Long-Term Trend of Polycyclic Aromatic 1 Hydrocarbon (PAH) Concentrations in Tokyo from 2007 to 2016: Effects of Changes in PAH Emissions and Degradation.

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in aerosol were measured in Shinjuku, which is central Tokyo, Japan, for 10 years from 2007 to 2016. The effects of changes in emission sources and their degradation by reaction with ozone were assessed in this study. There was no significant increasing or decreasing trend of the PAH concentrations during 10 years (P > 0.05). The average selected seven the PAH concentrations (0.88 ng m−3) during 10 years was lower than those in New York and Paris. However, the trend of ozone concentrations is increasing in central Tokyo. This inconsistency raises a question. Did the fact that the ozone concentration was higher than the PAH concentrations promote PAH degradation? To apportion the PAH sources, we used PAH concentration profiles and positive matrix factorization analysis. The contribution of vehicle emissions to the PAHs ranged from 40 to 80 %. Ozone concentrations increased by 3.70 %/year during 10 years. The theoretical degradation rates of PAHs by ozone, which were calculated using a pseudo-first-order rate equation, suggested that the lifetimes of benzo[a]pyrene (BaP) decreased by 1 min from 2007 to 2016. We investigated the aging of BaP using the profile of the isomer ratios. We found that the aging of BaP at the urban and roadside sites were nearly identical indicating aging regardless of the season. Although the decomposition of BaP is promoted by the photochemical oxidation reaction, this result suggests that a certain threshold value exists as the degree of the decomposition. This degradation of PAH can improve chemical loss processes in air quality model.

Bioaccumulation and Consumption Safety of a Sea Food, Gastropod Mollusc (Thais coronata): Polycyclic Aromatic Hydrocarbon (PAH) Perspective

Seafood and other environmental matrices are major entry route of harmful pollutants into humans due to constant contamination of the aquatic environment hence requires monitoring. This study scientifically explored the hypothesis that benthic gastropods bioaccumulate harmful pollutants that pose health risk to consumers of the sea food. Fifty samples of Thais coronata were collected per site from major regional fish landings. Two hundred samples were collected monthly for eight months to determine the concentrations of polycyclic aromatic hydrocarbon-PAH and possible health risks due to consumption using regulatory limits for guidance. Total PAH concentrations (μg/kg) varied between 65.68–173.52 suggesting differences in consumed concentrations at different times. The concentration of individual PAH congeners (1.376 ± 0.07-40.356±2.21 μg/kg) and PAH4 were below the European Union maximum limits. The Daily Dietary Intake values ranged from 0.075-2.212 μg/kg for individual PAH congeners while that of PAH4 was 1.359 μg/kg and were all below their respective reference oral doses. The carcinogenic potencies of the PAH congeners ranged from 0.001-143.389, the carcinogenic toxic equivalents (TEQs) of all PAH congeners was 0.1522 while that of PAH4 was 0.0044. The Excess cancer risk (ECR) value (10-8–10-5) was within USEPA guideline of 10-6 while the margin of exposure (MOE) of individual PAHs and PAH4 were higher than critical border line of 10,000 given by European Food Safety Authority but diagnostic ratio suggested PAH sources of pyrogenic origin in samples monitored. The study concluded low health risk for consumers of the shellfish (Thais coronata) in the study region but with recommendation advisory for regular monitoring to observe changes.

Atmospheric concentration, temporal and spatial variations, and sources identification of persistent organic pollutants in urban and semi-urban areas using the passive air samplers

In this study, the ambient persistent organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) concentrations were measured for 12 months at urban and semi-urban areas using the passive air sampler. During the sampling period, a total of 14 PAH (∑14PAH) concentrations measured in urban and semi-urban areas were found as 54.4 ± 22.6 ng/m3 and 51.7 ± 34.3 ng/m3, respectively. Molecular diagnostic ratios (MDRs) were used to determine PAH sources. According to the MDR values, combustion sources are the most important PAH sources in both sampling areas. However, since the urban area is close to the industrial zone, the combustion sources occurred at high temperatures (> 800 oC), while the semi-urban area generally consisted of burning petrogenic fuels. ∑50PCB concentrations measured in the urban and semi-urban areas were found as 522.5 ± 196.9 pg/m3 and 439.5 ± 166.6 pg/m3, respectively. Homologous group distributions were used to determine the source of PCBs. According to homologous group distributions, Tri-, Tetra-, and Penta- chlorinated PCBs were dominant in both sampling areas. ∑10OCP concentrations measured in urban and semi-urban areas were found as 242.5 ± 104.6 pg/m3 and 275.9 ± 130.9 pg/m3, respectively. Also, α-HCH/γ-HCH and β-/(α + γ)-HCH ratios were used to determine the source of OCPs. Lindane was the predominated OCP in both sampling areas.

Urbanization-Related Changes Over the Last 20 Years in Occurrence, Sources and Human Health Risks of Soil PAHs in Rural Tianjin, China

Polycyclic aromatic hydrocarbons (PAHs), one of the key pollutants in urban areas, have presented a great risk to the resident health. So far, however, studies in-depth on changes of local PAH emissions and associated health risks closely related to urbanization are scarce. Here, the concentrations of PAHs were determined in 57 surface soil samples obtained from two rural districts in 2018 in Tianjin, China. The sources, risks and the linkage between urbanization and PAH contamination of soil PAHs in 2018 were compared with the data in 2001 from a previous study to investigate the changes related to urbanization effects. The temporal changes in the concentrations and composition of PAHs for two districts were similar. The increased total concentrations of soil PAHs could be attributed to the fact that ANT and DahA became the dominated compounds, which was related to changes of the PAH sources. Results of the positive matrix factorization model suggest that the major sources of soil PAHs changed from coal combustion (32.9%), petroleum sources (32.1%), and traffic sources (22.1%) in 2001 to traffic sources (63.7%) and petroleum and biomass combustion (18.7%) in 2018. Results from incremental lifetime cancer risk (ILCR) model showed that the carcinogenic risk of soil PAHs to residents also increased from safe level to low level, and dermal contact was the prevailing pathway of PAH exposure. The increase in cancer risks were mainly related to the alterations of PAH sources.

Improvements in identification and quantitation of alkylated PAHs and forensic ratio sourcing

Parent and alkylated polycyclic aromatic hydrocarbons (PAHs) are present in a number of different sources in varying proportions depending on the source material and weathering. This range of PAH sources can make it difficult to determine the origin of exposure(s). Ratios of alkylated and parent PAHs have been applied as a forensic tool to distinguish between different sources. However, few studies have examined PAH ratios comprehensively as indicators for sourcing beyond a single study area or matrix type. In this paper, we introduce an expanded analytical method based on ASTM D7363-13a which we adapted for a gas chromatography triple quadrupole mass spectrometry instrument. The modifications increase selectivity and sensitivity compared to the ASTM method. We added five alkylated series to the method. This method has then been applied to 22 independent forensic ratios. We evaluated the method and the forensic ratios with certified reference materials and known environmental samples. This analytical method and thirteen PAH ratios were found to accurately predict sources of PAHs. Graphical abstract

Pollution Sources and Carcinogenic Risk of PAHs in PM1 Particle Fraction in an Urban Area

Airborne particles are composed of inorganic species and organic compounds. PM1 particles, with an aerodynamic diameter smaller than 1 μm, are considered to be important in the context of adverse health effects. Many compounds bound to particulate matter, such as polycyclic aromatic hydrocarbons (PAH), are suspected to be genotoxic, mutagenic, and carcinogenic. In this study, PAHs in the PM1 particle fraction were measured for one year (1/1/2018–31/12/2018). The measuring station was located in the northern residential part of Zagreb, the Croatian capital, close to a street with modest traffic. Significant differences were found between PAH concentrations during cold (January–March, October–December) and warm (April–September) periods of the year. In general, the mass concentrations of PAHs characteristic for car exhausts (benzo(ghi)perylene (BghiP), indeno(1,2,3-cd)pyrene (IP), and benzo(b)fluoranthene (BbF)) were higher during the whole year than concentrations of fluoranthene (Flu) and pyrene (Pyr), which originated mostly from domestic heating and biomass burning. Combustion of diesel and gasoline from vehicles was found to be one of the main PAH sources. The incremental lifetime cancer risk (ILCR) was estimated for three age groups of populations and the results were much lower than the acceptable risk level (1 × 10−6). However, more than ten times higher PAH concentrations in the cold part of the year, as well as associated health risk, emphasize the need for monitoring of PAHs in PM1. These data represent a valuable tool in future plans and actions to control PAH sources and to improve the quality of life of urban populations.