Cigarette smoking (CS) and betel quid (BQ) chewing are two known risk factors that have synergistic potential for the enhancing the development of oral squamous cell carcinoma (OSCC) in Taiwan. Most mutagens and carcinogens are metabolically activated by cytochrome P450 (CYP450) to exert their mutagenicity or carcinogenicity. Previous studies have shown that metabolic activation of the tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), by CYP2A6 activity determines NNK-induced carcinogenesis. In addition, safrole affects cytochrome P450 activity in rodents. However, the effect of BQ safrole on the metabolism of tobacco-specific NNK and its carcinogenicity remains elusive. This study demonstrates that safrole (1 mg/kg/d) induced CYP2A6 activity, reduced urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) levels, and increased NNK-induced DNA damage, including N7-methylguanine, 8-OH-deoxyguanosine and DNA strand breaks in a Syrian golden hamster model. Furthermore, altered NNK metabolism and increased NNK-induced DNA damage were also observed in healthy subjects with CS and BQ chewing histories compared to healthy subjects with CS histories. In conclusion, BQ containing safrole induced tobacco-specific NNK metabolic activation, resulting in higher NNK-induced genotoxicity. This study provides valuable insight into the synergistic mechanisms of CS- and BQ-induced OSCC.

Pyrethroids are a class of man-made insecticides associated with various adverse health outcomes including respiratory problems. However, there were limited evidences on the relation between 3-phenoxybenzoic acid (3-PBA) as a metabolite of pyrethroids and pulmonary function, particularly among elderly population who have declining pulmonary function. Therefore, we collected urine samples and performed pulmonary function test (PFT) repeatedly in a total of 559 Korean elderly living in Seoul as an urban area. After measurement of urinary 3-PBA levels, cross-sectional relations of visit-to-visit variation in 3-PBA level on visit-to-visit variation in PFT parameters were evaluated using linear mixed effect models and generalized additive mixed models after adjustment for age, sex, body mass index, smoking status, education, visit episode, and phthalate metabolite levels. The Korean elderly were highly exposed to pyrethroids with 30.2% of elderly people with 3-PBA level over reference value derived on the 95th percentile of representative samples (2 ng/mL). Forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and forced expiratory flow between 25% and 75% of FVC (FEF₂₅–₇₅) as PFT parameters showed significant reductions by an increase of 3-PBA level (FEV₁, β = −1.48, p-value < 0.01; FVC, β = −1.14, p-value < 0.01; and FEF₂₅₋₇₅, β = −1.11, p-value = 0.03). The negative associations of 3-PBA level with FEV₁, FVC, and FEF₂₅₋₇₅ were found only for females (FEV₁, β = −1.64, p-value < 0.01; FVC, β = −1.47, p-value < 0.01; and FEF₂₅₋₇₅, β = −1.06, p-value = 0.07), but not for males. However, the longitudinal effect of 3-PBA level on the trajectory of FEV₁, FVC, and FEF₂₅₋₇₅ declines in females was not found. Community-level exposure to pyrethroids was associated with pulmonary function reduction in elderly population, indicating that more stringent control of pyrethroids is necessary to protect the elderly who have declining pulmonary function.

Environmentally persistent free radicals (EPFRs) are a new class of environmental risk substances that can stably exist in atmospheric particles and pose a potential threat to human health. In this study, electron paramagnetic resonance (EPR) spectroscopy was used to study the concentration levels, species characteristics, and sources of EPFRs in PM₂.₅ in Xi'an in 2017. The results showed that the concentrations of EPFRs in PM₂.₅ in Xi'an in 2017 ranged from 9.8 × 10¹¹ to 6.9 × 10¹⁴ spins/m³. The highest concentration of EPFRs occurred in winter when the average concentration was 2.1 × 10¹⁴ spins/m³. The lowest concentration of EPFRs occurred in autumn when the average concentration was 7.0 × 10¹³ spins/m³. According to the annual average atmospheric concentration of EPFRs, the amount of EPFRs inhaled by people in Xi'an is equivalent to approximately 5 cigarettes per person per day and approximately 23 cigarettes per person per day in winter when haze occurs. The results of the study on the EPFR characteristics show that the EPFRs in PM₂.₅ in Xi'an are mainly C-center organic radicals that are primarily non-decaying types, accounting for approximately 75% and 85% of total concentration of EPFRs in autumn and winter, respectively. Finally, a correlation analysis was used to explore the origins of EPFRs in PM₂.₅. Significant positive correlations were found between EPFRs and SO₂, NO₂ and the thermally derived OC3 and OC4 carbonaceous components. The results suggested that coal-fired and traffic may be important sources of EPFRs in PM₂.₅ in Xi'an. In addition, EPFRs are significantly positively correlated with O₃ in summer, suggesting that some EPFRs may also originate from secondary processes. This study provides important basic data and evidence for further assessments of the potential health risks of EPFRs in PM₂.₅ and the development of effective air pollution control measures.

An influx of chloride ions from road de-icing solutions can result in toxicological effects to organisms in terrestrial and aquatic environments. As such, “eco-friendly” de-icing alternatives are sought to mitigate environmental impacts of de-icing impervious surfaces, while maintaining human safety. While many alternative de-icers are economically impractical for municipal use, the residential commercial market is flooded with de-icing formulations claiming to be “eco-friendly”. Given the little regulation and guidance that surrounds eco-labeling, the meaning of “eco-friendly” remains unclear in the context of biological systems. The objective of the current study was to determine the toxicity of three “eco-friendly” de-icing formulations to Chironomus dilutus using 10 d toxicity tests. The toxicity of these three formulations was compared to a traditional formulation composed entirely of chloride salts. Two of the “eco-friendly” de-icers demonstrated LC₅₀s of 6.61 and 6.32 g/L, which were similar in toxicity to the traditional sodium chloride formulation with a LC₅₀ 6.29 g/L. The comparable toxicities of these formulations is likely due to the presence of chloride salts in each of the “eco-friendly” de-icers. The third “eco-friendly” formulation, a urea-based de-icer, demonstrated toxicity an order of magnitude higher than that of the traditional formulation with an LC₅₀ of 0.63 g/L. While C. dilutus may not have been the intended endpoint in consideration when marketing these products as “eco-friendly”, consideration of how eco-labeling is utilized and the role of environmental scientists in determining the meaning of such claims must be considered to ensure continued and future protection of the environment.

Tungstate enrichment in aquatic systems may cause negative environmental and health effects. This study addresses tungstate removal from aqueous solution by nanocrystalline iowaite, an iron-bearing layered double hydroxide, which has not been used for treatment of tungstate-rich waters so far. Tungstate sorption experiments were conducted with various contact times, temperatures, initial tungstate concentrations (0.001–2 mM), and solution pH values (2–13), the results indicating that iowaite sorbed aqueous tungstate effectively and quickly, and the sorption maximum can be up to 71.9 mg/g. Moreover, the tungsten sorption capacity keeps nearly constant at a wide pH range from 3 to 11. Duo to its pH buffering effect, the alkaline conditions were generated by the addition of iowaite, which are favorable for the removal of aqueous tungstate because the polymerization of tungstate can be prohibited at alkaline pH values. Zeta potential, XRD and XPS analyses were employed to clarify the sorption mechanisms, and it was concluded that tungstate was sorbed via its exchange with the chloride originally intercalated into iowaite interlayers as well as its stronger inner-sphere complexation with the Fe atoms located in iowaite layers. Nanocrystalline iowaite is suitable for treating both tungstate-bearing natural waters with moderately high tungstate concentrations and industrial wastewaters extremely rich in tungstate.

The increased bioeconomy targets for the biomass share of renewable energy production across Europe should be met using land unsuitable for food production. Miscanthus breeding programs targeted the production of plants with a diverse range of traits allowing a wider utilization of land resources for biofuel production without competing with arable crops. These traits include increasing tolerances to drought, chilling, and to metal(loid)s excess. Two novel Miscanthus hybrids, GNT41 and GNT34, were compared against Miscanthus x giganteus (Mxg) on metal-contaminated arable land in Poland. This study aimed at evaluating their yield, biomass quality and quantifying seasonal differences in photosynthetic and transpiration parameters. A secondary objective was to identify key physiological mechanisms underlying differences in metal accumulation between the investigated plants. The new hybrids produced a similar yield to Mxg (13–15 t ha−1 yr−1), had shorter shoots, higher Leaf Area Index and stem number. Based on gas exchange measurements, GNT34 exhibited isohydric (water-conserving) behavior. The stomatal response to light of the new hybrids was at least twice as fast as that of Mxg, a trait that is often associated with increased seasonal water use efficiency. This contributed to the almost 40% reduction in shoot Pb and Cd concentrations for the new hybrids as compared to Mxg. This suggested that promoting stomatal regulation in conjunction with improved water conservation may be a target for improving plants for wider use on metals contaminated land.

We studied the size distribution of ions (Cl⁻, NO₃⁻, SO₄⁼, Na⁺, NH₄⁺, K⁺, Mg⁺⁺, Ca⁺⁺) and elements (As, Ba, Cd, Co, Cs, Cu, Fe, Li, Mn, Ni, Pb, Rb, Sb, Se, Sn, Sr, Ti, Tl, V, Zn) during the winter and summer seasons of seven consecutive years (2008–2014) in an area of the Po Valley (Northern Italy) characterised by industrial, agricultural and urban settings. The study included the collection and analysis of 41 series of size-segregated samples (MOUDI sampler, 10 stages, cut sizes from 0.18 to 18 μm). Ions were analysed by ion chromatography; elemental analysis was carried out by ICP-MS, by applying a chemical fractionation method able to increase the selectivity of PM source tracers.Our results indicate that important winter/summer variations occurred in both the concentration and size distribution of most PM components. These variations were explained in terms of variations in the strength of the prevailing sources of each component.The contribution of biomass burning for domestic heating was highlighted by the well-known tracer K⁺ but also by the soluble fraction of Rb, Cs and Li. Biomass burning contribution to atmospheric PM was mostly contained in the fine fraction, with a broad size-distribution from 0.18 to 1.8 μm. This source also appreciably increased the concentration of other elements in fine PM (As, Cd, Co, Mn, Pb, Sb, Sn).A few PM components (tracers of sea-spray, brake lining and some industries) did not show marked seasonal variations in concentration and size distribution. However, during winter, for brake lining and industry tracers we observed an upward shift in the dimension of fine particles and a downward shift in the dimension of coarse particles, due to the ageing of the air masses.

There is a need to develop highly efficient materials for capturing uranium from nuclear wastewater. Here, 5-methylbenzotriazole modified graphene oxide (MBTA-GO) was used to adsorb U(VI) from aqueous solution. By the trials of different conditions, we found that the removal of U(VI) from acidic solution was strongly dependent on pH but independent of ionic strength. The U(VI) adsorption was perfectly conformed to the pseudo-second-order kinetics and the adsorption isotherms were simulated by the Langmuir model well. A high removal capacity (qₘₐₓ = 264 mg/g) for U(VI) at pH 3.5 was obtained. XPS, EXAFS analyses and DFT calculations revealed that the mechanism of uranium capture was ascribed to (i) the surface complexation by benzotriazole and carboxyl groups (providing lone pair electrons) on MBTA-GO and (ii) enhanced synergistic coordination ability of delocalized π-bond of triazole group toward U due to the transfer of electrons from graphene sheet to benzotriazole. DFT calculations further demonstrated that benzotriazole displayed stronger binding with U(VI) compared to carboxyl group due to higher binding energy of [Side/Surface-U-MBTA-GO] (79.745, 54.986 kcal/mol) than [MBTA-GO–COOH–U] (27.131 kcal/mol). This work will provide valuable insight into designing novel nitrogen-containing adsorbents for practical application in wastewater treatment.

Organic pollutants are widely detected in surface water, groundwater and irrigation sewage in farmland soil, some of which can form complexes with heavy metal ions as ligands in the environment. Acesulfame (ACE), one of the most popular artificial sweeteners, has been found in wastewater sometimes at tens of microgram per liter. However, the combined effects of heavy metals and ACE are still unclear. In the present study, the effects of ACE on cadmium (Cd) absorption and translocation in rice seedlings (Oryza sativa L.) under different exposure conditions were investigated using hydroponic experiments. Under the combined exposure treatments of ACE and Cd, absorption of Cd and ACE in rice significantly decreased when compared with the single exposure treatments, while the alleviation of oxidative damage in rice was also found. Under the sequential exposure treatments of Cd and ACE, the post-exposed ACE activated the pre-absorbed Cd in plant, and accelerated the release of Cd to the environment as well as its translocation from the roots to shoots. In addition, compared with the single Cd exposure, the accumulated ACE can alleviate the oxidative damage in rice shoots induced by Cd, although the Cd concentrations in shoots changed little. In summary, the combined pollution of artificial sweetener ACE was beneficial to relieve the toxicological damage and ecological risk caused by Cd.

The toxic potentially toxic metals elements (PTEs) discharged from industrial activities and agricultural practices persistently pose multiple hazards to environment and living organisms. Microbe-assisted phytoremediation provide an effective approach to remediate PTEs-contaminated soils. A phytoextraction process involved the application of Streptomyces pactum (Act12, 1.0, 2.0 and 3.0 g kg⁻¹ dry soil, respectively) alone/jointly with sulfur was executed. The main texture of the tested soil was sandy loam and with a pH 8.27. The obtained results showed that the leaf pigments and plant biomass were improved after the application of the Act12, while the shoot fresh weight, chlorophyll a and chlorophyll b decreased by 57.8, 38.2 and 40.7%, respectively, after treatment with sulfur. Similarly, sulfur application facilitated the malondialdehyde (MDA) production by 18.4–33.6% compared to the control (no amendments). Both peroxidase (POD) and superoxide dismutase (SOD) activities were boosted, while the catalase (CAT) activity was suppressed with Act12 alone/jointly with sulfur treatment. The sulfur combined with elevated Act12 levels notably increased the cadmium (Cd) and zinc (Zn) concentrations both in shoots and roots, while the elemental extraction amount showed the removal efficiency following the order: Act12 alone ＞ control ＞ Act12 jointly with sulfur. Taken together, the results suggested that Streptomyces pactum and sulfur assisted the phytoremediation process, while further studies should be conducted in the field to test practical application.