Sources, bioaccessibility and health risk of heavy metal(loid)s in the particulate matter of urban areas.

Exposure to heavy metal(loid)s in airborne particulate matter (PM) could lead to various adverse health effects. The study investigated the total contents and the bioaccessibility of PM-bound heavy metal(loid)s (Cr, Mn, Co, Ni, Cu, Zn, As, Cd, and Pb), identified their potential sources, and evaluated the associated health risk via inhalation in eight typical cities in China (Nanjing, Mianyang, Huangshi, Nanchang, Kunming, Xiamen, Guangzhou, and Wuzhishan). The results showed that PM-bound Cr (VI) and As of all eight cities exceeded the limits of World Health Organization. The bioaccessibility of PM-bound heavy metal(loid)s exhibited large variations, with their means following the order of Cd > Mn > Co > Ni > Cu > Cr > As > Zn > Pb. Traffic and industrial emissions were identified as primary sources in most urban areas. The emission sources have important effects on the bioaccessibility of PM-bound heavy metal(loid)s. In particular, atmospheric Cu has its bioaccessibility significantly correlated with the contributions from traffic emissions. The bioaccessibility-based health risk assessment obtained different results from those using total contents, showing that the non-carcinogenic risks posed by most metal(loid)s were acceptable except for As in Huangshi and Nanchang. These findings highlight the source dependence of bioaccessibility of heavy metal(loid)s in airborne PM, facilitate the identification of priority pollution sources and enhance effective risk-oriented source regulatory strategies in urban areas.

Naringenin relieves paclitaxel-induced pain by suppressing calcitonin gene-related peptide signalling and enhances the anti-tumour action of paclitaxel.

BACKGROUND AND PURPOSE: Chemotherapy-induced peripheral neuropathy (CIPN) commonly causes neuropathic pain, but its pathogenesis remains unclear, and effective therapies are lacking. Naringenin, a natural dihydroflavonoid compound, has anti-inflammatory, anti-nociceptive and anti-tumour activities. However, the effects of naringenin on chemotherapy-induced pain and chemotherapy effectiveness remain unexplored. EXPERIMENTAL APPROACH: Female and male mouse models of chemotherapy-induced pain were established using paclitaxel. Effects of naringenin were assessed on pain induced by paclitaxel or calcitonin gene-related peptide (CGRP) and on CGRP expression in dorsal root ganglia (DRG) and spinal cord tissue. Additionally, we examined peripheral macrophage infiltration, glial activation, c-fos expression, DRG neuron excitability, microglial M1/M2 polarization, and phosphorylation of spinal NF-κB. Furthermore, we investigated the synergic effect and related mechanisms of naringenin and paclitaxel on cell survival of cancer cells in vitro. KEY RESULTS: Systemic administration of naringenin attenuated paclitaxel-induced pain in both sexes. Naringenin reduced paclitaxel-enhanced CGRP expression in DRGs and the spinal cord, and alleviated CGRP-induced pain in naïve mice of both sexes. Naringenin mitigated macrophage infiltration and reversed paclitaxel-elevated c-fos expression and DRG neuron excitability. Naringenin decreased spinal glial activation and NF-κB phosphorylation in both sexes but influenced microglial M1/M2 polarization only in females. Co-administration of naringenin with paclitaxel enhanced paclitaxel's anti-tumour effect, impeded by an apoptosis inhibitor. CONCLUSION AND IMPLICATIONS: Naringenin's anti-nociceptive mechanism involves CGRP signalling and neuroimmunoregulation. Furthermore, naringenin facilitates paclitaxel's anti-tumour action, possibly involving apoptosis. This study demonstrates naringenin's potential as a supplementary treatment in cancer therapy by mitigating side effects and potentiating efficacy of chemotherapy.

Characterization of atmospheric mercury from mercury-added product manufacturing using passive air samplers.

Although alternatives to mercury (Hg) are available in most products and industrial activities, Hg continues to be an ingredient in some products, including fluorescent lamps and electrical and electronic equipment (EEE). In this work, low-cost passive air samplers (PASs) were used to investigate the atmospheric Hg pollution in Zhongshan, a large industrial city and major hub of mercury-added product manufacturing in South China. The GEM concentrations in the atmosphere were measured for two weeks during the summer of 2019 at a total of 144 sites across Zhongshan. Comparison with the results of active sampling confirmed that the PASs yielded accurate and reliable gaseous elemental mercury (GEM) concentrations and were thus well-suited for multi-site field monitoring. The mean GEM concentrations in the areas with mercury-added product manufacturing activities (5.1 ± 0.4 ng m-3) were significantly higher than those in other parts of Zhongshan (1.5 ± 0.4 ng m-3), indicating that local releases, rather than regional transport, were responsible for the atmospheric Hg pollution. Elevated GEM concentrations (up to 11.4 ng m-3) were found in the vicinity of fluorescent lamp and EEE factories and workshops, indicating significant Hg vapor emissions, presumably from the outdated production technologies and non-standard operation by under-trained workers. The Hg emissions from mercury-added product manufacturing were estimated to be 0.06 and 7.8 t yr-1 for Zhongshan and China, respectively, based on the scales of fluorescent lamp and EEE production. The non-carcinogenic health risk of Zhongshan residents from inhalation and ingestion was judged acceptable, whereby the inhalation exposure in Hg-polluted areas exceeded that of dietary ingestion. These findings demonstrate that mercury-added product manufacturing still contributes notably to anthropogenic gaseous Hg releases in the industrial areas with intense mercury-added product manufacturing activities.

Layer-by-layer assembly induced strong, hydrophobic and anti-bacterial TEMPO oxidized cellulose nanofibrils films for highly efficient UV-shielding and oil-water separation.

Anti-ultraviolet material with cost-effectiveness, environmental friendliness, and multifunction is urgently needed to address the serious problem of ultraviolet radiation. However, traditional anti-ultraviolet products based on plastics are unsustainable and harmful to the environment. Herein, the cellulose films with a sandwich structure using a surface assembly technique were reported. Natural L-phenylalanine was grafted onto cellulose nanofibrils via amidation to enhance their UV-shielding property. To address the hydrophilic nature and limited mechanical strength of cellulose films, we employed octadecyltrichlorosilane and 4ARM-PEG-NH2 for hydrophobic coating and mechanical reinforcement, respectively. In addition to providing complete UV resistance in the wavelength range of 200-320 nm, sample OPT5 exhibited significantly improved tensile stress, Young's modulus, and toughness, measuring 174.09 MPa, 71.11 MPa, and 295.33 MJ/m3, respectively. Furthermore, due to the presence of antibacterial amine groups, the modified film demonstrated a satisfactory inhibitory effect on the growth of Escherichia coli and Bacillus subtilis. Compared to natural cellulose films, the hydrophobically modified material achieved a contact angle of up to 121.1°, which enabled efficient separation of oil-water mixtures with a maximum separation efficiency of 93.87 %. In summary, the proposed TOCNF-based UV-shielding film with multifunctionality holds great potential for replacing petrochemical-derived plastics and serving as an applicable and sustainable membrane material.

Bioaccessibility and public health risk of heavy Metal(loid)s in the airborne particulate matter of four cities in northern China.

Atmospheric coarse particulate matter (PM10) enriched with heavy metal(loid)s could pose potentially significant health risk to humans, while accurate health risk assessment calls for characterization of their bioaccessibility, besides the total contents. The health risk of major toxic heavy metal(loid)s in the PM10 from four large cities in northern China via inhalation was investigated based on their total contents and bioaccessibility. The annual mean concentrations of PM-bound Zn, As, Pb, and Mn in the atmosphere of the four cities were 650, 305, 227, and 177 ng⋅m-3, respectively. The levels of heavy metal(loid)s in the PM10 were generally higher in winter but lower in summer in all four cities, which resulted primarily from the emissions associated with coal combustion for district and household heating and the unfavorable meteorological conditions in winter. The bioaccessibility of heavy metal(loid)s in the PM10 ranged from 0.9 to 48.7%, following the general order of Mn > Co > Ni > Cd > Cu > As > Cr > Zn > Pb. Based on their total contents in the PM10, most heavy metal(loid)s posed significant public health risk via inhalation exposure in the four cities. However, after accounting for the bioaccessibility of metal(loid)s, the non-carcinogenic risk of most metal(loid)s was negligible, except for As in the PM10 of Jinzhong, while only the carcinogenic risk posed by Cr and As in the PM10 exceeded the acceptable level. These findings demonstrate the importance of characterizing the bioaccessibility of airborne PM-bound heavy metal(loid)s in health risk assessment and could guide the on-going efforts on reducing the public health risk of PM10 in northern China.

Atmospheric mercury pollution caused by fluorescent lamp manufacturing and the associated human health risk in a large industrial and commercial city.

Although already eliminated in most industrial processes, mercury, as an essential ingredient in all energy-efficient lighting technologies, is still used in fluorescent lamp manufacturing. This study was conducted to investigate the atmospheric pollution caused by fluorescent lamp production and assess the associated public health risk in a large industrial and commercial city of south China, Zhongshan, which is a major production hub of lighting products. Concentrations of total gaseous mercury (TGM) in the atmosphere were measured over a total of 342 sites in the industrial, commercial, and residential areas. The average levels of TGM in the industrial, commercial, and residential areas prior to the landing of a typhoon were 12 ± 11, 3.6 ± 2.1, and 2.7 ± 1.3 ng⋅m-3, respectively. TGM concentrations in the industrial areas exhibited significant diurnal variation, with levels in the working hours being much higher than those in the non-working hours, which indicates that the high atmospheric mercury concentrations were contributed by local emissions, instead of regional transport. Most fluorescent lamp manufacturing activities in the city were shut down during a typhoon event, which resulted in a significant reduction in the average TGM level (down to 1.6 ± 1.8 ng⋅m-3) and rendered the difference in the average TGM levels in the industrial areas no longer significant between the working and non-working hours. Elevated TGM levels (up to 49 ng⋅m-3) were found near clusters of small-scale fluorescent lamp workshops in both industrial and commercial areas, which is indicative of significant emissions of mercury vapor resulting from obsolete equipment and production technologies. No significant non-carcinogenic risk was found for the general residents in the sampling area over the study period, while the risk for the workers in the fluorescent lamp manufacturing facilities and workshops could be higher. These findings indicate that fluorescent lamp manufacturing in the developing countries is a major source of atmospheric mercury.

Buckling Effect of Sole Zeolitic Imidazolate Framework-8 Nanoparticles Adsorbed at the Water/Oil Interface.

The buckling phenomenon of sole zeolitic imidazolate framework-8 (ZIF-8) particles adsorbed at the water/oil interface was systematically studied. The droplet of ZIF-8 water dispersion was pended in oil for a certain time period and manually extracted to decrease the volume. With the reduction of interfacial area, the ZIF-8 particles were jammed together to form a wrinkling solid film at the water/oil interface, which could withstand the extraction of the droplet and be regenerated. The size and concentration of the particles affected the assembly kinetics. The rapidest assembly was observed for the medium-sized ZIF-8 particles (m-ZIF-8) among the three sizes tested (1.81 µm, 258 nm, and 51 nm). The droplet of 0.91 wt % m-ZIF-8 reached a nearly full surface coverage in 13 min, faster than those with the lower concentration of 0.46 or 0.28 wt %. The pH of the solution, ranging between 6 and 10.7, affected both the assembly kinetics and film stability. Cryo-scanning electron microscopy images of frozen m-ZIF-8-stabilized Picking emulsions showed a monolayer of ZIF-8 wetted by both oil and water phases. The observed buckling effect could be attributed to the stable adsorption of ZIF-8 at the water/oil interface and the interparticle interactions, related to the unique surface chemistry and polyhedral shape of the ZIF-8 crystals. This work provided some understanding on the interfacial property of ZIF-8 and the mechanism of sole ZIF-8-stabilized Pickering emulsions.