Search

The ability to accurately assess the health risks of contaminants is limited by the shortcomings of toxicological standards. Using organophosphate esters (OPEs) as an example, this study attempted to integrate physiologically based pharmacokinetic (PBPK)-based forward dosimetry and in vitro bioassays to assess the likelihood of contaminants inducing biological effects in humans. The total exposure level of OPEs for Chinese residents was 19.5 ± 8.71 ng/kg/day with inhalation being the main exposure pathway. Then, human PBPK models were developed for individual OPEs to predict their steady-state concentrations in human tissues, and the predicted median levels in blood were close to the measurements. The reference doses (RfDs) of OPEs based on in vitro bioassays were comparable to in vivo animal-derived RfDs, demonstrating the reliability of in vitro bioassays. Therefore, the likelihood of OPEs inducing bioactivities in humans (RQ

Site-specific water quality criteria considering hydrochemical conditions are needed for zoning control of environmental risks. However, the differences in water quality parameters between regions have not been fully considered in the current research on water quality criteria and risk assessment of lead. In this study, lead concentration and total hardness (TH) data of surface water in 13 major river basins and 31 administrative regions in China were collected. Based on the normalization of the TH of the toxicity data, the short-term and long-term water quality criteria of lead in China's surface water in the specific TH condition (100 mg/L) were derived using the species sensitivity distribution method, which were 90.7 μg/L and 2.1 μg/L, respectively. Furthermore, this study provided general derivation formulas for the water quality criteria based on the TH of surface water and obtained the site-specific criteria for different regions/basins in China. On this basis, an ecological risk assessment considering the TH was proposed for the first time. The results showed that there was a clear risk of lead in the Pearl River Basin and the rivers in Zhejiang-Fujian. The southern coastal provinces were at an unacceptable risk level, although the lead concentrations in the surface water were medium; the opposite was true in northern China, which meant that a high concentration of lead did not necessarily pose a high ecological risk and about 25 % of the variation in the predicted risk can be explained by the TH in Monte Carlo simulation.

Microplastics (MPs) are emerging contaminants that have attracted worldwide attention in recent years. Compared with MPs, nanoplastics (NPs) may exhibit greater toxicity and higher potential risks because of their unique physiochemical nanoscale properties. However, the environmental fate, ecosystem toxicity, and potential risks associated with NPs have been less explored. This study summarizes the current research status of NPs through a comprehensive bibliometric analysis. The research hotspots and future trends of NPs were identified. We comprehensively searched the Web of Science Core Collection scientific database from its inception (2004) to November 26, 2020. The results showed that the number of papers on NPs has increased significantly since 2014. The keywords used in NP research were divided into three clusters. Cluster 1 related to the physical, chemical, and biological behaviors of NPs in aquatic environments. Cluster 2 represented a relatively new and hot research field concerning the exposure, accumulation, and toxicity of NPs in organisms. Cluster 3 corresponded to the identification and quantification of NPs in marine environments and sediments. Moreover, we systematically elaborated the main areas of NP research, such as the characterization, occurrence, environmental behavior, ecological toxicity, and human health risks of NPs. The results showed that the quantification of NPs at environmentally relevant concentrations remains a challenge. Most studies have investigated polystyrene NPs, spherical NPs, and NPs in marine environments, while few studies have examined the aggregation, deposition, and ecological toxicity of NPs under environmentally relevant conditions. In addition, much less is known about the human health risks associated with NPs because little research has been conducted on estimating the overall human exposure to NPs and its effect. Finally, the current challenges and future perspectives of NP research are discussed.

According to extensive in situ investigations, the microplastics (MPs) determined in current wastewater treatment plants (WWTPs) are mostly aged, with roughened surfaces and varied types of oxygen-containing functional groups (i.e., carbonyl and hydroxyl). However, the formation mechanism of aged MPs in WWTPs is still unclear. This paper systematically reviewed MP fragmentation and generation mechanisms in WWTPs at different treatment stages. The results highlight that MPs are prone to undergo physical abrasion, biofouling, and chemical oxidation-associated weathering in WWTPs at different treatment stages and can be further decomposed into smaller secondary MPs, including in nanoplastics (less than 1000 nm or 100 nm in size), suggesting that WWTPs can act as a formation source for MPs in aquatic environments. Sand associated mechanical crashes in the primary stage, microbes in active sewage sludge-related biodegradation in the secondary stage, and oxidant-relevant chemical oxidation processes (light photons, Cl

Covalent organic frameworks (COFs) are promising supports for the synthesis of noble metal nanoparticles (NM NPs) with controllable sizes and dispersities. However, it is still challenging to synthesize COFs using green and efficient routes. Herein, COFs (TpMA) were prepared by ball milling, which required less solvent and time. They were then used as a support for the growth of ultrafine Au NPs. Using the COFs as supports, five size-controlled ultrafine Au NPs (2.5 ± 0.55- 4.32 ± 1.39 nm) were synthesized (Au@TpMA). It was found that the Au NPs exhibited remarkable dispersibility owing to the support of TpMA. The reduction of 4-nitrophenol to 4-aminophenol was used as a model reaction to evaluate the performance of the Au@TpMA catalyst, which showed excellent catalytic activity for the reduction of 4-nitrophenol. The Au@TpMA catalyst exhibited good stability and recyclability, and the reduction rate was 95% at the end of six successive experiments. In addition, in the presence of the Au@TpMA catalyst, the maximum pseudo-first-order reaction rate constant of 4-nitrophenol was 0.2379 min

Natural iron oxides nanomaterials have important roles in biogeochemical processes. In this study, the effects of pH, natural organic matter, and cations on aggregation and sedimentation of natural goethite and artificial Fe

The coronavirus disease 2019 (COVID-19) pandemic is challenging the current public health emergency response systems (PHERSs) of many countries. Although environmental factors, such as those influencing the survival of viruses and their transmission between species including humans, play important roles in PHERSs, little attention has been given to these factors. This study describes and elucidates the roles of environmental factors in future PHERSs. To improve countries' capability to respond to public health emergencies associated with viral infections such as the COVID-19 pandemic, a number of environmental factors should be considered before, during, and after the responses to such emergencies. More specifically, to prevent pandemic outbreaks, we should strengthen environmental and wildlife protection, conduct detailed viral surveillance in animals and hotspots, and improve early-warning systems. During the pandemic, we must study the impacts of environmental factors on viral behaviors, develop control measures to minimize secondary environmental risks, and conduct timely assessments of viral risks and secondary environmental effects with a view to reducing the impacts of the pandemic on human health and on ecosystems. After the pandemic, we should further strengthen surveillance for viruses and the prevention of viral spread, maintain control measures for minimizing secondary environmental risks, develop our capability to scientifically predict pandemics and resurgences, and prepare for the next unexpected resurgence. Meanwhile, we should restore the normal life and production of the public based on the "One Health" concept, that views global human and environmental health as inextricably linked. Our recommendations are essential for improving nations' capability to respond to global public health emergencies.

Polycyclic aromatic hydrocarbon (PAH) emissions from the combustion of household solid coal for cooking and heating cause great harm to public health in China, especially in less developed areas. Children are one of the most susceptible population groups at risk of indoor air pollutants due to their immature respiratory and immune systems. However, information on PAH exposure of children is limited due to limited monitoring data. In this study, we aimed to assess the seasonal differences of PAHs in classrooms, analyze the pollutant sources, and calculate the incremental lifetime cancer risk attributable to PAHs in Shanxi Provence. A typical school using household coal combustion in Shanxi Province was selected. Fine particulate matter (PM2.5)samples were collected by both individual samplers and fixed middle-flow samplers during the heating and non-heating seasons in December 2018 and April 2019. The PAH concentrations in PM2.5 samples were analyzed by a gas chromatograph coupled to a mass spectrometer. The results showed that PAH concentrations in PM2.5 varied between 89.1 ng/m3 in the heating season and 1.75 ng/m3 in the non-heating season. The mean concentrations of benzo[a]pyrene (BaP), a carcinogenic marker of PAHs, were 10.3 and 0.05 ng/m3 in the heating and non-heating seasons, respectively. Source allocation analysis of individual portable and passive samplers revealed that the main contributors during heating and non-heating seasons were coal combustion and gasoline sources, respectively. According to the results of a Monte Carlo simulation, the incremental lifetime cancer risk values from the inhalation of PAHs in the heating and non-heating seasons were 3.1 &times, 10&minus, 6 and 5.7 &times, 8, respectively. The significant increase in PAHs and the incremental lifetime cancer risk in the heating season indicates that children are more exposed to health threats in winter. Further PAH exposure control strategies, including reducing coal usage and promoting clean fuel applications, need to be developed to reduce the risk of PAH-induced cancer.

As a well-known human carcinogen, arsenic (As) could pose various detrimental health effects to humans mainly through the exposure pathway of food ingestion. In comparison with other foods, rice can accumulate more arsenic due to its tissue specificity. Thus, it is of great significance to assess the health risk of As due to rice ingestion. However, the study on risk assessment from exposure to As in rice is still in an early stage and lack accuracy to date. In this study, after obtaining the rice exposure behavior patterns based on a questionnaire survey, a total of 160 rice samples, which consisted of 4 types (i.e., japonica, indica, glutinous and brown rice), rice from 4 areas and consumed by most of the population in Beijing, were collected. On the basis of the actual intake rate and the species weighted average concentration of consumed rice, average daily exposure dose and health risks of inorganic As (iAs) from rice ingestion were assessed for the population among different genders and ages in Beijing. The results show that japonica rice and rice from Northeast China had higher As content, with the same value of 0.064 mg kg−1. And, they were the most popular rice consumed by people, with the intake rates of 75.50 g d−1, and 67.91 g d−1, respectively. The proportion of iAs to total As (tAs) was 58.34%, with a range of 43.18–71.88%. The average daily dose of iAs for the population was 1.15 × 10–4, which mainly came from japonica rice and the rice from Northeast China ingestion. In comparison with the acceptable non-cancer risk, which had a HQ value of 0.38, the carcinogenic risk of the population in Beijing was 1.73 × 10–4 on average. Furthermore, males had higher carcinogenic risk (1.88 × 10–4) than females (1.62 × 10–4), and the people in the age of 45–55 suffered from the highest carcinogenic risk (2.22 × 10–4), which mainly was attributed to the japonica rice and the rice from Northeast China. This study strengthened that appropriate dietary patterns should be paid more attention in order to control the health risk due to As exposure.

Science-based water quality criteria are the cornerstone of water quality standards. This paper improved the methodology for the derivation of human health water quality criteria (HHWQC) and applied it for benzo[a]pyrene (BaP) to provide a scientific basis for the management of polycyclic aromatic hydrocarbons (PAHs) in surface waters. First, the national bioaccumulation factors (BAFs) for BaP were derived using field-measured BAFs and field-measured biota-sediment accumulation factors (BSAFs) across China, respectively, which results were comparable and demonstrated the reliability of the obtained national BAFs for BaP. The HHWQC for BaP derived using the probabilistic approach were 3.98-4.70 ng/L and were comparable with those derived by the deterministic approach, suggesting the accuracy of derived HHWQC for BaP. Through the probabilistic approach, the probability distributions of lifetime incremental cancer risk from BaP in water were provided and the consumption rates of aquatic products at trophic level 2 and 3 were identified as factors influencing risks of BaP significantly. The derived HHWQC for BaP in China are approximately 33-36 times higher than those in the United States because of the high national BAFs and cancer slope factor of BaP used for the United States. In addition, the recommended HHWQC for BaP conform to the situation in China and are approximately 1.5 times higher than the standard value of BaP in the current National Surface Water Quality Standard (GB 3838-2002) in China (2.80 ng/L), which will play an important role in the amendment of National Surface Water Quality Standard in the future. Approximately 36% of the studied surface freshwater in China contains BaP with levels exceeding the recommended HHWQC, suggesting the pollution of BaP in surface freshwater is severe and needs to be given more attention. This study is significant for the scientific development of HHWQC worldwide and the management of pollutants in water.

Stunting adversely affects physical and mental outcomes of children. It has not been examined whether household air pollution from solid fuel combustion is a risk factor for stunting in children. In a total of 41,439 children aged 6-17 across China, height was measured using a unified protocol. Multivariable linear regression models and logistic regression models were used to assess the associations of solid fuel use for cooking/heating with stunting in children. Adjusted for covariates, cooking/heating with solid fuel was significantly associated with a lower z-score for height for age and sex (β = -0.21 [-0.32 to -0.09] and -0.17 [-0.31 to -0.03], respectively) and an increased risk of stunting with an estimated ORs of 1.34 [1.07~1.68] and 1.37 [1.02~1.83], respectively. The risk of stunting associated with solid fuel use was statistically significant in high-age children. And the effect was greater on girls than on boys, though the difference was not statistically significant. Our study suggested that Chinese children living in households using solid fuel had a significantly higher risk of stunting than those living in households using cleaner fuel.

Large-scale preparation of stable and efficient covalent organic frameworks (COFs) for photo-catalysts is challenging. In this work, an environmentally-friendly ball milling method was applied to synthesize COFs (TpMA) by use of appropriate symmetry combinations (C3 + C3) of building blocks (i.e., melamine (MA) and 1,3,5-Triformylphloroglucinol (Tp)). Characterization confirmed that TpMA were successfully synthesized and exhibit thin ribbon-like structure with wrinkles and rough edges. A concentration of 120 mg/L sulfathiazole, could be completely degraded in the presence of 30 mg TpMA under visible light (λ > 420 nm). The rate of photo-degradation was 0.1498 min−1, which was more than three times than that of TpMA prepared by solvothermal method. Compared with commercial g-C3N4 and self-prepared g-C3N4, TpMA with “g-C3N4 active center-photo-eletron shift platform-electron withdrawing unit” triadic structure shows greater photo-catalytic activity, which exhibited rapid charge separation and electron transport capabilities, and low recombination rates of electron-hole pairs. In addition, TpMA retained 88.5% photocatalytic activity after four cycles under the same experiment conditions, which indicates TpMA had outstanding stability and recyclability. Superoxide radical (·O2−) was determined to play a dominant role in photo-degradation of sulfathiazole through radical scavenging experiments. TpMA was used to treat two industrial wastewaters including cellulose-containing wastewater and polyvinyl alcohol-containing wastewater to determine the practicality of TpMA. The results showed that TpMA possessed favorable anti-interference ability and high photocatalytic activity, which indicates TpMA has practical application potential. The method of ball milling has broad application prospects in the fields of large-scale preparation of COFs, which is conducive to bottom-up preparation of COFs with excellent degradation capacity of organic pollutants.

The light-scattering properties of surface materials on Mars are typically modeled using in situ spectrophotometric imaging sequences taken at multiple times of day to provide sufficient phase coverage. Herein, we report analyses of observations acquired at one time of day but under varying emission angles using the Mars Hand Lens Imager (MAHLI) on the robotic arm of the Mars Science Laboratory (MSL) rover as a goniometer. A multiple-viewpoint data set was acquired on Sol 544 by manipulating the arm to provide MAHLI images from 20 arm positions, all centered at the same location and from a near-constant distance of 1 m from the surface, permitting a phase angle coverage from ∼8 to 100°. From these images, we constructed a digital terrain model of the scene, and used it in combination with atmospheric scattering models to remove the diffuse components of radiance from surface units. Radiative transfer models using Hapke theory were conducted using the direct radiance components from specific rock and soil units. Despite the relatively limited number of observations, our modeled Hapke parameters were well-constrained for terrain types such as soils and certain types of rocks that were common within the scene, but the errors increased for rock types with fewer observations. Results from one-term and two-term Henyey-Greenstein phase functions show the soil units to be more backscattering than rocks, consistent with previous photometric studies of martian landing sites. Overall, we find that the MAHLI goniometer sequences can produce reasonable and consistent photometric results, providing a new and efficient means of acquiring spectrophotometric data by arm cameras on rovers such as MSL.

This study used 454 pyrosequencing, Illumina high-throughput sequencing and metagenomic analysis to investigate bacterial pathogens and their potential virulence in a sewage treatment plant (STP) applying both conventional and advanced treatment processes. Pyrosequencing and Illumina sequencing consistently demonstrated that Arcobacter genus occupied over 43.42% of total abundance of potential pathogens in the STP. At species level, potential pathogens Arcobacter butzleri, Aeromonas hydrophila and Klebsiella pneumonia dominated in raw sewage, which was also confirmed by quantitative real time PCR. Illumina sequencing also revealed prevalence of various types of pathogenicity islands and virulence proteins in the STP. Most of the potential pathogens and virulence factors were eliminated in the STP, and the removal efficiency mainly depended on oxidation ditch. Compared with sand filtration, magnetic resin seemed to have higher removals in most of the potential pathogens and virulence factors. However, presence of the residual A. butzleri in the final effluent still deserves more concerns. The findings indicate that sewage acts as an important source of environmental pathogens, but STPs can effectively control their spread in the environment. Joint use of the high-throughput sequencing technologies is considered a reliable method for deep and comprehensive overview of environmental bacterial virulence.