Particulate matter with diameter less than 1 μm (PM1) has been found to be closely associated with air quality, climate changes, and even adverse human health. However, a large gap in our knowledge concerning the large-scale distribution and variability of PM1 remains, which is expected to be bridged with advanced remote-sensing techniques. In this study, a hybrid model called principal component analysis-general regression neural network (PCA-GRNN) is developed to estimate hourly PM1 concentrations from Himawari-8 aerosol optical depth in combination with coincident ground-based PM1 measurements in China. Results indicate that the hourly estimated PM1 concentrations from satellite agree well with the measured values at national scale, with R2 of 0.65, root-mean-square error (RMSE) of 22.0 μg/m3 and mean absolute error (MAE) of 13.8 μg/m3. On daily and monthly time scales, R2 increases to 0.70 and 0.81, respectively. Spatially, highly polluted regions of PM1 are largely located in the North China Plain and Northeast China, in accordance with the distribution of industrialisation and urbanisation. In terms of diurnal variability, PM1 concentration tends to peak in rush hours during the daytime. PM1 exhibits distinct seasonality with winter having the largest concentration (31.5±3.5 μg/m3), largely due to peak combustion emissions. We further attempt to estimate PM2.5 and PM10 with the proposed method and find that the accuracies of the proposed model for PM1 and PM2.5 estimation are significantly higher than that of PM10. Our findings suggest that geostationary data is one of the promising data to estimate fine particle concentration on large spatial scale.

Aerosol samples (as PM₁₀, n = 250) were collected from three rural/remote receptor locations in the mid Brahmaputra plain region and were chemically characterized for metals (Al, Fe, Co, Cu, Cr, Cd, Mn, Ni, Pb), ions (Ca²⁺, Mg²⁺, Na⁺, K⁺, NH₄⁺, F⁻, Cl⁻, NO₃⁻, SO₄²⁻), and carbon. Vital ratios like NO₃⁻/SO₄²⁻, EC/OC, K⁺/EC, K⁺/OC, enrichment factors and inter-species correlations were exploited to appreciate possible sources of aerosol. These empirical analyses pointed towards anthropogenic contributions of aerosol, particularly from biomass burning, vehicular emission, and road dust. The chemically characterized concentration data were subsequently fed into two receptor models viz. Principal Component Analysis-Multiple Linear Regression (PCA-MLR) and Chemical Mass Balance (CMB) for apportionment of sources of aerosol. The PCA-MLR estimates identified that the combustion sources together accounted for ∼42% of aerosol and the contribution of secondary formation to be 24%. Road and crustal dusts have been well apportioned by PCA-MLR, which together accounts for ∼26% of the aerosol. The CMB model estimates explained that the combustion sources taken together contributed ∼47% to the aerosol, which includes biomass burning (27%), vehicular emission (13%), coal (1%), kerosene (4%), and petroleum refining (2%). Other major sources that were apportioned were road dust (15%), crustal dust (26%), and construction dust (6%). There are inherent limitations in the source strength estimations because of uncertainty present in the source emission profiles that have been applied to the remote location of India. However, both the models (PCA-MLR and CMB) estimated the contribution of combustion sources to 42 and 47% respectively, which is comparable.

Groundwater is an essential public and drinking water supply and its protection is a goal for global policies. Here, we investigated the presence and prevalence of antibiotic residues, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and microbial contamination in groundwater environments at various distances from urban areas. Antibiotic concentrations ranged from below detection limit to 917 ng/L, being trimethoprim, macrolide, and sulfonamide the most abundant antibiotic classes. A total of eleven ARGs (aminoglycoside, β-lactam, chloramphenicol, Macrolide-Lincosamide-Streptogramin B - MLSB, sulfonamide, and tetracycline), one antiseptic resistance gene, and two MGEs were detected by qPCR with relative abundances ranging from 6.61 × 10−7 to 2.30 × 10−1 copies/16S rRNA gene copies. ARGs and MGEs were widespread in the investigated groundwater environments, with increased abundances not only in urban, but also in remote areas. Distinct bacterial community profiles were observed, with a higher prevalence of Betaproteobacteria and Bacteroidetes in the less-impacted areas, and that of Firmicutes in the contaminated groundwater. The combined characteristics of increased species diversity, distinct phylogenetic composition, and the possible presence of fecal and/or pathogenic bacteria could indicate different types of contamination. Significant correlations between ARGs, MGEs and specific taxa within the groundwater bacterial community were identified, revealing the potential hosts of resistance types. Although no universal marker gene could be determined, a co-selection of int1, qacEΔ1 and sulI genes, a proxy group for anthropogenic pollution, with the tetC, tetO, tetW resistance genes was identified. As the tet group was observed to follow the pattern of environmental contamination for the groundwater samples investigated in this study, our results strongly support the proposal of this group of genes as an environmental tracer of human impact. Overall, the present study investigated several emerging contaminants in groundwater habitats that may be included in monitoring programs to enable further regulatory and protection measures.

This study evaluated associations between the bioreactivity of PM2.5in vitro and emission sources in the vicinity of a petrochemical complex in Taiwan. The average PM2.5 was 30.2 μg/m3 from 9 February to 23 March 2016, and the PM2.5 was clustered in long-range transport (with major local source) (12.8 μg/m3), and major (17.3 μg/m3) and minor industrial emissions (4.7 μg/m3) using a k-means clustering model. A reduction in cell viability and increases in the cytotoxicity-related lactate dehydrogenase (LDH), oxidative stress-related 8-isoprostane, and inflammation-related interleukin (IL)-6 occurred due to PM2.5 in a dose-dependent manner. The PM2.5 from major industrial emissions was significantly correlated with increased 8-isoprostane and IL-6, but this was not observed for long-range transport or minor industrial emissions. The bulk metal concentration was 9.52 ng/m3 in PM2.5. We further observed that As, Ba, Cd, and Se were correlated with LDH in the long-range transport group. Pb in PM2.5 from the major industrial emissions was correlated with LDH, whereas Pb and Se were correlated with 8-isoprostane. Sr was correlated with cell viability in the minor industrial emissions group. We demonstrated a new approach to investigate particle bioreactivity, which suggested that petrochemical-emitted PM2.5 should be a concern for surrounding residents' health.

Information on exposure levels to organochlorine compounds (OCs) in child population is limited, despite their greater vulnerability to the adverse health effects of these chemicals.To determine serum concentrations of 10 OCs (including organochlorine pesticides and polychlorinated biphenyls –PCBs–) in children living in agricultural communities from Almería (South-Eastern Spain), and to identify the main predictors of exposure related to socio-economic characteristics, diet and lifestyle.A cross-sectional study was conducted on 133 children aged 6–11 years selected from public schools of the study area. OCs compounds were determined in serum samples by GC/ECD. Anthropometric measures were obtained during sample collection. Information on sociodemographic characteristics, parental occupation, residential history, lifestyle and frequency of food consumption, among other relevant factors, was obtained by questionnaires administered to the mothers.Geometric means of serum concentrations (ng/ml) were 0.11 for β-hexachloro-cyclohexane (β-HCH), 0.09 for endosulfan, 0.20 for endosulfan-ether, 0.51 for hexachorobenzene (HCB), 0.08 for mirex, 0.06 for oxychlordane, 0.36 for p,p'-DDE, 0.20 for PCB 138, 0.36 for PCB 153, and 0.45 for PCB 180. Percentage of samples above the limit of detection (0.05 ppb) ranged from 32 (β-HCH) to 100 (HCB). A high variability in OC levels depending on the compound was observed between our results and others found in similar studies carried out in children. Variables related to fish consumption were found to be the major dietary determinant of PCB 138, p,p´-DDE, endosulfan-α, β-HCH, mirex and oxychlordane levels.Children participating in this study showed detectable levels of many OC, despite these compounds are no longer used. Their presence in children serum can be explained by their high lipophilicity and environmental persistence, leading to contamination of fatty food. In this line, fish consumption seemed to be the most relevant determinant of OC levels found in our study.

Microplastics exposure could be detrimental to marine organisms especially under high concentrations. However, few studies have considered the multiphasic nature of marine invertebrates' life history and investigated the impact of experiencing microplastics during early development on post-metamorphic stages (legacy effect). Many planktonic larvae can feed selectively and it is unclear whether such selectivity could modulate the impact of algal food-sized microplastic. In this two-stage experiment, veligers of Crepidula onyx were first exposed to additions of algae-sized micro-polystyrene (micro-PS) beads at different concentrations, including ones that were comparable their algal diet. These additions were then either halted or continued after settlement. At environmentally relevant concentration (ten 2-μm microplastic beads ml⁻¹), larval and juvenile C. onyx was not affected. At higher concentrations, these micro-PS fed larvae consumed a similar amount of algae compared to those in control but grew relatively slower than those in the control suggesting that ingestion and/or removal of microplastic was/were energetically costly. These larvae also settled earlier at a smaller size compared to the control, which could negatively affect post-settlement success. Juvenile C. onyx receiving continuous micro-PS addition had slower growth rates. Individuals only exposed to micro-PS during their larval stage continued to have slower growth rates than those in the control even if micro-PS had been absent in their surroundings for 65 days highlighting a legacy effect of microplastic exposure.

Dietary fish oil used in aquafeed transfers marine pollutants to farmed fish. However, the entire transfer route of marine pollutants in dietary fish oil from ocean to table fish has not been tracked quantitatively. To track the entire transfer route of marine pollutants from wild fish to farmed fish through dietary fish oil and evaluate the related human health risks, we obtained crude and refined fish oils originating from the same batch of wild ocean anchovy and prepared fish oil-containing purified aquafeeds to feed omnivorous lean Nile tilapia and carnivorous fatty yellow catfish for eight weeks. The potential human health risk of consumption of these fish was evaluated. Marine persistent organic pollutants (POPs) were concentrated in fish oil, but were largely removed by the refining process, particularly dioxins and polychlorinated biphenyls (PCBs). The differences in the POP concentrations between crude and refined fish oils were retained in the fillets of the farmed fish. Fillets fat content and fish growth were positively and negatively correlated to the final POPs deposition in fillets, respectively. The retention rates of marine POPs in the final fillets through fish oil-contained aquafeeds were 1.3%–5.2%, and were correlated with the POPs concentrations in feeds and fillets, feed utilization and carcass ratios. The dietary crude fish oil-contained aquafeeds are a higher hazard ratio to consumers. Prohibiting the use of crude fish oil in aquafeed and improving growth and feed efficiency in farmed fish are promising strategies to reduce health risks originating from marine POPs.

The anthropogenic contamination of water bodies with metals via fertilizer, industrial sewage and urban wastewater has resulted in widespread problems in aquatic organisms, but also poses a risk to consumer health. Shellfish from coastal and estuarine environments bioaccumulate toxic metals in their tissues due to their ability to concentrate inorganic contaminants several orders of magnitude above ambient levels. The aim of this study was to evaluate the presence of trace elements in adult specimens of indigenous clams (Ruditapes decussatus). To this end, wild clams were collected from four different brackish areas of Sardinia (Western Mediterranean Sea, Italy) devoted to extensive aquacultural practices. The concentration of 16 trace elements (Al, Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sn, Tl and Zn) in the tissues of the clams was quantified. The legal limits set by European Regulations for cadmium; mercury and lead were never exceeded. However, unexpectedly high values for aluminium and iron (mean 207 mg kg⁻¹ and 113 mg kg⁻¹ wet weight) were found in Santa Gilla lagoon, which is close to industrial settlements and had the highest values for the majority of chemical elements investigated. The highest values of the metalloid arsenic (As) were reported in the Porto Pozzo and San Teodoro lagoons (9.6 and 6.8 mg kg⁻¹ w.w., respectively). The clam R. decussatus confirmed the capacity of bivalves as suitable bioindicators of trace elements pollution. Further investigations are necessary for constant monitoring of clams, 32 which constitute an important traditional resource for the fishing activity in Sardinia.

Pollen allergy risk is modified by air pollutants, including ozone, but the chemical modifications induced on pollen grains are poorly understood. Pollen lipidic extract has been shown to act as an adjuvant to the allergenic reaction and therefore, the modification of lipids by air pollutants could have health implications. Birch pollen was exposed in vitro to ozone to explore the reactivity of O₃ on its surface and on its lipidic fraction. Uptake coefficients of ozone were determined for ozone concentration of 117 ppb on the surface of native birch pollen (8.6 ± 0.8 × 10⁻⁶), defatted pollen (9.9 ± 0.9 × 10⁻⁶), and for crushed pollen grains (34±3 × 10⁻⁶). The mass of ozone uptaken was increased by a factor of four for crushed pollen compared to native pollen showing a higher susceptibility to ozone of cytoplasmic granules and broken pollen grains. A total mass of extractible lipids of 27 mg per gram of birch pollen was found and a fraction of these lipids was identified and quantified (fatty acids, alkanes, alkenes and aldehydes). The distribution of lipids was modified by ozone exposure of 115 and 1000 ppb for 16 h with the following reactivity: consumption of alkene, formation of aldehydes and formation of nonanoic acid and octadecanoic acid. The quantity of ozone trapped in the lipidic fraction during 15 min at 115 ppb is enough to contribute to the reactivity of one-third of the alkenes demonstrating that pollen could be susceptible to an atmospheric increase of ozone concentration even for a very short duration complicating the understanding of the link between pollen allergy and pollution.

The transfer of pollutants from chemical fertilizers through food webs within cropland is well documented; however, its impacts on the wild animals that forage on croplands but roost in other locations remain poorly understood. The potential for this cross-ecosystem ‘spillover’ of pollutants is greatest for bats, some of which exploit urban settlements as roosting niches but must travel long distances to reach croplands as foraging niches. Here, we used hairs from a colony of insectivorous bats, Chinese Noctule (Nyctalus plancyi), from an urban area in Southwest China to assess whether exposure to heavy metals/metalloids by the bats varied from 1975 to 2016. Historical changes occurred in hair cadmium (Cd) concentrations in adult females, which was exclusively explained by the regional fertilizer application intensity (FAI), even considering the potential impacts of Cd emissions in urban areas, as indicated by camphor trees (Cinnamomum camphora) near the bats' roosting niche, and the potential impacts of Cd in industrial wastewater, as documented in authorized databases. Therefore, the data from this bat colony, as urban dwellers, indicates Cd accumulation and cross-ecosystem transfer from rural croplands to an urban area.