Population growth, urbanization, environmental conditions and rapid development have caused particulate matter (PM) levels to rise above all national and international health standards during the last two decades in many South-East Asian countries. These PM levels needs to be reduced urgently as they increase the risk of cardiovascular and respiratory health problems for millions of people. Plants have shown to efficiently reduce PM in the air by accumulation on their leaves. In order to investigate which plant species accumulate most PM, we screened 49 common plant species for their PM accumulation capacity in one of the tropical cities with the highest PM concentrations of the world, Hanoi (Vietnam). Using this subset of plants, we tested if certain leaf characteristics (leaf hydrophilicity, stomatal densities and the specific leaf area) can predict the PM accumulation efficiency of plant species. Our results show that the PM accumulation capacity varies substantially among species and that Muntingia calabura accumulated most PM in our subset of plants. We observed that plants with hydrophilic leaves, a low specific leaf area and a high abaxial stomatal density accumulated significantly more PM. Plants with these characteristics should be preferred by urban architects to reduce PM levels in tropical environments.

Polychlorinated biphenyls (PCBs) in dated sediment cores from the East China Marginal Seas (ECMSs) and the chronology of the net fluxes to sediments were analyzed. The accumulation of 27 PCBs (ΣPCBs) in the ECMS sediments is about 5–26 ng cm⁻², with the net depositional fluxes of ΣPCBs 10 times lower than those observed in the Great Lakes during the 1960s–1970s. Exponential increases in PCB deposition to the ECMS sediments since the 1990s were observed, which closely follows the fast growth of PCB emissions from industrial thermal processes and e-waste related sources in China. Recent PCB fluxes to the study sites in the ECMSs and the Great Lakes are comparable; the former surged forward with a rising tendency, while the latter showed continued decline after the late 1970s. Due to the different PCB application histories and sources between the two regions, the ECMS sediments may remain as a net sink for land-derived PCBs, while sediments in the Great Lake may have been acting as a secondary source releasing PCBs to water. A higher proportion of trichlorobiphenyls in the ECMS sediments than the Great Lakes was indicated, which may imply the net transport of atmospheric PCBs from China.

Forecasting wastewater discharge is the basis for wastewater treatment and policy formulation. This paper proposes a novel mixed-data sampling regression model, i.e., combination-MIDAS model to forecast quarterly wastewater emissions in China based on dynamic factors at different frequencies. The results show that a significant auto-correlation for wastewater emissions exists and that water consumption per ten thousand gross domestic product is the best predictor of wastewater emissions. The forecast performances of the combination-MIDAS models are robust and better than those of the benchmark models. Therefore, the combination-MIDAS models can better capture the characteristics of wastewater emissions, suggesting that the proposed method is a good method to deal with model misspecification and uncertainty for the control and management of wastewater discharge in China.

Increased public awareness of the health impacts of atmospheric fine particulate matter (PM₂.₅) has led to increased demand and deployment of indoor air cleaners. Yet, questions still remain about the effectiveness of indoor air cleaners on indoor PM₂.₅ concentrations and personal exposure to potentially hazardous components of PM₂.₅. Metals in PM₂.₅ have been associated with adverse health outcomes, so knowledge of their sources in urban indoor and outdoor areas and how exposures are influenced by indoor air cleaners would be beneficial for public health interventions. We collected 48-h indoor, outdoor, and personal PM₂.₅ exposure samples for 43 homes with asthmatic children in suburban Shanghai, China during the spring months. Two sets of samples were collected for each household, one set with a functioning air filter placed in the bedroom (“true filtration”) and the other with a non-functioning (“sham”) air cleaner. PM₂.₅ samples were analyzed for elements, elemental carbon, and organic carbon. The major sources of metals in PM₂.₅ were determined by Positive Matrix Factorization (PMF) to be regional aerosol, resuspended dust, residual oil combustion, roadway emissions, alloy steel abrasion, and a lanthanum (La) and cerium (Ce) source. Under true filtration, the median indoor to outdoor percent removal across all elements increased from 31% to 78% and from 46% to 88% across all sources. Our findings suggest that indoor air cleaners are an effective strategy for reducing indoor concentrations of PM₂.₅ metals from most sources, which could translate into improved health outcomes for some populations.

Polycyclic aromatic hydrocarbons (PAHs) in urban soils are a risk to the health of residents. To predict those risks, the distribution and the factors influencing the concentration of PAHs were studied by collecting 1120 records of soil PAHs published during 2006–2017 from 26 cities. The mean concentrations of 16 PAHs (∑PAHs) in soil varied from 123 μg/kg to 5568 μg/kg, with a mean value of 1083 μg/kg, suggesting that a few cities were polluted. The distribution of ∑PAHs in the cities followed two gradients, namely from northern China through eastern China to southern China and from industrial cities through developed cities to cities that are main tourist attractions. The concentrations were significantly correlated to annual temperature, the efficiency of energy use, and to such measures of air quality as PM₁₀ and NO₂ concentrations. A regression equation developed to predict the concentration of ∑PAHs in soil and the corresponding health risks to residents of 35 major Chinese cities of China showed that the risks to adults and children were slight in most cities but those in a few industrial cities were of concern, and field investigations are recommended to assess the risk in greater detail. The method offers a useful tool for predicting such risks in other cities even when data on soils PAHs are not available.

The current study investigates the concentration of eleven trace elements in biomaterials including hair (85) and nails (85) along with seventy five (75) road dust samples collected from a healthy population of habitable urban-industrial areas of Hefei, China. The samples were acid digested and analyzed using ICP-MS for trace elements content. The mean concentration of Elements followed descending order of Zn > Mg > Fe > Cr > Al > Sn > Sr > Ti > Cu > As > Cd and Mg > Zn > Fe > Cr > Al > Sn > Ti > Cu > Sr > As > Cd in hair and nails, respectively. Overall, the concentration of elements was found to be high in female subject as compared to male. The concentration of trace elements in hair and nail exceeded the maximum permissible limits in most cases. The corresponding mean values from dust samples were fairly high as compared to background values of trace elements. Middle age groups (21–30 years and 31–40 years) were observed to be the most vulnerable there-by posing a high health risk, as the concentration of trace elements was significantly high in these groups except for Al, which was detected high in age < 20 in case of both male and female. A significantly high correlation was found between trace elements in biomaterials and those detected in dust samples. In hair samples, a significantly positive correlation was noticed for As with Mg, Zn, Sn and Fe, Sn/Mg and Mg/Ti. In the case of nails, a significant correlation was observed for elements like Al, Mg, Zn, Cr, and Cu. The Cluster and principal component analysis revealed industrial and vehicular emissions as main sources for trace elements exposure in humans.

In this study, we analysed a data set from 10 low-cost PM₂.₅ sensors using the Internet of Things (IoT) for air quality monitoring in Mae Sot, which is one of the most vulnerable areas for high PM₂.₅ concentration in Thailand, during the 2018 burning season. Our objectives were to understand the nature of the plume movement and to investigate possibilities of adopting IoT sensors for near real-time forecasting of PM₂.₅ concentrations. Sensor data including PM₂.₅ and meteorological parameters (wind speed and direction) were collected online every 2 min where data were grouped into four zones and averaged every 15 min interval. Results of diurnal profile plot revealed that PM₂.₅ concentrations were high around early to late morning (3:00–9:00) and gradually reduced till the rest of the day. During the biomass burning period, maximum daily average concentration recorded by the sensors was 280 μg/m³ at Thai Samakkhi while the minimum was 13 μg/m³ at Mae Sot. Lag time concentrations, attributed by biomass burning (hotspots), significantly influenced the formation of PM₂.₅ while the disappearance of PM₂.₅ was found to be influenced by moderate wind speed. The PM₂.₅ concentrations of the next 15 min at the downwind zone (MG) were predicted using lag time concentrations with different wind categories. The next 15 min predictions of PM₂.₅ at MG were found to be mainly influenced by its lag time concentrations (MG_Lag); with higher wind speed, however, the lag time concentrations from the upwind zones (MS_Lag and TS_Lag) started to show more influence. From this study, we have found that low-cost IoT sensors provide not only real-time monitoring information but also demonstrate great potential as an effective tool to understand the PM₂.₅ plume movement with temporal variation and geo-specific location.

Mangrove sediments can store high amount of pollutants that can be more or less bioavailable depending on environmental conditions. When in available forms, these elements can be subject to an uptake by mangrove biota, and can thus become a problem for human health. The main objective of this study was to assess the distribution of some trace elements (Fe, Mn, Co, Ni, Cr, As, and Cu) in tissues of different plants and snails in a tropical mangrove (Can Gio mangrove Biosphere Reserve) developing downstream a megacity (Ho Chi Minh City, Vietnam). In addition, we were interested in the relationships between mangrove habitats, sediment quality and bioaccumulation in the different tissues studied. Roots and leaves of main mangrove trees (Avicennia alba and Rhizophora apiculata) were collected, as well as different snail species: Chicoreus capucinus, Littoraria melanostoma, Cerithidea obtusa, Nerita articulata. Trace elements concentrations in the different tissues were determined by ICP-MS after digestion with concentrated HNO₃ and H₂O₂. Concentrations differed between stands and tissues, showing the influence of sediment geochemistry, species specific requirements, and eventually adaptation abilities. Regarding plants tissues, the formation of iron plaque on roots may play a key role in preventing Fe and As translocation to the aerial parts of the mangrove trees. Mn presented higher concentrations in the leaves than in the roots, possibly because of physiological requirements. Non-essential elements (Ni, Cr and Co) showed low bioconcentration factors (BCF) in both roots and leaves, probably resulting from their low bioavailability in sediments. Regarding snails, essential elements (Fe, Mn, and Cu) were the dominant ones in their tissues. Most of snails were “macroconcentrators” for Cu, with BCF values reaching up to 42.8 for Cerithidea obtusa. We suggest that high quantity of As in all snails may result from its high bioavailability and from their ability to metabolize As.

Petroleum biomarkers (hopanes, terpanes and steranes) are frequently assessed in estuarine sediments as tracers of oil input. In order to compare distinct patterns of hydrocarbon accumulation in mudflats, salt marsh and mangrove, sediments from two transects (control and impacted areas) were sampled in Paranaguá Bay, SW Atlantic. Concentrations of n-alkanes, polycyclic aromatic hydrocarbons (PAHs) and petroleum biomarkers (hopanes, terpanes and steranes) were determined, as well as bulk parameters (TOC, grain size and δ13C). N-alkanes concentrations were similar between control and impacted sites (respectively, 3.03 ± 1.20 μg g−1 and 4.11 ± 3.02 μg g−1) and reflected a high biogenic input. Conversely, PAHs and petroleum biomarker concentrations were three to six times higher in impacted site than the control site (respectively, 60.4 ± 23.3 ng g−1 and 22.0 ± 25.0 ng g−1 for PAHs and 197.7 ± 51.8 ng g−1 and 40.2 ± 32. ng g−1 for hopanes). Despite these differences, concentrations were lower than those reported for highly impacted areas worldwide. Diagnostic ratios and hydrocarbon parameters (e.g. total PAHs and total petroleum biomarkers) helped to distinguish human impact in the ecological zones, suggesting different sources and/or levels of weathering, confirmed by ANOVA tests. TOC played a fundamental role to the concentration of hydrocarbons, showing similar distributions along the transects. Petroleum biomarkers could clearly indicate the preferential sites of deposition and assign different levels of anthropic contamination by hydrocarbons, thus providing clear information about the chronic petroleum pollution in coastal sediments.

Transcription factors including pregnane X receptor (Pxr) and nuclear factor-erythroid 2-related factor-2 (Nrf2) are important modulators of Adenosine triphosphate-binding cassette (ABC) transporters in mammalian cells. However, whether such modulation is conserved in zebrafish embryos remains largely unknown. In this manuscript, pxr- and nrf2-deficient models were constructed with CRISPR/Cas9 system, to evaluate the individual function of Pxr and Nrf2 in the regulation of ABC transporters and detoxification of heavy metal ions like Cd²⁺ and Ag⁺. As a result, both Cd²⁺ and Ag⁺ conferred extensive interactions with ABC transporters in wild type (WT) embryos: their accumulation and toxicity were affected by the activity of ABC transporters, and they significantly induced the mRNA expressions of ABC transporters. These induction effects were reduced by the mutation of pxr and nrf2, but elevations in the basal expression of ABC transporters compensated for the loss of their inducibility. This could be an explanation for remaining transporter function in both mutant models as well as the unaltered toxicity of metal ions in pxr-deficient embryos. However, mutation of nrf2 disrupted the production of glutathione (GSH), resulting in the enhanced toxicity of Cd²⁺/Ag⁺ in zebrafish embryos. In addition, elevated expressions of other transcription factors like aryl hydrocarbon receptor (ahr) 1b, peroxisome proliferator-activated receptor (ppar)-β, and nrf2 were found in pxr-deficient models without any treatment, while enhanced induction of ahr1b, ppar-β and pxr could only be seen in nrf2-deficient embryos after the treatment of metal ions, indicating different compensation phenomena for the absence of transcription factors. After all, pxr-deficient and nrf2-deficient zebrafish embryos are useful tools in the functional investigation of Pxr and Nrf2 in the early life stages of aquatic organisms. However, the compensatory mechanisms should be taken into consideration when interpreting the results and need in-depth investigations.