Differences in the uptake and translocation of differentially charged microplastics by the taproot and lateral root of mangroves.

The interception of microplastics (MPs) by mangrove roots plays an indispensable role in reducing the environmental risks of MPs. However, there remains limited research on the fate of the intercepted MPs. Hereby, the uptake and subsequent translocation of 0.2 µm and 2 µm PS MPs with different coating charge by the typical salt-secreting mangrove plants (Aegiceras corniculatum) were investigated. Compared to amino-functionalized PS with positive charge (PS-NH2), the visualized results indicated that the efficient uptake of carboxy-functionalized PS with negative charge (PS-COOH) was more dependent on taproots. But for the lateral roots, it only allowed the entry of PS-NH2 instead of PS-COOH. The specific uptake pathways of PS-NH2 on the lateral roots could attribute to the release of H+ and organic acids by root hairs, as well as the relative higher Zeta potential. After entering the Aegiceras corniculatum roots, the translocation of PS MPs was restricted by their particle sizes. Furthermore, the release of PS MPs from Aegiceras corniculatum leaf surfaces through the salt glands and stomata was observed. And the decline in the photochemical efficiency of leaves under PS MPs exposure also indirectly proved the foliar emission of PS MPs. Our study improved the understanding of the environmental behaviors and risks of the retained MPs in mangroves.

Identification and health risk evaluation of soil contaminated by polycyclic aromatic hydrocarbons at shale gas extraction sites based on positive matrix factorization.

The impact of shale gas extraction on surrounding environmental media remains unclear. In this study, the current state of contamination by polycyclic aromatic hydrocarbons (PAHs), which are high-frequency contaminants of shale gas, was investigated in the soil surrounding emerging shale gas development sites. The source analysis of PAHs was conducted in the soils of shale gas extraction sites using positive matrix factorization (PMF). The health risk assessment (HRA) was calculated for ingestion, dermal contact, and inhalation exposures, and the priority sources of PAHs in the soil were jointly identified by PMF and HRA to refine the contribution level of different individual PAHs to the carcinogenic risk. The results showed that both Sichuan and Chongqing mining site soils were contaminated to different degrees. Shale gas extraction has an impact on the surrounding soil, and the highest contributing source of PAHs in the mining site soil of Sichuan was anthropogenic activity, accounting for 31.6%, whereas that in the mining site soil of Chongqing was biomass combustion and mixed automobile combustion, accounting for 35.9%. At the two mining sites in Sichuan and Chongqing, none of the three exposure pathways (ingestion, dermal contact, and inhalation) posed a carcinogenic risk to children, whereas the dermal exposure pathway posed a carcinogenic risk to adults. Health risk assessments based on specific source assignments indicate that when managing soil pollution, the control of fossil fuel combustion and vehicular emissions should be prioritized.

Probabilistic human health risk assessment of PCDD/Fs near municipal solid-waste incinerator using Monte Carlo analysis coupled with triangular fuzzy numbers.

PCDD/Fs are dioxins produced by waste incineration and pose risks to human health. We aimed to detail the health risks of airborne and soil PCDD/Fs near a municipal solid-waste incinerator (MSWI) for the surrounding population and develop a new model that improves upon existing methods. Thus, we conducted field sampling and then investigated a MSWI in the Pearl River Delta (2016-2018). Our results showed that the carcinogenic and non-carcinogenic risk values of PCDD/Fs exposed to residents in nearby areas were acceptable, with hazard index (HI) values lower than 1.0 and a total carcinogenic risk lower than 1.0E-6. Notably, the results raised concerns regarding higher non-carcinogenic risks in children than in adults. Comparative analysis of the frequency accumulation diagram, accumulated probability risk, and the absolute value of error (δ) between the 95% confidence interval (CI) and the 90% CI of the Monte Carlo stochastic simulation-triangular fuzzy number (MCSS-TFN) and the MCSS model, respectively, demonstrated that the MCSS-TFN exhibited less uncertainty than the MCSS model, regardless of the health risk value of PCDD/Fs in ambient air or in soil. This observation underscores the superiority of the MCSS-TFN model over other models in assessing the health risks associated with PCDD/Fs in situations with limited data. Our new method overcomes the limited dataset size and high uncertainty in assessing the health risks of dioxin substances, providing a more comprehensive understanding of their associated health risks than MCSS models.

Health assessment based on exposure to microplastics in tropical agricultural soil.

Microplastic (MP) pollution of agricultural soils has caused global alarm over its widespread distribution and potential risks to terrestrial ecosystems and human health. This study assessed human health based on exposure to soil MPs through a comprehensive investigation of the factors influencing their occurrence and spatial distribution on Hainan Island, South China. The results showed that the abundance of soil MPs was 1128.6 ± 391.5 items·kg-1, whereas the normalized abundance of MPs based on using a power-law function was 19,261.4 items·kg-1. Regarding the extent of population exposure to agricultural soil MPs, the average daily exposure dose (pADD) model revealed that using mass as an indicator to assess the health risks associated with MP intake is more reliable than using abundance. However, abundance-based exposure assessments are also relevant because MPs with smaller particle sizes are more harmful to human health. Moreover, for adults, the normalized pADD values based on abundance and mass were 1.68E-02 item MPs·kg BW-1·d-1 and 7.23E-02 mg MPs·kg BW-1·d-1, respectively. Although the multidimensionality of MPs should be further aligned and quantified, the preliminary findings of this study contribute to the development of human health risk assessment frameworks for soil MPs.

Health risk assessment of trace metal(loid)s in agricultural soil using an integrated model combining soil-related and plants-accumulation exposures: A case study on Hainan Island, South China.

Traditional health risk assessment of trace metal(loid)s (TMs) in agricultural soil exclusively considers direct soil-related exposure and may underestimate the health risks they pose. In this study, the health risks of TMs were evaluated using an integrated model that combined soil-related and plant-accumulating exposures. A detailed investigation of common TMs (Cr, Pb, Cd, As, and Hg) coupled with probability risk analysis based on a Monte Carlo simulation was conducted on Hainan Island. Our results showed that, except for As, the non-carcinogenic risk (HI) and carcinogenic risk (CR) of the TMs were all within the acceptable ranges (HI < 1.0, and CR < 1E-06) for direct soil-related exposure to bio-accessible fractions and indirect exposure via plant accumulation (CR substantially lower than the warning threshold 1E-04). We identified crop food ingestion as the essential pathway for TM exposure and As as the critical toxic element in terms of risk control. Moreover, we determined that RfDo and SFo are the most suitable parameters for assessing As health risk severity. Our study demonstrated that the proposed integrated model combining soil-related and plant-accumulating exposures can avoid major health risk assessment deviations. The results obtained and the integrated model proposed in this study can facilitate future multi-pathway exposure research and could be the basis for determining agricultural soil quality criteria in tropical areas.

The role of pores in micro-zone distribution of Cd in a tropical paddy soil: Results from X-ray computed tomography combined energy dispersive spectroscopy analysis.

Accurate description of Cd micro-zone distribution and accumulation is the prerequisite for revealing Cd transfer and transformation processes. However, to date, the role of soil pores in the Cd micro-zone distribution characteristics in undisturbed soil is still unclear. In this study, the obvious heterogeneous distribution of Cd in and around the soil pores at the cross-sectional surface of the tropical undisturbed topsoil was visualized by the combination of X-ray micro-computed tomography and scanning electron microscope-energy dispersive spectroscopy. For both the air space and water-holding pores, the micro-zone distribution characteristics of Cd around the pores were dominated by pore sizes. For macropores and mesopores, Cd preferred to distribute in the micro-zone within 167.5-335 µm from pores. But for micropores, the highest content percentage of Cd was exhibited in the micro-zone within 67-167.5 µm from pores. The random forest model revealed that the occurrence of Fe (13.83%) and P (13.59%) contributed most to Cd micro-zone distribution around air space pores. While for water-holding pores, Fe occurrence (18.30%) contributed more significantly than P (11.92%) to Cd micro-zone distribution. Our study provided new insights into Cd retention mechanism, which is help for accessing Cd migration and transformation.

An unrecognized entry pathway of submicrometre plastics into crop root: The split of hole in protective layer.

Threats to food safety caused by the continuous accumulation of plastic particles in the terrestrial environment is currently a worldwide concern. To date, descriptions of how plastic particles pass the external biological barrier of crop root have been vague. Here, we demonstrated that submicrometre polystyrene particles passed unimpededly the external biological barrier of maize through the split of holes in the protective layer. We identified plastic particles induced the apical epidermal cells of root tips become round, thereby expanding the intercellular space. It further pulled apart the protective layer between the epidermal cells, and eventually formed the entry pathway for plastic particles. The enhancement of oxidative stress level induced by plastic particles was the main reason for the deformation of the apical epidermal cells (increased roundness values: 15.5%), comparing to the control. Our findings further indicated that the presence of cadmium was conducive to the "holes" formation. Our results highlighted the critical insights into the fracture mechanisms of plastic particles for the external biological barriers of crop roots, providing a strong incentive to access the risk of plastic particles in agriculture security.

Phosphorus fractions and iron oxides responsible for the variations in the Cd retention capacity in tropical soil aggregates under different cropping patterns.

The environmental behavior of Cd in soil has been widely studied because of its close relationship with food security and soil environmental pollution. In this study, the roles of P fractions and Fe oxides in the retention of Cd in typical tropical soil from five cropping patterns were investigated. Although there was no evident relationship between the Cd adsorption capacity and soil aggregate particle sizes, strong spatial associations of P, Fe, and Cd at the soil aggregates were observed via energy dispersive spectroscopy analysis. Among five cropping patterns, citrus plantations exhibited highest ratios (calculated by pixel area) of P overlapped with Cd (8.61%) and Fe overlapped with Cd (9.53%) in the microaggregates. Furthermore, the random forest model revealed that humic P and labile organic P greatly contributed to the sorptivity of Cd2+ by < 0.053 mm (13.3%) and 0.25-0.053 mm (13.4%) soil aggregates, respectively. Compared with the P fractions in different-sized soil aggregates, the contribution of Fe oxides to the sorption of Cd2+ by soil aggregates was more significant. Amorphous ferric oxide had the most significant contribution to the sorptivity of Cd2+ by < 0.053 mm (26.0%), 0.25-0.053 mm (23.0%), 2.0-0.25 mm (25.1%), and > 2.0 mm (33.9%) soil aggregates.

Antagonistic effect of polystyrene nanoplastics on cadmium toxicity to maize (Zea mays L.).

Nanoplastics (NPs) (<1 µm) have gradually attracted worldwide attention owing to their widespread occurrence, distribution, and ecosystem risks. Few studies have explored the interaction between NPs and heavy metals in crops. In this study, we investigated the influence of polystyrene nanoplastics (PSNPs; 10 mg/L and 100 mg/L) and cadmium (2 mg/L and 10 mg/L) on the physiological and biochemical indices of maize plants, grown in Hoagland solution with contaminants, for 14 days. The fresh weight and growth of the maize plants were significantly reduced after exposure to high concentrations of PSNPs and Cd (p < 0.05). Specifically, the fresh weight decreased by 30.3% and 32.5% in the PSNPs and Cd treatment, respectively. Root length and shoot length decreased by 11.7% and 20.0%, and by 16.3% and 27.8%, in the PSNPs and Cd treatment, respectively. However, there were no significant effects on the fresh weight and growth of maize plants as Cd levels increased from 2 to 10 mg/L in the presence of PSNPs. Polystyrene nanoplastics alleviated the phytotoxicity of Cd in maize. Scanning electron microscopy (SEM) showed that PSNPs and Cd could enter maize roots and were transported upwards to the leaves through the vascular bundle. The activities of peroxidase (POD) and catalase (CAT) in maize leaves increased significantly under high concentrations of PSNPs, whereas superoxide dismutase (SOD) activity decreased (p < 0.05). The differences in SOD activity may be related to the absence of microelements such as Zn, Fe, and Mn. This study provides a scientific basis for further exploration of the combined toxicological effects of heavy metals and NPs on the environment.

The Synergistic Effect of Biochar-Combined Activated Phosphate Rock Treatments in Typical Vegetables in Tropical Sandy Soil: Results from Nutrition Supply and the Immobilization of Toxic Metals.

Sandy soils in tropical areas are more vulnerable to potential toxic elements as a result of their low nutrition. The composite addition of biochar and phosphate material is considered a promising method of immobilizing toxic metals in sandy soils, but the synergistic effects of this process still need to be further explored, especially in typical tropical vegetables. In this study, a pot experiment was conducted to evaluate the agronomic and toxic metal-immobilization effects of single amendments (phosphate rock, activated phosphate rock, and biochar) and combined amendments, including biochar mixed with phosphate rock (BCPR) and biochar mixed with activated phosphate rock (BCAPR), on vegetables grown in tropical sandy soil. Among these amendments, the composite amendment BCAPR was the most effective for increasing Ca, Mg, and P uptake based on water spinach (Ipomoea aquatica L.) and pepper (Capsicum annuum L.), showing increased ratios of 22.5%, 146.0%, and 136.0%, respectively. The SEM-EDS and FTIR analysis verified that the activation process induced by humic acid resulted in the complexation and chelation of the elements P, Ca, and Mg into bioavailable forms. Furthermore, the retention of available nutrition elements was enhanced due to the strong adsorption capacity of the biochar. In terms of cadmium (Cd) and lead (Pb) passivation, the formation of insoluble mineral precipitates reduced the mobility of these metals within the BCAPR treatments, with the maximum level of extractable Cd (86.6%) and Pb (39.2%) reduction being observed in the tropical sandy soil. These results explore the use of sustainable novel cost-effective and highly efficient bi-functional mineral-based soil amendments for metal passivation and plant protection.

3D surface reconstruction of the femur and tibia from parallel 2D contours.

BACKGROUND: Segmented structures, such as bones, are typically stored as 2D contours contained on evenly spaced images (slices). Contour interpolation algorithms to turn 2D contours into a 3D surface may differ in their results, causing discrepancies in analysis. This study aimed to create an accurate and consistent algorithm for the interpolation of femur and tibial contours that can be used in computer-assisted surgical navigation systems. METHODS: The implemented algorithm performs contour interpolation in a step-by-step manner, determining an optimal surface between each pair of consecutive contours. Determining such a surface is reduced to the problem of finding certain minimum-cost cycles in a directed toroidal graph. The algorithm assumes that the contours are ordered. The first step in the algorithm is the determination of branching patterns, followed by the removal of keyholes from contours, optimization of a target function based on the surface area, and mesh triangulation based on the optimization results and mesh seal. RESULTS: The algorithm was tested on contours segmented on computed tomography images from femoral and tibial specimens; it was able to generate qualitatively good 3D meshes from the set of 2D contours for all the tested examples. CONCLUSION: The contour interpolation algorithm proved to be quite effective using optimization based on minimizing the area of the triangles that form the 3D surface. The algorithm can be used for the 3D reconstruction of other types of 2D cuts, but special attention must be paid with the branches, since the proposed algorithm is not designed for complex branching structures.

Sex-specific associations of prenatal exposure to bisphenol A and its alternatives with fetal growth parameters and gestational age.

BACKGROUND: Bisphenol A (BPA) can cause detrimental effects on fetal growth. However, the effects of BPA alternatives, such as bisphenol F (BPF) and bisphenol S (BPS), on fetal growth are less known. OBJECTIVE: To investigate the relationships of prenatal BPA, BPF, and BPS exposures with fetal growth parameters and gestational age. METHODS: Urinary BPA, BPF, and BPS were measured in 1,197 pregnant women before delivery in a Chinese cohort. The associations of prenatal exposure to BPA, BPF, and BPS with fetal growth parameters and gestational age were examined, and associations stratified by fetal sex were also conducted. We used a restricted cubic splines (RCS) model to examine the dose-response associations between exposures and outcomes. RESULTS: Maternal urinary BPA and BPF were negatively related to birth length (-0.30 cm, 95% CI: -0.44, -0.15 and -0.21 cm, 95% CI: -0.36, -0.07 comparing the extreme exposure groups, respectively, both p for trends < 0.01). These associations were more pronounced in girls with inverted U-shaped dose-response relationships. Maternal urinary BPA and BPF were positively related to ponderal index (0.05 g/cm3 × 100, 95% CI: 0.01, 0.09 and 0.04 g/cm3 × 100, 95% CI: 0.01, 0.08 comparing the extreme exposure groups, respectively, both p for trends = 0.02), and maternal urinary BPS was associated with shorter gestational age (-0.20 weeks, 95% CI: -0.37, -0.03 comparing the extreme exposure groups, p for trend = 0.02). These associations were only observed in girls and exhibited a linear dose-response relationship. CONCLUSIONS: Prenatal BPA, BPF, and BPS exposures were associated with detrimental effects on fetal growth parameters, and stronger effects were noted in female infants.

Effects of organochlorine exposure on male reproductive disorders in an electronic waste area of South China.

Several studies suggest that organochlorine exposure can affect male reproductive functions, causing poor semen quality, endocrine disruption, or dysregulation of thyroid hormones. This study uses multiple linear regression (MLR) models to analyze the correlation between male reproductive functions and polychlorinated biphenyl (PCBs) congeners or p,p'-DDE levels in serum, semen, and indoor dust samples. Multiple comparisons were all adjusted using the false discovery rate (FDR). The results revealed that the PCB congener levels in seminal plasma were significantly associated with the quality parameters of human semen (i.e., sperm count, morphology, and motility) and thyroid hormones after adjusting for covariates, e.g., associations of the sperm concentration with levels of CB105 (ß = -0.323, 95% CI: -0.561, -0.085, p = 0.009), CB44 (ß = 0.585, 95% CI: 0.290, 0.880, p < 0.001), and CB66 (ß = -0.435, 95% CI: -0.728, -0.143, p = 0.004) in the seminal plasma were observed. Correlations between serum pollutants levels and the semen quality, reproductive hormones, or thyroid hormones were also observed. Moreover, our results demonstrate that the quantification of PCBs in seminal plasma can better describe male reproductive disorders than that in serum or dust. Organochlorine exposure measured in serum or dust, especially in seminal plasma, was associated with semen quality, as well as reproductive and thyroid hormones, thus suggesting that the impacts of persistent pollutants on male reproductive health require further investigation.

Levels and congener profiles of halogenated persistent organic pollutants in human serum and semen at an e-waste area in South China.

Typical halogenated persistent organic pollutants (Hal-POPs), including polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), polychlorinated biphenyls (PCBs), and dichlorodiphenyltrichloroethane (DDT), are a group of ubiquitous organic pollutants with an endocrine disrupting effect. This study evaluated the accumulation and congener profiles of Hal-POPs in the bodies of men who live/work in areas of South China where electronic wastes are collected and managed, especially in their semen samples. The results show that the detection frequency and serum concentrations of Hal-POP congeners within the high-exposure group (HEG) were higher than those of the low-exposure group (LEG). Furthermore, an identical trend was observed for the seminal plasma concentrations of Hal-POPs. The distribution characteristics, such as their mean, median, and discrete values, of PBDE congeners in serum and semen samples from the same subjects were consistent with each other. However, the distribution characteristics of PCB congeners in serum samples were different from those in semen samples. BDE153 was one of the most abundant congeners found in the serum and semen samples; hence, it can be identified as an indicator PBDE congener. Further research is needed to explore the mechanism of Hal-POPs distribution in human semen and serum samples.

Enhanced adsorption of tetrabromobisphenol a (TBBPA) on cosmetic-derived plastic microbeads and combined effects on zebrafish.

Microplastics (MPs) pollution and its potential environmental risks have drawn increasing concerns in recent years. Among which, microbeads in personal care and cosmetic products has becoming an emerging issue for their abundance as well as the knowledge gaps in their precise environmental behaviors in freshwater. The present study investigated the sorption process of tetrabromobisphenol A (TBBPA), the most widely applied and frequently encountered flame retardant in aquatic environments, on two sources of polyethylene (PE) particles (pristine PE particles and microbeads isolated from personal care and cosmetic products). Significantly enhanced adsorption capacity of microbeads was observed with up to 5-folds higher than the pristine PE particles. The sorption efficiency was also governed by solution pH, especially for the cosmetic-derived microbeads, indicating the strong adsorption of TBBPA on PE was dominated by both hydrophobic and electrostatic interactions. Additionally, combined effects on redox status of zebrafish were evaluated with two environmental relevant concentrations of PE particles (0.5 and 5 mg L-1) using integrated biomarker response (IBR) index through a 14-d exposure. Co-exposure induced significant antioxidative stress than either PE or TBBPA alone when exposed to 0.5 mg L-1 of MPs. After 7-d depuration, the IBR value for combination treatments [TBBPA + PE (L)] was 3-fold compared with that in MP-free groups, indicating the coexistence might exert a prolonged adverse effects on aquatic organisms. These results highlight the probability of risk from microbead pollution in freshwater, where toxic compounds can be adsorbed on microbeads in a considerable amount resulting in potential adverse effects towards aquatic organisms.

Health implication of heavy metals exposure via multiple pathways for residents living near a former e-waste recycling area in China: A comparative study.

Herein, crop (vegetables and rice, n = 30), soil (n = 14), dust (n = 12), and PM10 (n = 25) samples were collected to assess the environmental quality of a former e-waste recycling area and evaluate the related health risks. In dust and PM10, the concentrations of heavy metals (Cd, Cu, Ni, Pb, and Zn) were lower than previously reported values, although the numbers for soil, vegetables, and rice remained high. The average accumulation factors of heavy metals in crops decreased in the order of Zn > Cd > Ni > Cu > Pb, and soil was identified as the largest contributor to crop pollution. Heavy metal ingestion largely occurred via rice consumption, which accounted for a significant fraction of the total average daily dose (ADD; 75.2-86.7% in children and 78.0-91.7% in adults), especially for Cd, Cu, Ni, and Zn. However, in the case of Pb, soil ingestion accounted for 48.9% of the ADD in adults, while in children, vegetable, rice, and dust ingestion accounted for 44.7%, 28.6%, and 23.7% of the ADD, respectively. The combined exposure hazard indices at the fifth, median, and 95th percentiles for all heavy metals were determined as 2.54, 9.40, and 40.1 for adults and as 3.75, 13.7, and 58.4 for children, respectively. In terms of health risk, crop consumption was identified as the major exposure pathway for both children and adults, featuring a contribution of 99.9%. In addition, the 95th percentile carcinogenic risks for Pb exceeded the acceptable level. Thus, this work shows that to reduce the health risk for local residents in the former e-waste area, more attention should be paid to soil repair.

Polycyclic aromatic hydrocarbons (PAHs) in multi-phases from the drinking water source area of the Pearl River Delta (PRD) in South China: Distribution, source apportionment, and risk assessment.

Sixteen priority polycyclic aromatic hydrocarbons (PAHs) were investigated in the water dissolved phase (DP), suspended particulate matter (SPM), and sediment collected from the water source zone of the Pearl River Delta region. The sum of 16 PAH concentrations ranged from 92.8 to 324 ng/L in the water DP, from 28.8 to 205 ng/L in the SPM, and from 55.7 to 381 ng/g (d.w.) in the sediment. Compared with other areas globally, the PAH levels were considerably moderate in the DP and SPM and relatively low in the sediment. Spatial distribution of PAHs was site-specific, and relatively higher PAH levels were found in the areas with dense population and heavy traffic. The PAH profile was dominated by two- and three-ring PAHs, and PAH pollution was identified of pyrolytic origins. Based on risk quotient, the ecological risk in water was ranked as moderate, but the adverse health risk associated with water ingestion was minimal. Naphthalene and fluorene of the sediment samples showed potential biological impairment in some locations; nevertheless, the mean effects range median quotient suggested that the ecological risk of multiple PAHs was quite low (less than 10% incidence of adverse effects).

Effects of ambient air pollution from municipal solid waste landfill on children's non-specific immunity and respiratory health.

This cross-sectional study investigated the association between air pollutant (AP) and respiratory health of 951 children residing near a municipal solid waste (MSW) landfill in Northern China. Results showed that students in non-exposure areas had significantly higher levels of lysozyme, secretory immunoglobulin A (SIgA), and better lung capacity than students in exposure areas (p < .05). Multiple regression model analysis indicated that lysozyme levels exhibited a consistent negative association with methane (CH4: ß = -76.3, 95% CI -105 to -47.7) and sulfuretted hydrogen (H2S: ß = -11.7, 95% CI -20.2 to -3.19). In addition, SIgA levels were negatively associated with H2S (ß = -68.9, 95% CI -97.9 to -39.9) and ammonia (NH3: ß = -30.3, 95% CI -51.7 to -8.96). Among all AP, H2S and sulfur dioxide (SO2) were the most robustly related with reduced lung function. H2S exposure was negatively associated with six lung function indices, 1-s forced expiratory volume (FEV1%), mean forced expiratory flow between 25% and 75% (MMF), maximum voluntary ventilation (MVV), and forced expiratory flow at 25%, 50%, and 75% of the pulmonary volume (FEF25, FEF50, FEF75); and SO2 was negatively associated with FEV1%, MVV, FEF25, FEF50 and FEF75. Our results suggested that AP exposure was negatively associated with more lung function parameters in boys than in girls. In conclusion, our findings suggested that children living adjacent to landfill sites were more likely to have deficient non-specific immunity and impaired lung function.

Associations between PBDEs exposure from house dust and human semen quality at an e-waste areas in South China-A pilot study.

Previous studies have confirmed that house dust is one of the main sources of polybrominated diphenyl ethers (PBDEs) exposure, and also indicated that PBDEs might affect human semen quality. The aim of this study was to explore the association between PBDEs concentration in house dust and the semen quality of male resident. Results showed that the semen qualities of the residents living around the e-waste dismantling workshops for a long time (3-17years) at the e-waste areas in South China significantly decreased, and the DNA damage of sperms were aggravated. The adjusted correlation analysed by multiple linear regression model showed that the sperm concentration and count both had negative correlation with BDE47 level in semen (ß = -0.295, 95%CI: -0.553∼-0.036; ß = -0.400, 95%CI: -0.708∼-0.092, respectively). In addition, the sperm progressive motility [(A+B)%] and sperm viability both had negative correlation with BDE100 level in dust (ß = -0.360, 95%CI: -0.680∼-0.040; ß = -0.114, 95% CI: -0.203∼-0.025, respectively). And there were significant linear positive correlation between PBDE congener (e.g. BDE28, 47, 153) concentrations in dust and in paired semen samples (rs = 0.367-0.547, p < 0.05). This study suggested that exposure to PBDEs from house dust might have adverse effects on human semen quality. But the results need to be confirmed in further studies with a large-scale sampling, and find out more direct and convincing evidence.

In vivo assessment of dermal adhesion, penetration, and bioavailability of tetrabromobisphenol A.

Individuals are exposed to brominated flame retardants (BFRs), including tetrabromobisphenol A (TBBPA), on a daily basis because of their widespread usage. These compounds may have adverse effects on human health. In the present study, dermal absorption experiments were conducted in vivo to predict the adhesion, penetration, and bioavailability of TBBPA. TBBPA was administered to Wistar rats for 6 h by repeated dermal exposure at doses of 20, 60, 200, and 600 mg of TBBPA per kg of body weight (bw). The skin adhesion coefficient (AC) was calculated using a difference-value method and ranged from 0.12 to 3.25 mg/cm2 and 0.1 to 2.56 mg/cm2 for the male and female rats, respectively. The adhesion rate was 70.92%. According to Fick's first law of diffusion, the diffusion constant (D) was 1.4 × 10-4 cm2/h and the permeation coefficient (Kp) was 1.26 × 10-5 cm/h for TBBPA. TBBPA levels in the blood, urine, and feces of the male rats were significantly higher than those in the female rats. The dermal bioavailability of TBBPA was 24.71% for male rats and 20.05% for female rats 24 h after exposure.