HMW Polycyclic Aromatic Hydrocarbons Research Articles

Multimedia distribution, dynamics, and seasonal variation of PAHs in Songhua wetland: Implications for ice-influenced conditions

The knowledge of polycyclic aromatic hydrocarbons (PAHs) in wetlands remains limited. There is a research need for the dynamics between interfaces of multimedia when ice is present in this fragile ecosystem. In this study, sediment, open-water, sub-ice water, and ice samples were collected from the Songhua wetland to study the behaviors of PAHs with and without influences from ice. The concentration of all individual PAHs in sub-ice water (370–1100 ng/L) were higher than the open-water collected from non-ice-covered seasons (50–250 ng/L). Enrichment of PAHs in the ice of wetland was found, particularly for high-molecular-weight PAHs (HMW). This could be attributed to the relatively lower polarity of hydrocarbons compounds, making them more likely to remain in the ice layer during freezing. Source assessments reveal common sources for sub-ice water and ice, which differ from those in the open water in non-ice-covered seasons. This difference is primarily attributed to heating activities in the Harbin during winter. The average percentage contributions were 79% for sub-ice water and 36% for ice related to vehicle exhausts and coal combustion. Additionally, wood burning contributed 25% to sub-ice water and 62% to ice. Sediment in the wetland was found to serve as a final deposit particularly for heavier PAHs, especially those with 6 rings. Sediment also has the potential to act as a source for the secondary emission of low-molecular-weight PAHs (LMW) congeners into the water. PAHs in wetland displayed low ecological risk, while HMW PAHs with relative higher ecological risk is recommended to be further monitored.

Toxicological Risk Evaluation of Polycyclic Aromatic Hydrocarbons in Soils from a Petroleum Spillage Site at Kokori in the Niger Delta Region of Nigeria

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants that are produced by the incomplete combustion of organic sources and are widely found in soils. This present research was carried out to evaluate the concentrations and toxicological risk assessment of the United States Environmental Protection Agency's sixteen priority polycyclic aromatic hydrocarbons (16 priority PAHs) in soils from the vicinity of an oil spillage site in Delta State of Nigeria. The level of pollution and potential toxicological health hazards of the PAHs were assessed in surface soil samples using soxhlet extraction of and Gas Chromatography-Mass Spectrometry (GC-MS). Thirteen out of the sixteen USEPA priority PAHs were detected in the soil sample. The concentrations of PAHs in the petroleum-contaminated soils in this investigation ranged from 0.01181 ppm to 1.16054 ppm, with the total estimated concentration of the 16 priority PAHs being 5.6713 ppm. Furthermore, the distribution of the PAHs in the study area was predominated by LMW PAHs (62%) over HMW PAHs (38%). Additionally, the total toxicity equivalency quotients TEQ (B[a]Peq) result of the carcinogenic potency of the USEPA priority PAHs was calculated as 0.08689 ppm (8.689%) and was discovered to be within the Canadian TEQ (B[a]Peq) threshold of 0.6 ppm. This suggests that the soil in the study area is safe based on the Canadian TEQ (B[a]Peq) standard and does not constitute a carcinogenic risk. However, the long-term bioaccumulation of these low quantities of PAHs in human has been found to constitute a potential health concern due to bioaccumulation in living systems.

Source, distribution, and risk assessment of polycyclic aromatic hydrocarbons in sediment and fish samples from River Owan, Edo State, Nigeria

Polycyclic aromatic hydrocarbons (PAHs) are persistent environmental contaminants that present several environmental risks including human health. The 16 priority PAHs including its 1-methylnaphthalene, and 2-methylnaphthalene were determined in sediment and fish samples (Clarias anguillaris and Oreochromis niloticus) of River Owan, Edo State, Nigeria using gas chromatography (GC) equipped with flame ionization detector (FID) and other standard laboratory protocols. The isomeric ratio was used for source diagnosis, sediment quality guidelines, and risk models of incremental lifetime cancer were used for risk assessment. 1-methylnaphthalene and 2-methylnaphthalene were most predominant in all sediment samples analysed. The ∑LMW PAHs ranged between 0.093—0.250 μg/kg; ∑HMW PAHs were 0.107—0.579 μg/kg. The sediment samples range for ∑PAHs was 0.280–0.810 μg/kg with concentration order of increase: SE5>SE4>SE3>SE6>SE1>SE2>SE7 for the seven sampling locations. The ∑PAHs for Oreochromis niloticus was 0.190 μg/kg, which is higher than the value of Clarias anguillaris 0.080 μg/kg, and these values were greatly lesser when compared to the European Commission limit of 12.00 μg/kg. The diagnostic ratio indicates that the sources are more pyrogenic than petrogenic, revealing combustion from grass, wood, and bush burning. Sediment quality assessment showed that the ∑PAHs were lower than the regulatory values of sediment quality guidelines (SQG) assessment suggesting no ecotoxicological effects on the benthic organisms in this area at present. The Incremental Life Cancer Risk results were in the range of 9.15 × 10−12—1.46 × 10−6 for children, and 7.78 × 10−12—1.76 × 10−6 for adults considering the three routes of exposure. The incremental life cancer risk assessment showed a negligible risk.

Trends and patterns of polycyclic aromatic hydrocarbons (PAHs) in forest fire-affected soils and water mediums with implications on human health risk assessment

Forest fires are extreme natural/artificial events releasing polycyclic aromatic hydrocarbons (PAHs), which are carcinogenic. Most of the released PAHs are trapped in burnt ash, a part of which is transported and settle on different mediums like soil and water. After strong rainfall events, PAHs enter into surface water bodies through surface runoff, thereby deteriorating water quality. Changes in PAHs levels during the post-fire duration and human health risks due to PAHs released from forest fires need attention. This study aim to explain the trends and patterns of PAHs and health risks due to exposure to soil and water contaminated with PAHs. Forest fires release a higher percentage of low molecular weight PAHs (LMW PAHs) than high molecular weight PAHs (HMW PAHs). Ash and burnt soils contain a higher percentage of LMW PAHs since biomass burning releases huge amounts of LMW PAHs. Whereas, sediments contain a higher percentage of HMW PAHs since most of the LMW PAHs are already degraded. HMW PAHs were causing higher risk to humans (both cancer and non-cancer) due to their higher oxidation potential. Exposure to water contaminated by PAHs resulted in higher health risks for both BaP equivalent and a mixture of PAHs. Exposure to sediment produced the highest health risk due to a higher percentage of HMW PAHs, followed by surface water, burnt soil, ash, and unburnt soil. Cancer and non-cancer risk due to dermal exposure was more elevated than oral exposure. The mixture of PAHs in sediment produced a higher average dermal risk for children (2.21E+00 for cancer and 7.69E+03 for non-cancer risk) and oral cancer risk for adults (7.11E-03). However, exposure to BaP equivalent in sediment produced higher oral non-cancer risk (7.01E+02) for children. Thus, effective PAHs monitoring is required in both soil and surface water mediums for ensuring proper treatment in water supply systems.

A review of the sources, distribution sequences, and health risks associated with exposure to atmospheric polycyclic aromatic hydrocarbons

Atmospheric polycyclic aromatic hydrocarbons (PAHs) are associated with adverse health effects in exposed populations. Understanding PAH pollution in ambient air and its adverse impacts is essential for developing effective actions for combating air pollution. This review paper summarised and discussed the findings of research work that determined the concentrations, distribution sequence, and health risk exposure levels of atmospheric PAHs in cities worldwide. It also gave an overview of the sources and the methodology for appraising the health risk of exposure to atmospheric PAHs. Eighty-five articles published in peer-reviewed journals from 2010 to 2023 were identified in academic research databases, with 55 reporting on sources and distribution of atmospheric PAHs, while 30 evaluated the health risk of exposure to PAHs in ambient air. The narrative review approach was employed to critically analyse and produce descriptive summaries of distribution patterns and health risk exposure levels of atmospheric PAHs in a tabular form. The review showed that the total PAH concentration in urban areas was about eight times greater than in rural environments and emanated from diverse sources. However, vehicle exhaust and industrial emissions were the primary sources of atmospheric PAHs. The distribution sequence of PAHs in particulate and gas phases was HMW>MMW>LMW PAHs and LMW>MMW>HMW PAHs, respectively. Chronic exposure to PAHs in the environment increased the risk of asthma, cardiovascular disease, and lung cancer. Adoption of stricter emission standards, cleaner energy sources, and more efficient industrial technology will aid in the reduction of particulate PAH pollution and its negative health consequences in urban areas.

In situ investigation of N deposit effects on polycyclic aromatic hydrocarbons (PAHs) photolysis in snow

As snow is an ideal scavenger of polycyclic aromatic hydrocarbons (PAHs) for both particulate- and gas-phase PAHs, a large amount of PAHs are accumulated in snowpacks. These PAHs could be released from seasonal snowpacks into environment over a short time during the snow melting period, causing a flush of contaminants. Understanding the fate of PAHs in snow therefore is important to evaluate the contaminant flush during snow melting. However, as an important natural process, PAH photolysis in snow is still unclear, especially in the context of global climate change. Therefore, photolysis of the 16 PAHs, which are listed as priority controlled pollutants by United States Environmental Protection Agency (US EPA), was investigated with N deposit in field in snow in this study. A mixture of the 16 US EPA priority PAHs and nitrate/ammonia were spiked into sealed quartzose bottles containing snow samples in field. The bottles were then exposed to solar radiation in field for 6 h. Experimental results showed that >50% of PAHs were lost during 6 h photolysis, mostly occurred in the first hour. Generally, HMW PAHs were photolyzed faster than LMW PAHs, though the photolysis rate did not strictly increase with molecular weight. Low concentrations of nitrate can enhance photolysis of Ant and Pyr, while photolysis of investigated PAHs was inhibited with nitrate concentration increasing. In contrast, both low and high concentration of ammonium can inhibit PAH photolysis. The inhibiting effect of both nitrate and ammonia on photolysis of HMW PAH is stronger than that of LMW PAHs, indicating direct photolysis of PAHs is the main pathway of PAH degradation in snow in situ. This study firstly showed the effect of N deposition on PAH photolysis in snow. Under current increasing N deposition in northeast China, this study implied that more PAHs in snow could be preserved during winter and released shortly during snowmelt, resulting in high ecological risk in spring.

Dissolved/dispersed polycyclic aromatic hydrocarbon spatial and temporal changes in the Western Gulf of Mexico

Oil extraction and transport activities in the Gulf of Mexico (GoM), along with major marine oil spills and riverine inputs, are exerting environmental pressure on this system by increasing the concentration of oil-related pollutants such as polycyclic aromatic hydrocarbons (PAHs). To fully identify these changes related to oil activities, current PAH levels should be established. Here, we present the PAH concentration and the low molecular weight/high molecular weight (LMW/HMW) ratios obtained in the Perdido Fold Belt area in surface and bottom water at four cruises from May 2016 to September 2017. The Perdido 1 (P1) cruise was conducted in May 2016, the Perdido 2 (P2) cruise in September–October 2016, the Perdido 3 (P3) cruise in June 2017, and the Perdido 4 (P4) cruise in September 2017. Samples were taken during each cruise at up to 3,500-m depth, the deepest ever recorded for the GoM. Results show that the highest concentrations of PAH, LMW PAHs, and HMW PAHs were found in the P4 cruise (1.15, 1.05, and 0.10 µg/L, respectively), well below the 300 µg/L guideline for acute exposure. LMW/HMW ratios show that only the P1 cruise indicates pyrogenic hydrocarbons, while P2, P3, and P4 were petrogenic. The spatial distribution of total PAH, LMW, and HMW showed higher values in the southern and northeastern areas, except for P4, which showed high values related to riverine inputs. The complex hydrodynamic in the region was found to have a significant effect on PAH seasonal changes, river contributions, eddy circulation, and fronts to promote their dispersion.

Snow-Dependent Biogeochemical Cycling of Polycyclic Aromatic Hydrocarbons at Coastal Antarctica.

The temporal trend of polycyclic aromatic hydrocarbons (PAHs) in coastal waters with highly dynamic sources and sinks is largely unknown, especially for polar regions. Here, we show the concurrent measurements of 73 individual PAHs and environmental data, including the composition of the bacterial community, during three austral summers at coastal Livingston (2015 and 2018) and Deception (2017) islands (Antarctica). The Livingston 2015 campaign was characterized by a larger snow melting input of PAHs and nutrients. The assessment of PAH diagnostic ratios, such as parent to alkyl-PAHs or LMW to HMW PAHs, showed that there was a larger biodegradation during the Livingston 2015 campaign than in the Deception 2017 and Livingston 2018 campaigns. The biogeochemical cycling, including microbial degradation, was thus yearly dependent on snow-derived inputs of matter, including PAHs, consistent with the microbial community significantly different between the different campaigns. The bivariate correlations between bacterial taxa and PAH concentrations showed that a decrease in PAH concentrations was concurrent with the higher abundance of some bacterial taxa, specifically the order Pseudomonadales in the class Gammaproteobacteria, known facultative hydrocarbonoclastic bacteria previously reported in degradation studies of oil spills. The work shows the potential for elucidation of biogeochemical processes by intensive field-derived time series, even in the harsh and highly variable Antarctic environment.

Polycyclic Aromatic Hydrocarbons (PAHs) Contamination in Chrysichthys nigrodigitatus Lacépède, 1803 from Lake Togo-Lagoon of Aného, Togo: Possible Human Health Risk Suitable to Their Consumption.

The Lake Togo-Lagoon of Aného is located in the coastal zone where phosphorite mining is carried out. This mining discharges all kinds of waste such as fuel oil into the surrounding environment without prior treatment. Moreover, the hydrosystem receives runoff and river inputs after having crossed and leached from mining and urban soils. This study aims to determine the polycyclic aromatic hydrocarbons (PAHs) contamination in commercially consumed fish species (Chrysichthys nigrodigitatus) from that hydrosystem and the associated health risks for consumers. For that, fish sample collection was performed during the dry season. Afterwards, their muscles, gills, and livers were cut and 12 PAHs were analyzed using gas chromatography coupled with a mass spectrometer (GC-MS). The total PAHs (tPAHs) concentrations in fish tissues ranged from 5.24 to 48.40 µg/kg with average concentration of 14.51 ± 8.95 µg/kg in muscles, from 5.90 to 28.20 µg/kg averaging 14.90 ± 5.19 µg/kg in gills, and from 43.20 to 149.00 µg/kg with an average of 80.74 ± 27.08 µg/kg in livers. The average concentrations of low molecular weight PAHs (LMW PAHs) were 10.82 ± 9.61 µg/kg in muscles, 8.25 ± 5.43 µg/kg in gills, and 47.97 ± 22.56 µg/kg in livers whereas those of high molecular weight of PAHs (HMW PAHs) were 4.10 ± 2.14 µg/kg in muscles, 7.98 ± 3.96 µg/kg in gills, and 32.77 ± 8.66 µg/kg in livers. An overall trend of decreasing concentrations with increasing fish size classes was observed for some PAHs (Naphtalene, Pyrene in muscles, for Pyrene, Benzo(a)Anthracene, Chrysene in gills and for Naphtalene, Phenanthrene in livers). The PAHs in these fish might have pyrogenic and petrogenic sources, with the dominance of pyrogenic, and all of the total hazard quotients (THQ) are less than 1. This situation must not be neglected for better planning sustainable management of the target ecosystem.

Biochar reduces uptake and accumulation of polycyclic aromatic hydrocarbons (PAHs) in winter wheat on a PAH-contaminated soil

Biochar has been used previously for remediation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soils for years, which has achieved remarkable results in improving removal of soil PAHs and reducing PAHs uptake in crops. However, the underlying mechanism of biochar application in reducing the uptake and accumulation of PAHs in winter wheat remains unclear. Pot trials using PAHs-contaminated soils were conducted for whole plant growth period of winter wheat, which were amended with 2% (w/w) bamboo biochar (BB), coconut shell biochar (CB) and maize straw biochar (MSB) or not (CK). Compared with CK, application of the three types of biochar significantly (p < 0.01) reduced grain PAHs concentration, the total equivalent concentration (TEC) values and the incremental lifetime cancer risk (ILCR) of grain PAHs, indicating that application of biochar reduced the exposure risk of PAHs in wheat grain, especially for MSB. Consistently, application of the three types of biochar significantly (p < 0.05) reduced uptake and accumulation of PAHs in root and stem of wheat, which may be due to that application of biochar enhanced the degradation of PAHs in the rhizosphere soil. Compared with CK, application of the three types of biochar significantly (p < 0.05) reduced the concentration of PAHs in the rhizosphere soil by 15.9%, 26.1% and 33.7%, respectively. It was found that the degradation rate of HMW PAHs (high molecular weight PAHs, 5-6 ring PAHs) was significantly (p < 0.05) higher than that of LMW PAHs (low molecular weight PAHs, 2-4 ring PAHs) regardless of types of biochar used. Additionally, application of the three types of biochar significantly increased the relative abundance of dominant bacterial phyla and genera in soil. Redundancy analysis and correlation analysis results also showed that there was a strong correlation between the removal rate of PAHs and dominant bacteria in the rhizosphere soil. The present study indicated that biochar could reduce dietary risk of PAHs in wheat grains mainly by increasing the abundance of bacteria related to PAHs degradation, promoting the biodegradation of PAHs in the rhizosphere soil and consequently reducing PAHs uptake in wheat.

Kapaciteti Hedera helix iz borskog regiona za akumulaciju PAU u korenu i implikacije za fitostabilizaciju

Polycyclic aromatic hydrocarbons (PAHs) are considered as the pollutants of highest priority, and their remediation is of a global concern. The purpose of this study was to investigate the phytoremediation potential of Hedera helix (Hh) determining the content of 16 priority PAHs in its soil and root samples collected from the rural and industrial zones of the Bor's municipality (Serbia). The content of Ʃ16 PAHs in the soils was: 326.49 mg/kg at the site Borsko jezero to maximal 1937.64 mg/kg at the site Slatinsko naselje. The level of soil pollution (depending on the concentration of S16 PAHs), was high at many tested sites and it was under the significant influence of anthropogenic activities. The concentration for S16 PAHs in the samples of roots ranged from 480.71 mg/kg at the site Krivelj to 1748.32 mg/kg at the site Naselje Sunce. Interestingly, the extremely toxic benzo(a)pyrene, was not detected in the roots of Hh. Bioconcentration factors (BCFs) were applied to determine the capacity of Hh for PAH accumulation in the root, and consequently, for determination of its phytostabilization potential. In most cases, BCF values were higher at the locations from UI zone. The calculated BCFs were higher for LMW PAHs than for HMW PAHs. At the majority of the investigated locations, the tested plant species was especially successful in the root accumulation of the compounds such as acenaphthene, fluorene, anthracene, dibenzo(a,h)anthracene, and the sum of benzo(k)fluoranthene and benzo(b)fluoranthene. These findings showed that Hh can be successfully used in phytostabilization of many PAHs.

Dissipation of a mix of priority PAHs in soils by using availability enhancers. Effect of aging and pollutant interactions.

A remediation strategy using three non-toxic availability enhancers (two cyclodextrins and a rhamnolipid biosurfactant) was applied to various soils artificially contaminated with a mix of Polycyclic Aromatic Hydrocarbons (PAHs) considered priority pollutants at two levels of contamination: only with 7 low molecular weight PAHs (LMW PAHs, 5 with 3-ring and 2 with 4-ring - fluoranthene and pyrene) or with 14 PAHs (from 3 to 6 rings). Natural attenuation of PAHs in all soils showed degradation capacity for the LMW PAHs, with a final content of LMW PAHs <5% of their initial concentration. Conversely, the rest of PAHs (high molecular weight PAHs, HMW) remained in the soils (61% - 83.5%), indicating abiotic dissipation of HMW PAHs due to formation of non-extractable residues in soils. The influence of the presence of HMW PAHs on the degradation of the 7 LMW PAHs was also tested, showing a general decrease in the time to obtain 50% dissipation (DT50), statistically significant for acenaphthene, acenaphthylene and fluorene. Availability enhancers showed different effects on PAHs dissipation. 2-hydroxypropyl-β-cyclodextrin (HP) decreased DT50 of some of the lighter PAHs, whereas the rhamnolipid (RL) caused a slight DT50 increase due to its initial toxicity on native soil microorganisms, but showing later high degradation rate for LMW PAHs. On the contrary, randomly methylated-β-cyclodextrin (RAMEB) slowed down PAHs degradation due to its high adsorption onto soil surface, blocking the desorption of PAHs from the soils. The high number of experimental factors not studied simultaneously before (soil type, co-contamination, availability enhancers and incubation time) allowed to conduct a statistical analysis which supported the conclusions reached. Principal Component Analysis separated the studied PAHs in 3 groups, in relation with their molecular weight and Kow. The first principal component was related with LMW PAHs, and separate the inefficient RAMEB from the other availability enhancers.

PAH EXPOSITION AND CARCINOGENICITY RISK EVALUATION IN SOILS FROM NIGER DELTA, NIGERIA

Environmental pollution has become a cross-cutting issue in recent decades, garnering the attention of governments, governmental agencies, the general public, and scientific communities, and (PAHs) is one of the biggest hazards to public health. PAHs were evaluated in Niger Delta soils using a gas chromatography-mass spectrometry (GC-MS) technique to assess their distribution, exposure, and carcinogenicity risk. The SS1 location in the city had the highest amounts of PAH. The toxic equivalency factor (TEF), incremental lifetime cancer risk (ILCRs) and as well as a global comparison analysis was employed. The results showed that three city sample locations surpassed the clean-up standards for BaP, 0.1 mg/kg, according to the data. Carcinogenic polycyclic aromatic hydrocarbons (PAHs) are those polycyclic aromatic hydrocarbons (PAHs) determined as Group A (known human) and Group B (probable) carcinogens and currently seven PAHs classified probable human carcinogens (Group B2). The majority of the risk associated with PAHs is attributed to benzo (a) pyrene and a few other PAHs. The results further revealed that six out of the seven HMW PAHs are known human carcinogens. The results of this study were found to be within permissible levels recommended. However, the authors strongly advocate a remediation alternative aiming at decontaminating the PAH-polluted soils at SS1, SS3, and SS2.

Effect of magnetite on the catalytic oxidation of polycyclic aromatic hydrocarbons in fly ash from MSW incineration: A comparative study of one-step and two-step hydrothermal processes

Polycyclic aromatic hydrocarbons (PAHs), many of which are carcinogenic, teratogenic, and mutagenic, exist in fly ash (FA) produced from municipal solid waste incineration (MSWI). Hydrothermal treatment (HT) is an efficient approach to remove PAHs from MSWI FA. Here, magnetite (Fe3O4) was used as the catalyst and hydrogen peroxide (H2O2) as the oxidant for one-step and two-step catalytic hydrothermal methods. When the magnetite dosage increased to 15 wt%, the maximum degradation rates of PAHs were 84.36% and 92.51%, respectively; however, the toxicity equivalent quantity (TEQ) degradation rates of the PAHs both increased upon increasing the magnetite dose. At 20 wt% Fe3O4, the maximum TEQ degradation rates of the PAHs were 93.29% and 97.76%, respectively. The reaction between OH and PAHs is non-selective, which means that LMW, MMW, and HMW PAHs were all degraded. The decrease in TEQ was mainly due to the degradation of HMW PAHs, i.e., those with five rings. Under the same Fe3O4 dose, oxidant dose, and reaction time, the detoxification of PAHs by the two-step method was significantly better than that of the one-step method, possibly because the two-step method more effectively produced OH. The first step degraded more than 90% of PAHs, and the residual PAHs in the HT products of the first step limited the utilization of the oxidant during the second step. The minerals in the HT products implied that the two-step hydrothermal method not only produced more OH, which reacted with PAHs, but also generated metal-magnetite substitution, which affected its surface reactivity during heavy metal adsorption and catalysis. These results revealed that both magnetite and the two-step hydrothermal treatment degraded PAHs. 20 wt% magnetite was the optimal amount during the two-step hydrothermal catalytic oxidation of MSWI FA.

Assessment of Polycyclic Aromatic Hydrocarbons Content in Marine Organisms of Commercial Interest from the Romanian Black Sea Coast

The purpose of this work was to assess the levels of polycyclic aromatic hydrocarbons (PAHs) in some mollusks and fish species, collected during the summer of 2016–2018, from three sites representing the southern, middle, and northern areas of the Romanian Black Sea coast. The PAHs concentrations were determined from the edible tissues of some important seafood (Rapana venosa and Mytilus galloprovincialis mollusk species; Sprattus sprattus, Engraulis encrasicolus, and Trachurus mediterraneus ponticus pelagic fish species and Neogobius cephalarges benthic fish species). The PAHs were analyzed using gas chromatography-mass spectrometry. The average concentrations of these PAHs ranged from below detection limit of 0.0001 to 103.09 ± 11.18 µg/kg wet wt. in mollusk species, from 0.0001 to 147.45 ± 9.28 µg/kg wet wt. in pelagic fish species and from 0.0001 to 45.73 ± 5.28 µg/kg in benthic fish species. Among the two mollusks species, Rapana venosa accumulated significantly higher concentrations (p < 0.05) of PAHs, while among fish species, Trachurus mediterraneus ponticus accumulated significantly higher concentrations (p < 0.05) of total PAHs. Total PAH concentrations varied between the sites; the main presence of PAHs was observed in site 2 (middle location), the major contribution being given by the presence of phenanthrene (Ph), anthracene (An), and naphthalene (Na). PAHs contents in organisms varied according to the different species, their location in the water, their feeding habits (pelagic and benthic organisms) and differences in the quantification of LMW and HMW PAHs. PAH distribution patterns in pelagic and mollusk species are characterized by the abundance of LMW-PAHs. Most of the PAHs had a petrogenic origin, which indicates that the anthropogenic activities influenced PAH concentrations. Apart from Neogobius cephalarges species, the benzo[a]pyrene concentrations, measured in mollusks and fish species did not exceed the EU recommended limit.

Occurrence and distribution of OCPs and PAHs in water, soil and sediment of Daye lake

To elucidate the concentrations, spatial distribution, sources, and risk of sixteen polycyclic aromatic hydrocarbons (PAHs) and twenty-four organochlorine pesticides (OCPs), thirteen sites were chosen for collecting water, sediment, and soil samples from Daye lake in April 2019. All pollutants were frequently observed in three media of Daye lake. Higher concentrations of OCPs were determined in the soil whereas PAHs were dominant among sediment samples. However, the water of Daye lake is contaminated with both of the pollutants. In water, ΣDRINs, ΣDDTs, ΣHCHs and LMW PAHs accounted for 22.1%, 19.6%, 17.9% and 85.5%, respectively. Among sediments, OCPs and PAHs were ranged from 1.53–51.38 ng·g−1 and 14.38–4659.66 ng·g−1, respectively. While soil accounted for a larger percentage of heptachlorepoxide i.e. 96.5% and HMW PAHs i.e. 82.7%. Furthermore, the low α-to γ-HCH ratio suggested fresh input of HCH and the higher ratio of (DDE + DDD)/DDT determined the historical use of DDT. Additionally, diagnostic molecular ratio along with principal component analysis evaluated that PAHs mainly came from fossil fuel, biomass, and coal combustion. Moreover, ecological risk assessment of Daye lake indicated that the carcinogenic PAHs in water and soil can pose 10% risk to the environment also OCPs in sediments has a visible effect on ecology. According to incremental lifetime cancer risks (ILCRs) evaluation, OCPs have negligible to low cancer risk among all sites for water, soil, and sediments while PAHs value fluctuate in the midst of 10−6 to 10−2 which shows the potential risk of cancer on children as well as adults. Therefore, measures should be taken to control them in time.

Investigation and Assessment of Polycyclic Aromatic Hydrocarbons Concentrations in Sediments at Drainage Discharge Points into the Mangrove Stretch of New Calabar River, Port Harcourt, Nigeria

Sediment samples were collected from surface of sediments from parts of the mangrove wetlands of the New Calabar River at points of effluents discharge. The samples were treated according to standard procedures and analyzed for the concentrations of polycyclic aromatic hydrocarbons (PAHs). The results showed the presence of ten PAHs at Iwofe Jetty and Police Post stations and eleven PAHs at the Minipiti station. The summation of the total PAHs in the stations showed 23.440, 33.694 and 51.094 mg/Kg in sediments from Iwofe Jetty, Minipiti and Police Post stations respectively. Pyrene was the most abundant PAH in sediment from Iwofe station, Dibenzo (a,h) anthracene was the most abundant PAH at the Minipiti Station and acenaphthylene was the most abundant PAH at the Police Post Station. The categorization of the PAHs classes showed that the high molecular weight PAHs (HMW PAHS) were more abundant than the low molecular weight (PAHs) in all the stations examined, although, at the Police Post station, the values were very close. The 4-membered rings were more abundant in sediments from Iwofe Jetty station. The 4 and 5-membered rings were more abundant at the Minipiti station and the 2-3 membered rings were dominant at the police Post station. The 6-membered rings were the least abundant or undetected in all the stations. Source and origin diagnosis showed that LMW/ HMW PAHs as pyrogenic in all the stations, An/(An+Phe) ratio revealed pyrogenic sources of PAHs, Fl/(Fl+Pyr) analysis in all the stations indicated petrogenic origin of PAHs, BaA/ (BaA+Chr) evaluation in all the stations revealed pyrogenic sources of PAHs. The mixed sources of PAHs in the wetlands drainage discharge points calls for concern and therefore, efforts should be geared to identify the points at which they were introduced into the effluents and be adequately controlled to prevent harm to the environment.

Sources and sinks evaluation of PAHs in leaves of Cinnamomum camphora in megacity: From the perspective of land-use types

Direct and indirect effects of complex urban land-use types on polycyclic aromatic hydrocarbons (PAHs), including their total amount, composition, sources and sinks, were evaluated from 84 sampling points in the megacity of Shanghai. We measured the content and composition of PAHs adsorbed by the leaves of Cinnamomum camphora and established buffers of different radii at each point. The different land-use types areas were counted therewith to investigate their effects on the sources and sinks of PAHs in leaves. Results showed that the average value of PAHs in the leaves was 3014.06 ± 1879.713 ng g−1. The substance profiles were dominated by medium-molecular-weight (MMW, 54%) and high-molecular-weight (HMW, 45%) PAHs, and these fractions were much higher than that of low-molecular-weight (LMW, 1%) PAHs. Through correlation analysis, the land-use type of industry, road, business, and residential areas were initially assessed as the sources of PAHs, whereas water, farmland, and woodland areas were sinks. Lasso regression proved that road and residential areas have proven to be the main source of PAHs in Shanghai, rather than industry and business areas. Woodland was found to be a better sink for PAHs than water and farmland. Sources and sinks of PAHs with different benzene rings also differed greatly: the main sources of MMW PAHs were industrial emissions and commercial activities, with the main sinks being water and woodland; the primary sources of HMW PAHs were traffic emissions and residential activities, with the main sink being farmland. This study assessed the sources and sinks of PAHs in cities, from the perspective of varied effects of different urban land-use types on PAH composition and spatial distribution, and bridged the gap between urban PAHs alleviation and the land-use planning in megacity, with instructive significance for planning policy development.

Placental levels of polycyclic aromatic hydrocarbons (PAHs) and their association with birth weight of infants

As an alarming group of pollutants, polycyclic aromatic hydrocarbons (PAHs) gather much public health concern not only because of their carcinogenic or co-carcinogenic risk but also by interfering with hormone systems or by causing oxidative damage, henceforth liable to toxic actions on reproduction. Accordingly, the present study was aimed to explore the association between in-utero exposure to PAHs by evaluating their placental levels and infant birth weight among 110 healthy and nonsmoking pregnant women. Placental tissue samples were collected instantly after delivery and were analyzed for the presence of sixteen Environmental Protection Agency (EPA) listed PAHs with the help of Gas chromatography equipped with flame ionization detector (GC-FID). Chrysene and benzo(k)fluoranthene were the predominant PAHs detected in tissue samples. To assess the source of origin of PAHs in placenta tissue samples, the ratio of low molecular weight PAHs to high molecular weight (∑LMW/∑HMW PAHs) was calculated, showing the predominance of pyrogenic sources of PAHs possibly responsible for the exposure of the studied population. Results of regression analysis demonstrated the inverse although not significant association of naphthalene (Nap), acenaphthylene (Acy), anthracene (Anth), pyrene (Pyr), benzo(b)fluoranthene (BbF), benzo(k)Fluoranthene (BkF), benzo(a)pyrene (BaP), indeno (123 cd pyrene (IcdP), dibenzo(ah)anthracene (DahA) and benzo(ghi)Perylene (BghiP) with birth weight of neonates. Additionally, the regression model lay light upon the significant association of fluoranthene (Fla) (coefficient= −1.41 gram, p < 0.05) to the depletion trend of birth weight after adjusting for potential covariates. These findings suggest the possible role of an environmental contaminants like PAHs on impairment of fetal growth.

Excitation–Emission Matrix Spectroscopy for Analysis of Chemical Composition of Combustion Generated Particulate Matter

Analysis of particulate matter (PM) is important for the assessment of human exposures to potentially harmful agents, notably combustion-generated PM. Specifically, polycyclic aromatic hydrocarbons (PAHs) found in ultrafine PM have been linked to cardiovascular diseases and carcinogenic and mutagenic effects. In this study, we quantify the presence and concentrations of PAHs with lower molecular weight (LMW, 126 < MW < 202) and higher molecular weight (HMW, 226 < MW < 302), i.e., smaller and larger than Pyrene, in combustion-generated PM using excitation-emission matrix (EEM) fluorescence spectroscopy. Laboratory combustion PM samples were generated in a laminar diffusion inverted gravity flame reactor (IGFR) operated on ethylene and ethane. Fuel dilution by Ar in 0% to 90% range controlled the flame temperature. The colder flames result in lower PM yields however, the PM PAH content increases significantly. Temperature thresholds for PM transition from low to high organic carbon content were characterized based on the maximum flame temperature (Tmax,c ∼ 1791 to 1857 K) and the highest soot luminosity region temperature (T*c ∼ 1600 to 1650K). Principal component regression (PCR) analysis of the EEM spectra of IGFR samples correlates to GCMS data with R2 = 0.988 for LMW and 0.998 for HMW PAHs. PCR-EEM analysis trained on the IGFR samples was applied to PM samples from woodsmoke and diesel exhaust, the model accurately predicts HMW PAH concentrations with R2 = 0.976 and overestimates LMW PAHs.