Toxic Effects of Heavy Metals and Organic Polycyclic Aromatic Hydrocarbons in Sediment Porewater on the Amphipod Hyalella azteca and Zebrafish Brachydanio rerio Embryos from Different Rivers in Taiwan

The amphipod (Hyalella azteca) and zebrafish (Brachydanio rerio) embryos were used for toxicological sediment porewater testing. Porewaters from 35 sampling stations of eight streams in southern Taiwan were screened for toxic effects and their relationship with 6 metal and 16 polycyclic aromatic hydrocarbons (PAHs). Concentration analysis results showed that the following PAHs, naphththalene, benzo(b)fluoranthene, dibenz(a,h)anthracene, acenaphthalene, and the heavy metal cadmium were not detected in 35 sampling stations. The highest detection rate of 94.1% was caused by the PAHs fluoranthene and pyrene. The highest detection rate of the metal zinc was 88.6% of 35 analyzed samples. The majority of samples (88%) were classified as level tier 1 according to USEPA national sediment inventory. This indicates the probability of adverse effects on aquatic life or human health. The results of a zebrafish embryo test showed that heart rate and survival were significantly reduced with all porewater samples. Therefore, fish exposed to contaminated river conditions may be affected in their cardiovascular functions. Looking at correlations between toxic effects of metals and PAHs, we found that phenanthrene, anthracene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, and benzo(a)pyrene were low, while fluorene was highly correlated with toxic effects of metals.

Unraveling the Transport and Fate of Polycyclic Aromatic Hydrocarbons Through Coupling Fluvial Geomorphic Modeling and Measured Data

Coastal zones receive upstream runoff and sediments, as well as the contaminants transported with sediments and flow. Constant urban growth in many coastal areas has raised an increasing concern about stream and floodplain contamination. This is a particularly challenging issue because fluvial hydraulics in the coastal zone is complex, due to the presence of backwater (BW) conditions which alter flow patterns and sediment transport regime. Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants that are widely distributed in urban areas and can be transported through stormwater runoff and by sediment facilitated transport. Even though this is a widespread problem in urban areas, the relationship between fluvial deposition and concentrations of PAHs is largely uninvestigated. To fill this gap, this paper investigates the correlation between PAHs concentration and sediment deposition in a backwater zone, using the lower Darby Creek, PA as a case study. A BW geomorphologic model was used to simulate the hydraulics of the flow in Darby Creek. The model identified locations of high and low shear stresses, erosion, and deposition of fluvial sediment. Twenty-eight core sediment samples, capturing a range of soil depths, were collected from the bed, the banks, and the floodplains of the creek and were analyzed for PAHs on a GC-MS. The results showed that PAHs concentrations were generally highest on depositional banks and were highly variable on the channel bed and in the floodplain. Further, PAH concentrations were more uniform across the cross section (bed, bank, and floodplain) at downstream sites compared to upstream. The results also showed that in erosional sites, unlike the depositional sites, there was little variation in PAHs concentration in the soil column. This analysis provides deeper insight into the transport and fate of PAHs in urban streams and floodplains, ultimately helping mitigate the impacts of pollutants on the environment.

Characterization of PAHs Trapped in the Soot from the Combustion of Various Mediterranean Species

Climate change causes more frequent and destructive wildfires even transforming them into megafire. Moreover, all biomass fires produce emissions of carbon compounds in the form of soot to the atmosphere with a significant impact on the environment and human health. Indeed, the soot is causing the formation of PAHs from (a) the high temperature thermal alteration of natural product precursors in the source organic matter and (b) the recombination of molecular fragments in the smoke. However, these molecules are known to have carcinogenic effects on human health. It is therefore interesting to quantify the 16 PAHs concentration extracted from soot emitted in open diffusion flame of biomass combustion. To achieve this objective, an analytical method developed for the study of kerosene combustion has been adapted for soot from biomass. This new method allowed to quantify the 16 PAHs defined as priority pollutants by the US EPA for their carcinogenic mutagenic effect and on human health.

Multiple Land-Use Fugacity Model to Assess the Environmental Fate of PAHs – A Mega-City Under COVID-19 Pandemic

Along with the accelerated process of urbanization, the contradiction between social development and environment become increasingly conspicuous. Herein, we access the transport and fate of polycyclic aromatic hydrocarbons (PAHs) by a newly proposed multiple land-use fugacity (MLUF) model to provide comprehensive understanding of PAHs distribution in an urban and suburban areas. PAHs behave differently towards distinct soil types and land covers within the soil phase. We suggest and implement the MLUF model to estimate the PAHs distribution in diverse land types. Moreover, we introduce a multivariate interpretation and systematic model calibration framework to validate the MLUF model adaptability in different land-use area. Accordingly, the organic film on impervious surfaces holds the highest PAHs concentration than other compartments, also soil and sediment phases keep most of PAHs. The potential cancer risk of PAHs in different land-usecompartments follow the order of urban green space > agricultural area > forest and semi-nature area. Besides, the dynamic MLUF model is developed and implemented to the period of COVID-19 pandemic for quantitively estimating the dynamic variations of the PAHs concentration. Finally, we can realize the better scientific understanding of the typical PAHs environmental pollutants transfer phenomena and distribution fates in urban and suburban areas.

Predicting the Total PAHs Concentrations in Sediments from Selected Congeners Using a Multiple Linear Relationship

In this study, four congeners, i.e., naphthalene (Nap), acenaphthylene (Acy), phenanthrene (Phe) and benz(a)anthracene (BaA), screened out by hierarchical clustering analysis from 16 PAHs, are the characteristic PAHs congeners in emission sources and in sediments. Novel multiple linear relationships, i.e., the total PAHs emission factors and the total PAHs concentration with the emission factors of Nap, Acy, Phe and BaA and their sediment concentrations data reported in the past 30 years were established, respectively. The same characteristic congeners observed for PAHs in sediments and in emission sources indicates that the concentration of PAHs in sediments are largely dependant on the PAHs emission. Moreover, the ratio of multicomponents coefficient from the multiple linear relationship in sediments to that in emission sources correlated positively with the logKow values and biodegradation half-lifes of four characteristic congeners, indicating PAHs concentrations in sediments are also alternated by their environmental behaviors including sorption and biodegradation. However, the established relationship gives a useful way to predicted C∑PAHs in sediments without the PAHs emissions data and can eliminate the effects of environmental behaviors and the difference of emissions in various regions.

Degradation of Polycyclic Aromatic Hydrocarbons by Consortium 5H Under Hypersaline Conditions

PAHs were widely detected accumulated in saline and hypersaline environments. The halotolerant and halophilic microbes were considered as the most suitable player for the elimination of PAHs in such environments. In this study, consortium 5H was enriched under 5% salinity that was able to completely degrade phenanthrene in 5 days. By high-throughput sequencing, consortium 5H was identified mainly composed of Methylophaga, Marinobacter and Thalassospira. Combined with the investigation of intermediates and enzymatic activities, the degradation pathway of consortium 5H on phenanthrene was proposed. Meanwhile, consortium 5H was identified with ability to tolerate a wide range of salinity (1% to 10%) and initial PAHs concentration (50 mg/L to 400 mg/L). It was also able to work under neutral to week alkaline conditions (pH from 6 to 9) and the phytotoxicity of the produced intermediates showed no significant difference with distilled water. This study expanded the knowledge of PAH-degradation under hypersaline environments and consortium 5H was proposed with a good potential for the elimination of PAHs pollution under saline/hypersaline environments.

Environment impact and probabilistic health risks of PAHs in dusts surrounding an iron and steel enterprise

Dust can be regarded as environmental medium that indicates the level and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) coming from different pollution sources. In this study, samples including road dust, roof dust, and bare soil near an iron and steel enterprise (ISE) in Laiwu city of North China were collected. To assess the environment impact, atmosphere particulates and one flue dust from a coking plant were simultaneously sampled. Sixteen USEPA PAHs were detected quantitatively by Gas Chromatography Mass Spectrometry (GC–MS). A laser particle size analyzer was used to obtain the grain size of the dust particle samples. The results showed that PAH concentrations displayed great variability in the dust samples. The ∑16PAHs concentration was found to be between 0.460 and 46.970 μg/g (avg ± sd 10.892 ± 1.185 μg/g) in road dust, between 0.670 and 17.140 μg/g (avg ± sd 6.751 ± 0.692 μg/g) in roof dust, and 13.990 ± 1.203 μg/g in bare soil. In the environment atmosphere sites, the ∑16 PAHs value in PM2.5 constituted a very large proportion of PM10, indicating that PAHs in finer particle sizes should be given greater emphasis. The ∑16PAHs concentration was relatively high in the area close to the ISE because of the great impact of the ISE industrial activities. PAH concentration curves were similar, and the most abundant individual PAHs in the atmosphere sites were BbF, BkF, and Flu, and BbF, BkF, and Chry in dusts. Toxicity analysis revealed that PAHs with four rings, including carcinogenic PAHs, were the dominant pollutants in the studied area. The toxic equivalency value (TEQBaP), the carcinogenic health risk assessment value recommended by the US EPA, was calculated for seven carcinogenic PAHs, revealing that they account for more than 93.0% of the total TEQBap of the 16 PAHs and indicating the major toxic equivalent concentration contributor. Incremental lifetime cancer risk (ILCR) estimation results showed that PAHs tended to bring about great health risks through skin contact, followed by ingestion and inhalation. By comparison, road dust exhibited greater carcinogenic risks than roof dust, and bare soil may undergo heavier pollution. Therefore, the results of this study would be helpful in the effort to understand the PAHs pollution from the steel industry, which will provide some guidance for the probabilistic assessment of local health risks.

Characteristics and Health Risks of Polycyclic Aromatic Hydrocarbons and Nitro-PAHs in Xinxiang, China in 2015 and 2017

Fine particulate matter (PM2.5) samples were collected in the summer and winter of 2015 and 2017 in Xinxiang, China. Nine polycyclic aromatic hydrocarbons (PAHs) and three nitro-PAHs (NPAHs) in PM2.5 were detected via high-performance liquid chromatography (HPLC). The PAHs concentration in summer and winter decreased from 6.37 ± 1.30 ng/m3 and 96.9 ± 69.9 ng/m3 to 4.89 ± 2.67 ng/m3 and 49.8 ± 43.4 ng/m3 from 2015 to 2017. NPAHs decreased in winter (from 1707 ± 708 pg/m3 to 1192 ± 1113 pg/m3), but increased in summer from 2015 (336 ± 77.2 pg/m3) to 2017 (456 ± 312 pg/m3). Diagnostic ratios of PAHs indicated that petroleum combustion was the main emission source in summer, and pollutants originating from the combustion of petroleum, coal and biomass dominated in winter. The 2-nitrofluoranthene (2-NFR)/2-nitropyrene (2-NP) ratio in this study demonstrated that the OH radical pathway was the main pathway for the formation of 2-NP and 2-NFR. The mean total benzo[a]pyrene-equivalent concentrations (BaPeq) and incremental lifetime cancer risk (ILCR) values decreased from 2013 to 2017. The high value of total BaPeq in the winter of 2017 in Xinxiang revealed that a high-risk of cancer remained for residents. The results of this study demonstrate that the decreases in PAHs and NPAHS concentrations from 2015 to 2017. Combined with reducing gaseous pollutants concentration, the reduction in this study might be attributable to emissions reductions by implementing the air pollution control regulations in Xinxiang city in 2016.