Ultrasensitive mechanical/thermal response of a P(VDF-TrFE) sensor with a tailored network interconnection interface.

Ferroelectric polymers have great potential applications in mechanical/thermal sensing, but their sensitivity and detection limit are still not outstanding. We propose interface engineering to improve the charge collection in a ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) copolymer (P(VDF-TrFE)) thin film via cross-linking with poly(3,4-ethylenedioxythiophene) doped with polystyrenesulfonate (PEDOT:PSS) layer. The as-fabricated P(VDF-TrFE)/PEDOT:PSS composite film exhibits an ultrasensitive and linear mechanical/thermal response, showing sensitivities of 2.2 V kPa-1 in the pressure range of 0.025-100 kPa and 6.4 V K-1 in the temperature change range of 0.05-10 K. A corresponding piezoelectric coefficient of -86 pC N-1 and a pyroelectric coefficient of 95 µC m-2 K-1 are achieved because more charge is collected by the network interconnection interface between PEDOT:PSS and P(VDF-TrFE), related to the increase in the dielectric properties. Our work shines a light on a device-level technique route for boosting the sensitivity of ferroelectric polymer sensors through electrode interface engineering.

Distribution, partitioning behavior, and ecological risk assessment of phthalate esters in sediment particle-pore water systems from the main stream of the Haihe River, Northern China.

The distribution, partitioning behavior and risk assessment of phthalate esters (PAEs) in the surface sediment-pore water system of the Haihe River were investigated. The total cumulative concentrations of 21 PAE species (Σ21PAEs) in the surface sediment ranged from 45.9 to 1474.1 ng·g-1 dry weight (dw) and were from 17.9 to 2628.8 ng·mL-1 in the pore water. Di (2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), and diisobutyl phthalate (DIBP) were the dominant components, and their sum accounted, on average, for 88.4% and 72.0% of Σ21PAEs in the surface sediment and pore water, respectively. The spatial distributions of Σ21PAEs in the surface sediment and pore water indicated that large amounts of the consumed products contained plasticizers in the urban and nearshore areas and increased the discharge of PAEs into the Haihe River. The river dam also affected PAEs distributions. The organic carbon normalized partitioning coefficient (logKOC) followed a sequence as dry season (2.47 ± 0.35 mL·g-1) > wet season (2.02 ± 0.45 mL·g-1) > normal season (1.98 ± 0.42 mL·g-1). The risk quotient (RQ) method was employed to assess the potential ecological risk from specific species. High ecological risks of DEHP to the sensitive algae, crustacean, and fish species along with high ecological risks of DIBP to sensitive fish species were found in the surface sediment and pore water for all sampling seasons. In addition, DBP in the surface sediment and pore water exhibited moderate and high ecological risks to sensitive aquatic species. The highest RQ values for PAEs were found in the surface sediment and pore water in suburban and urban areas, respectively, and indicated that anthropogenic activities may cause severe river pollution and high risk to the local aquatic ecosystem. CAPSULE: High levels and ecological risks from PAEs were found in the urban river, and the partitioning behaviors of PAEs between the surface sediment and pore water were not significantly affected by their hydrophobicity, especially for species with low KOW.

Occurrence and characteristics of microplastics in the Haihe River: An investigation of a seagoing river flowing through a megacity in northern China.

Freshwater systems serve as important sources and transportation routes for marine microplastic pollution, and inadequate attention has been paid to this situation. Data on microplastic pollution of typical seagoing rivers in northern China are lacking. In the current study, we investigated the distribution and characteristics of microplastics in the main stream of the Haihe River, which flows through a metropolis with a high population density and level of industrialization and then flows into the Bohai Sea. The microplastic samples were collected by manta trawls with pore sizes of 333 µm, and the microplastic concentrations ranged from 0.69 to 74.95 items/m3. Fibers dominated in the surface water of the Haihe River; their shapes that were categorized as fibers, film, foam, fragments, and spheres, and contributed 17.4-86.7% of the total microplastics studied. The size distribution of the microplastics was concentrated in a range of 100-1000 µm, with 54.7% of the total sizes corresponding to the 333-µm trawl. Micro-Fourier transform infrared (µ-FT-IR) spectra showed that the main components were polyethylene, poly(ethylene-propylene) copolymer, and polypropylene. Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) measurements revealed scratches, micropores, and cracks on the surfaces of the microplastics due to mechanical friction, chemical oxidation and degradation processes. The results of this study confirmed the high abundance and high diversity of microplastics in an urban river and indicated appreciable impacts from point-source inputs on the microplastic pollution, such as effluents from wastewater treatment plants (WWTPs).

Structural equation modeling of PAHs in surrounding environmental media and field yellow carrot in vegetable bases from Northern China: In comparison with field cabbage.

During a harvest period, a set of field samples, including ambient air (gaseous and particulate phases), dust fall, surface soil and peel-surrounding soil, and yellow carrot tissues (leaf, peel, and core), were collected in a vegetable bases near a large coking manufacturer in Shanxi Province, Northern China. Based on the determinations of the concentrations and compositions of 15 USEPA priority polycyclic aromatic hydrocarbons (PAHs), the statistical results determined by a factor analysis (FA), combined with the isomeric ratios of paired species and the local emission inventory, indicated that coal combustion and vehicular exhaust served as the main emission sources of PAHs in the local environment and in yellow carrot tissues and that the coking industry was a secondary source. In terms of the transport pathways of PAHs in the surrounding media and yellow carrot tissues, the simulation results of a structural equation model (SEM) showed that the PAHs in ambient air were closely associated with those in dust fall, and these in turn had a positive correlation with the PAHs in surface soil, due to air-soil exchange. Furthermore, the PAHs in yellow carrot leaf were mainly derived from those in dust fall via leaf surface absorption, while peel uptake played a dominant role in the accumulation of PAHs in the edible core of yellow carrot. This was different from the case of cabbage, which was characterized by the prevailing contribution from leaf surface absorption. The current study supplied additional evidence to explore the transport pathways of PAHs from environmental media to tissues of different vegetables (leafy vegetables and root vegetables). CAPSULE: A combination of structural equation modeling with factor analysis was employed to quantitatively identify the dominant transport pathways of PAHs among multiple surrounding media and the different tissues of yellow carrot.

Distribution characteristics of and personal exposure with polycyclic aromatic hydrocarbons and particulate matter in indoor and outdoor air of rural households in Northern China.

Gaseous and particulate polycyclic aromatic hydrocarbons (PAHs) and size-segregated particulate matter (PM) in indoor air and outdoor air, along with personal exposure, were monitored in rural households of Northern China. The daily average concentrations of 28 species were 1310 ±â€¯811, 738 ±â€¯321, 465 ±â€¯247, and 655 ±â€¯250 ng/m3 in kitchen air, bedroom air, and outdoor air, and for personal exposure, respectively. PAHs tended to occur in the particulate phase with increasing molecular weight. Absorption by particulate organic carbon was dominant in the gas-particle partitioning process. The daily averaged concentrations of PM2.5 and PM1.0 were 104 ±â€¯39.5 and 88.4 ±â€¯39.3 µg/m3 in kitchen air, 79.0 ±â€¯63.2 and 65.7 ±â€¯57.5 µg/m3 in bedroom air, 52.9 ±â€¯16.5 and 41.5 ±â€¯12.5 µg/m3 in outdoor air, and 71.7 ±â€¯30.8 and 61.5 ±â€¯28.4 µg/m3 for personal exposure, respectively. The non-priority components contributed 5.5 ±â€¯2.8% to the total PAHs, while their fraction of carcinogenic risk reached 85.6 ±â€¯6.9%. The mean cancer risk posed to rural residents via inhalation exposure to PAHs exceeded the current acceptable threshold of 1.0 × 10-6 and the national average estimated in China. The personal exposure levels of PAHs and PM in households using clean energy were lower than those in households using traditional biomass by 30.0%, 29.4%, and 38.5% for PAH28, PM2.5, and PM1.0, respectively. However, the cancer risk of personal inhalation exposure to PAH28 from using liquid petroleum gas (LPG) was higher than that from using firewood, implying the adoption of LPG may not effectively reduce the cancer risk despite the decreasing exposure levels of PAH28 and PM with respect to the use of firewood. Cooking individuals suffered higher exposure levels of PAH28 and PM1.0 compared with non-cooking individuals, and the cancer risk of personal inhalation exposure to PAH28 for cooking individuals was 1.7 times that for non-cooking individuals. Cooking was a critical factor that affected the personal exposure levels of the local male and female residents.

Effects of temperature on the emission of particulate matter, polycyclic aromatic hydrocarbons, and polybrominated diphenyl ethers from the thermal treatment of printed wiring boards.

The effects of temperature on the emission of pollutants during the thermal treatment of electronic waste have rarely been investigated. The emission of particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs) from the thermal treatment of printed wiring boards was investigated over a temperature range of 320-600 °C. The emission factors (EFs) were determined to be within 1.6-7.6 g/kg, 2.23-11.9 µg/g, and 0.9-5.5 µg/g, respectively. High temperatures increased the formation of PAHs and CO, but decreased the emission of PBDEs, PM, and organic carbon. A temperature of 480 °C was determined to be optimal. Low-molecular-weight components were the dominant PAH species. The compositional profiles of PBDEs were clearly observed to vary with the temperature. Small particles (< 2.1 µm) that were more affected by temperature were dominant in PM, particle-bound PAHs, and PBDEs at all temperatures. High temperature increased the EFs of gaseous PAHs but had no remarkable effect on those of particulate PAHs. The freshly emitted PAHs primarily existed in the particulate phase at low temperatures, while the gaseous phase PAHs became prevailing at ≥ 520 °C. The particulate PBDEs were more susceptible to temperature and overwhelmingly dominant over the entire temperature range considered.

Emission factors of particulate matter, CO and CO2 in the pyrolytic processing of typical electronic wastes.

A self-designed experimental device was employed to simulate the pyrolytic dismantling process of selected electronic wastes (E-wastes), including printed wiring boards (PWBs) and plastic casings. The generated particulate matter (PM) of different particle sizes, carbon monoxide (CO) and carbon dioxide (CO2) were determined, and the corresponding emission factors (EFs) were estimated. Finer particles with particle sizes of 0.4-2.1 µm accounted for 78.9% and 89.3% of PM emitted by the pyrolytic processing of PWBs and plastic casings, respectively, and the corresponding EFs were 9.68 ±â€¯4.81 and 18.49 ±â€¯7.2 g/kg, respectively. The EFs of CO and CO2 from PWBs and plastic casings were 55.9 ±â€¯26.9 and 1182 ±â€¯439 g/kg, and 133.6 ±â€¯34.6 and 2827 ±â€¯276 g/kg, respectively. Compared with other emission sources, such as coal, biomass, and traffic exhaust, the EFs of E-wastes were relatively higher, especially for PM. There were significant positive correlations (p < 0.05) of the initial contents of carbon and nitrogen in PWBs with the related EFs of PM, CO, and CO2, while the correlations for plastic casings were insignificant. The EFs of CO of PWBs were significantly positively correlated with the corresponding EFs of PM and the parent polycyclic aromatic hydrocarbons (PAHs); however, the same result was not observed for plastic casings.

Emission behaviors of nitro- and oxy-polycyclic aromatic hydrocarbons during pyrolytic disposal of electronic wastes.

Emission factors (EFs) of polycyclic aromatic hydrocarbon (PAH) derivatives (12 nitro-PAHs and 4 oxy-PAHs) during the pyrolysis of two types of electronic waste (E-waste) were measured. Compositional profile, particle size distribution, gas-particle partitioning, correlations with precursor species and influences of pyrolytic temperature were investigated. The derivative products were dominated by oxy-PAHs. The averaged EFs of oxy-PAHs were 3.37 ±â€¯4.10 µg/g and 32.6 ±â€¯18.1 µg/g for PWBs and plastic casings, respectively, and those of nitro-PAHs were 85.7 ±â€¯92.4 ng/g and 83.3 ±â€¯69.7 ng/g, respectively. Most EFs of derivative species significantly correlated with their corresponding parent PAHs (p < 0.05), except a few cases, indicating formation of derivatives via related reactions of parent species. Most nitro-PAHs occurred in fine particles with the size < 2.1 µm, and oxy-PAHs were prevailing in fine particles with the size between 0.4 µm and 2.1 µm. Proportions of oxy-PAHs in particulate phase, especially those with higher molecular weight, were noticeably greater than those of the corresponding parent species. Below 480 °C, there was no evident difference in the EFs of PAH derivatives, while the EFs noticeably increased from 520 °C. With the increasing temperature, the majority of oxy-PAHs still occurred on finer particles, while the contribution of coarser particles tended to increase.

Multimedia modeling of the PAH concentration and distribution in the Yangtze River Delta and human health risk assessment.

Emissions of polycyclic aromatic hydrocarbons (PAHs) in China remain at a high level compared to those in developed countries. The Yangtze River Delta (YRD) is an economic and industrial center in China with an extremely large population. The potentially high emissions and excess cancer risk from human exposure in this region cannot be neglected. This study applied a multimedia model to estimate the concentrations of 16 US EPA priority PAHs in the environment in the YRD with a well-developed PAH-emission inventory for 2014. The model predicted that the average concentrations of ΣPAHs were 274 ng/m3 in the air, 255 ng/g in the soil, 15 ng/g in vegetation, 147 ng/L in freshwater and 144 ng/g in sediment, as well as 99 ng/L and 80 ng/g in seawater and sediment, respectively. Soil is the PAH sink in this region, and the net flux of the total PAHs is always from air to soil for each isomer. A deterministic assessment observed that the ELCR (excess lifetime cancer risk) ranged from 2.5 × 10-6 to 3.0 × 10-5 for exposure by air inhalation and from 3.5 × 10-7 to 7.9 × 10-6 for exposure by soil ingestion. The probabilistic results did not find any probability of ELCR >10-4 by exposure via soil ingestion in the YRD. The probabilistic ELCR induced by inhalation exposure varied from 8.1 × 10-7 to 3.1 × 10-4 in the YRD. This study provided a comprehensive overview of PAHs occurrence in natural environments and of the relevant human health risks. The information presented in this study could help authorities to enact a strategy regarding emission reduction and pollution control relevant to PAHs. CAPSULE: Multimedia modeling predicted distributions and compositions of PAHs in different environmental compartments, and deterministic and probabilistic ELCRs induced by air inhalation and soil ingestion were also provided.

Characteristics of perfluoroalkyl acids in atmospheric PM10 from the coastal cities of the Bohai and Yellow Seas, Northern China.

The concentration distributions, compositional profiles and seasonal variations of 17 perfluoroalkyl acids (PFAAs) in PM10 (particles with aerodynamic diameters < 10 µm) were determined in seven coastal cities of the Bohai and Yellow Seas. The detection rates of perfluorooctanoic acid (PFOA) and short-chain components (perfluoroalkyl carboxylic acids (PFCAs) with ≤7 carbon atoms and perfluoroalkane sulfonic acids (PFSAs) with ≤5 carbon atoms) were much higher than those of other long-chain PFAA species. The annual average concentration of total PFAAs in PM10 ranged from 23.6 pg/m3 to 94.5 pg/m3 for the sampling cities. The monthly mean concentrations of PFAAs in PM10 in some sampling cities reached a peak value in winter, while no significant seasonal differences presented in other cities. High concentrations of PFAAs in the northern cities generally occurred during the local heating period (from November to March). Generally, the dominant components of PFAAs were PFOA and perfluorobutyric acid (PFBA). Some significantly positive correlations (p < 0.01) between the 10 dominant components were revealed in the sampling cities, which implied similar sources and fate behaviors. Based on the simulated 72-hr backward trajectory tracking of air masses, the clustering results demonstrated the sampling cities were affected mainly by the atmospheric transport in sequence from the northwest, the southwest and the open seas, and many transport trajectories of air masses passed by the local fluorine chemical manufacturers in Liaoning, Shandong, Jiangsu, and Hubei Provinces. The estimated average daily intake (ADI) corresponding to the residents in different age groups indicated insignificant contributions to PFOA and perfluorooctane sulfonate (PFOS) exposures by inhalation of PM10 compared to ingestion by daily diet, while the higher ADI of PFOA than the reported levels for adults should be a concern. The calculated hazard ratios (HR) exhibited low noncancer risks by inhalation exposure to PFOA and PFOS in PM10.

Structural equation modeling of PAHs in ambient air, dust fall, soil, and cabbage in vegetable bases of Northern China.

A series of field samples including ambient air (gaseous and particulate phases), dust fall, surface soil, rhizosphere soil and cabbage tissues (leaf, root and core), were collected in vegetable bases near a large coking manufacturer in Shanxi Province, Northern China, during a harvest season. A factor analysis was employed to apportion the emission sources of polycyclic aromatic hydrocarbons (PAHs), and the statistical results indicated coal combustion was the dominant emission source that accounted for different environmental media and cabbage tissues, while road traffic, biomass burning and the coking industry contributed to a lesser extent. A structural equation model was first developed to quantitatively explore the transport pathways of PAHs from surrounding media to cabbage tissues. The modeling results showed that PAHs in ambient air were positively associated with those in dust fall, and a close relationship was also true for PAHs in dust fall and in surface soil due to air-soil exchange process. Furthermore, PAHs in surface soil were correlated with those in rhizosphere soil and in the cabbage leaf with the path coefficients of 0.83 and 0.39, respectively. PAHs in the cabbage leaf may dominantly contribute to the accumulation of PAHs in the edible part of cabbages.

Emission characteristics of polycyclic aromatic hydrocarbons from pyrolytic processing during dismantling of electronic wastes.

Two typical types of electronic waste (E-waste) were selected to investigate the emission characteristics of polycyclic aromatic hydrocarbons (PAHs) during pyrolytic processing, including emission factor, compositional profile, size distribution and gas-particle partitioning. The mean emission factors (EFs) of total PAHs were measured to be 2.77 ±â€¯1.41 µg/g and 23.65 ±â€¯14.52 µg/g for printed wiring boards and plastic casings, respectively, lower than those for coal combustion and biomass burning. Low molecular weight species were predominant in exhaust fumes, with overwhelming amounts of naphthalene (NAP) and phenanthrene (PHE) in the gaseous phase and particulate phase, respectively. The particle-size distribution exhibited the largest enrichment of total PAHs in finer particles less than 2.1 µm. Similarly, the distributions of individual species were dominated by finer particles. Most freshly emitted PAHs were liable to exist in particulate phase relative to gaseous phase. Based on the benzo[a]pyrene equivalent carcinogenic power, PAHs in particulate phase may have much stronger toxicity compared with those present in gaseous phase. The gas-particle partitioning behaviors of freshly emitted PAHs from pyrolytic processing of E-wastes were mainly regulated by absorption rather than adsorption, and the gas-particle partitioning did not reach equilibrium.

PBDE emission from E-wastes during the pyrolytic process: Emission factor, compositional profile, size distribution, and gas-particle partitioning.

Polybrominated diphenyl ether (PBDE) pollution in E-waste recycling areas has garnered great concern by scientists, the government and the public. In the current study, two typical kinds of E-wastes (printed wiring boards and plastic casings of household or office appliances) were selected to investigate the emission behaviors of individual PBDEs during the pyrolysis process. Emission factors (EFs), compositional profile, particle size distribution and gas-particle partitioning of PBDEs were explored. The mean EF values of the total PBDEs were determined at 8.1 ±â€¯4.6 µg/g and 10.4 ±â€¯11.3 µg/g for printed wiring boards and plastic casings, respectively. Significantly positive correlations were observed between EFs and original addition contents of PBDEs. BDE209 was the most abundant in the E-waste materials, while lowly brominated and highly brominated components (excluding BDE209) were predominant in the exhaust fumes. The distribution of total PBDEs on different particle sizes was characterized by a concentration of finer particles with an aerodynamic diameter between 0.4 µm and 2.1 µm and followed by less than 0.4 µm. Similarly, the distribution of individual species was dominated by finer particles. Most of the freshly emitted PBDEs (via pyrolysis) were liable to exist in the particulate phase with respect to the gaseous phase, particularly for finer particles. In addition, a linear relationship between the partitioning coefficient (KP) and the subcooled liquid vapor pressure (PL0) of the different components indicated non-equilibrium gas-particle partitioning during the pyrolysis process and suggested that absorption by particulate organic carbon, rather than surface adsorption, governed gas-particle partitioning.

Uptake of PAHs by cabbage root and leaf in vegetable plots near a large coking manufacturer and associations with PAHs in cabbage core.

Samples of ambient air (including gaseous and particulate phases), dust fall, surface soil, rhizosphere soil, core (edible part), outer leaf, and root of cabbage from eight vegetable plots near a large coking manufacturer were collected during the harvest period. Concentrations, compositions, and distributions of parent PAHs in different samples were determined. Our results indicated that most of the parent PAHs in air occurred in the gaseous phase, dominated by low molecular weight (LMW) species with two to three rings. Specific isomeric ratios and principal component analysis were employed to preliminarily identify the local sources of parent PAHs emitted. The main emission sources of parent PAHs could be apportioned as a mixture of coal combustion, coking production, and traffic tailing gas. PAH components with two to four rings were prevailing in dust fall, surface soil, and rhizosphere soil. Concentrations of PAHs in surface soil exhibited a significant positive correlation with topsoil TOC fractions. Compositional profiles in outer leaf and core of cabbage, dominated by LMW species, were similar to those in the local air. Overall, the order of parent PAH concentration in cabbage was outer leaf > root > core. Partial correlation analysis and multivariate linear stepwise regression revealed that PAH concentrations in cabbage core were closely associated with PAHs present both in root and in outer leaf, namely, affected by adsorption, then absorption, and translocation of PAHs from rhizosphere soil and ambient air, respectively.

Spatial distribution, emission source and health risk of parent PAHs and derivatives in surface soils from the Yangtze River Delta, eastern China.

243 surface soil samples were collected from the Yangtze River Delta (YRD) region, and the concentration distributions and compositional profiles of 27 parent PAHs (PPAHs), nitro- and oxy-derivatives (NPAHs and OPAHs), respectively, and health risk of 16 PPAHs were determined. Atmospheric samples were collected at two sites with high topsoil concentrations of PAHs to assist in identifying the emission sources of PPAHs. The total concentrations of PPAHs, NPAHs and OPAHs fell in the ranges of 21.0-3563.2 ng/g, 0.4-4.6 ng/g and 2.1-834.1 ng/g, respectively. PPAHs in topsoil were dominated by low and medium molecular weight species. The main components of OPAHs were 9FO and ANQ. For NPAHs, only 1N-NAP was frequently detected. Overall, the northern parts of the YRD region were more heavily contaminated by PPAHs and their corresponding derivatives. The soil TOC fraction and GDP per capita were significantly correlated with the spatial distribution of PPAHs. Specific ratios of isomeric species and principal component analysis (PCA) designated combustion of industrial coal and biomass, and traffic exhaust as the main mixed emission sources of PPAHs in surface soils in this region. The detected NPAHs and OPAHs were significantly associated with the corresponding PPAHs. The estimated incremental lifetime cancer risk attributed to 16 PPAHs in surface soil was greater than 10-6, indicating a potential risk of contracting cancer by exposure to topsoil from the YRD region. The cumulative probability of cancer risk for both adults and children via three exposure pathways followed the sequence of dermal contact > ingestion > inhalation.