Incorporating bioaccessibility into health risk assessment of heavy metals in particulate matter originated from different sources of atmospheric pollution

Exposure to multiple metals and prevalence for preeclampsia in Taiyuan, China

BACKGROUND

Several studies with small sample size have reported inconsistent associations between single metal and preeclampsia (PE). Very few studies have investigated metal mixtures and PE.

METHODS

Blood concentrations of chromium (Cr), cadmium, mercury (Hg), arsenic (As), lead (Pb), nickel, cobalt, and antimony were measured using inductively coupled plasma-mass spectrometry among 427 PE women and 427 matched controls from Taiyuan, China. Multivariate logistic regression models, weighted quantile sum (WQS) regression, and principal component analysis were employed to examine exposure to single metals and metal mixtures in relation to PE.

RESULTS

An increased prevalence of PE was associated with Cr (OR = 1.76, 95% CI: 1.18, 2.62 and 1.90, 1.22, 2.93 for the middle and high vs. low), Hg (OR = 1.60, 95% CI: 1.08, 2.38 for the high vs. low) and As (OR = 1.64, 95% CI: 1.07, 2.52 for the middle vs. low). The WQS index, predominated by Cr, Hg, Pb, and As, was positively associated with PE. A principal component characterized by Cr and As also exhibited excessive association with PE. The highest PE prevalence was found among women who were overweight/obese before pregnancy and had high Cr levels compared to women who had pre-pregnancy normal body mass index (BMI) and low Cr levels.

CONCLUSIONS

Our study provided evidence that exposure to multiple metals was associated with increased prevalence of PE, and the observed association with multiple metals was dominated by Cr, As. Our study also suggested that pre-pregnancy BMI might modify the association between Cr and PE.

Atmospheric deposition of arsenic, cadmium, copper, lead, and zinc near an operating and an abandoned lead smelter

Atmospheric deposition samples were collected over 15 mo at several locations near an operating smelter and an abandoned Pb smelter to investigate the contribution of Pb smelting to depositional fluxes and potential local air quality degradation. Samples were analyzed for As, Cd, Cu, Pb, and Zn and subjected to scanning electron microscopy (SEM)-energy dispersive spectroscopy (EDS). Concentrations of Cd and Pb at both sites were greater than at the control site (p < .05), and significant correlations existed between Cd and Pb concentrations at both sites (p < .05). Monthly depositional flux variations at both sites were similar, with greater deposition during cold and dry periods. Heavy metal(loid)s deposition during these periods was correlated with wind speed. Greater Cd depositional flux differences were found between the smelter and control sites compared with other elements. The SEM images suggested that some particles at the operating smelter site were from Pb smelting material. However, most particles at both sites had no characteristics of smelting, suggesting reactions occurred between the smelter-emitted particles and soil components. The EDS results indicated that atmospheric deposition from both sites had lower Pb concentrations than smelting material or ash. The main atmospheric deposition source at the operating and abandoned sites was likely from the resuspension of heavy metal(loid)-enriched soil particles. Greater risk of air pollution from historical Pb smelting facilities exists years after closing down. Reducing soil wind erosional losses may help reduce heavy metal(loid)s dispersion across environments.

Mapping of atmospheric heavy metal deposition in Guangzhou city, southern China using archived bryophytes

Atmospheric heavy metal contamination is becoming a serious threat to environmental and human health in Chinese megacities. This study evaluated the concentrations of arsenic (As), cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) and Pb isotopic compositions in herbarium and native bryophytes collected from Guangzhou from 1932 to 2018. Relatively low mean metal concentrations were measured for bryophytes collected in the 1930s. The highest mean concentrations of Cd (0.72 ± 0.32 mg/kg), Cu (28.1 ± 9.8 mg/kg), Pb (125.9 ± 62.4 mg/kg) and Zn (273 ± 130 mg/kg) were found in the bryophytes from 1979 to 2000, following the commencement of the Reform and Opening-Up Program in 1978. The mean Pb concentrations (74.7 ± 6.3 mg/kg) decreased sharply from 2001 onwards, following the cessation of leaded petrol across the Chinese mainland in 2000. However, these values are still higher than those in 1950-1978, corresponding to a significant increase in atmospheric Pb emissions from coal combustion, nonferrous metal smelting and motor vehicle petrol consumption in China in the 2000s. The lead isotopic ratios of bryophyte archives (²⁰⁶Pb/²⁰⁷Pb 1.141-1.229, ²⁰⁸Pb/²⁰⁷Pb 2.376-2.482) indicate that lithogenic input and anthropogenic input arising from leaded petrol and industrial emissions have been the main sources of atmospheric heavy metal deposition in the city of Guangzhou over the past 85 years. Herbarium bryophyte can be utilised to reconstruct temporal and spatial shifts in atmospheric heavy metal deposition to better understand and manage the current air quality in Chinese megacities.

Biomagnetic monitoring of atmospheric heavy metal pollution using pine needles: the case study of Isfahan, Iran

Atmospheric deposition particles are fine-sized having a high adsorption capacity. Therefore, they can easily transfer the contamination to other areas. Plants can absorb certain pollutants using their leaves and then accumulate them in their biomass. In this study, the spatial and temporal variability of air pollution was assessed using pine needles as the bioindicators of atmospheric pollution. The magnetic susceptibility (MS) at low and high frequencies (χlf, χhf) and the concentration of selected heavy metals of pine needles (Pinus mugo) were estimated in order to address the possible relationships between needles' MS and the heavy metal concentration in the city of Isfahan, central Iran. In addition, the relationship between the heavy metal concentration of pine needles and that of the atmospheric dust was examined using the published data. Tree pine needles were monthly sampled, from April to December 2015 (T1-T9), during 9 months, from 30 different sites in the Isfahan city. There were two treatments including washed + unwashed (WU) and washed + washed (WW). The heavy metal total concentrations including Zn, Fe, Cu, Co, Pb, and Ni were measured. The mean concentrations of Fe, Zn, Pb, Cu, Ni, and Co were 80.4, 3.9, 1.8, 1.4, 0.6, and 0.3 mg kg-1, respectively. The results revealed that the concentration of heavy metals and MS in the pine needles followed the order Fe > Zn > Pb > Cu > Ni > Co. Also, the heavy metal concentration in the pine needles with different treatments had the following trend: WU > WW. It was shown that there was a significant correlation (p < 0.01) between the heavy metal concentrations and the leaf MS values of the pine needles and the concentration of heavy metals in atmospheric dust. Besides, similar trends were detected for the spatial variability of heavy metals and the pine needles' MS. In general, it could be concluded that the biomagnetic approach could serve as a comparatively fast and low-cost method to detect highly polluted urban areas with selected heavy metals, particularly the areas which are under the influence of anthropogenic and other traffic-related sources.

Occurrence, sources and health risks of toxic metal(loid)s in road dust from a mega city (Nanjing) in China

Potential toxic metal(loid)s (PTMs) in road dust are a major concern in relation to urban environmental quality. Identifying pollution hotspots and sources of PTMs is an essential prerequisite for pollution control and management. Herein, the concentrations, pollution and potential health risks of 8 PTMs (As, Cd, Co, Cu, Hg, Mo, Pb and Zn) in road dust from the highly urbanized areas of Nanjing were studied. Spatial occurrences and sources of PTMs were explored using geostatistics, principal component analysis (PCA) and local Moran's index. The contamination factor (CF) results showed that Co was mainly natural in origin, while the other PTMs were polluted, with average CFs ranging from 1.4 to 11.0 as follows: Hg > Mo > Cd > Cu > Pb > Zn > As, indicating moderate to very high contamination. Except for Co and Hg, the other PTMs were heavily loaded on PC1, which explained 44.72% of the total variance. Combining the statistical results and distributions of potential sources, we deduced that industrial emissions dominated the spatial patterns of all polluted PTMs in road dust, which showed high levels in the northern parts of the study region and generally decreasing levels southwards. Moreover, Pb and Zn in the south-central area and Cd in the north-central area displayed hotspots, with maximum CFs of 5.5 (Pb), 4.2 (Zn) and 16.2 (Cd), which were related to additional automotive and railway braking emissions, respectively. The resuspension of legacy pesticides in soil is likely responsible for the As pollution hotspot in the southwestern part. Despite the high anthropogenic contributions (27% for As and 68-88% for the other metals) to the PTMs in road dust, their noncarcinogenic and carcinogenic health risks were rarely found for children and adults based on the values of the hazard index and carcinogenic risk index. However, attention still should be paid to the pollution hotspots in the northern region.

Chemical fractionation and bioaccessibility of potentially toxic elements in area of artisanal gold mining in the Amazon

Artisanal mining may have modified the mobility, bioavailability and bioaccessibility of potentially toxic elements (PTEs) in the Serra Pelada gold mine, eastern Amazon, Brazil, which has not yet been studied. The objectives were to perform chemical fractionation of barium (Ba), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn), and to determine the bioaccessibility of these elements in soils and mining wastes collected in agriculture, forest, mining, and urban areas from the influence zone of the Serra Pelada gold mine. Pseudo total concentrations were obtained by acid digestion, chemical fractionation was performed using the Bureau Community of Reference (BCR) sequential extraction, oral bioaccessibility was obtained by the Simple Bioaccessibility Extraction Test (SBET) and lung bioaccessibility was obtained through Gamble's solution. The pseudo total concentrations indicated contamination by Ba, Cu and Ni. The sequential extraction revealed the predominance of all elements in the residual fraction. However, Ba is in high concentrations in the greater mobility forms, ranging from 166.36 to 1379.58 mg kg^-1. Regardless of the area, Cr and Cu are more oral bioaccessible in the intestinal phase, and Zn in the gastric phase. Ba, Cr and Zn are not lung bioaccessible, while Cu, Ni and Pb are bioaccessible via inhalation. The PTEs studied deserve attention not only due to the high pseudo total concentrations found (which indicate potential risk), but also the concentrations in high mobility forms and bioaccessible fractions, especially in the areas of greatest anthropogenic occupation.

Multi-elemental analysis of particulate matter PM2.5 and PM10 by ICP OES

The complexity of aerodynamic particulate matter's (PM) matrices poses a challenge for the extraction and quantification of metals, especially for analytes with low concentration. Aiming to solve this issue, a precise and accurate protocol with the ultrasound extraction combined with microwave radiation digestion (USMW), was applied to PM samples with excellent compensations in sample throughput, digestion efficiency, and energy consumption. After the digestion and extraction procedures, the inorganic analytes, including rare earth elements, were determined by ICP OES. Two types of particulate matter sampled from two stations, Gobernacion (GOB10 and GOB2.5) and Milan (MIL10), corresponding to PM_2.5 and PM₁₀, were digested with a combination between HF, HNO₃, and H₃BO₃. The absolute limits of detection ranged from 0.42 pg m^-³ for V, to 3459 pg m^-³ for As. The accuracy of the experimental study was assessed using two certified reference materials (CRMs), Coal Fly Ash (NIST1633b) and Fly Ash (BCR176). The method presented good accuracy, with recoveries ranging from 90 to 115%, except for Al (120%) and Fe (123%). Considering the replicates for the determination of analyte elements, the repeatability was below 10% for the relative standard deviation (RSD). A cloud point extraction (CPE) procedure, with parameters optimized for the determination of Pd and Pt, was successfully applied in digested PM samples with detection limits of 1.43 and 2.05 pg m^-³ for Pd and Pt in MIL10 sample, respectively, and 76.6 pg m^-³ for Pd and 110 pg m^-³ for Pt, in samples GOB10 and GOB2.5, respectively.

Determination and characterization of metal nanoparticles in clams and oysters

With the extensive application of nanotechnology, metal nanoparticles (MNPs) have been widely used, thus are universally detected in the environment. This has caused increasingly concerns due to their toxicity and the potential health risks they pose to humans. In this work, the concentrations and particle size distributions of MNPs and concentrations of associated metal ionic species in shellfish seafood (clams and oysters) were investigated using single particle inductively coupled plasma mass spectrometry (sp-ICP-MS) and inductively coupled plasma mass spectrometry (ICP-MS). The MNPs in the clam and oyster tissues were extracted via an alkaline digestion method with a recovery rate of 95.9% (for gold nanoparticles (AuNPs)). Then total concentrations of 41 metal elements were measured in the two types of seafood, of which 20 were selected for sp-ICP-MS analysis. The results showed that 5 types of MNPs were detectable in clams (Y, La, Ce, Pr, Gd) and 5 types of MNPs were detectable in oysters (Y, La, Ce, Pr, Nd). Size distributions of MNPs in clams and oysters were in the range of 35-55 nm and 30-65 nm, respectively. Nanoparticle concentrations in clams and oysters ranged from 0.6 to 37.7 ng/g and 4.2-19.7 ng/g, and accounted for 3.4%-50% and 5.5%-46% of the total metal content, respectively. Based on this analysis, the health risks of metals in the two kinds of seafood were evaluated by comparing the Provisional Tolerable Weekly Intake (PTWI) with limits recommended by the World Health Organization (WHO)/Food and Agriculture Organization (FAO). These results provide important information about the presence of metal nanoparticles in seafood and, to the best of our knowledge, this is the first time that the nanoparticles of rare earth elements have been detected and reported in bivalve mollusc tissues.

Bioaccessibility of metals/metalloids in willow catkins collected in urban parks of Beijing and their health risks to human beings

Air pollution and its resulting health risks in Beijing City have been widely investigated by scientists and administrators. However, the health risks caused by willow and poplar catkins in April and May (known as "spring snow") have been rarely reported. Poplar and willow are the two common trees in Beijing City that generate many whirling catkins in the air. The chemical composition of catkins remains unknown. In this study, catkins and dust samples were collected in several parks in Beijing. The total concentrations of metals/metalloids in catkins measured through inductively coupled plasma mass spectrometry were generally lower than those of the corresponding dust samples, and they were lower than the risk control standard for soil contamination of development land. The simulated rain and lung fluid extraction rates of catkin samples were significantly higher than those of the dust samples. The concentration of extracted Pb and Zn using simulated rainwater exceeded the environmental quality standards for surface water (0.1 and 2.0 mg/L for Pb and Zn, respectively), indicating the possibility of runoff pollution. Scanning electron microscopy images showed that fine particles (<10 μm) are attached to the surface of catkins. Therefore, the metals/metalloids in fine particles adsorbed by the catkin samples possess higher bioaccessibility than that in the dust samples based on different sizes of particles. A significant correlation is found between Pb in catkin and Pb in dust. Therefore, attention should be paid to the possible increase in metal/metalloid concentrations in catkins planted in contaminated areas.

Protective Effect of Diphlorethohydroxycarmalol Isolated from Ishige okamurae Against Particulate Matter-Induced Skin Damage by Regulation of NF-κB, AP-1, and MAPKs Signaling Pathways In Vitro in Human Dermal Fibroblasts

Particulate matters (PM), the main contributor to air pollution, have become a serious issue that threatens human's health. Skin is the largest organ in humans, as well as the primary organ exposed to PM. Overexposure of PM induces skin damage. Diphlorethohydroxycarmalol (DPHC), an algal polyphenol with the potential of skin protection, has been isolated from the edible brown seaweed Ishige okamurae. The purpose of the present study is to investigate the protective effect of DPHC against PM (ERM-CZ100)-induced skin damage in human dermal fibroblasts (HDF) cells. The results indicated that DPHC significantly and dose-dependently reduced intracellular reactive oxygen species generation in HDF cells. In addition, DPHC significantly induced collagen synthesis and inhibited collagenase activity in ERM-CZ100-stimulated HDF cells. Further study demonstrated that DPHC remarkably reduced the expression of human matrix metalloproteinases through regulation of nuclear factor kappa B, activator protein 1, and mitogen-activated protein kinases signaling pathways in ERM-CZ100-stimulated HDF cells. This study suggested that DPHC is a potential candidate to protect skins against PM-induced damage, and it could be used as an ingredient in pharmaceutical and cosmeceutical industries.