There is an increasing awareness of the threats posed by the worldwide presence of microplastics (MPs) in the environment. Due to their high persistence, MPs will accumulate in the environment and their quantities tend to increase with time. MPs end up in environments where often also chemical contaminants are present. Since the early 2000s, the number of studies on the sorption of chemicals to plastic particles has exponentially increased. The objective of this study was to critically review the literature to identify the most important factors affecting the sorption of chemical contaminants to MPs. These factors include the physicochemical properties of both the MPs and the chemical contaminants as well as environmental characteristics. A limited number of studies on soil together with an increased notion of the importance of this compartment as a final sink for MPs was observed. Therefore, we assessed the distribution of model chemicals (two PCBs and phenanthrene) in the soil compartment in the presence of MPs using a mass balance model. The results showed a high variation among chemicals and microplastic types. Overall, a higher partitioning to MPs of chemical contaminants in soil is expected in comparison to aquatic environments. As sorption to a large extent determines bioavailability, the effects of combined exposure to chemicals and MPs on the toxicity and bioaccumulation in biota are discussed. Finally, some considerations regarding sorption and toxicity studies using MPs are given.

Incineration has overtaken landfilling as the most important option for disposal of the increasing volumes of municipal solid waste (MSW) generated in China. Accordingly, disposal of the incineration fly ash, which is enriched with a range of heavy metals, has become a key challenge for the industry. This review analyzes the temporal and spatial trends in the distributions of As, Cd, Cr, Cu, Ni, Pb, Zn, and Hg in MSW incineration fly ash between 2003 and 2017, and estimates the inventories of heavy metals associated with the fly ash and the average levels of heavy metals in Chinese MSW based on their mass flow during MSW incineration. It was estimated that MSW incinerators in China released approximately 1.12 × 10², 2.96 × 10³, 1.82 × 10², 3.64 × 10⁴, 1.00 × 10², 7.32 × 10³, 2.42 × 10², and 1.47 × 10¹ tonnes of Cd, Pb, Cr, Zn, Ni, Cu, As, and Hg, respectively, with the fly ash in 2016. Due to the much greater fly ash generation rate, the incinerators based on circulating fluidized bed combustor (CFBC) technology released more heavy metals during incineration of MSW compared to those based on grate furnace combustor (GFC) technology. Results of mass-flow modeling indicate that the geometric mean contents of Cd, Pb, Cr, Zn, Ni, Cu, As, and Hg in Chinese MSW were 3.0, 109, 101, 877, 34, 241, 21, and 1.7 mg/kg, respectively, which are comparable to those in the MSW from other countries. To protect the environment from the significant potential ecological risk posed by heavy metals in the mismanaged fly ash, strict regulation enforcement and compliance monitoring are necessary to reduce the heavy metal pollution brought by improper disposal of MSW incineration fly ash, and more research and development efforts on advanced technologies for stabilization of heavy metals in fly ash and its environmentally sound reuse can help mitigate its environmental risk.

In recent years, ozone pollution has become more and more serious in China. Several epidemiological studies have demonstrated the correlation between short-term ozone exposure and several health risks including all-cause mortality, cardiovascular mortality, and respiratory mortality. In this study, the daily ozone exposure levels with 10 km × 10 km resolution were estimated based on satellite data derived from Ozone Monitoring Instrument (OMI) and the monitoring data. The health impacts for potential decrease in the daily ozone concentration and the corresponding economic benefits in 2016 were estimated by applying the environmental Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE) model. By reducing the daily maximum 8-h average concentration of ozone to 100 μg/m³, the estimated avoided all-cause mortalities were 120 × 10³ (95% confidence interval (CI): 67 × 10³, 160 × 10³) cases and the correspondingly economic benefits ranged from 36 to 64 billion CNY using amended human capital (AHC) and willingness to pay (WTP) method in 2016. If the daily maximum 8-h average concentration of ozone were rolled back to 70 μg/m³, the estimated avoided all-cause mortalities were 160 × 10³ (95% CI: 98 × 10³, 230 × 10³) cases and economic benefits ranged from 54 to 95 billion CNY based on AHC and WTP methods.

Rare earth elements (REEs) are typically present as mixtures in the environment, but a quantitative understanding of mixture toxicity and interactions of REEs is still lacking. Here, we examined the toxicity to wheat (Triticum aestivum L.) of Y, La, and Ce when applied individually and in combination. Both concentration addition (CA) and independent action (IA) reference models were used for mixture toxicity analysis because the toxicity mechanisms of REEs remain obscure. Upon single exposure, the EC50s of Y, La, and Ce, expressed as dissolved concentrations, were 1.73 ± 0.24 μM, 2.59 ± 0.23 μM, and 1.50 ± 0.22 μM, respectively. The toxicity measured with relative root elongation followed La < Y ≈ Ce, irrespective of the dose descriptors. The use of CA and IA provided similar estimates of REE mixture interactions and toxicity. When expressed as dissolved metal concentrations, nearly additive effects were observed in Y-La and La-Ce mixtures, while antagonistic interactions were seen in Y-Ce mixtures. When expressed as free metal activities, antagonistic interactions were found for all three binary mixtures. This can be explained by a competitive effect of REEs ions for binding to the active sites of plant roots. The application of a more elaborate MIXTOX model in conjunction with the free ion activities, which incorporates the non-additive interactions and bioavailability-modifying factors, well predicted the mixture toxicity (with >92% of toxicity variations explained). Our results highlighted the importance of considering mixture interactions and subsequent bioavailability in assessing the joint toxicity of REEs.

The genus Artemia sp. has been accepted as a reliable model organism for aquatic toxicity and nanotoxicity experiments, as far as the ISO TS 20787 has recently been published to standardize nanotoxicity test with this organism. Experimental and environmental conditions may affect the toxicity of nanomaterials on aquatic organisms including Artemia sp. nauplii. In this study, acute toxicity effects of silver nanoparticles (AgNPs) on the nauplii of Artemia salina was investigated under various conditions (e.g. different lights, salinities, temperatures, volume and agitation of exposure media and instar stages of nauplii). The EC values were calculated using Probit program and all data were analyzed statistically by SPSS software. At all test conditions, the immobilization rate of Artemia nauplii increased in a concentration-dependent manner (P < 0.05). The sensitivity of instar stage II to different concentrations of AgNPs was significantly higher than instar I (P < 0.05). The toxicity effect of AgNPs was affected by alteration of environmental conditions, so that the effective concentration (EC) values for instar I of A. salina decreased with increasing water temperature, decreasing water salinity and in continuous darkness condition. The EC50 value of AgNPs was significantly lower in 100 mL beakers (21.35 ± 5.67 mg L−1) than 10 mL well plates (42.44 ± 11.30 mg L−1). Agitation of exposure media did not affect the toxicity of AgNPs. The results indicated that the experimental and environmental conditions influence on the toxicity of AgNPs in the nauplii of A. salina.

Many cities in China are currently experiencing severe air pollution due to modernization. Previous studies investigating the effects of air pollutants exposure were particularly conducted in severe air polluted area and studies in low pollution areas were sparse.To quantitatively assess the short-term effects of ambient air pollutants (PM2.5, PM10, SO2, NO2, CO and O3) on outpatient visits in low pollution area, we conducted a time-series analysis from Jan 1, 2015 to Dec 31, 2016 in Shennongjia, China. Generalized additive model (GAM) was used to evaluate the influence of PM2.5 on daily hospital outpatient visits with different lag structures. We also conducted stratified analysis to explore the association between PM2.5 concentration and outpatient visits in different seasons.In the present study, per IQR increment of PM2.5, PM10, NO2, CO and O3 were related with 1.92% (0.76%–3.09%), 1.92% (0.77%–3.07%), 2.74% (95% CI: 1.65%–3.83%), 1.89% (95% CI: 0.68%–3.10%) and 2.30% (95% CI: 0.65%–3.95%) increase on respiratory outpatient visits. Significant associations were found between PM2.5, PM10, NO2 and respiratory outpatient visits at lag0:1, lag0:2 days. The effects of PM2.5 were more evident in the cool season than in the warm season.Our study showed that short-term exposures to PM2.5, PM10, NO2, CO and O3 were related with increased risk of outpatient visits of respiratory diseases, and highlighted the adverse effect of air pollutants exposure, especially PM2.5 exposure in cool season on health in low pollution area.

Plastic pollution is widespread in all the oceans and seas, representing a significant threat to most of their ecosystems even in marine protected areas (MPAs). This study determines the floating plastic distribution in four different periods between 2014 and 2015 in the recently approved Menorca Channel MPA (Balearic Islands). Plastic debris were persistent during all sampling periods on the surface of the Channel, composed mainly by the microplastic sizes. Average particle abundances ranged from 138,293 items⋅km−2 in autumn to 347,793 items⋅km−2 during the spring, while weight densities varied from 458.15 g(DW)⋅km−2 in winter to 2016.67 g(DW)⋅km−2 in summer. Rigid plastics were the most frequent particles in all the periods analysed (from 89.40%-winter to 94.54%-spring). The high-resolution and particle distribution models corroborated that the oceanographic variability shapes different patterns of presence of plastics, and in particular the existence of areas with almost no plastics.

Nail salon technicians face chronic exposure to volatile organic compounds (VOCs), which can lead to adverse health outcomes including cancer. In this study, indoor levels of formaldehyde, as well as benzene, toluene, ethylbenzene and xylene, were measured in 6 Colorado nail salons. Personal exposure VOC measurements and health questionnaires (n = 20) were also performed; questionnaires included employee demographics, health symptoms experienced, and protective equipment used. Cancer slope factors from the United States Environmental Protection Agency (US EPA) and anthropometric data from the Centers for Disease Control and Prevention were then used to estimate cancer risk for workers, assuming 20-yr exposures to concentrations of benzene and formaldehyde reported here. Results show that 70% of surveyed workers experienced at least one health issue related to their employment, with many reporting multiple related symptoms. Indoor concentrations of formaldehyde ranged from 5.32 to 20.6 μg m−3, across all 6 salons. Indoor concentrations of toluene ranged from 26.7 to 816 μg m−3, followed by benzene (3.13–51.8 μg m−3), xylenes (5.16–34.6 μg m−3), and ethylbenzene (1.65–9.52 μg m−3). Formaldehyde levels measured in one salon exceeded the Recommended Exposure Limit from the National Institute for Occupational Safety and Health. Cancer risk estimates from formaldehyde exposure exceeded the US EPA de minimis risk level (1 × 10−6) for squamous cell carcinoma, nasopharyngeal cancer, Hodgkin's lymphoma, and leukemia; leukemia risk exceeded 1 × 10−4 in one salon. The average leukemia risk from benzene exposure also exceeded the US EPA de minimis risk level for all demographic categories modeled. In general, concentrations of aromatic compounds measured here were comparable to those measured in studies of oil refinery and auto garage workers. Cancer risk models determined that 20-yr exposure to formaldehyde and benzene concentrations measured in this study will significantly increase worker's risk of developing cancer in their lifetime.

Microplastics in water environment and its ability to load various environmental pollutants have attracted wide attention in recent years. However, effect of microplastic size on the adsorption behavior of environmental pollutants and interaction mechanism has not been thoroughly explored. In this study, triclosan (TCS) was selected as model pollutant, and polyvinyl chloride (PVC) with different particle sizes (small size (<1 μm) is recorded as PVC-S and PVC-L means large particle size of about 74 μm) were used as the typical microplastics, the adsorption behavior of TCS on PVC was investigated by studying kinetics, isotherms, and other influencing factors, such as pH and salinity. The results indicate PVC-S has greater distribution coefficient kd values of TCS (1.35 L/g > 1.05 L/g) and stronger adsorption capacity (12.7 mg/g > 8.98 mg/g) compared with PVC-L, which may be due to higher specific surface area, stronger hydrophobicity and relatively small electronegative property of PVC-S. Moreover, the initial pH value and salinity of the solution played crucial role in the adsorption process. The distribution diffusion mechanisms (including liquid-film diffusion and intra-particle diffusion), hydrophobic interaction, electrostatic interaction, halogen bonding, and hydrogen bonding may be the important reasons for adsorption. These findings show that MPs with different particle sizes have vary adsorption behaviors and load capacities for environmental pollutants, which deserve our further concerned.

Per- and poly-fluoroalkyl substances (PFAS) have attracted considerable concern due to their widespread occurrence in the environment and potential human health risks. Given the complexity of PFAS retention in multi-phase systems, it would be useful for characterization and modeling purposes to be able to readily determine the relative significance of the individual retention processes for a given PFAS and set of subsurface conditions. A quantitative-structure/property-relationship (QSPR) analysis was conducted for adsorption of PFAS by soils, sediments, and granular activated carbon (GAC), and integrated with a prior analysis conducted for adsorption to air-water and oil-water interfaces. The results demonstrated that a model employing molar volume provided reasonable predictions of organic-carbon normalized soil/sediment adsorption coefficients (log Kₒc), GAC-adsorption coefficients (log Kd), and air/oil-water interfacial adsorption coefficients (log Kᵢ) for PFAS. The relative magnitudes of solid-water and air/oil-water interfacial adsorption were compared as a function of controlling variables. A nomograph was developed that provides a first-order determination of the relative significance of these interfacial adsorption processes in multi-phase porous-media systems.