Evaluation Of Polycyclic Aromatic Hydrocarbons Research Articles

Chronological evaluation of polycyclic aromatic hydrocarbons in sediments of tangxun lake in central China and impacts of human activities.

This study sheds light on the contamination of polycyclic aromatic hydrocarbons (PAHs) in Tangxun Lake sediments, an urban lake reflecting environmental changes in Central China. By analyzing sediment cores from both the inner and outer areas of the lake, we determined the historical trends and sources of PAHs over the past century. The results reveal a significant increase in PAHs concentrations, particularly since the 1980s, coinciding with China's rapid urbanization and industrialization. Using diagnostic ratios and Absolute principal component score-multivariate linear regression (APCS-MLR) methods, we identified petroleum combustion, coal combustion, and biomass combustion as the primary sources of PAHs in the lake sediments. The spatial analysis indicates higher PAHs levels in the inner lake, likely due to its closer proximity to industrial activities. Moreover, by comparing PAH trends in Tangxun Lake with those in other urban, suburban, and remote lakes across China, based on data from 49 sedimentary cores, we highlight the impact of regional socio-economic dynamics on PAH deposition. These insights are crucial for developing effective pollution mitigation strategies and promoting sustainable development in rapidly urbanizing regions.

Levels, distribution, origins, and human health risk evaluation of polycyclic aromatic hydrocarbons in groundwater around a petroleum depot wastewater discharge point

This study is an attempt to assess the influence of the oil storage depot discharges on proximate water sources in Ibadan, southwest Nigeria. Fifteen priority polycyclic aromatic hydrocarbons (PAHs) were examined in a total of 15 water samples (10 groundwater +4 surface water samples) utilizing gas chromatography–mass spectrometry, after extraction of the waters with dichloromethane and clean-up of the extracts. Results revealed that values of overall PAHs in groundwater (GW) and surface water (SW) varied from 0.01 to 3.45 mg/L (mean = 0.42 mg/L) and 0.01 to 0.09 mg/L (mean = 0.05 mg/L), correspondingly. The highest value of ∑15 PAHs (3.45 mg/L) was observed at 24 m to the discharge point. The ring wise distribution pattern of the PAHs in collected water samples follows the order: 2–3 rings >5–6 rings >4 – ring PAHs and low molecular weight (LMW) PAHs accounted for 90.73% relative to HMW (9.27%) in groundwater samples. The diagnostic ratios suggested that the PAHs pollution in water were likely from incomplete combustion of fossil fuels, vehicle emissions and released petroleum effluents from nearby depot. The concentration of carcinogenic PAHs in GW and SW ranged from 1×10−2to 9×10−2 mg/L and 1×10−2to 7×10−2 mg/L, correspondingly, which highlights possible human health risks. The values of hazard index (HI) for the studied samples via the oral ingestion and dermal exposure pathways are less than unity, suggesting no adverse non-carcinogenic health effects. The calculated incremental lifetime cancer risk (ILCR) for adults and children are in the 10−2–10−3 range, implying noteworthy possible carcinogenic health effects to human beings, with children being the most susceptible. Correspondingly, dibenzo [a, h] anthracence (DahA) and Benzo [a] pyrene (BaP) were established to be of greater carcinogenic threats in the waters taken from the study location. The study advocates complete discontinuance of discharge release into the neighboring environment.

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.

Dietary Exposure, Risk and Toxicological Evaluation of Polycyclic Aromatic Hydrocarbons in Some Grains (Beans, Soya Beans, Corn, Guinea Corn) from Markets in Nigeria

Dietary Exposure, Risk and Toxicological Evaluation of Polycyclic Aromatic Hydrocarbons in Some Grains (Beans, Soya Beans, Corn, Guinea Corn) from Markets in Nigeria

Occurrence and exposure evaluation of polycyclic aromatic hydrocarbons in tea samples consumed in Beijing-Tianjin-Hebei regions of China

In this study, the concentrations of polycyclic aromatic hydrocarbons (PAHs) were investigated in a total of 129 tea samples marketed in Beijing-Tianjin-Hebei (BTH) regions of China. The total concentrations of 16 PAHs (Σ16 PAHs) varied from 16.6 to 781.6 μg/kg with a mean value of 211.7 μg/kg. Tea samples were contaminated mainly with low molecular weight PAH compounds. During tea infusion, 4.9–9.3% of the Σ16 PAHs contained in different types of tea samples were released into the liquor. The dietary exposure of PAHs and risk assessments of adults in BTH region were then performed by calculating estimated daily intake (EDI), margin of exposure approach (MOE) and incremental lifetime cancer risk (ILCR). Compared to semi-fermented or unfermented tea samples, EDIs of PAHs in fullyfermented tea displayed the highest exposure risk. The MOEs results in all six types tea for local population are at safe range (MOE ≥ 10,000). These ILCR values indicated there is significant potential of carcinogenic risk related to tea consumption, but no significant cancer risk.

Evaluation of polycyclic aromatic hydrocarbons and potentially toxic metals in commonly consumed pasta products available in the Nigerian markets

BackgroundLevels of polycyclic aromatic hydrocarbons (PAHs) and potentially toxic metals (Cd, Co, Cu, Mn, Pb, and Zn) were determined in three batches of eight types of commonly consumed pasta products (A - H) available in Nigeria. This was done in order to evaluate the health hazards associated with unguarded consumption of the products. MethodsA gas Chromatography-Flame Ionization Detector (GC-FID) was used to identify and quantify the levels of sixteen polycyclic aromatic hydrocarbons in Soxhlet-extracted fractions of powdered pasta product samples using n-hexane, while Atomic Absorption Spectrometer (AAS) was also used to quantify the levels of the metals in the acid digested pasta samples. ResultsThe recovery results (%R>90) confirmed the efficiency of the adopted analytical procedures. Levels of PAHs detected in the samples ranged between below detection limit (BDL) and 17.18 μg g-1 with total PAHs (μg g-1) occurring in the order: F > H > D > C > E > A > G > B. Potentially toxic metal concentrations (µg g-1) in the various pasta samples were of the order: Cd ˂ Cu ˂ Zn ˂ Mn, while Co and Pb were BDL in all the pasta samples. ConclusionThe pasta samples contained PAHs and potentially toxic metals at levels that could not cause immediate health infection but which could threaten the health of the consumers over prolonged regular consumption.

Evaluation of polycyclic aromatic hydrocarbons in sediments of Balsas River Mouth, Pacific Coast, Mexico: Sources, risks, and genotoxicity

Polycyclic aromatic hydrocarbons (PAHs) were assessed in sediments (n = 7) collected from the mouth of the Balsas River, Pacific Coast, Mexico. The total PAH levels ranged between 142.1 and 3944.07 μg kg−1 in the summer and 137.65–3967.38 μg kg−1 in the winter, probably reflecting the anthropogenic activities of the region. Calculation of the four analytical ratios of [Anthracene/(Anthracene + Phenanthrene)]: [Fluoranthene/(Fluoranthene + Pyrene)], [Fluoranthene/Pyrene: Fluoranthene/(Fluoranthene + Pyrene)], [Indeno [123-cd]Pyrene/(Indeno [123-cd]Pyrene + Benzo [ghi]Perylene)]: [Benzo [a]anthracene/(Benzo [a]Anthracene + Chrysene)], and [Anthracene/Phenanthrene]: [Fluoranthene/(Fluoranthene + Pyrene)] revealed a mixed PAH source, from petroleum and biomass combustion. Significant statistical correlations (r2 = 0.90) between the 4 and 5 ringed PAHs denote that adsorption is the principal mechanism for accumulation in sedimentary archives. Ecotoxicological indices (Mean Effect Range Medium Quotient and Mean Probable Effect Level Quotient) indicated moderate pollution with adverse biological impacts on ambient benthonic organisms. The calculations of Toxicity Equivalent Quotient and Mutagen Equivalent Quotient values proposed that the region is highly polluted by mutagenic and carcinogenic PAH compounds. The genotoxic evaluation of Lutjanus guttatus (Spotted rose snapper) presented significant DNA damage and discrepancies in Ethoxyresorufin-O-Deethylase activity. Based on the toxicological and genotoxicological evaluation of PAHs in sediments, the region was observed to be largely impacted from biological damage.

Evaluation of polycyclic aromatic hydrocarbons (PAHs) in processed cereals: A meta-analysis study, systematic review, and health risk assessment

BackgroundThe present study investigated the contamination of processed cereals such as bread, spaghetti, flour, and bran, with polycyclic aromatic hydrocarbons (PAHs). Scope and approachThe databases such as PubMed, Scopus, and Science Direct were searched from 14/December/1972 to 25/May/2021. Key findingsWe identified 639 articles and selected 18. The highest PAH concentrations found in bread, spaghetti, flour, and bran were related to anthracene, chrysene, fluorene, and naphthalene, respectively. On the other hand, the lowest PAH concentrations found in bread, spaghetti, flour, and bran were related to benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, anthracene and dibenz[a,h]anthracene, respectively. Moreover, carcinogenetic and mutagenic risk assessment of the PAHs revealed a country-to-country variation. As a result, evaluation and control of PAHs in cereals should be done.

Evaluation of Polycyclic Aromatic Hydrocarbons in Smoked Cheeses Made in Poland by HPLC Method.

Smoked cheeses are particularly popular among consumers for their flavor and aroma. Of interest, therefore, is the health aspect related to the likelihood of polycyclic aromatic hydrocarbons (PAHs), which are known carcinogens found in smoked products. Thus, the purpose of this study was to evaluate the occurrence of 15 polycyclic aromatic hydrocarbons (PAHs) in smoked and non-smoked cheeses purchased in Poland to monitor their safety. The level of selected PAHs in cheese samples was determined using the HPLC-DAD-FLD method. Most of the cheeses tested met the maximum level of benzo[a]pyrene (2 μg/kg) and the sum of benz[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene (12 μg/kg) established for these products. However, all the cheeses studied in this work had relatively low amounts of the sum of these compounds compared to the information available in the cheese literature, ranging from <LOD to 24.5 μg/kg. This amount does not pose a health risk to consumers. The predominant PAHs found were naphthalene, phenanthrene, fluorene and acenaphthene. Benzo[a]pyrene, the marker compound representing carcinogenic PAHs, was found in 100% and 0% of Polish smoked and non-smoked cheeses, respectively. Although there are currently no regulations for smoked cheeses and maximum concentrations of PAHs in this type of food product, control of PAHs content in cheeses is important due to the mutagenic and carcinogenic potential of these chemicals.

Toxicity evaluation of polycyclic aromatic hydrocarbons (PAHs) in soils of coal chemical industry areas, North China.

Objectives of this study were to investigate the concentrations, distributions, toxicities, and risk assessment of 16 polycyclic aromatic hydrocarbons in surface soils surrounding a coal chemical industrial zone in the southeast of Shanxi province, China. A total of 52 topsoil samples were collected from different land-use areas: cereal agriculture, roadsides, and parkland. Results show that the total PAHs (∑16PAHs) ranged from 3.87 × 103 to 116 × 103µg kg-1 and that the total carcinogenicity PAHs (∑BPAHs) ranged from 3.11 × 103 to 94.2 × 103µg kg-1, with the highest concentration of ∑16PAHs noted in the RS samples, followed by PS and AS. The entire risk quotient of all PAH maximum permissible concentrations (RQ∑PAHMPCi) was greater than 1.0, and the minimum concentration entire risk quotient (RQ∑PAHNCi) of 84.3% of all samples was higher than 800. The value of the total toxicity equivalent concentration of PAH (PAHBapeq) for areas surrounding the coal chemical industrial zone was higher than the value of the standard level, and the incremental lifetime cancer risk (ILCR) far exceeds the U.S. EPA's risk standard. The toxic properties of PAHs indicated that the soils in the survey areas have a high risk to human health and the environment.

Evaluation of polycyclic aromatic hydrocarbons (PAHs) in bottled water samples (non-carbonated, mineral, carbonated and carbonated flavored water) in Tehran with MSPE-GC/MS method: a health risk assessment

Polycyclic aromatic hydrocarbons (PAHs) are dangerous environmental compounds that are sometimes found in food. The objective of present study was to measure the level of 16 PAHs in bottled water samples (non-carbonated or drinking, mineral, carbonated and carbonated flavored water) in Tehran by using magnetic solid-phase extraction and gas chromatography–mass spectrometry (MSPE/GC–MS) method. The limit of detections (LOD), limit of quantifications (LOQ) and recovery of PAH compounds were 0.010–0.210, 0.03–0.700 μg/L and 92.5–103.4%, respectively. The results showed that the mean of total PAHs in samples was 2.98 ± 1.63 µg/L and the mean of Benzo[a]pyrene (BaP) was 0.08 ± 0.03 µg/L, which were lower than standard level of the US-EPA (0.2 µg/L, BaP in drinking water). Also, our results showed that carbonated flavored water had maximum mean of total PAHs (4.95 ± 0.8 µg/L) and mineral water had minimum mean of total PAHs (1.24 ± 0.8 µg/L). The Monte Carlo method was applied to calculate the Estimated Daily Intake (EDI) and Incremental Life Cancer Risk (ILCR) indexes. In all samples, the rank order of the estimated CDI values based on the 95 percent percentile was F > B(a)A > Ace > Fl > Na > Ph > B(b)F > B(k)F > B(a)P > P > Ac > A. The cancer risk and uncertainty analysis of 95th Percentile for bottled waters studied gave values lower permissible limit of 10−6, indicating not pose a serious concern to humans.

Evaluation of polycyclic aromatic hydrocarbons in silky sharks Carcharhinus falciformis collected from Western Indian Ocean and human health risk assessment

The silky shark (Carcharhinus falciformis) is the most abundant and widely distributed shark species in the marine system of tropical regions. However, it appears that there is limited information on USEPA 16 polycyclic aromatic hydrocarbons (PAHs) concentration in silky shark muscle tissue, which has together with the lack of a health risk assessment of human consumption of silky shark filets. The potential toxicity of PAHs in muscles of silky sharks and cancer and non-cancer risk of consumers were assessed. Results showed that the total PAHs (TPAHs) concentration in the muscle tissue of silky sharks was between 62 and 657 ng/g ww, with an average of 234 ± 221 (mean ± standard deviation) ng/g ww, and can be considered as minimally to moderately contaminated level. Naphthalene (NA), phenanthrene (PH), and fluoranthene (FLU) are the most abundant PAHs in silky sharks muscle tissue, accounting for 38.6%, 11.0%, and 19.0% of TPAHs, respectively. The average values of toxic benzo[a]pyrene (BaP) equivalent (TEQcarc) and toxic dioxin equivalent (TEQfish) of PAHs equal to the potency of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in silky shark muscle are 13.5 ± 16.4 ng BaP/g ww and 34.1 ± 77.4 pg TCDD/g ww, respectively, and they showed a good linear relationship (r = 0.928; p < 0.001). The TEQcarc of silky sharks muscle is higher than USEPA's screening value of PAHs of 3.2 ng BaP/g ww for adults, indicating a potential negative impact on public health. The calculated hazard index (HI) of PAHs is less than 1, suggesting that residents eating silky shark muscle will not expect to cause significant non-cancer risk. However, the incremental lifetime cancer risk (ILCR) of BaP as 10.6–26.3% and 8.2–32.4% in males and females, respectively, may pose a significant cancer risk. In general, children and the elderly have relatively higher risks, as well as males have a higher cancer and non-cancer risk than females.

Evaluation of Polycyclic Aromatic Hydrocarbons in Dried Leaves of Yerba Mate (Ilex paraguariensis) and Their Extraction into Infusions

ABTRACT Herbal teas and yerba mate infusions are an important part of the human diet that may contain toxic contaminants due to the industrial processing of the herbal material. The presence of the lipophilic compounds polycyclic aromatic hydrocarbons (PAHs) was investigated in dry yerba mate samples and how they transfer into the infusions. Samples were selected among eight different brands, and three types of yerba mate products (aged, green, and roasted). Synchronized fluorescence scanning (SFS) was used as primary screening method for PAHs in dried yerba mate, and high-performance liquid chromatography with fluorescence detection for the analysis of the infusions. SFS screening showed presence of PAHs in the dry herbal material, and the PAHs ratios suggest that the contamination originates from pyrogenic sources. Using an experimental setup to simulate the traditional yerba mate consumption (successive extractions with small amounts of water), the sum of the six PAHs in each infusion of yerba mate sample ranged from 4.8 to 30.2 ng g−1. Benzo [a] pyrene concentration ranged from n.d. to 1.1 ng g−1 while phenanthrene reached a maximum of 59 ng g −1 in the yerba mate samples tested. An estimated 0.11% to 0.54% of the six PAH analytes were transferred into the infusion and the SFS method can be used to screen the presence of PAHs in the dry material. The chemical profile of the most abundant PAHs found in the infusions indicate a low total equivalent exposure index.

Evaluation of polycyclic aromatic hydrocarbons (PAHs) in the corn drying process

The pre-processing of agricultural products has great importance in the quality of the product, the most critical process, is the drying of grains, in which thermal energy is demanded. Since biomass burning produces polycyclic aromatic hydrocarbons (PAHs), which can be associated with carcinogenesis The objective of this study was to perform an assessment of the presence of PAHs derived from the maize drying process using Cavaco burning as a fuel source. The experiment was conducted in the municipality of Cascavel-Paraná, in a storage unit located in Colônia Melissa, using a Kepler Weber column dryer model ADS 150, with a capacity of 150 t/h, with an IMTAB chip burner, with capacity of 8,000,000 kcal/h. To assess the presence of PAHs, corn samples were collected at the entry of the product into the storage unit (control) and samples were collected after the drying process with two passes in the dryer, for five days, every hour during eight hours a day, in the period of harvest/2020. All results obtained were below the detectable limit of 0.6 µg/kg. It is concluded with this study that the drying process of corn using chips in burners does not significantly produce PAHs, thus not harming the quality of the grain.

Toxicological risk evaluation of polycyclic aromatic hydrocarbons in boreholes located within unsanitary dumpsite in Nnewi, Anambra State, Nigeria

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) from unlined dumpsites have contributed significantly to the pollution of the environment. This study investigates the pollution level of unlined dumpsite by determining the PAH levels of boreholes around the dumpsite. 16 upstream samples and 16 downstream samples (control) were obtained during the wet and dry seasons. The levels of PAH were evaluated using Gas Chromatography interfaced with a flame ionisation detector. Carcinogenic (TEQ) and mutagenic (MEQ) equivalents of PAHs in the borehole samples were evaluated. Carcinogenic and non-carcinogenic related risks were evaluated via dermal and ingestion pathways. Possible sources of PAHs in the borehole were evaluated. The PAH levels in the upstream and downstream locations ranged from ND – 113.13 µg/L and ND – 1.25 µg/L respectively. Total PAHs concentrations in the upstream and downstream ranged from 12.36–135.68 µg/L and 3.63–5.57 µg/L respectively. The upstream samples PAHs concentrations were greater than the downstream samples PAHs values in the wet and dry seasons. The PAH values in the rainy season were greater than the dry season values, which was associated with leachate infiltration from the dumpsite. Dibenz(a,h)anthracene was established to be of greater carcinogenic and mutagenic threats in the borehole samples from the study areas. The non-carcinogenic risk seems unlikely through dermal absorption, while they are a possibility of carcinogenic risk through dermal absorption for both child and adult age categories. The hazard index value of 3.219 recorded for the child age category at the upstream location, was the only possible chance of non-carcinogenic risk through ingestion. Carcinogenic risks through ingestion were unlikely but can accumulate to toxic levels if not checked. Diagnostic ratio’s values inferred that PAH’s origins arepredominantly from pyrolytic and petrogenic sources for upstream sites and petrogenic sources for downstream sites.

PAH source differentiation between historical MGP and significant urban influences for sediments in San Francisco Bay

A forensic source evaluation of polycyclic aromatic hydrocarbons (PAHs) in nearshore sediments in San Francisco Bay examined total PAH greater than ambient concentrations in sediments, and potential pyrogenic source relationships with respect to PAH compounds typically associated with point and nonpoint pyrogenic source types, including PAHs potentially associated with historical manufactured gas plant (MGP) operations. Diagnostic source ratio analysis was employed for determination of potential PAH source relationships. A two-model approach indicated distinct potential source signatures, as identified from the distributions of higher PAH concentrations in some sediments. Source characterization was aided by Polytopic Vector Analysis (PVA) and data visualization with t-Distributed Stochastic Neighbor Embedding (t-SNE). Two signatures exhibited pyrogenic character likely consistent with historical MGP sources, and one signature was related to creosote. A distinct and significant source of PAHs to the investigation area sediment consisted of ubiquitous nonpoint and potential unidentified point sources is termed “urban influence”.

Evaluation of Polycyclic Aromatic Hydrocarbons (PAHs) in Bamboo Shoots from Soil.

The toxicity, carcinogenicity and persistence of polycyclic aromatic hydrocarbons (PAHs) pose a great threat to the ecological system and human health. The contamination levels, translocation and source analysis of 16 PAHs in bamboo shoot and its planted soil were investigated. The average concentrations of total PAHs were 18.80 ± 1.90 µg/kg and 123.98 ± 113.36 µg/kg in bamboo shoots and soils, respectively. The most abundant PAH was Phenanthrene (PHE), with the detected average concentrations of 5.85 µg/kg in bamboo shoots and 19.28 µg/kg in soils. The highest detected types of PAHs were 3 rings and 4 rings, with the proportions of 80.69% (bamboo shoots) and 35.23% (soils). The transfer factors of PAHs were ranged from 0.011 to 0.895, in which PAHs with 3 rings showed the strongest transfer ability. The combustion of biomass and petroleum might be the main source of PAHs in the planted soils of bamboo shoots.

Concentration and Risk Evaluation of Polycyclic Aromatic Hydrocarbons in Soils from the Vicinity of Selected Petrol Stations in Kogi State-Nigeria

Polycyclic aromatic hydrocarbons (PAHs) are highly teratogenic, persistent, carcinogenic, and ubiquitous environmental contaminants. They present potential threats to the ecological environment and human health. Nine composite soil samples (three from each town) were collected at a depth of 0 – 30 cm using soil auger from the vicinity of selected petrol handling facilities (petrol stations) within three major towns in Kogi State-Nigeria, between September and October, 2020. The samples were analyzed for concentrations, distribution, sources and toxic potentials of emission of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs), since no such comprehensive study had been conducted in the area. The total concentrations of PAHs (∑PAHs) in soil samples from the vicinity of nine petrol stations within three major towns in Kogi State-Nigeria ranged from 2.66 to 5.64 μg/kg at Ankpa, 1.58 to 7.58 μg/ kg at Anyigba and 3.72 to 4.98 μg/kg at Idah, with an average of 4.03 μg/kg. Lower molecular weight PAHs (2 - 3 ring PAHs) dominated the PAH profiles, accounting for 69.2% of total PAH mass. The levels of individual PAHs in all the soil samples were below the Dutch maximum permissible concentration (MPC) for urban residential and agricultural soils. The average benzo[a]pyrene equivalent concentration (BaPeq) of the detected PAHs in the study area was 0.245 μg/kg, indicating a relatively low toxicity and carcinogenic potential. Diagnostic ratios of the results showed that PAHs in surface soil samples from the study area were of mixed origin (petrogenic and pyrolytic sources). The Pearson product moment correlation (PPMC) coefficient (r) explored the correlation between the environmental properties and the occurrence of PAHs. Among the physicochemical parameters studied, organic carbon and soil organic matter showed high positive correlation with PAHs concentration. When compared with the Maximum Permissible Concentrations for soil, statistical test at P < 0.05 revealed that the difference in PAHs concentrations is not significant. This is an indication that filling station soils in the study area within the period of investigation was safe. However, strict adherence to Department of Petroleum Resources (DPR) guidelines is highly recommended in siting and operating petrol handling facilities to further mitigate the presence of these pollutants.

The distribution and toxicity evaluation of polycyclic aromatic hydrocarbons in the textile dyeing sludge

The distribution and toxicity evaluation of polycyclic aromatic hydrocarbons in the textile dyeing sludge

A systematic evaluation of polycyclic aromatic hydrocarbons in South Atlantic subtropical mangrove wetlands under a coastal zone development scenario

Mangrove forests worldwide are threatened environments considered vulnerable to chronic contamination by hydrophobic contaminants such as polycyclic aromatic hydrocarbons (PAHs). These ecosystems have a key role in the dynamics of biogenic and anthropogenic carbon storage and provide proper conditions for accumulation. One of most important subtropical mangrove swamps in the South Atlantic is located in the Paranaguá Estuarine System (PES), the largest bay of South Brazil surrounded by well-preserved Atlantic rainforests; however, the PES is under imminent risks of damage, e.g., due to incidental oil spills during port operations. In this scenario, PAHs were assessed for the first time in the mangrove sediments of the PES. The concentrations of 16 priority PAHs (EPA) (<DL – 234.3 ng g−1, 36 samples) were higher than those observed in previous studies for bottom sediments and had a similar order of magnitude as those for other human-impacted mangroves but were lower than those of other heavily impacted mangroves. A moderate level of anthropic contamination was observed, and the main probable sources of PAHs were navigation and domestic effluents. Bulk parameters (TOC/TN ratio and δ13C) showed the estuarine land-sea gradient and helped define the preferential sites of PAH deposition due to its correlation with TOC and fine sediments. Marine hydrodynamics and/or dilution processes had a major influence on PAH distribution, resulting in higher concentrations in the inner/sheltered areas of the estuary and lower values in the outer zone of the estuary with higher hydrodynamic energy. The environmental features and anthropogenic forcing of the PES added to the relative absence of a detailed evaluation of the levels of and environmental risks posed by PAHs in other subtropical mangrove ecosystems located in the Southern Hemisphere, reinforcing the importance of the current study.