be, 7203.3 μg/kg (117–69813 μg/kg) for Sb, 471.3 μg/kg (143.4–2351.3 μg/kg) for As, 1.5 mg/kg (2.1–12.5 mg/kg) for Hg and 523.7 mg/kg (27.1–3859 mg/kg) for Cr. The BFRs - a sum Polybrominated Biphenyls, Polybrominated Diphenyl Ethers and Hexabromocyclododecane - were not detected except for two samples, which was an average of 234.5 μg/kg for nona-BDE and deca-BDE. The total bromine (Br) concentration varied from 0 to 471 mg/kg (average value of 87.9 mg/kg) , while Tetrabromobisphenol A (TBBP-A) showed an average concentration of 214.3 μg/kg. In the case of potential human health risks, Hg contributed the major risk for carcinogens and non-cancer disease in the plastics, but the contribution of Pb was also significant. In the case of eco-toxicity, Cr posed the most significant risks in the plastics. Overall, the results show that the toxic substances are below the limit values of substances regulated in the RoHS Directive in China and Europe. However, the results of LCIA highlight the growing importance to avoid the open burning practices of e-waste plastics that contain Hg, Pb, Cr ad Sb. Additionally, the results set a new database for the e-waste plastics recycling industry and provide information for ecodesign in EEE production.
Abstract
Cement plays a dual role in the global carbon cycle like a sponge: its massive production contributes significantly to present-day global anthropogenic CO
2
emissions, yet its hydrated ...products gradually reabsorb substantial amounts of atmospheric CO
2
(carbonation) in the future. The role of this sponge effect along the cement cycle (including production, use, and demolition) in carbon emissions mitigation, however, remains hitherto unexplored. Here, we quantify the effects of demand- and supply-side mitigation measures considering this material-energy-emissions-uptake nexus, finding that climate goals would be imperiled if the growth of cement stocks continues. Future reabsorption of CO
2
will be significant (~30% of cumulative CO
2
emissions from 2015 to 2100), but climate goal compliant net CO
2
emissions reduction along the global cement cycle will require both radical technology advancements (e.g., carbon capture and storage) and widespread deployment of material efficiency measures, which go beyond those envisaged in current technology roadmaps.
Express delivery services are booming in both developed and emerging economies due to their low cost, convenience, and the fast growth in online shopping. The increasing environmental impacts of ...express delivery services and mitigation potentials, however, remain largely unexplored. Here we addressed such a gap for China, a country which is expanding online retail sales and express delivery rapidly. We found a total of 8.8 Mt of scrap packaging materials were generated by the express delivery sector in China in 2018. Its transportation-related GHG emissions surged from 0.3 Mt in 2007 to 13.7 Mt of CO
-equivalent (CO
e) in 2018, with an average of 0.27 kgCO
e per piece. Over 80% from online shopping deliveries. We predict these emissions will reach 75 MtCO
e by 2035. Nevertheless, it is possible to mitigate such GHG emissions by 102~134 MtCO
e between 2020 and 2035 if a suite of policies is adopted, including a slowdown of delivery speed, fuel system upgrades, packaging materials reduction, logistics optimization, and carbon pricing.
Urban subway system, as an important type of urban transportation infrastructure, can provide mass mobility service and help address urban sustainability challenges such as traffic congestion and air ...pollution. The continuous construction of subways, however, causes large amounts of construction materials and embodied greenhouse gas (GHG) emissions. In this study, we characterized the patterns of subway development, construction material stocks, and embodied emissions covering all 219 cities in the world in which subways are found by July 2020. The global subway length reached 16,419 km in 2020, and the construction material stocks amounted to 2.5 gigatons, equaling to an embodied emission of 560 megatons. In particular, China’s subway system contributes to ~40% of the total global stocks, with a pattern of moderate and steady stocks growth before 2010 and a rapid expansion afterwards, implying the late-development advantages and infrastructure-based urbanization mode. Our results demonstrated that identifying the spatiotemporal characteristics of subway materials stocks development is imperative for benchmarking future resource demand, informing sustainable subway planning, prospecting urban mining and waste management opportunities and challenges, and mitigating the associated environmental impacts for global GHG emission reduction.
Many developing countries have not significantly changed their course with regard to electronic waste contamination, and they are still facing the specter of mountains of hazardous electronic waste, ...with serious consequences for both the environment and public health. An efficient and stable analytical method was developed to determine the inventory and emission factors of polybrominated dibenzo-p-dioxin and dibenzofurans (PBDD/Fs) and polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) formed from the incineration of scrap printed circuit boards (PCBs). Both PBDD/Fs and PCDD/Fs have been found in all experimental sections with a maximum formation rate at temperatures between 250 and 400 °C. The amounts tended first to increase and then began to decrease as the temperature rose. When subjected to a heating temperature of 325 °C, the total content of twelve 2,3,7,8-substituted PBDD/Fs congeners (tetra- through octabromo-) gathered from three outputs was the largest, at 19 000, 160 000, and 57 ng TEQ/kg in solid, liquid, and gaseous fractions, respectively; the total content of seventeen 2,3,7,8-substituted PCDD/Fs congeners (tetra- through octachloro-) was 820, 550, and 1.4 ng TEQ/kg. The formation of PCDD/Fs was remarkably less than that of PBDD/Fs because bromine concentrations considerably exceeded chlorine concentrations. The ingredients and conditions necessary to form PCDD/Fs or PBDD/Fs were definitely present, such as products of incomplete combustion, halogenides, an oxidizing atmosphere, and a catalystCu salts being the most effective, significantly increasing the yields of PCDD/Fs and PBDD/Fs and decreasing the optimum temperature range.
A large amount of demolition waste was generated due to the rapid urbanization. Prior to designing corresponding management measures, it is imperative to understand the amount, composition, and flows ...of the generated waste. This study proposes a novel approach to quantifying the demolition waste from generation to final disposal and, consequently, formulates corresponding strategies to managing the demolition waste, by using spatial and temporal dimensions in the Geographic information system. Specifically, a GIS-based model is proposed and consequently applied to a case study. Results show that over 135 million tons of demolition waste will be generated in the Nan Shan District between 2015 and 2060, and the recycling potential is valued at $ 6072 million under the optimistic scenario. By contrast, under the worst-case scenario, over 54 million m3 of land area which equals to approximate $ 218 billion could be needed for landfill. Compared to the worst-case scenario, the optimum scenario would reduce the amount of waste to be disposed in landfills by 80% and increase the value of recycling by 65%. The results revealed that, as a rapidly developing city, Shenzhen would likely experience the peak in the generation of demolition waste. Therefore, it is imperative to improve the recycling rate as it helps to raise the potential economic benefits and to reduce the landfill demand. This research is innovative in terms of the systemization, visual representation and analysis of quantifying the demolition waste flows via a novel method. The findings about the generation trends, economic values and environmental effects provide valuable information for the future waste management exercises of various stakeholders such as government, industry and academy.
•One method to quantify the demolition waste with spatial and temporal distribution was developed.•The recycling potentials of demolition waste and associated demand of landfills were evaluated.•GIS is a promising approach to quantify and manage the demolition waste.•GIS-approach could be applied to manage the demolition waste at both regional and national-level.
With the continuing growth of urbanization and the boom of the construction sector in China, a substantial quantity of construction and demolition waste has been generated. However, there has been ...little research to characterize the waste from buildings’ interior renovation (repair and maintenance) or decoration activities. The primary purpose of this study was to provide a systematic analysis for the generation and flows of decoration and renovation waste based on field investigation. Taking Shenzhen city - a fast-growing megacity (over 20 M population) in South China - as an example, the results show that approximately 1 Mt of decoration and renovation waste was generated in Shenzhen city in 2017, with an annual growth rate of 10% over the past decade. Concrete waste and brick (block) account for 72% of the total decoration and renovation waste. The landfilling rate of decoration and renovation waste has reached 83%, of which a majority was disposed of by open dumping. The renovation of older residential buildings produced more than half of the total decoration and renovation waste. Although the amount of hazardous materials such as gypsum and painting materials only account for a very low weight fraction of 2%, they could still pose significant environmental impacts, compared to other types of construction and demolition waste. Accelerating the construction of sorting facilities to separate toxic and valuable materials is crucial, to realize decoration and renovation waste minimization and lower environmental risks. Overall, the findings of this study could be applied to formulate environmentally sound management measures from a policy standpoint, for Shenzhen city. The methods could also be useful for decoration and renovation waste estimation and projection in other cities in China and beyond.
•This study characterizes the generation and flow of D&R waste in a megacity in China.•Approximately 1 Mt (50 kg per person per year) D&R waste were generated in 2017.•Landfilling rate reached to 83% and a majority were disposed of by open dumping.•D&R waste from residential building renovation is the major generator, by 27.5 kg/m2.•The cumulative generation of D&R waste could reach to 19 Mt from 2018 to 2030.
Carbon capture and storage is becoming increasingly feasible. This study provides a novel quantitative analysis of the global CO2 mitigation potential through accelerated carbon sequestration in ...concrete debris separated from construction and demolition waste. We consider the economic and environmental tradeoff. Based on data collection from 14 large regions and countries, we created a method to estimate and project the generation of concrete debris, recycling and carbonation rates, and cost. The overall concrete debris generation was more than 3.0 (±0.6) billion tonnes (Bt) in 2017 worldwide, mainly from emerging countries such as China and India. This debris has the potential to mitigate 62.5 (±8.9) million tonnes (Mt) CO2 under optimal carbonation conditions determined by pressure, temperature, humidity, time, CO2 concentration, and debris size. Our scenario analysis reveals that the global cumulative carbonation of concrete debris could be as high as 3.0 Bt CO2 between 2018 and 2035, which equals approximately one third of the total CO2 emissions from fuel combustion of China in 2016. In our scenarios, the economic benefits of storing CO2 by concrete debris are mainly from recycled concrete aggregate rather than carbon sequestration, but also consider the current carbon price in major carbon markets. These findings highlight an effective and practical approach to reuse concrete debris as well as enhancing economic benefits. This approach could be helpful to better manage the fast-growing concrete debris and need for carbon mitigation as well as bridging the gap of CO2 sequestration by concrete debris between research and application.
•The tradeoff between environmental and economic benefits has been determined.•62.5 Mt CO2 could have been sequestered with profit of 3.3 billion USD in 2017.•Cumulative CO2 mitigation potential could be as high as 3.0 Bt from 2018 to 2035.
Associated with the rapid development of the information and electronic industry, liquid crystal displays (LCDs) have been increasingly sold as displays. However, during the discarding at their ...end-of-life stage, significant environmental hazards, impacts on health and a loss of resources may occur, if the scraps are not managed in an appropriate way. In order to improve the efficiency of the recovery of valuable materials from waste LCDs panel in an environmentally sound manner, this study presents a combined recycling technology process on the basis of manual dismantling and chemical treatment of LCDs. Three key processes of this technology have been studied, including the separation of LCD polarizing film by thermal shock method the removal of liquid crystals between the glass substrates by the ultrasonic cleaning, and the recovery of indium metal from glass by dissolution. The results show that valuable materials (e.g. indium) and harmful substances (e.g. liquid crystals) could be efficiently recovered or separated through above-mentioned combined technology. The optimal conditions are: (1) the peak temperature of thermal shock to separate polarizing film, ranges from 230 to 240
°C, where pyrolysis could be avoided; (2) the ultrasonic-assisted cleaning was most efficient at a frequency of 40 KHz (
P
=
40
W) and the exposure of the substrate to industrial detergents for 10 min; and (3) indium separation from glass in a mix of concentrated hydrochloric acid at 38% and nitric acid at 69% (HCl:HNO
3:H
2O
=
45:5:50, volume ratio). The indium separation process was conducted with an exposure time of 30 min at a constant temperature of 60
°C.
The dismantling of printed circuit board assemblies (PCBAs) and the recovery of their useful materials can lead to serious environmental impacts mainly due to their complicated physical structure and ...the variety of toxic elements contained in their material composition. So far, less attention has been paid to their responsible recycling compared to that of bare printed circuit boards. Combined with other materials recovery process, proper dismantling of PCBAs is beneficial to conserve scarce resources, reuse the components, and eliminate or safely dispose of hazardous materials. In analyzing the generation, resources potential and hazardous risk of scrap PCBAs, technologies used for the dismantling of waste PCBAs have been widely investigated and reviewed from the aspects of both industrial application and laboratory-scale studies. In addition, the feasibility of PCBA dismantling has been discussed, the determinants of which, including the heating conditions and mechanical properties have been identified. Moreover, this paper evaluates the environmental consequences caused by the dismantling of PCBAs.
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