On-road mobile sources play a significant role in air quality modeling and these models require gridded, hourly emission inputs. Due to its geographical and meteorological diversity and stringent air quality regulations, California state always poses big challenge for air quality modelers and policy makers. At the same time, the impact of ambient temperature on vehicle emissions has been well researched in the past few decades and it is vital to prepare a reliable on-road gridded emission inventory for air quality modeling. This technical paper introduces a gridding method that takes temperature impacts into account, calculates emissions from grid-level to county, and attempts to quantify the likely effects of such a bottom-up, temperature sensitive approach on a gridded on-road emission inventory. To provide confidence in the proposed SMOKE-EMFAC method, a detailed analysis was carried out to compare the results with the default EMFAC output, and the results were within ±1%. Applying detailed grid level temperatures, we also found that criteria pollutant distributions are sensitive to them, and they are in accordance with previous US-EPA study. The proposed method could be very useful while testing different complex emission regulations and policies due to its inherent flexibility.

Recent studies suggest an association between particulate matter (PM) air pollution and gastrointestinal (GI) disease. In addition to direct deposition, PM can be indirectly deposited in oropharynx via mucociliary clearance and upon swallowing of saliva and mucus. Within the GI tract, PM may alter the GI epithelium and gut microbiome. Our goal was to determine the effect of PM on gut microbiota in a murine model of PM exposure via inhalation. C57BL/6 mice were exposed via inhalation to either concentrated ambient particles or filtered air for 8-h per day, 5-days a week, for a total of 3-weeks. At exposure's end, GI tract tissues and feces were harvested, and gut microbiota was analyzed. Alpha-diversity was modestly altered with increased richness in PM-exposed mice compared to air-exposed mice in some parts of the GI tract. Most importantly, PM-induced alterations in the microbiota were very apparent in beta-diversity comparisons throughout the GI tract and appeared to increase from the proximal to distal parts. Changes in some genera suggest that distinct bacteria may have the capacity to bloom with PM exposure. Exposure to PM alters the microbiota throughout the GI tract which maybe a potential mechanism that explains PM induced inflammation in the GI tract.

Controlling blooms of toxigenic phytoplankton, including cyanobacteria, is a high priority for managers of aquatic systems that are used for drinking water, recreation, and aquaculture production. Although a variety of treatment approaches exist, hydrogen peroxide (H2O2) has the potential to be an effective and ecofriendly algaecide given that this compound may select against cyanobacteria while not producing harmful residues. To broadly evaluate the effectiveness of H2O2 on toxigenic phytoplankton, we tested multiple concentrations of H2O2 on (1) four cyanobacterial cultures, including filamentous Anabaena, Cylindrospermopsis, and Planktothrix, and unicellular Microcystis, in a 5-day laboratory experiment and (2) a dense cyanobacterial bloom in a 7-day field experiment conducted in a nutrient-rich aquaculture pond. In the laboratory experiment, half-maximal effective concentrations (EC50) were similar for Anabaena, Cylindrospermopsis, and Planktothrix (average EC50 = 0.41 mg L−1) but were ∼10x lower than observed for Microcystis (EC50 = 5.06 mg L−1). Results from a field experiment in an aquaculture pond showed that ≥1.3 and ≥ 6.7 mg L−1 of H2O2 effectively eliminated Planktothrix and Microcystis, respectively. Moreover, 6.7 mg L−1 of H2O2 reduced microcystin and enhanced phytoplankton diversity, while causing relatively small negative effects on zooplankton abundance. In contrast, 20 mg L−1 of H2O2 showed the greatest negative effect on zooplankton. Our results demonstrate that H2O2 can be an effective, rapid algaecide for controlling toxigenic cyanobacteria when properly dosed.

This work presents studies on the co-combustion of anthracite coal and wood pellets in fluidized bed. Prior to the fluidized bed combustion, thermogravimetric analysis are performed to investigate the thermodynamic behavior of coal and wood pellets. The results show that the thermal decomposition of blends is divided into four stages. The co-firing of coal and wood pellets can promote the combustion reaction and reduce the emission of gaseous pollutants, such as SO₂ and NO. It is important to choose the proportion of wood pellets during co-combustion due to the low combustion efficiency caused by large pellets with poor fluidization. Wood pellets can inhibit the volatilization of trace elements, especially for Cr, Ni and V. In addition, the slagging ratio of wood pellets ash is reduced by co-firing with coal. The research on combustion of coal and wood pellets is of great significance in engineering.

Shallow aquifers are the most accessible reservoirs of potable groundwater; nevertheless, they are also prone to various sources of pollution and it is usually difficult to distinguish between human and natural sources at the watershed scale. The area chosen for this study (the Campania Plain) is characterized by high spatial heterogeneities both in geochemical features and in hydraulic properties. Groundwater mineralization is driven by many processes such as, geothermal activity, weathering of volcanic products and intense human activities. In such a landscape, multivariate statistical analysis has been used to differentiate among the main hydrochemical processes occurring in the area, using three different approaches of factor analysis: (i) major elements, (ii) trace elements, (iii) both major and trace elements. The elaboration of the factor analysis approaches has revealed seven distinct hydrogeochemical processes: i) Salinization (Cl⁻, Na⁺); ii) Carbonate rocks dissolution; iii) Anthropogenic inputs (NO₃⁻, SO₄²⁻, U, V); iv) Reducing conditions (Fe²⁺, Mn²⁺); v) Heavy metals contamination (Cr and Ni); vi) Geothermal fluids influence (Li⁺); and vii) Volcanic products contribution (As, Rb). Results from this study highlight the need to separately apply factor analysis when a large data set of trace elements is available. In fact, the impact of geothermal fluids in the shallow aquifer was identified from the application of the factor analysis using only trace elements. This study also reveals that the factor analysis of major and trace elements can differentiate between anthropogenic and geogenic sources of pollution in intensively exploited aquifers.

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.

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.

This study investigated the treatment performance and nitrogen removal mechanism of highly alkaline ammonia-stripped digestate effluent in horizontal subsurface flow constructed wetlands (CWs). A promising nitrogen removal performance (up to 91%) was observed in CWs coupled with intensified configurations, i.e., aeration and effluent recirculation. The results clearly supported that the higher aeration ratio and presence of effluent recirculation are important to improve the alkalinity and pollutant removal in CWs. The influent pH (>10) was significantly decreased to 8.2–8.8 under the volumetric hydraulic loading rates of 0.105 and 0.21 d−1 in the CWs. Simultaneously, up to 91% of NH4+-N removal was achieved under the operation of a higher aeration ratio and effluent recirculation. Biological nitrogen transformations accounted for 94% of the consumption of alkalinity in the CWs. The significant enrichment of δ15N-NH4+ in the effluent (47–58‰) strongly supports the occurrence of microbial transformations for NH4+-N removal. However, relatively lower enrichment factors of δ15N-NH4+ (−1.8‰ to −11.6‰) compared to the values reported in previous studies reflected the inhibition effect of the high pH alkaline environment on nitrifiers in these CWs.

Biochar has been used for immobilizing heavy metals in soils due to its abundant surface functional groups and mineral components. However, as carbonaceous material, biochar in soils is susceptible to natural aging, which could alter its structural properties and ability to retain heavy metals. In this study, the impacts of pre- and post-application aging on the properties of dairy manure and sawdust biochars and the significance of different mechanisms of complexation with surface functional groups and mineral precipitation for Cd immobilization in soils were investigated. The simulated natural aging including 25 dry-wet cycles and 25 freeze-thaw cycles decreased the pH of biochar from 8.2 to 10.7 to 7.5–9.7 while increased the release of dissolved organic carbon from 4.1 to 10.9 to 5.9–21.3 mg L⁻¹, O/C ratios from 0.09 to 0.30 to 0.17–0.33, and O-containing functional groups, especially -OH and -C=O groups. New minerals such as CaC₂O₄ and MgO·MgCO₃ were formed during freeze-thaw cycles. The capacity of pre-aged biochars to immobilize Cd in soils decreased from 57-70% to 53–63%, compared to that of fresh biochar, which was mainly due to decrease of CdCO₃ or Cd₃(PO₄)₂ precipitation as evidenced by XRD and MINTEQ modeling. By contrast, post-aging of biochar application in soil with dry-wet and freeze-thaw cycling had little effect on the biochar's alkalinity while increased the O/C ratios from 0.10 to 0.24 to 0.15–0.27 and intensity of O-containing functional groups. The immobilization capacity of biochars for Cd in soil increased from 44-68% to 59–73% due to the enhanced surface complexation with O-containing groups. In short, biochar subjected to pre-aging had a reduced capacity to immobilize Cd, while biochars with post-aging in soil increased its Cd immobilization capacity as a soil amendment.

Sediments from a waste pit in Houston Ship Channel (HSC) were characterized using a number of molecular markers of natural organic matter fractions (e.g., pyrogenic carbon residues, PAHs, lignins), in addition to dioxins, in order to test the hypothesis that the dispersal and mobility of dioxins from the waste pit in the San Jacinto River is minimal. Station SG-6, sampled at the site of the submerged waste pit, had the highest dioxin/furan concentrations reported for the Houston Ship Channel/Galveston Bay (HSC/GB) system (10,000–46,000 pg/g), which translated into some of the highest reported World Health Organization Toxic Equivalents (TEQs: 2000–11,000 pg/g) in HSC sediments. Using a multi-tracer approach, this study confirmed our hypothesis that sludges from chlorinated pulps are a very likely source of dioxins/furans to this pit. However, this material also contained large quantities of additional hydrophobic organic contaminants (PAHs) and pyrogenic markers (soot-BC, levoglucosan), pointing to the co-occurrence of petroleum hydrocarbons and combustion byproducts. Comparison of dioxin/furan signatures in the waste pit with those from sediments of the HSC and a control site suggests that the remobilization of contaminated particles did not occur beyond the close vicinity of the pit itself. The dioxins/furans in sediments outside the waste pit within the HSC are rather from other diffuse inputs, entering the sedimentary environment through the air and water, and which are comprised of a mixture of industrial and municipal sources. Fingerprinting of waste pit dioxins indicates that their composition is typical of pulp and paper sources. Measured pore water concentrations were 1 order of magnitude lower than estimated values, calculated from a multiphase sorption model, indicating low mobility of dioxins within the waste pit. This is likely accomplished by co-occurring and strong sorbing pyrogenic and petrogenic residues in the waste pit, which tend to keep dioxins strongly sorbed to particles.