Physicochemical Characterization of the Particulate Matter in New Jersey/New York City Area, Resulting from the Canadian Quebec Wildfires in June 2023

The global increase in wildfires, primarily driven by climate change, significantly affects air quality and health. Wildfire-emitted particulate matter (WFPM) is linked to adverse health effects, yet the toxicological mechanisms are not fully understood given its physicochemical complexity and the lack of spatiotemporal exposure data. This study focuses on the physicochemical characterization of WFPM from a Canadian wildfire in June 2023, which affected over 100 million people in the US Northeast, particularly around New Jersey/New York. Aerosol systems were deployed to characterize WFPM during the 3 day event, revealing unprecedented mass concentrations mainly in the WFPM0.1 and WFPM0.1-2.5 size fractions. Peak WFPM2.5 concentrations reached 317 μg/m3, nearly 10 times the National Ambient Air Quality Standard (NAAQS) 24 h average limit. Chemical analysis showed a high organic-to-total carbon ratio (96%), consistent with brown carbon wildfires nanoparticles. Large concentrations of high-molecular-weight PAHs were found predominantly bound to WFPM0.1, with retene, a molecular marker of biomass burning and a known teratogen, being the most abundant (>70%). Computational modeling estimated a total lung deposition of 9.15 mg over 72 h, highlighting the health risks of WFPM, particularly due to its long-distance travel capability and impact on densely populated areas.

Assessing the potential risks, sources and the relationship between the dissolved and particulate polycyclic aromatic hydrocarbons (PAHs) in the typical semi-enclosed bay, Bohai Bay of China

This study aimed to investigate the spatial and temporal distribution as well as the partitioning behavior of dissolved and particulate polycyclic aromatic hydrocarbons (PAHs) during the summer and autumn seasons of 2020. It was found that the average concentration of PAHs in surface seawater was significantly higher in autumn (58.16 ng L-1) than in summer (40.47 ng L-1) due to a large amount of input in autumn and more photodegradation and biodegradation affected by higher temperatures in summer. The spatial distribution indicated that the river had a significant dilution effect on PAHs in summer and became a significant input source in autumn. In addition, a large number of oil and gas development platforms were distributed throughout the Bohai Bay, and the discharge of production and domestic sewage contributed to the PAHs pollution level. As a semi-enclosed bay, the water exchange capacity of Bohai Bay was poor, leading to a greater accumulation of PAHs in the marine environment. The diagnostic ratios and PCA-MLR indicated that petroleum was the most important source of PAHs with a contribution of 45%, followed by fuel combustion (39%) such as coal and oil. Photooxidation in seawater resulted in a reduction of BaP/BeP, indicating that seasonal variations in photooxidation had a significant impact on the composition of PAHs (summer: 1.49, autumn: 2.96). The concentration of particulate PAHs was correlated with the concentration of dissolved PAHs and SPM, and the proportion of 3-rings (43.8%) and 4-rings (49.8%) PAHs was significantly higher on SPM. The distribution coefficients Log Kd and φspm-water showed a trend of increasing and then decreasing as the number of rings increased, with the 4-rings Pyr exhibiting the highest value. According to the ecological risk assessment, the ecological risk of total PAHs was low (RQNCs < 800, RQMECs < 1), but the ecological risk of individual PAHs and the carcinogenicity of high-ring PAHs could not be ignored (＞96.5%). This study is significant for investigating the "sources and sinks" of PAHs in the complex marine environment by analyzing the partitioning behavior of PAHs in different phases.

Spatio-temporal distribution and sources identifications of polycyclic aromatic hydrocarbons and their alkyl homolog in surface sediments in the central Arabian Gulf

The quantitative analysis of 18 parents and their alkyl homologs was performed in sediment samples from the central Arabian Gulf (Gulf) around Qatar Peninsula in six sequential seasons, winter 2014 to spring 2015, at 21 locations with a water depth range of 1.5-60 m. PAHs distribution was patchy with higher concentrations found inside semi-enclosed coastal areas like harbors and bays. The mean PAHs concentration was 112 ng·g^-1 dry weight with a range of 0.6 to 1560 ng·g^-1 and a variability coefficient of 2.4. The PAHs mean concentration was highest in the winter by a factor of 5 compared to mean summer concentration. A significant seasonal variability in the concentrations of ∑PAHs is mainly attributed to variability in the concentrations of the low molecular weight PAHs fraction and the less alkylated PAHs. Alkylated-PAHs were the most dominant PAHs comprising about 50% of the ∑PAHs, and with about 6 times higher than the mean concentrations in the winter compared to the mean summer concentration. The LPAHs concentrations correlated negatively with temperature and ∑PAHs correlated positively with % clay. Principal component analysis was used to identify sources of PAHs. PAHs in the Gulf have mixed sources with an estimated 57% from petroleum and 43% from pyrogenic sources. Coastal water hydrodynamics and lateral transport processes affect the distribution and composition of PAHs in the central Gulf.

Concentration and sources of fine particulate associated polycyclic aromatic hydrocarbons at two locations in the western coast of India

PM2.5 particulate matter (PM) and their associated polycyclic aromatic hydrocarbons (PAHs) were studied at Urban and Sub-urban sites in the western coast of India. The concentration of PM2.5 ranged from 66.29 μg m-3 to 182.15 μg m-3, being the highest at Sub-urban site than the urban site. There were total six carcinogenic PAHs found to be dominated in particulate samples at these locations. The general trends observed for individual carcinogenic PAHs concentration at urban location was, benzo(a)pyrene (BaP) Collapse

Key Words

• Carcinogenicity
• Fine particulate matter
• PAHs
• Source apportionment
• Urban and sub-urban

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MESH Headings Collapse

Grants

• EPA999999 Intramural EPA

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Affiliation(s)

Jamson Masih Department of Chemistry, Wilson College, Mumbai 400007, India
Swathi Dyavarchetty Department of Chemistry, Wilson College, Mumbai 400007, India
Ashwati Nair Department of Chemistry, Wilson College, Mumbai 400007, India
Ajay Taneja Department of Chemistry, Dr. Bhimrao Ambedkar University, Agra 282002, India
Raj Singhvi Environmental Response Team, USEPA, Edison, NJ, USA

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Polybrominated diphenyl ethers, organochlorine pesticides, and polycyclic aromatic hydrocarbons in water from the Jiulong River Estuary, China: levels, distributions, influencing factors, and risk assessment

Estuarine systems play an important role in the transportation and transformation of organic pollutants from rivers. Polybrominated diphenyl ether (PBDE), organochlorine pesticide (OCP), and polycyclic aromatic hydrocarbon (PAH) concentrations in water of the Jiulong River Estuary (JRE), China, were investigated to characterize their distribution, possible source, and potential ecological risk as well as the influencing factors. The total concentrations of PBDEs, OCPs, and PAHs varied from 5.2 to 12.3 pg L^-1, from 29.1 to 96.4 ng L^-1, and from 28.6 to 48.5 ng L^-1, respectively. Their compositions were all consistent at different stations; even the input pathways were multifarious. A source analysis showed that PBDEs may come from the flame retardant usages of penta-BDE and deca-BDE; hexachlorocyclohexane isomers (HCHs) were from the use of technical HCHs, while DDTs were attributed to early residuals of industrial sources, and PAHs were mainly from pyrolytic sources. The spatial distributions of PBDEs and OCPs were quite similar with their concentrations, decreasing along the estuary and then increasing when passing the Xiamen Harbor. PAH concentrations were similar along the whole estuary, suggesting that local sources and hydrological conditions might be the influencing factors. The concentrations of these pollutants changed with tidal conditions and were positively correlated with SPM, DOC, and chlorophyll a but negatively correlated with salinity. The ecological risk assessment revealed that OCPs and PAHs posed slightly higher potential risks to aquatic organism in the study area.