The fate of phthalate acid esters in wastewater treatment plants and their impact on receiving waters.

Phthalates (PAEs) are gaining attention and being researched as an endocrine disruptor as global plastic use surge. There is an urgent need to explore the key factors affecting the removal of PAEs from wastewater and the impact of wastewater effluent on receiving water. Here we investigated the levels and distribution patterns of 16 typical PAEs in surface water and five wastewater treatment plants (WWTPs) along the Dongyang River from Yiwu, China, collecting 42 surface water and 31 wastewater samples. We found that influent PAEs concentration and treatment process were the key factors affecting the degradation efficiency of PAEs in primary and secondary treatment, respectively. In primary treatment, long-chain PAEs were more easily removed (and sometimes less likely to accumulate) than short-chain PAEs, regardless of the influent PAEs concentration (a key factor in primary treatment), while in secondary treatment, short-chain PAEs were easily removed regardless of the treatment process (a factor in secondary treatment). This was not the case for long-chain PAEs, which were only more readily removed in the A/A/O process. In addition, by comparing the significant differences between wastewater and surface water, we found that the total PAEs in the treated effluent were significantly lower than in surface water upstream and in built-up urban areas, indicating that wastewater discharges in the study area did not increase PAEs in the receiving water. Finally, river in the city center and artificial treatment facilities in the study area were identified as requiring priority attention. The results of this study can serve as a model for controlling PAEs in other similar developing cities in China and provide valuable information on the fate of endocrine disruptor from wastewater treatment in China and their impact on surface water.

Flow and stock accumulation of plastics in China: Patterns and drivers.

Plastic pollution has always been a hot issue of global concern. Previous studies have mainly focused on the flow of plastics. However, information on the patterns and characteristics of flow, stock, and waste in the plastic life cycle and their driving factors is limited in China, and effective waste reduction and sustainable strategies are missing. Therefore, this research established a flow model of polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET); further analyzed the driving factors; and proposed strategies for waste reduction and sustainable development. We found that the total consumption, stock, and waste of PET, PE, and PP in 2010-2017 reached 552.96, 292.70, and 257.18 Tg, respectively. Building and construction (B&C), packaging, and textiles were the sectors with the largest stock of PE, PP, and PET. From 2010 to 2013, the stock of PE increased by 440 %, which was mainly driven by the increase in material utilization intensity (MUI). Similarly, the growth of MUI was the main driving factor driving PP (351 %) and PET (367 %) stocks. Notably, from 2014 to 2017, economic growth was the main factor driving the plastic stock. These results will provide a scientific basis for promoting the sustainable utilization of PE, PP, and PET and be of great significance to achieve the strategic goal of a no-waste city.

Dynamic flows of polyethylene terephthalate (PET) plastic in China.

Polyethylene terephthalate (PET) is a widely used plastic material that may cause significant environmental pollution. China is a major global producer and consumer of PET. Previous studies have focused on the effects of toxic elements from PET (e.g., antimony leached from PET products) on the environment. However, detailed information about PET, particularly about the PET production, trade, use, and recycling in China, is limited. This study developed a network model of PET flows in China, including the production, market trade, manufacturing and use, and waste management and recycling stages. Based on this network model, the characteristics of PET flows during three periods of development for the PET industry were analyzed. The results show that the fiber and bottle manufacturing industries are the industries with the largest PET in-use stocks. The PET flows showed different characteristics in the terms of waste import, recycling, and disposal (mechanical recycling, chemical recycling, incineration, landfill, and discarding) in the different periods of PET industrial development. Notably, the amount of discarded PET was significant, and the treatment of waste PET would probably be a challenge in the future. Policies for improving the PET cycling system were provided on the basis of the study results to promote the management and sustainable utilization of PET materials.

Dynamic flow and pollution of antimony from polyethylene terephthalate (PET) fibers in China.

Antimony (Sb), a regulated contaminant, is added as a catalyst in the process of polyethylene terephthalate (PET) synthesis. Previously, Sb release from PET bottles and films was studied. However, Sb release from PET fibers (the most common form of PET) is limited. Therefore, a network model of material flow for PET fibers in China is developed, and the anthropogenic Sb flow and release entering into the hydrosphere, pedosphere, and atmosphere are studied based on microexperiments and macromodels. To compensate for the uncertainty caused by material flow analysis, Sb pollution in the surrounding areas (the drinking water of nearby residents and sediments of nearby river area) is further explored by combining field investigations and sample analysis. The results are as follows: 1) the manufacture stage of PET fibers is the main source of Sb release (2926 t), followed by the dyeing (2223 t) and weaving (908 t) stages; 2) Sb release (1108 t) from waste PET fibers subjected to landfill disposal is the highest. Sb release (872 t) from discarded fiber waste is second highest. Sb release from PET fibers subjected to mechanical recycling, incineration, and chemical recycling is 784, 284, and 25 t, respectively; and 3) an obvious source-sink relationship is found between anthropogenic Sb in the rivers and sediments and the intensity of the industries. This study suggests that Sb from PET fibers should be properly managed to prevent widespread dispersion in the hydrosphere, pedosphere, and atmosphere.

Toxicity and bioavailability of antimony in edible amaranth (Amaranthus tricolor Linn.) cultivated in two agricultural soil types.

Although elevated levels of antimony (Sb) in agricultural soil and plant systems can have harmful effects on human health and ecosystems, little is known about the toxicity of Sb to plants and its mechanism. The assessment of Sb bioavailability is essential for understanding its potential risks and toxicity. In this study, we used pot experiments with two agricultural soil types spiked with Sb to investigate the dose-effect relationship between exposure to Sb and toxic effects (growth and bioaccumulation) on edible amaranth (Amaranthus tricolor Linn.). Soil solution (pore water) and seven single extractants were used to assess the bioavailability of Sb. Different toxic effects of Sb to amaranth cultivated in two types of soils (alkaline and acid soil) were observed. In alkaline soil (chestnut soil, pH 8.39), antimony is more easily absorbed by root and transported to shoot by plants, leading to more adverse effects, than in acid soil (pH 4.91) under the same exposure level. Our findings also highlight the need for more attention on asymptomatic accumulation of Sb in plants, especially for agricultural products cultivated in contaminated areas. The extraction efficiency of Sb was various in different extractants and soil types, Mehlich 3, NaHCO3 and Na2HPO4 for Sb were more efficient than other extractants in both tested alkaline and acid soil. Based on the extractability and correlation coefficients of toxic effects on amaranth and extractable Sb, we found that 0.1 M Na2HPO4 is the best extractant to predict the bioavailability of Sb in soil, and M3 is a suitable alternative. Antimony concentration in soil solution can also be used as an alternative indicator of the bioavailability of Sb.

Anthropogenic antimony flow analysis and evaluation in China.

China is facing a shortage of antimony (Sb) resources, and Sb emissions are worsening. In exploring solutions to these issues, this paper attempts to apply substance flow analysis (SFA) to track Sb flow among the lithosphere, anthroposphere, and biosphere in China. The results are as follows: (1) China's Sb ore faces the risk of depletion. Although China has the largest Sb reserves in the world, the import of Sb concentrate accounted for a large proportion of the total material input during the production stage, which has increased from 9.78% in 2006 to 30.22% in 2016. Moreover, since 2013, the net export rate of Sb products during the manufacture and fabrication (M&F) stage has been growing, reaching 21.32% in 2016. (2) The Sb industry is highly dependent on ores. Moreover, the resource efficiency and cycling ratio of Sb are quite low. (3) Sb emissions cannot be ignored in industrial processes, particularly Sb emissions from the M&F and usage stages. Sb emissions discharged into the biosphere reached 1915.58 Gg in the period from 2006 to 2016.