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Polycyclic aromatic hydrocarbons (PAHs) are endocrine-disrupting chemicals. Few studies have evaluated the association between pubertal development in girls and PAH exposures quantified by urinary biomarkers.We examined associations of urinary PAH metabolites with pubertal development in 358 girls 6-16 years of age from the San Francisco Bay Area enrolled in a prospective cohort from 2011 to 2013 and followed until 2020. Using baseline data, we assessed associations of urinary PAH metabolites with pubertal development stage. In prospective analyses limited to girls who at baseline had not yet started breast (N = 176) or pubic hair (N = 179) development or menstruation (N = 267), we used multivariable Cox proportional hazards regression to assess associations of urinary PAH metabolites with the onset of breast and pubic hair development, menstruation, and pubertal tempo (interval between the onset of breast development and menstruation).We detected PAH metabolites in98% of girls. In cross-sectional analyses using baseline data, PAH metabolites were not associated with the pubertal development stage. In prospective analyses, higher concentrations (≥ median) of some PAH metabolites were associated with two-fold higher odds of earlier breast development (2-hydroxy naphthalene, 1-hydroxy phenanthrene, summed hydroxy phenanthrenes) or pubic hair development (1-hydroxy naphthalene) among girls overweight at baseline (body mass index-for-age percentile ≥85) compared with nonoverweight girls with lower metabolites concentrations. PAH metabolites were not associated with age at menarche or pubertal tempo.PAH exposures were widespread in our sample. Our results support the hypothesis that, in overweight girls, PAHs impact the timing of pubertal development, an important risk factor for breast cancer.

Multiple studies indicate that United States veterans have an increased risk of developing amyotrophic lateral sclerosis (ALS) compared to civilians. However, the responsible etiological factors are unknown. In the general population, specific occupational (e.g. truck drivers, airline pilots) and environmental exposures (e.g. metals, pesticides) are associated with an increased ALS risk. As such, the increased prevalence of ALS in veterans strongly suggests that there are exposures experienced by military personnel that are disproportionate to civilians. During service, veterans may encounter numerous neurotoxic exposures (e.g. burn pits, engine exhaust, firing ranges). So far, however, there is a paucity of studies investigating environmental factors contributing to ALS in veterans and even fewer assessing their exposure using biomarkers. Herein, we discuss ALS pathogenesis in relation to a series of persistent neurotoxicants (often emitted as mixtures) including: chemical elements, nanoparticles and lipophilic toxicants such as dioxins, polycyclic aromatic hydrocarbons and polychlorinated biphenyls. We propose these toxicants should be directly measured in veteran central nervous system tissue, where they may have accumulated for decades. Specific toxicants (or mixtures thereof) may accelerate ALS development following a multistep hypothesis or act synergistically with other service-linked exposures (e.g. head trauma/concussions). Such possibilities could explain the lower age of onset observed in veterans compared to civilians. Identifying high-risk exposures within vulnerable populations is key to understanding ALS etiopathogenesis and is urgently needed to act upon modifiable risk factors for military personnel who deserve enhanced protection during their years of service, not only for their short-term, but also long-term health.

Purpose of Review Despite increasing awareness of the ubiquity of microplastics (MPs) in our environments, little is known about their risk of developmental toxicity. Even less is known about the environmental distribution and associated toxicity of nanoplastics (NPs). Here, we review the current literature on the capacity for MPs and NPs to be transported across the placental barrier and the potential to exert toxicity on the developing fetus. Recent Findings This review includes 11 research articles covering in vitro, in vivo, and ex vivo models, and observational studies. The current literature confirms the placental translocation of MPs and NPs, depending on physicochemical properties such as size, charge, and chemical modification as well as protein corona formation. Specific transport mechanisms for translocation remain unclear. There is emerging evidence of placental and fetal toxicity due to plastic particles based on animal and in vitro studies. Summary Nine out of eleven studies examined in this review found that plastic particles were capable of placental translocation. In the future, more studies are needed to confirm and quantify the existence of MPs and NPs in human placentas. Additionally, translocation of different plastic particle types and heterogenous mixtures across the placenta, exposure at different periods of gestation, and associations with adverse birth and other developmental outcomes should also be investigated.

The U.S. CDC announced on 04/03/2020 that all citizens should wear face coverings when in public, potentially increasing demand for medical face masks from the public and exacerbating mask shortages for Covid-19 response staff. One solution is reuse after disinfection for the general public. Prior studies have shown that heating for 30 mins at 70°C or above effectively kills SARS, including SARS-CoV-2, and Influenza viruses on masks. Black carbon (BC) particles generated from a kerosene-lamp were used as a proxy for Coronavirus aerosols to test mask performance after disinfection given overlapping size distributions. We determined filtration efficiency (FE) measurements by comparing BC values on both sides of the respirators or masks (Moldex N95 and 3M N95 respirators, HSI surgical masks) placed under vacuum on mannequins. To obtain the maximum FE, each mask type was first measured while taped or modified to tightly fit a mannequin’s face when new and after each heating cycle. No reduction in average FE was observed even after 10 disinfection cycles, with FE statistically greater than 95% for N95 respirators and 70% for surgical masks. In sharp contrast, the FE of all medical masks with no additional sealing decreased to ~ 40%, confirming the effectiveness of facial masks relies upon a tight fit. For solving this issue, we designed a method for making individualized custom nose clips to hold a mask tightly to face; FE of 3M N95 respirators and surgical masks remained above 95% and 80%, respectively. Surprisingly, the FE of three homemade thick cloth coverings (in normal use) were 55%. Though more work is still needed, this result supports the public announcements that the public could wear cloth coverings instead of N95 respirators or surgical masks in low-risk environments. When worn with a customized nose clip, N95 respirators and surgical masks have higher FE than the CDC design for cloth coverings.

BackgroundPolycyclic aromatic hydrocarbon (PAH) exposures from tobacco smoke, automobile exhaust, grilled or smoked meat and other sources are widespread and are a public health concern, as many are classified as probable carcinogens and suspected endocrine-disrupting chemicals. PAH exposures can be quantified using urinary biomarkers.MethodsSeven urinary metabolites of naphthalene, fluorene, phenanthrene, and pyrene were measured in two samples collected from girls aged 6-16 years from the San Francisco Bay Area. We used Spearman correlation coefficients (SCC) to assess correlations among metabolite concentrations (corrected for specific gravity) separately in first (n=359) and last (N=349) samples, and to assess consistency of measurements in samples collected up to 72 months apart. Using multivariable linear regression, we assessed variation in mean metabolites across categories of participant characteristics and potential outdoor, indoor, and dietary sources of PAH exposures.ResultsThe detection rate of PAH metabolites was high (4 metabolites in ≥98% of first samples; 5 metabolites in ≥95% of last samples). Correlations were moderate to strong between fluorene, phenanthrene and pyrene metabolites (SCC 0.43-0.82), but weaker between naphthalene and the other metabolites (SCC 0.18-0.36). SCC between metabolites in first and last samples ranged from 0.15 to 0.49. When classifying metabolite concentrations into tertiles based on single samples (first or last samples) vs. the average of the two samples, agreement was moderate to substantial (weighted kappa statistics 0.52-0.65). For specific metabolites, concentrations varied by age, race/ethnicity, and body mass index percentile, as well as by outdoor sources (season of sample collection, street traffic), indoor sources (heating with gas, cigarette smoke), and dietary sources (frequent use of grill, consumption of smoked meat or fish) of PAH exposures.ConclusionsUrinary PAH exposure was widespread in girls aged 6-16 years and associated with several sources of exposure. Tertile classification of a single urine sample provides reliable PAH exposure ranking.

Based on graphene sheet (GS) and gold-magnetic nanoparticles (Au–Fe3O4), a novel bioelectrochemical sensor was developed to detect toxoplasmosis-specific IgM antibody (Tg-IgM). This kind of bioelectrochemical sensor combined the high specific surface area of GS and the high biocompatibility of Au–Fe3O4 nanomaterials. The anti-IgM-HRP modified by Au–Fe3O4 nanoparticles was used as the detection probe, and the preparation method of composite detection probe and the corresponding sensor performance were provided. In addition, by a systematic simulation modeling, this study further investigated the effect of CV scanning speed, pH value, H2O2 concentration and graphene concentration on the detection sensitivity of the proposed bioelectrochemical sensor.

Air pollution addresses short-term health effects on morbidity, especially for children. Assessing the impacts of air pollution on elementary students is critical for developing preparedness response strategies for this sensitive group. In the 2016-17 academic year, up to 687,748 groups of illness-related absence records and the information on whether the absentee had gone to a hospital or not were collected from 2564 elementary schools across Jiangsu Province China. We explored the associations between air pollution and illness-related records using a time-stratified case-crossover analysis with distributed lag non-linear design. An increase of 10 μg/m

BackgroundCystatin SN (cystatin 1, CST1) regulates the progression of many cancers and serves as a diagnostic marker; however, its significance in gastric cancer has not been fully elucidated. MethodsWe first analyzed the expression levels of CST1 in gastric cancer dataset in oncomine and UALCAN databases. We next analyzed the relationship between CST1 and prognosis of gastric cancer patients in KM Plotter database and downloaded TCGA GC data to verify this result. We further divided GC patients into two groups according to the level of CST1 expression for GSEA enrichment analysis. Finally, we validated the role of CST1 in gastric cancer by in vitro functional assays.ResultsWe found that CST1 expression levels in gastric cancer tissues were significantly higher than those in normal control tissues and patients with high CST1 expression had a poorer prognosis. GSEA enrichment analysis showed that the main KEGG signaling pathways enriched in the CST1 high expression group were Coagulation, Epithelial-Mesenchymal-Transition, Complement, Apoptosis, Glycolysis. In vitro functional assay confirmed that inhibition of CST1 significantly inhibited the proliferation, colony-formation,migration and invasion ability of gastric cancer cells.ConclusionsOur study shows that the expression level of CST1 correlates with the development of gastric cancer, and CST1 may be used as a diagnostic marker for poor prognosis of gastric cancer.

The increasing use of electronic nicotine delivery systems (ENDS) is of concern due to multiple emerging adverse health effects. Most analyses of the harmful chemicals of ENDS have targeted metals or carbonyls generated by thermal decomposition of carrier liquids such as propylene glycol. However, new complex compounds not routinely identified and with unknown health consequences could be formed. ENDS aerosol samples were collected by the direct aerosol droplet deposition method. Untargeted analysis was performed using Orbitrap mass spectrometry with high mass accuracy. We identified more than 30 “features” in the aerosol characterized by pairs of the mass-to-charge ratio “ m/ z” of the compound and the retention time. We identified several compounds containing nicotine and propylene glycol (NIC-PG), whose abundance relative to nicotine increased along with vaping power used. On the basis of the prediction by the Environmental Protection Agency Toxicity Estimation Software Tool, these compounds exert developmental toxicity. In addition, a nitrogen-containing compound, likely tributylamine (a known lung irritant), was identified based on the molecular weight. This compound has not been previously identified in ENDS e-liquids and aerosols. ENDS produce not only small toxic compounds such as aldehydes, but also large complex toxic compounds such as NIC-PG. Predicted development toxicity for NIC-PG is concerning for fetal development in pregnant women who use ENDS, children exposed to secondhand or thirdhand ENDS aerosols, and teenage ENDS users whose brains are still developing. The strong positive association between NIC-PG levels and ENDS power output supports regulating high-powered ENDS.

BACKGROUND: Understanding spatial variation of air pollution is critical for public health assessments. Land Use Regression (LUR) models have been used increasingly for modeling small-scale spatial variation in air pollution concentrations. However, they have limited application in China due to the lack of spatially resolved data. OBJECTIVE: Based on purpose-designed monitoring networks, this study developed LUR models to predict fine particulate matter (PM(2.5)), black carbon (BC) and nitrogen dioxide (NO(2)) exposure and to identify their potential outdoor-origin sources within an urban/rural region, using Taizhou, China as a case study. METHOD: Two one-week integrated samples were collected at 30 PM(2.5) (BC) sites and 45 NO(2) sites in each two distinct seasons. Samples of 1/3 of the sites were collected simultaneously. Annual adjusted average was calculated and regressed against pre-selected GIS-derived predictor variables in a multivariate regression model. RESULTS: LUR explained 65% of the spatial variability in PM(2.5), 78% in BC and 73% in NO(2). Mean (±Standard Deviation) of predicted PM(2.5), BC and NO(2) exposure levels were 48.3 (±6.3) μg/m(3), 7.5 (±1.4) μg/m(3) and 27.3 (±8.2) μg/m(3), respectively. Weak spatial corrections (Pearson r = 0.05–0.25) among three pollutants were observed, indicating the presence of different sources. Regression results showed that PM(2.5), BC and NO(2) levels were positively associated with traffic variables. The former two also increased with farm land use; and higher NO(2) levels were associated with larger industrial land use. The three pollutants were correlated with sources at a scale of ≤5 km and even smaller scales (100–700m) were found for BC and NO(2). CONCLUSION: We concluded that based on a purpose-designed monitoring network, LUR model can be applied to predict PM(2.5), NO(2) and BC concentrations in urban/rural settings of China. Our findings highlighted important contributors to within-city heterogeneity in outdoor-generated exposure, and indicated traffic, industry and agriculture may significantly contribute to PM(2.5), NO(2) and BC concentrations.

Although short-duration elevated exposures (peak exposures) to pollutants may trigger adverse acute effects, epidemiological studies to understand their influence on different health effects are hampered by lack of methods for objectively identifying peaks. Secondhand smoke from cigarettes (SHS) in the residential environment can lead to peak exposures. The aim of this study was to explore whether peaks in continuous PM2.5 data can indicate SHS exposure. A total of 41 children (21 with and 20 without SHS exposure based on self-report) from 28 families in New York City (NY, USA) were recruited. Both personal and residential continuous PM2.5 monitoring were performed for five consecutive days using MicroPEM sensors (RTI International, USA). A threshold detection method based on cumulative distribution function was developed to identify peaks. When children were home, the mean accumulated peak area (APA) for peak exposures was 297 ± 325 hour*µg/m3 for children from smoking families and six times that of the APA from non-smoking families (~50 ± 54 hour*µg/m3 ). Average PM2.5 mass concentrations for SHS exposed and unexposed children were 24 ± 15 µg/m3 and 15 ± 9 µg/m3 , respectively. The average SHS exposure duration represents ~5% of total exposure time, but ~13% of children's total PM2.5 exposure dose, equivalent to an additional 2.6 µg/m3 per day. This study demonstrated the feasibility of peak analysis for quantifying SHS exposure. The developed method can be adopted more widely to support epidemiology studies on impacts of short-term exposures.

Portable monitors such as MicroPEM can accurately characterize personal exposure of pollutants, which is critical for linking exposure and health effects of air pollution. The RTI (RTI International, Research Triangle Park, NC, USA) MicroPEM V3.2A provides both real-time fine particulate matter (PM2.5) concentrations and time-integrated PM samples collected onto Teflon filters that can be used to correct real-time data as well as allow further lab chemical analysis of species on filters (e.g., metal, black carbon). Due to the optical reflectivity of local PM sources can be very different from available standard reference particles used for calibration by RTI, there is a need for gravimetric correction and validation at each study location. However, assessments of MicroPEM have been limited in locations with severe air pollution, such as Beijing. We selected a variety of weather and air quality conditions, including both clear and hazy days in Beijing, to compare PM2.5 data among MicroPEMs as well as between MicroPEM and other types of samplers. We also compared MicroPEM real-time PM2.5 concentrations with data from nearby fixed-sites. The results show MicroPEM performed well across a wide range of PM2.5 concentrations (6–461 μg/m3) and MicroPEM data, after gravimetric correction, were consistent with those from moderate-volume samplers. Good agreement was also found between real-time data from MicroPEM and fixed-site data. The present study covered a wide range of pollution levels in actual environments and validated the usage of MicroPEM as a PM2.5 monitor in locations with elevated PM2.5 levels.

Airborne black carbon (BC) particles have serious implications for human health and climate change and thus represent a prime target for mitigation policies. The sources of BC include vehicles burning diesel fuel , which are common in urban areas in low-income countries. The objective of this study was to examine the possible relationship between traffic and airborne BC concentrations near roadways in Nairobi, Kenya. We measured personal exposure levels of BC in Nairobi in a field campaign in summer 2009, and subsequently confirmed our ability to estimate BC quantitatively by conducting a co-location experiment in Nairobi in the fall of 2011. The central business district of Nairobi recorded 11-h average daytime BC concentrations in the range 20–42 µg m −3 while the main highways feeding into Nairobi recorded BC levels of 17–79 µg m−3 . As far as we are aware, the data reported here include the highest multi-hour BC concentrations ever reported in Africa. Samples from gradient sampling showed rapid reduction of BC concentrations with distance away from traffic. The measured BC near the curbside of roadways was estimated to be in the range of 34–56% of PM 2.5, implying traffic was a dominant source of PM2.5 emissions in Nairobi. The high concentrations of BC that we observed raises concern regarding potential health threats to workers, residents, and visitors, and highlights the need for policies to address traffic-related air pollution in Nairobi.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with M1-type macrophage activation. Mesenchymal stem cells (MSCs) therapies have shown promise in models of pathologies relevant to SLE, while the function and mechanism of MSC-derived exosomes (MSC-exo) were still unclear. We aimed to interrogate the effect of MSC-exo on M1-type polarization of macrophage and investigate mechanisms underlying MSC-exo. Exosomes were isolated from MSC and the effect of MSC-exo on macrophage polarization was evaluated. The key tRNA-derived fragments (tRFs) carried by exosomes were identified by small RNA sequencing and verified in clinical samples. The effect of exosomal-tRFs on macrophage polarization was examined. In this study, MSC-exo dramatically suppressed expression of M1 markers, and reduced the levels of TNF-α and IL-1β, while increased M2 markers in macrophages. A total of 243 differently expressed tRFs (DEtRFs) were identified between MSC-exo treated and untreated macrophage, among which 103 DEtRFs were up-regulated in response to MSC-exo treatment, including tsRNA-21109. The target genes of tsRNA-21109 were mainly enriched in DNA transcription-related GO function, and mainly involved in inflammatory-related pathways, including Rap1, Ras, Hippo, Wnt, MAPK, TGF-beta signaling pathway. The tsRNA-21109 was lowly expressed in clinical samples and was associated with the patient data in SLE. Compared to the normal MSC-exo, the tsRNA-21109-privative MSC-exo up-regulated M1 marker (CD80, NOS2, MCP1) and down-regulated M2 marker (CD206, ARG1, MRC2), also increased the levels of TNF-α and IL-1β in macrophages. Western blot and immunofluorescence confirmed that the proportion of CD80/ARG-1 was increased in macrophages treated with tsRNA-21109-privatived MSC-exo compared to that with control MSC-exo. In conclusion, MSC-exo inhibited the M1-type polarization of macrophages, possibly through transferring tsRNA-21109, which may develop as a novel therapeutic target for SLE.

Background Potential hazards of fine particulate matter (PM2.5) constituents on preterm birth (PTB) have rarely been explored in China. Objective To quantify the associations of PM2.5 constituents with PTB. Methods This study was based on a nationwide cohort of 3,723,169 live singleton births delivered between January 2010 and December 2015 in China. We applied satellite-based estimates of five PM2.5 constituents (organic carbon; black carbon; sulfate; ammonium; and nitrate). We used Cox proportional hazards regression models adjusted for individual covariates, temperature, humidity, and seasonality to evaluate the associations. Results During the entire pregnancy, each interquartile range (29 μg/m3) increase in PM2.5 concentrations was associated with a 7% increase in PTB risk [hazard ratio (HR): 1.07; 95% confidence interval (CI): 1.07-1.08). We observed the largest effect estimates on carbonaceous components (HR: 1.09; 95% CI: 1.08-1.10 for organic carbon and black carbon). Early pregnancy appeared to be the critical exposure window for most constituents. Women who were older, exposed to second-hand smoke, overweight or obese before pregnancy, conceived during winter, and living in northern China or rural areas were more susceptible. Conclusions Carbonaceous components of PM2.5 were associated with higher PTB risk. Findings on characteristics of vulnerability underlined targeted protections on susceptible subgroups.

Background: Assessing the impacts of air pollution on school absenteeism due to illness is critical for developing future preparedness response strategies for the sensitive elementary students. Methods: We collected 693,081 absenteeism records due to illness from 2,564 elementary schools across Jiangsu Province, China in the 2016-17 academic year. Exposure levels of the six major air pollutants, including carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), coarse and fine particle (PM10, PM2.5), and sulfur dioxide (SO2), were estimated via Kriging interpolation of the measured data from routine monitoring network. We examined the associations between air pollutants and illness-related absenteeism using a time-stratified case-crossover design. Findings: We found that an increase of 10 µg/m3 in the current-day concentration of air pollutants, including PM2.5, PM10, NO2, SO2, and 100 µg/m3 for CO, was overall associated with absenteeism due to illness overall, with a 0·6% to 16·8% increase in the risk of absenteeism. Students in up to 40% illness-related absenteeism received home nursing instead of going to hospital. The increase in the number of illness cases associated with the above five air pollutants estimated based on the illness-related absence data was 43-52% higher than that accessed based on hospital visit records. The risk due to O3 exposure alone existed only for students frequently absented (>5 times during the study period). After controlling with other pollutants, the risk from PM2·5 decreased but persisted while risk from O3 appeared. Adjustment for PM10 and O3 led to a risk boost for multiple pollutants. Interpretation: Our findings validate the use of illness-related absence records in studies for public health purposes and provide evidence of the health risk of air pollution in school-aged children. Improvement in air quality and home health care education are warranted for children’s health benefits. Funding: National Natural Science Foundation of China and the Jiangsu Social Development Project. Declaration of Interest: We declare no competing interests.

Background Mesenchymal stem cells transplantation gradually become a potential treatment for bone defect in clinic practice. This study aimed to investigate the molecular mechanism of PRP and autophagy for osteogenic differentiation in bone marrow mesenchymal stem cells (BMSCs). Methods Thrombin activated PRP was prepared and the BMSCs were treated with activated PRP with different concentration and transfected with miR-140-3p vector (mimics or inhibitor), si-SPRED2 or co-transfected with miR-140-3p inhibitor and si-SPRED2, respectively. qRT-PCR and Western blotting were used to determine the mRNA expression and protein expression. A luciferase reporter assay was conducted to identified the targeting relationship between iR-140-3p and SPRED2 Subsequently, cell proliferation was detected by MTT and ALP activity was also determined. Alizarin red staining was used for the evaluating the formation of calcium nodules. Results MiR-140-3p expression was found to be inhibited by PRP in a dose-dependent manner, besides, cell proliferation, ALP activity, the expression of COL-I, OPN, Runx2 and OCN, and the formation of calcium nodules related to osteogenic differentiation were enhanced by PRP. Subsequently, we found that PRP activated autophagy and up-regulated SPRED2 expression in BMSCs through suppressing miR-140-3p expression. Moreover, we confirmed that miR-140-3p targeted SPRED2 and negatively regulation its expression. Finally, the findings showed that inhibition of miR-140-3p enhanced cell proliferation, osteogenic differentiation and autophagy of BMSCs by negatively regulating SPRED2 expression. Conclusion Thrombin activated PRP accelerated osteogenic differentiation of BMSCs by activing autophagy through miR-140-3p/SPRED2 axis.

BACKGROUND: Airborne polycyclic aromatic hydrocarbons (PAH) possess carcinogenic and endocrine disrupting properties linked to mammary tumorigenesis. These effects may be initiated during a prenatal period of susceptibility to PAH activation of the aryl hydrocarbon receptor (Ahr) and through downstream effects on estrogen receptor (Er) α. PURPOSE: We hypothesized prenatal airborne PAH exposure induces sustained effects in female adult wild type BALB/cByj mice detected in the offspring (F1) and grandoffspring (F2) generation. We hypothesized these effects would include altered expression and epigenetic regulation of Erα and altered expression of aryl hydrocarbon receptor repressor (Ahrr, Ahrr/aryl hydrocarbon receptor nuclear translocator (Arnt), and breast cancer type 1 susceptibility (Brca1). Further, we hypothesized that PAH would induce precancerous outcomes such as epithelial cell proliferation and epithelial cell hyperplasia in mammary glands of adult female offspring and grandoffspring. RESULTS: Prenatal ambient PAH exposure lowered Erα mRNA expression (F1 and F2: p

To investigate the environmental impacts of reclaimed asphalt pavement (RAP) while it was freshly processed (i.e. hot mixed asphalt or HMA) and after being subjected to weathering, three RAP materials, namely north-RAP, central-RAP, south-RAP, from three plants and one fresh HMA loose mix samples (Fresh-HMA) throughout New Jersey, USA underwent four different weathering processes including: UV and precipitation weathering on unbounded RAP, UV and precipitation weathering on compacted RAP, weathering by heat and moisture cycles, and groundwater flow-through leaching. Batch experiments were conducted to mimic releasing of trace elements in weak acidic leachate from landfills. North-RAP and central-RAP released levels of Pb greater than the United States Environmental Protection Agency (USEPA) primary drinking water maximum contaminant level (MCL) of 15 μg/L. Novel two-column experiments (a RAP column followed by a soil column) were conducted to investigate the release of trace elements from RAP and the attenuation effect of soil on potential pollutants. The results of these experiments showed that pollutants released from RAPs such as Mn and Ni were largely attenuated in the soil. The results suggest that RAP can be used as an unbound material in environments except those acidic (i.e., pH < 5 as in mines with sulfur-containing minerals and landfills with acidic environment).

Several studies have confirmed the ubiquitous presence of microplastics in marine environments and marine animals at different trophic levels. Understanding how they reach the ocean is crucial for ...

Selenium (Se) is an essential trace element. However, Se in soil is often accompanied by heavy metals, such as cadmium (Cd), because of geological background. The safe utilization of such Se-rich land resources remains a challenge. A typical Se-rich area located in Enshi County, China, was systematically investigated with geochemical and epidemiological methods. The results show that Se in the topsoil is 0.84 ± 1.39 μg/g, whereas that of Cd is 0.93 ± 1.63 μg/g. And the concentration of Se and Cd in corn is 0.22 ± 0.96 μg/g and 0.15 ± 0.32 μg/g, respectively, which is mainly related to the high concentrations in soil. The benchmark dose limit of urinary Cd for β2-microglobulin in subjects (n = 160) was calculated as 3.27 µg/g Cr. In view of crop–human dose effect and combining the relationship among the concentrations of crops and human biomarkers and the concentrations of crops and topsoil, this study established the models of land resource safety zoning. With that, the risk screening value of Cd in the soil could be obtained as 0.98 μg/g in this typical area. The proportions of priority utilization, safe utilization, and strict management of agricultural land area were 58.85%, 22.90%, and 18.25%, respectively, in Enshi, China. These results could provide scientific support for local agricultural development and ecological sustainability.

Efficient and reproducible measurements of multiple polycyclic aromatic hydrocarbon (PAH) metabolites in urinary samples are required to evaluate the complex health effects of PAH exposure. Here, we demonstrate a highly practical, automated off-line solid-phase extraction (SPE) of deconjugated hydroxylated PAHs followed by LC-MS/MS to simultaneously measure eight mono-hydroxylated PAH compounds: 1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 1-hydroxyphenanthrene, 23-hydroxyphenanthrene, 4-hydroxyphenanthrene and 1-hydroxypyrene. Initially, we observed low recovery rates (e.g., 16% for 1-hydroxypyrene) when using previously published methods. We optimized the procedure by choosing polymeric absorbent-based cartridges, automating the sample loading step by diluting samples with 15% methanol/sodium acetate, and most importantly, replacing acetonitrile with methanol as the eluting solvent. Optimized sample preparation has improved the recovery rates to more than 69% for analytes of interest. This improvement led to higher method sensitivity and detection frequency, especially for 1-hydroxypyrene, in all of 100 urine samples collected in the New York City site of the Legacy Girls Study. The limits of detection ranged from 7.6 pg/mL to 20.3 pg/mL using 1 mL of urine, compared to the 2 mL required in CDC, method 09-OD. The average coefficients of variance of quality control samples (n = 60) ranged between 7 and 21%; variance of repeated measurements (n = 45) was less than 10%. This efficient and reliable method for measuring PAH metabolites will greatly benefit epidemiology studies and biomonitoring programs.

Oxalic acid potentially enhances pump-and-treat for groundwater As remediation by accelerating mobilization. This study examines how oxalic acid mobilizes As from Fe(III)-oxide coated sand under hydrodynamic conditions. Four columns were packed with metal-substituted ferrihydrite or goethite to 1% Fe, presorbed to 50% As surface coverage, and reacted with pH = 2.2 artificial groundwater amended with 10 mM oxalic acid at 1 m day−1. Arsenic elution was affected by both As and Fe speciation. Although the As(V) columns experienced faster substrate dissolution, As(V) elution was delayed by re-adsorption, whereas As(III) elution was rapid due to pH decrease that prevented re-adsorption. Cr-ferrihydrite and Ni-goethite dissolved both effectively initially but then diverged. The Cr-ferrihydrite columns experienced continuous stoichiometric Fe and Cr release, and As release could be sustained. The Ni-goethite columns initially experienced nonstoichiometric Fe and Ni release, and As release was extensive. Such release, however, was not sustained. We hypothesized that Ni-goethite contained sites with distinct reactivity, and oxalic acid targeted readily-dissolved, sorption-dense sites. Our data indicate that oxalic acid-enhanced pump-and-treat methods would be easier to apply to aquifers dominated by As(III), requiring less amendment to be injected; such oxalic acid-enhanced methods remove reactive sediment Fe and As, potentially preventing future groundwater contamination.

Personal air pollution monitoring in research studies should not interfere with usual patterns of behavior and bias results. In an urban pediatric cohort study we tested whether wearing an air monitor impacted activity time based on continuous watch-based accelerometry. The majority (71%) reported that activity while wearing the monitor mimicked normal activity. Correspondingly, variation in activity while wearing versus not wearing the monitor did not differ greatly from baseline variation in activity (P = 0.84).

Background: Epidemiologic studies of PM2.5 (particulate matter with aerodynamic diameter ≤2.5 μm) and black carbon (BC) typically use ambient measurements as exposure proxies given that individual measurement is infeasible among large populations. Failure to account for variation in exposure will bias epidemiologic study results. The ability of ambient measurement as a proxy of exposure in regions with heavy pollution is untested. Objective: We aimed to investigate effects of potential determinants and to estimate PM2.5 and BC exposure by a modeling approach. Methods: We collected 417 24 h personal PM2.5 and 130 72 h personal BC measurements from a panel of 36 nonsmoking college students in Shanghai, China. Each participant underwent 4 rounds of three consecutive 24-h sampling sessions through December 2014 to July 2015. We applied backwards regression to construct mixed effect models incorporating all accessible variables of ambient pollution, climate and time-location information for exposure prediction. All models were evaluated by marginal R2 and root mean square error (RMSE) from a leave-one-out-cross-validation (LOOCV) and a 10-fold cross-validation (10-fold CV). Results: Personal PM2.5 was 47.6% lower than ambient level, with mean (±Standard Deviation, SD) level of 39.9 (±32.1) μg/m3; whereas personal BC (6.1 (±2.8) μg/m3) was about one-fold higher than the corresponding ambient concentrations. Ambient levels were the most significant determinants of PM2.5 and BC exposure. Meteorological and season indicators were also important predictors. Our final models predicted 75% of the variance in 24 h personal PM2.5 and 72 h personal BC. LOOCV analysis showed an R2 (RMSE) of 0.73 (0.40) for PM2.5 and 0.66 (0.27) for BC. Ten-fold CV analysis showed a R2 (RMSE) of 0.73 (0.41) for PM2.5 and 0.68 (0.26) for BC. Conclusion: We used readily accessible data and established intuitive models that can predict PM2.5 and BC exposure. This modeling approach can be a feasible solution for PM exposure estimation in epidemiological studies. Keywords: Personal exposure, Ambient measurement, PM2.5, BC, Modeling

Background Fine particulate matter (PM2.5) is associated with various adverse health outcomes. The MicroPEM (RTI, NC), a miniaturized real-time portable particulate sensor with an integrated filter for collecting particles, has been widely used for personal PM2.5 exposure assessment. Five-day deployments were targeted on a total of 142 deployments (personal or residential) to obtain real-time PM2.5 levels from children living in New York City and Baltimore. Among these 142 deployments, 79 applied high-efficiency particulate air (HEPA) filters in the field at the beginning and end of each deployment to adjust the zero level of the nephelometer. However, unacceptable baseline drift was observed in a large fraction (> 40%) of acquisitions in this study even after HEPA correction. This drift issue has been observed in several other studies as well. The purpose of the present study is to develop an algorithm to correct the baseline drift in MicroPEM based on central site ambient data during inactive time periods. Method A running baseline & gravimetric correction (RBGC) method was developed based on the comparison of MicroPEM readings during inactive periods to ambient PM2.5 levels provided by fixed monitoring sites and the gravimetric weight of PM2.5 collected on the MicroPEM filters. The results after RBGC correction were compared with those using HEPA approach and gravimetric correction alone. Seven pairs of duplicate acquisitions were used to validate the RBGC method. Results The percentages of acquisitions with baseline drift problems were 42%, 53% and 10% for raw, HEPA corrected, and RBGC corrected data, respectively. Pearson correlation analysis of duplicates showed an increase in the coefficient of determination from 0.75 for raw data to 0.97 after RBGC correction. In addition, the slope of the regression line increased from 0.60 for raw data to 1.00 after RBGC correction. Conclusions The RBGC approach corrected the baseline drift issue associated with MicroPEM data. The algorithm developed has the potential for use with data generated from other types of PM sensors that contain a filter for weighing as well. In addition, this approach can be applied in many other regions, given widely available ambient PM data from monitoring networks, especially in urban areas.

Despite a recent increase in e-cigarette use, the adverse human health effects of exposure to e-cigarette aerosol, especially on the central nervous system (CNS), remain unclear. Multiple neurotoxic metals have been identified in e-cigarette aerosol. However, it is unknown whether those metals accumulate in the CNS at biologically meaningful levels. To answer this question, two groups of mice were whole-body exposed twice a day, 5 days a week, for two months, to either a dose of e-cigarette aerosol equivalent to human secondhand exposure, or a 5-fold higher dose. After the last exposure, the olfactory bulb, anterior and posterior frontal cortex, striatum, ventral midbrain, cerebellum, brainstem, remaining brain tissue and spinal cord were collected for metal quantification by inductively coupled plasma mass spectrometry and compared to tissues from unexposed control mice. The two-month exposure caused significant accumulation of several neurotoxic metals in various brain areas - for some metals even at the low exposure dose. The most striking increases were measured in the striatum. For several metals, including Cr, Cu, Fe, Mn, and Pb, similar accumulations are known to be neurotoxic in mice. Decreases in some essential metals were observed across the CNS. Our findings suggest that chronic exposure to e-cigarette aerosol could lead to CNS neurotoxic metal deposition and endogenous metal dyshomeostasis, including potential neurotoxicity. We conclude that e-cigarette-mediated metal neurotoxicity may pose long-term neurotoxic and neurodegenerative risks for e-cigarette users and bystanders.

Fine particulate matter (PM2.5) is a complex mixture of components which has been associated with various cardiovascular effects, such as elevated blood pressure (BP). However, evidences on specific sources behind these effects remain uncertain. Based on 140 72-h personal measurements among a panel of 36 health college students in Shanghai, China, we assessed associations between source-apportioned PM2.5 exposure and BP changes. Based on personal filter samples, PM2.5 source apportionment was conducted using Positive Matrix Factorization (PMF) model. Linear mixed-effects models were applied to evaluate associations of source-specific PM2.5 exposure with BP changes. Seven sources were identified in PMF analysis. Among them, secondary sulfate (41%) and nitrate (24%) sources contributed most to personal PM2.5, followed by industrial emissions (15%), traffic-related source (10%), coal combustion (6.2%), dust (2.4%) and aged sea salt (1.1%). We found nitrate, traffic-related source and coal combustion were significantly associated with increased BP. For example, an interquartile range increase in PM2.5 from traffic-related source was significantly associated with increase in systolic BP [1.5 (95% CI: 0.26, 2.7) mmHg], diastolic BP [1.2 (95% CI: 0.10, 2.2) mmHg] and mean arterial pressure [1.2 (95% CI: 0.15, 2.2) mmHg]. This is the first investigation linking personal PM2.5 source profile and BP changes. This study provides evidence that several anthropogenic emissions (especially traffic-related emission) may be particularly responsible for BP increases, and highlights that the importance of development of health-oriented PM2.5 source control strategies.

Background Neonatal alloimmune thrombocytopenia (NAIT), caused by maternal antibodies raised against alloantigens carried on foetal platelets, is a very common haematological abnormality in newborns worldwide. However, baseline data on NAIT in China are lacking. Therefore, this study seeks to explore the incidence of alloantibody against the human platelet antigen (HPA) in pregnant women and its associations with NAIT in China. Methods A multicentre, prospective cohort study design will be used, and 55,497 pregnant women will be recruited for the first screening of the anti-HPA antibody at 12 to 28 weeks of gestational age. Subjects who are positive in the first screening for the anti-HPA antibody will be included in the exposure group. Re-tests of the antibody titre, antigen-specificity and genotyping of HPA and HLA will be conducted during admission. A ratio of 1:1 paired individuals with the same ethnicity and parity but testing negative for the anti-HPA antibody will be randomly selected to be included in the non-exposure group. NAIT will be diagnosed in the newborns on day one of the birth. The HPA of the neonates in the exposure group will also be genotyped by sequencing. Associations of maternal HLA with the occurrence of the anti-HPA antibody and correlation of the severity of NAIT with the titre of the anti-HPA antibody will be further analysed. Discussion The study is expected to provide baseline data on NAIT in China. Besides, we hope to find out a population who expresses particular HLA molecules has significant higher risk of HPA alloimmunization in Chinese individuals. We also hope to find a Chinese-specific cut-off antibody titre for the prediction of the severity of NAIT and to provide a means to evaluate the necessity of antenatal treatment. Trial registration ClinicalTrials.gov: NCT02934906 (date registered: 13.10.2016).