The link between phthalate exposure and the risk of subclinical atherosclerosis in young population remains unclear. This study investigated the association between phthalate exposure and subclinical atherosclerosis, in terms of carotid intima-media thickness (CIMT), in young population. From a nationwide mass urine screening for renal health, conducted in 1992–2000 among school children 6–18 years of age in Taiwan, we recruited 789 subjects to participate in the cardiovascular health examination in 2006–2008. Among them, 787 received measurements of 7 urinary phthalate metabolites and CIMT. Results showed both mean and maximal values of CIMT at all segments of carotid arteries significantly increased with the urinary mono-2-ethylhexyl phthalate (MEHP), ∑ di-(2-ethylhexyl) phthalate (DEHP), and mono-n-butyl phthalate (MnBP) in a dose-response relationship after adjustment for multiple linear regression models. Multivariate logistic regression analysis showed that higher quartiles of urinary concentrations of MEHP, ∑DEHP, and MnBP were associated with a higher risk of thicker CIMT. Compared to subjects with the lowest quartile (Q1) of urinary MEHP, the adjusted odds ratios (95% confidence interval) for thicker CIMT among subjects with higher urinary MEHP were 2.13 (1.18–3.84) at Q2, 4.02 (2.26–7.15) at Q3 and 7.39 (4.16–13.12) at the highest Q4. In conclusion, urinary phthalate metabolites of MEHP, ∑DEHP, and MnBP are strongly associated with CIMT in adolescents and young adults in Taiwan.

Metal flux measurements inform the mobility, potential bioavailability and risk of toxicity for metals in contaminated sediments and therefore is an important approach for sediment quality assessment. The binding and release of metals that contribute to the net flux is strongly influenced by the presence and behaviors of benthic organisms. Here we studied the effects of bioturbation on the mobility and efflux of metals from multi-metal contaminated sediments that inhabited by oligochaete worms or both worms and bivalves. Presence of bivalves enhanced the release of Mn, Co, Ni and Zn but not for copper and chromium, which is likely due to the high affinities of copper and chromium for the solid phase. Metals in the overlying water were primarily associated with fractions smaller than 10 kDa, and the fractionation of all metals were not affected by the presence of the bivalve. Metal fluxes attributed to different processes were also distinguished, and the bioturbation induced effluxes were substantially higher than the diffusive effluxes. Temporal variabilities in the total net effluxes of Mn, Co, Ni and Zn were also observed and were attributed to the biological activities of the bivalves. Overall, the present study demonstrated that the response of different metals to the same bioturbation behavior was different, resulting in distinct mobility and fate of the metal contaminants.

A comprehensive spatio-vertical survey of short-chain (SCCPs, C10-13) and medium-chain (MCCPs, C14-17) chlorinated paraffins (CPs) was performed in surface and core soils from Chinese nation-wide agricultural lands in 2016, and a total of 48 congener groups were measured. The shorter carbon chain C10-11 in SCCP and C14-15 in MCCP homologue groups, and the lower chlorinated congeners (Cl5-7) for both CP groups were predominant. The ∑SCCP and ∑MCCP concentrations in surface soils ranged from 39 to 1609 ng/g and 127–1969 ng/g, dry weight (dw), respectively. The spatial distribution trend showed that SCCP congener groups with relatively low octanol-water partition coefficient (KOW) and octanol-air partition coefficient (KOA) are uniformly distributed across surface soils compared to MCCP congener groups. Significant relationships were observed between the spatial variation of SCCP concentrations and the driving factors responsible for dispersion and deposition. The distribution behavior of SCCPs and MCCPs in highland and plain surface soils showed an increasing trend of MCCP concentrations with elevation, indicating the “mountain cold-trapping effect”. Vertical distribution profile revealed similar homologue group composition patterns of SCCP and MCCP congener groups as those of surface soils. Furthermore, the penetration potential ratios (r) of chlorine and carbon atoms of CPs demonstrated that the lower chlorinated (Cl5-7) and the shorter carbon chain (C10-13) congener groups are more prone to vertical movement into deeper soil layers compared to the longer carbon chain (C14-17) and highly chlorinated (Cl8-10) congener groups.

Tributyl phosphate (TBP) is recognised as a global environmental contaminant because of its wide use in floatation reagents, nuclear fuel reprocessing and plasticisers. This contaminant is hardly degraded by hydrolysis in the environment due to its special physicochemical properties. In this study, one TBP-degrading strain was isolated from TBP-contaminated abandoned mine tailings, and 16S rRNA identification revealed that the strain belonged to the genus Sphingomonas. Results validated that the strain could utilise TBP as the sole carbon source, and vitamin was not the essential factor for its growth. Liquid chromatography time-of-flight mass spectrometry analysis identified di-n-butyl phosphate (DnBP) and mono-n-butyl phosphate (MnBP) as the intermediate metabolites for TBP biodegradation. No obvious change in carbon and hydrogen isotope composition was observed in biodegradation processes (cell suspension and crude extract degradation), which indicated that the first irreversible bond cleavage did not involve carbon or hydrogen. Hence, the TBP degradation scheme by Sphingomonas sp. proposed that the first irreversible step of TBP transferred to DnBP would lead to PO bond cleavage. This study combined the identification of products and isotope fractionation in substrates to investigate the transformation mechanism, thereby providing an eco-friendly and cost-effective way for the in situ bioremediation of TBP-contaminated sites by the isolated TBP degradation strain.

Dibenzofuran (DBF) derivatives have caused serious environmental problems, especially those produced by paper pulp bleaching and incineration processes. Prominent for its resilient mutagenicity and toxicity, DBF poses a major challenge to human health. In the present study, a new strain of Pseudomonas aeruginosa, FA-HZ1, with high DBF-degrading activity was isolated and identified. The determined optimum conditions for cell growth of strain FA-HZ1 were a temperature of 30 °C, pH 5.0, rotation rate of 200 rpm and 0.1 mM DBF as a carbon source. The biochemical and physiological features as well as usage of different carbon sources by FA-HZ1 were studied. The new strain was positive for arginine double hydrolase, gelatinase and citric acid, while it was negative for urease and lysine decarboxylase. It could utilize citric acid as its sole carbon source, but was negative for indole and H2S production. Intermediates of DBF 1,2-dihydroxy-1,2-dihydrodibenzofuran, 1,2-dihydroxydibenzofuran, 2-hydroxy-4-(3′-oxo-3′H-benzofuran-2′-yliden)but-2-enoic acid, 2,3-dihydroxybenzofuran, 2-oxo-2-(2′-hydrophenyl)lactic acid, and 2-hydroxy-2-(2′-hydroxyphenyl)acetic acid were detected and identified through liquid chromatography-mass analyses. FA-HZ1 metabolizes DBF by both the angular and lateral dioxygenation pathways. The genomic study identified 158 genes that were involved in the catabolism of aromatic compounds. To identify the key genes responsible for DBF degradation, a proteomic study was performed. A total of 1459 proteins were identified in strain FA-HZ1, of which 100 were up-regulated and 104 were down-regulated. A novel enzyme “HZ6359 dioxygenase”, was amplified and expressed in pET-28a in E. coli BL21(DE3). The recombinant plasmid was successfully constructed, and was used for further experiments to verify its function. In addition, the strain FA-HZ1 can also degrade halogenated analogues such as 2, 8-dibromo dibenzofuran and 4-(4-bromophenyl) dibenzofuran. Undoubtedly, the isolation and characterization of new strain and the designed pathways is significant, as it could lead to the development of cost-effective and alternative remediation strategies. The degradation pathway of DBF by P. aeruginosa FA-HZ1 is a promising tool of biotechnological and environmental significance.

Atmospheric particulate matter (PM) pollution and soil trace metal (TM) contamination are binary environmental issues harming ecosystems and human health, especially in the developing China with rapid urbanization and industrialization. Since PMs contain TMs, the air-soil nexus should be investigated synthetically. Although the PMs and airborne TMs are mainly emitted from urban or industrial areas, they can reach the rural and remote mountain areas owing to the ability of long-range transport. After dry or wet deposition, they will participate in the terrestrial biogeochemical cycles of TMs in various soil-plant systems, including urban soil-greening trees, agricultural soil-food crops, and mountain soil-natural forest systems. Besides the well-known root uptake, the pathway of leaf deposition and foliar absorption contribute significantly to the plant TM accumulation. Moreover, the aerosols can also exert climatic effects by absorption and scattering of solar radiation and by the cloud condensation nuclei activity, thereby indirectly impact plant growth and probably crop TM accumulation through photosynthesis, and then threat health. In particular, this systematic review summarizes the interactions of PMs-TMs in soil-plant systems including the deposition, transfer, accumulation, toxicity, and mechanisms among them. Finally, current knowledge gaps and prospective are proposed for future research agendas. These analyses would be conducive to improving urban air quality and managing the agricultural and ecological risks of airborne metals.

Metals are released from biochar (BC) in either the free or dissolved organic carbon (DOC)-combined form. The complexation of metals with DOC influences their toxicity and bioavailability in the environment. The endogenous release of metal species with heterogeneous DOC from BC is very complex; this process has been neglected and remains unaddressed in the literature to date. In this study, the yield and chemical properties of labile DOC from BC were characterized, and the release of endogenous metal/metalloid elements (K, Mg, Mn, Fe, Al, Cu, and Si) and their species from BC with various pyrolysis temperatures and particle sizes were systematically investigated under various solution chemistries. The results showed that pyrolysis temperature of BC significantly influenced the yield and composition of DOC and DOC-metal/metalloid complexes, while particle size had lower impact. The yield of BC-derived DOC significantly decreased and the components gradually changed from low-molecular weight and low-aromaticity hydrophilic humic acid-like substances to complex high-molecular weight and high-aromaticity hydrophobic substances as pyrolysis temperature increased from 200 to 700 °C. The release of total dissolved metals decreased with increasing pyrolysis temperature, while the highest total dissolved Si was released from BC with the moderate pyrolysis temperature (500 °C). The metal elements were mainly released in the DOC-combined form, while the released Si was mainly in the free form in the neutral water environment. The release of DOC increased while that of dissolved metals decreased with increasing solution pH. The release of total dissolved metals/metalloids increased but the ratio of the DOC-combined metals/metalloids decreased with increasing solution ionic strength. These results provide new insight into the understanding of endogenous metal/metalloid release from BC in the natural environment.

Nickel nanoparticles (NiNPs) have an estimated production of ca. 20 tons per year in the US. Nickel has been risk-assessed for long in Europe, but not NiNPs, hence the concern for the environment. In the present study, we focused on investigating the mechanisms of toxicity of NiNPs and the comparison to NiNO3. The high-throughput microarray for the soil ecotox model Enchytraeus crypticus (Oligochaeta) was used. To anchor gene to phenotype effect level, organisms were exposed to reproduction effect concentrations EC20 and EC50, for 3 and 7 days. Results showed commonly affected pathways between NiNPs and NiNO3, including increase in proteolysis, apoptosis and inflammatory response, and interference with the nervous system. Mechanisms unique to NiNO3 were also observed (e.g. glutathione synthesis). No specific mechanisms for NiNPs were found, which could indicate that longer exposure period (>7 days) is required to capture the peak response to NiNPs. A mechanisms scheme is assembled, showing both common and unique mechanisms to NiNO3 and NiNPs, providing an important framework for further, more targeted, studies.

This study characterized spatio-temporal variations in the concentration of benzene, toluene, ethylbenzene, and xylene (BTEX) compounds in the vicinity of gas and compressed natural gas (CNG) stations in Tehran, Iran. Health risk assessment (HRA) was computed using Monte Carlo simulations (MCS) for evaluating inhalation lifetime cancer risk (LTCR), the hazard quotient (HQ), and sensitivity analysis (SA) for BTEX exposure in different age groups (birth to <81) and as a function of distance (0–250 m) from the center of the stations. For all monitoring stations, the average values of benzene, toluene, ethylbenzene, and xylene in winter were 466.09 ± 132.25, 873.13 ± 233.51, 493.05 ± 141.22, and 910.57 ± 145.40 μg m⁻³, respectively. The mean wintertime ratios of T/B for the 12 stations ranged from 1.69 to 2.04. Furthermore, there was no significant relationship between the concentration of BTEX with either the specific month or distance from the center of stations (p > 0.05). Factors promoting BTEX formation in the study region were fuel evaporation and gas/CNG station emissions. The LTCRs for the target compounds in the winter for different age groups and distances from the center of stations was limited to 2.11 × 10⁻⁴ to 1.82 × 10⁻³ and 2.30 × 10⁻⁴ to 2.01 × 10⁻³, respectively, which exceeded proposed values by U.S. EPA. Moreover, the HQs for BTEX for three age groups and distances were limited to between 2.89 × 10⁻⁵ and 9.33 × 10⁻², which were lower than the acceptable limit (HQs < 1). The results of this work are applicable to similar areas that are heavily populated with vehicular traffic. This study motivates a closer look at mitigation strategies to limit the health effects of carcinogenic emissions such as benzene and ethylbenzene from gas/CNG stations.

Perfluorooctanoic acid (PFOA) toxicity is of considerable concern due to its wide application, environmental persistence, and bioaccumulation. In the current study, we used a scaffold-free three-dimensional (3D) spheroid model of mouse liver cells (AML12) to explore the toxicity of PFOA and emerging alternatives (HFPO-DA and PFO4DA). Comparing the short-term (24 and 72 h treatment) toxicity of PFOA between conventional 2D monolayer cells and 3D spheroids, we found that spheroids had higher EC₅₀ values and lower ROS levels after treatment, indicating their greater resistance to PFOA. Cell viability (i.e., adenosine triphosphate (ATP) content and lactate dehydrogenase (LDH) leakage) and liver-specific function (i.e., albumin secretion) were stable in spheroids through 28 day of culture. However, under 100 and 200 μM-PFOA treatment for 28 day, ROS levels, LDH leakage, and caspase3/7 activity all increased significantly. As a sensitive parameter, ROS showed a significant increase at 21 day, even in the 50 μM-PFOA group. Consistent with the elevation of ROS and caspase3/7, the expressions of oxidative stress- and apoptosis-related genes, including Gsta2, Nqo1, Ho-1, caspase3, p53, and p21, were induced in dose- and time-dependent manners after PFOA exposure. The peroxisome proliferator-activated receptor alpha (PPARα) pathway was also activated after treatment, with significant induction of its target genes, Fabp4 and Scd1. Similar to PFOA, both HFPO-DA and PFO4DA activated the PPARα pathway, induced ROS levels, and initiated cell damage, though at a relatively lower extent than that of PFOA. Our results imply that the 3D spheroid model is a valuable tool in chronic toxicological studies.