Landfills are considered an anthropogenic source of arsenic (As). The As species mediated by microbes in landfills vary significantly in toxicity. Based on random matrix theory, 16S rRNA genes were used to construct four microbial networks associated with different stages over 12 years of landfill ages. The results indicated that network size and microbial structure varied with landfill age. According to the network scores, about 208 taxa were identified as putative keystones for the whole landfill; the majority of them were Firmicutes, which accounted for 66.8% of all specialists. Random Forest analysis was performed to predict the keystone taxa most responsible for As species distribution under different landfill conditions; 17, 10 and 14 keystone taxa were identified as drivers affecting As species distribution at early, middle, and later landfill stages, respectively.

The toxicity of nano-sized particles of mercury (NP–Hg), which are thought to be generated during the detoxification of methyl mercury (MeHg), may differ from that of MeHg, elemental Hg (Hg⁰), and inorganic Hg (I–Hg). From a human health perspective, it is important to evaluate the presence of NP-Hg in seafoods. We investigated the in vivo formation of NP-Hg in fish and shellfish, which are the main sources of Hg exposure in humans. NP-Hg was measured in 90 fish samples with single-particle inductively coupled plasma mass spectrometry (spICP-MS) after enzyme degradation with pancreatin and lipase. In addition to NP-Hg, total Hg (T-Hg), MeHg, and selenium (Se) concentrations were evaluated. Transient Hg signals were detected as nanoparticles from almost all samples by using spICP-MS. Higher particle number concentrations (CPN) were observed in the tuna–swordfish group than in the shellfish group (17.7 × 10⁷ vs. 1.2 × 10⁶ particles/g, respectively). Although the CPN and maximum particle mass increased significantly with increasing T-Hg concentration, the increase in CPN was greater than those in maximum particle mass. Assuming that the NP-Hg detected was HgSe (tiemannite) and spherical based on previous reports, the maximum particle diameter was estimated to be 89 nm. The mean dietary exposures to NP-Hg, T-Hg, and MeHg were estimated to be 0.067, 5.75, and 5.32 μg/person per day, respectively. Generation of NP-Hg was inferred to be widespread in marine animals, with a preferential increase in the number of particles rather than an increase in particle size. The mean dietary exposure to NP-Hg in Japanese people was estimated to be 1.2 ng/kg body weight (BW) per day. Compared to PTWI of 4 μg/kg BW per week (0.57 μg/kg BW per day) derived by JECFA (2011), the health risk from redissolved I–Hg from NP-Hg is small.

The waste-to-energy (WTE) incinerator plant located in the Turin area (Italy) started to recover energy from the combustion of municipal solid waste in 2013. A health surveillance program was implemented to evaluate the potential health effects on the population living near the plant. This program included a longitudinal biomonitoring to evaluate temporal changes of some environmental pollutants, including polycyclic aromatic hydrocarbons (PAHs), in residents living in areas near the Turin incinerator (exposed group, E) compared to those observed in subjects living far from the plant (not exposed group, NE). Ten monohydroxy-PAHs (OH-PAHs), consisting in the principal metabolites of naphthalene, fluorine, phenanthrene, and pyrene, were analyzed in urines collected from the E and NE subjects after one (T₁) and three years (T₂) of plant activity and compared with those determined in the same cohort established before the plant start-up (T₀). Spearman correlation analysis was undertaken to explore possible associations between OH-PAHs and personal characteristics, lifestyle variables, and dietary habits. A linear mixed model (LMM) approach was applied to determine temporal trends of OH-PAHs observed in the E and NE subjects and to evaluate possible differences in trend between the two groups. Temporal trends of OH-PAHs determined by LMM analysis demonstrated that, at all times, the E group had concentrations lower than those assessed in the NE group, all other conditions being equal. Moreover, no increase in OH-PAH concentrations was observed at T₁ and T₂ either in E or in NE group. Significant positive correlations were found between all OH-PAHs and smoking habits. Regarding variables associated to outdoor PAH exposure, residence near high traffic roads and daily time in traffic road was positively correlated with 1-hydroxynaphthalene and 1-hydroxypyrene, respectively. In conclusion, no impact of the WTE plant on exposure to PAHs was observed on the population living near the plant.

PM₂.₅ (particulate matter having aerodynamic diameter ≤2.5 μm) samples were collected during wintertime from two polluted urban sites (Allahabad and Kanpur) in the central Indo-Gangetic Plain (IGP) to comprehend the sources and atmospheric transformations of light-absorbing water-soluble organic aerosol (WSOA). The aqueous extract of each filter was atomized and analyzed in a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Water-soluble organic carbon (WSOC) and WSOA concentrations at Kanpur were ∼1.2 and ∼1.5 times higher than that at Allahabad. The fractions of WSOC and secondary organic carbon (SOC) to total organic carbon (OC) were also significantly higher ∼53% and 38%, respectively at Kanpur compared to Allahabad. This indicates a higher abundance of oxidized WSOA at Kanpur. The absorption coefficient (bₐbₛ₋₃₆₅) of light-absorbing WSOA measured at 365 nm was 46.5 ± 15.5 Mm⁻¹ and 73.2 ± 21.6 Mm⁻¹ in Allahabad and Kanpur, respectively, indicating the dominance of more light-absorbing fractions in WSOC at Kanpur. The absorption properties such as mass absorption efficiency (MAE₃₆₅) and imaginary component of refractive index (kₐbₛ₋₃₆₅) at 365 nm at Kanpur were also comparatively higher than Allahabad. The absorption forcing efficiency (Abs SFE; indicates warming effect) of WSOA at Kanpur was ∼1.4 times higher than Allahabad. Enhancement in light absorption capacity was observed with the increase in f44/f43 (fraction of m/z 44 (f44) to 43 (f43) in organic mass spectra) and O/C (oxygen to carbon) ratio of WSOA at Kanpur while no such trend was observed for the Allahabad site. Moreover, the correlation between carbon fractions and light absorption properties suggested the influence of low-volatile organic compounds (OC3 + OC4 fraction obtained from thermal/optical carbon analyzer) in increasing the light absorption capacity of WSOA in Kanpur.

Biochemical oxidation and reduction are key processes in treating biological wastewater and they require the presence of electron acceptors. The functional impact of electron acceptors on microbiomes provides strategies for improving the treatment efficiency. This research focused on two of the most important electron acceptors, nitrate and oxygen. Molecule ecological network, null model, and functional prediction based on high-throughput sequencing were used to analyze the microbiomes features and assembly mechanism. The results revealed nitrate via the homogeneous selection (74.0%) decreased species diversity, while oxygen via the homogeneous selection (51.1%) and dispersal limitation (29.6%) increased the complexity of community structure. Microbes that were more strongly homogeneously selected for assembly included polyphosphate accumulating organisms (PAOs), such as Pseudomonas and variovorax in the nitrate impacted community; Pseudomonas, Candidatus_Accumulibacter, Thermomonas and Dechloromonas, in the oxygen impacted community. Nitrate simplified species interaction and increased the abundance of functional genes involving in tricarboxylic acid cycle (TCA cycle), electron transfer, nitrogen metabolism, and membrane transport. These findings contribute to our knowledge of assembly process and interactions among microorganisms and lay a theoretical basis for future microbial regulation strategies in wastewater treatment.

Goethite is a commonly found iron (hydr)oxide in soils and sediments that has been proven to possess abundant defects in structures. However, the underlying impact of these defects in goethite on arsenic immobilization remains unclear. In this study, goethite samples with abundant, moderate, and sparse defects were synthesized to evaluate their arsenic adsorption capacities. The characteristics of the defects in goethite were investigated by extended X-ray absorption fine structure (EXAFS), high angle annular dark field-scanning transmission electron microscopy-energy dispersion spectrum (HAADF-STEM-EDS) mapping, vibrating-sample magnetometry (VSM), and electron spin resonance (ESR). The characterization analysis revealed that the defects in as-synthesized goethite primarily existed in the form of Fe vacancies. Batch experiments demonstrated that the adsorption capacities of defect-rich goethite for As(V) and As(III) removal were 10.2 and 22.1 times larger than those of defect-poor goethite, respectively. The origin of the impact of Fe defects on arsenic immobilization was theoretically elucidated using density functional theory (DFT) calculations. The enhanced adsorption of goethite was attributed to the improvement of the arsenic affinity due to the Fe vacancy defect, thus considerably promoting arsenic immobilization. The findings of this study provide important insight into the migration and fate of arsenic in naturally occurring iron (hydr)oxides.

The main objective of this study was to investigate the 2019 and 2022 oil spill events that occurred off the coast of the State of Ceará, Northeastern Brazil. To further assess these mysterious oil spills, we investigated whether the oils stranded on the beaches of Ceará in 2019 and 2022 had the same origin, whether their compositional differences were due to weathering processes, and whether the materials from both were natural or industrially processed. We collected oil samples in October 2019 and January 2022, soon after their appearance on the beaches. We applied a forensic environmental geochemistry approach using both one-dimensional and two-dimensional gas chromatography to assess chemical composition. The collected material had characteristics of crude oil and not refined oils. In addition, the 2022 oil samples collected over 130 km of the east coast of Ceará had a similar chemical profile and were thus considered to originate from the same source. However, these oils had distinct biomarker profiles compared to those of the 2019 oils, including resistant terpanes and triaromatic steranes, thus excluding the hypothesis that the oil that reached the coast of Ceará in January 2022 is related to the tragedy that occurred in 2019. From a geochemical perspective, the oil released in 2019 is more thermally mature than that released in 2022, with both having source rocks with distinct types of organic matter and depositional environments. As the coast of Ceará has vast ecological diversity and Marine Protected Areas, the possibility of occasional oil spills in the area causing severe environmental pollution should be investigated from multiple perspectives, including forensic environmental geochemistry.

We aimed to explore the effects of mixtures of lead and various metals on blood pressure (BP) and the odds of pre-hypertension (systolic blood pressure (SBP) 120–139 mmHg, and/or diastolic blood pressure (DBP) 80–89 mmHg) and hypertension (SBP/DBP ≥140/90 mmHg) among Chinese adults in a cross-sectional study. This study included 11,037 adults aged 18 years or older from the 2017–2018 China National Human Biomonitoring. Average BP and 13 metals (lead, antimony, arsenic, cadmium, mercury, thallium, chromium, cobalt, molybdenum, manganese, nickel, selenium, and tin) in blood and urine were measured and lifestyle and demographic data were collected. Weighted multiple linear regressions were used to estimate associations of metals with BP in both single and multiple metal models. Weighted quantile sum (WQS) regression was performed to assess the relationship between metal mixture levels and BP. In the single metal model, after adjusting for potential confounding factors, the blood lead levels in the highest quartile were associated with the greater odds of both pre-hypertension (odds ratio (OR): 1.56, 95% CI: 1.22–1.99) and hypertension (OR:1.75, 95% CI: 1.28–2.40) when compared with the lowest quartile. We also found that blood arsenic levels were associated with increased odds of pre-hypertension (OR:1.31, 95% CI:1.00–1.74), while urinary molybdenum levels were associated with lower odds of hypertension (OR:0.68, 95% CI:0.50–0.93). No significant associations were found for the other 10 metals. WQS regression analysis showed that metal mixture levels in blood were significantly associated with higher SBP (β = 1.56, P < 0.05) and DBP (β = 1.56, P < 0.05), with the largest contributor being lead (49.9% and 66.8%, respectively). The finding suggests that exposure to mixtures of metals as measured in blood were positively associated with BP, and that lead exposure may play a critical role in hypertension development.

Previous studies have indicated that maternal exposure to particles with aerodynamic diameter <2.5 μm (PM₂.₅) is associated with adverse birth outcomes. However, the critical exposure windows remain inconsistent. A retrospective cohort study was conducted in Huai River Basin, Henan, China during 2013–2018. Daily PM₂.₅ concentration was collected using Chinese Air Quality Reanalysis datasets. We calculated exposures for each participant based on the residential address during pregnancy. Binary logistic regression was used to examine the trimester-specific association of PM₂.₅ exposure with preterm birth (PTB), low birth weight (LBW) and term LBW (tLBW), and we further estimated monthly and weekly association using distributed lag models. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for each 10 μg/m³ increase in PM₂.₅ exposure. Stratified analyses were performed by maternal age, infant gender, parity, and socioeconomic status (SES). In total, 196,780 eligible births were identified, including 4257 (2.2%) PTBs, 3483 (1.8%) LBWs and 1770 (0.9%) tLBWs. Maternal PM₂.₅ exposure during the second trimester were associated with the risk of PTB and LBW. At the monthly level, the PTB and LBW risks were associated with PM₂.₅ exposure mainly in the 4th -6th month. By estimating the weekly-specific association, we observed that critical exposure windows of PM₂.₅ exposure and PTB were in the 18th- 27th gestational weeks. Stronger associations were found in younger, multiparous mothers and those with a female baby and in low SES. In conclusion, the results indicate that maternal PM₂.₅ exposure during the second trimester was associated with PTB and LBW. Younger, multiparous mothers and those with female babies and in low SES were susceptible.

Microplastics debris in the marine environment have been widely studied across the globe. Within these particles, the most abundant and prevalent type in the oceans are anthropogenic microfibers (MFs), although they have been historically overlooked mostly due to methodological constraints. MFs are currently considered omnipresent in natural environments, however, contrary to the Northern Hemisphere, data on their abundance and distribution in Southern Oceans ecosystems are still scarce, in particular for sub-Antarctic regions. Using Niskin bottles we've explored microfibers abundance and distribution in the water column (3–2450 m depth) at the Burdwood Bank (BB), a seamount located at the southern extreme of the Patagonian shelf, in the Southwestern Atlantic Ocean. The MFs detected from filtered water samples were photographed and measured using ImageJ software, to estimate length, width, and the projected surface area of each particle. Our results indicate that small pieces of fibers are widespread in the water column at the BB (mean of 17.4 ± 12.6 MFs.L⁻¹), from which, 10.6 ± 5.3 MFs.L⁻¹ were at the surface (3–10 m depth), 20 ± 9 MFs.L⁻¹ in intermediate waters (41–97 m), 24.6 ± 17.3 MFs.L⁻¹ in deeper waters (102–164 m), and 9.2 ± 5.3 MFs.L⁻¹ within the slope break of the seamount. Approximately 76.1% of the MFs were composed of Polyethylene terephthalate, and the abundance was dominated by the size fraction from 0.1 to 0.3 mm of length. Given the high relative abundance of small and aged MFs, and the oceanographic complexity of the study area, we postulate that MFs are most likely transported to the BB via the Antarctic Circumpolar Current. Our findings imply that this sub-Antarctic protected ecosystem is highly exposed to microplastic pollution, and this threat could be spreading towards the highly productive waters, north of the study area.