Pollution characteristics and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the southern part of the Haihe River system in China

Polycyclic aromatic hydrocarbons in indoor mosques dust in Saudi Arabia: Levels, source apportionment, human health and carcinogenic risk assessment for congregators

Mosques are important places for Muslims where they perform their prayers. The congregators are exposed to hazardous pollutants such as polycyclic aromatic hydrocarbons (PAHs) associated with dust. However, studies on PAHs exposure in religious places are scarce. Air-condition filter (ACF) dust can correspond to air quality to a certain extent, since dust particles derived from indoor and outdoor places stick to it. Therefore, the present study aimed to evaluate the 16 EPA PAHs in ACF dust from mosques to determine their levels, profiles, sources and risks. Average Σ16 PAHs concentrations were 1039, 1527, 2284 and 5208 ng/g in AC filter dust from mosques in residential (RM), suburban (SM), urban (UM) and car repair workshop (CRWM), respectively, and the differences were statistically significant (p < 0.001). Based on the molecular diagnostic PAH ratios, PAHs in mosques dust is emitted from local incomplete fuel combustion, as well as complete fossil fuels combustion sources (pyrogenic), petroleum spills, crude and fuel oil, traffic emissions, and other possible sources of industrial emissions in different functional areas. The incremental lifetime cancer risks (ILCRs) values for children and adults across the different types of mosques follow the order: CRWM > UM > SM > RM. ILCRs values for both children and adults were found in order: dermal contact > ingestion > inhalation. The cancer risk levels via ingestion for children were relatively higher than the adults. The values of cancer risk for children and adults via dermal contact and ingestion (except in RM) were categorized in the 'potentially high risk' category (> 10-4). The mean values of total cancer risks (CR) for children (5.74 × 10-3) and adults (5.07 × 10-3) in mosques also exceeded the accepted threat value (>10-4). Finally, it is recommended that regular and frequent monitoring of PAHs should be carried out in mosques to improve the quality and maintain the health of congregators around the globe.

Organic matter sources and distribution along land-use gradient in a Himalayan foothills River: Insights from molecular markers

The analysis of hydrocarbon biomarkers in surface sediments along the Markanda River in the foothills of the Indian Himalayas was conducted to gain insights into the distribution and composition of organic matter (OM) within the sediments. This investigation is essential for comprehending how anthropogenic changes are influencing the OM dynamics in river systems. The study involved identification and quantification of various compound groups such as n-alkanes, hopanes, steranes, polycyclic aromatic hydrocarbons (PAHs), linear alkyl benzenes (LABs) and phthalate esters along with their respective parametric ratios. The variation in distribution of n-alkanes and associated indices (odd-even carbon number predominance (OEP), average chain length (ACL), terrigenous to aquatic ratio (TAR), carbon preference index (CPI), and natural n-alkanes ratio (NAR)) were used to distinguish the natural source of organic content from those influenced by anthropogenic contamination. The detection of petroleum contamination was indicated by the presence of prominent unresolved complex mixtures (UCM) as well as specific petroleum biomarkers such as hopanes, diasteranes, and steranes. The study revealed varying concentrations of the analyzed organic pollutants, with the average of PAHs at 24.6 ng/g dw, LABs at 18.1 ng/g dw, and phthalates at 8.3 μg/g dw. The variability in concentration of the investigated compound groups across different locations indicated spatial heterogeneity, and the land use patterns appears to modulate the sources of OM in surface sediments. The source contribution of PAHs and phthalates determined by positive matrix factorization (PMF) shows the predominant sources of the anthropogenic hydrocarbons were linked primarily to petroleum/petroleum-derived products emissions, industrial discharges, cultural practices and common household waste/sewage disposal. This analysis provides insights for developing mitigation strategies and informing relevant policy changes globally, thereby contributing to the broader understanding of anthropogenic impacts on water ecosystems.

Ecotoxicological and health risks associated with sediment-bound polycyclic aromatic hydrocarbons in peri-urban closed and open coastal lagoons

Coastal urbanisation has ramifications for the sustainable development of developing nations. There are often unquantified ecological and health risks associated with urbanisation. Sixteen polycyclic aromatic hydrocarbons (PAHs) were analysed in surface sediment from three peri-urban coastal lagoons in southern Ghana. We found significant spatial variations of sediment PAHs. These variations were attributed to physiography of the lagoons and diverse anthropogenic activities surrounding them. Total PAHs ranged from 20.81 to 24,801.38 μg/kg (dry weight), underscoring a low to very high pollution level. Diagnostic ratios revealed both pyrogenic and petrogenic origins. Over 50 % of individual PAHs were of moderate ecological risk to benthic organisms, and cancer risk to humans was above the World Health Organisation's recommended safety limit (1 × 10-6). These ecological and health risks should be wake-up call for a more integrated urban planning approach to coastal urbanisation as coastal communities largely depend on natural ecosystems for food and livelihood opportunities.

Extraction of persistent lagrangian coherent structures for the pollutant transport prediction in the Bay of Bengal

Lagrangian Coherent Structures (LCS) are the hidden fluid flow skeletons that provide meaningful information about the Lagrangian circulation. In this study, we computed the monthly climatological LCSs (cLCS) maps utilizing 24 years (1994-2017) of HYbrid Coordinate Ocean Model (HYCOM) currents and ECMWF re-analysis winds in the Bay of Bengal (BoB). The seasonal reversal of winds and associated reversal of currents makes the BoB dynamic. Therefore, we primarily aim to reveal the cLCSs associated with seasonal monsoon currents and mesoscale (eddies) processes over BoB. The simulated cLCS were augmented with the complex empirical orthogonal functions to confirm the dominant lagrangian transport pattern features better. The constructed cLCS patterns show a seasonal accumulation zone and the transport pattern of freshwater plumes along the coastal region of the BoB. We further validated with the satellite imagery of real-time oil spill dispersion and modelled oil spill trajectories that match well with the LCS patterns. In addition, the application of cLCSs to study the transport of hypothetical oil spills occurring at one of the active oil exploration sites (Krishna-Godavari basin) was described. Thus, demonstrated the accumulation zones in the BoB and confirmed that the persistent monthly cLCS maps are reasonably performing well for the trajectory prediction of pollutants such as oil spills. These maps will help to initiate mitigation measures in case of any occurrence of oil spills in the future.

Concentrations, sources and risks of polycyclic aromatic hydrocarbons in sediments from the Parnaiba Delta basin, Northeast Brazil

The Parnaíba River is the main river in the Parnaíba Delta basin, the largest delta in the Americas. About 18 polycyclic aromatic hydrocarbons (PAHs) were identified and the environmental risk associated with the sediments was evaluated. The study found that PAHs levels ranged from 5.92 to 1521.17 ng g-1, which was classified as low to high pollution, and that there were multiple sources of pollution along the river, with pyrolytic sources predominating, mainly from urban activity such as trucking, although the influence of rural activity cannot be ruled out. PAHs correlated with black carbon and organic matter and showed high correlation with acenaphthylene, phenanthrene, pyrene, benzo(a)anthracene, chrysene, benzo(ghi)perylene, and ∑PAHs. The benzo(a)pyrene levels were classified as a risk to aquatic life because the threshold effect level and the probable effect level were exceeded. In addition, the sediments were classified as slightly contaminated with a benzo(a)pyrene toxicity equivalent value of 108.43 ng g-1. Thus, the priority level PAH exhibited carcinogenic and mutagenic activity that posed a potential risk to human health.

Microbial electrochemical system: an emerging technology for remediation of polycyclic aromatic hydrocarbons from soil and sediments

Worldwide industrialization and other human activities have led to a frightening stage of release of hazardous, highly persistent, toxic, insoluble, strongly adsorbed to the soil and high molecular weight ubiquitous polycyclic aromatic hydrocarbons (PAHs) in soils and sediments. The various conventional remediation methods are being used to remediate PAHs with certain drawbacks. Time taking process, high expenditure, excessive quantities of sludge generation, and various chemical requirements do not only make these methods outdated but produce yet much resistant and toxic intermediate metabolites. These disadvantages may be overcome by using a microbial electrochemical system (MES), a booming technology in the field of bioremediation. MES is a green remediation approach that is regulated by electrochemically active microorganisms at the electrode in the system. The key advantage of the system over the conventional methods is it does not involve any additional chemicals, takes less time, and generates minimal sludge or waste during the remediation of PAHs in soils. However, a comprehensive review of the MES towards bioremediation of PAHs adsorbed in soil and sediment is still lacking. Therefore, the present review intended to summarize the recent information on PAHs bioremediation, application, risks, benefits, and challenges based on sediment microbial fuel cell and microbial fuel cell to remediate mount-up industrial sludge, soil, and sediment rich in PAHs. Additionally, bio-electrochemically active microbes, mechanisms, and future perspectives of MES have been discussed.

State of polycyclic aromatic hydrocarbon (PAH) contamination in the Saint John Harbour, New Brunswick, Canada

This study examined the concentrations and compositions of polycyclic aromatic hydrocarbon (PAH) contaminants in the surficial sediments of the Saint John Harbour (SJH) and assessed PAH exposure to local aquatic biota. Our findings suggest that sedimentary PAH contamination is heterogeneous and widespread in the SJH, with several sites exceeding the Canadian and NOAA recommended guidelines for the protection of aquatic life. Despite high concentrations of PAHs at some sites, there was no indication that local nekton was affected. Lack of a biological response may be due in part to a low bioavailability of sedimentary PAHs, presence of confounding factors (e.g., trace metals), and/or adaptation of local wildlife to the historic PAH contamination in this region. Overall, although no indication of effects to wildlife was observed with the data collected in the present study, continued efforts should be made to remediate highly contaminated areas and reduce the prevalence of these compounds.

Polycyclic aromatic hydrocarbons in aquatic media of Turkey: A systematic review of cancer and ecological risk

Polycyclic aromatic hydrocarbons (PAHs) have gathered worldwide attention due to their carcinogenicity and toxicity. This paper aims to review and extend current knowledge on PAHs in aquatic environments in Turkey, where expansion of the marine industry has caused contamination concerns. To assess cancer and ecological risks associated with PAHs, we systematically reviewed 39 research articles. Mean measured concentrations of total PAHs ranged from 61 to 249,900 ng L^-1 in surface waters, 1 to 209,400 ng g^-1 in sediments, and 4 to 55,000 ng g^-1 in organisms. Estimated cancer risks from concentrations in organisms were higher than those from surface waters and sediments. Negative ecosystem impacts of petrogenic PAHs were estimated to be larger than those of pyrogenic origin, despite the predominance of the latter. Overall, the Marmara, Aegean, and Black seas are highly-polluted and need remedial action, while further study is needed to confirm the status of other water bodies.

Polycyclic aromatic hydrocarbons (PAHs) in soils around oil refineries; Case study: Erbil and Kirkuk refineries, Iraq- A modelling approach

Purpose

Political tensions in Iraq have made attention to environmental issues not a priority for the authorities. Therefore, the influence of Kirkuk and Erbil refineries on contamination of the surrounding soil by polycyclic aromatic hydrocarbons (PAHs), were studied.

Methods

25 soil samples were collected and analyzed using high-performance liquid chromatography (HPLC), and their fate and health risk were investigated using Exposure Model for Soil-Organic Fate and Transport (EMSOFT) and the Monte Carlo Simulation (MCS) model.

Results

High ∑PAHs contamination (raged from 212.8 to 12,790.4 ppb), the dominance of pyrogenic sources, and high ecological risk were observed. The mean hazard index values for children (0.043) are higher than those for adults (0.02), while the incremental lifetime carcinogenic risk values for adults (8.50E-4) are greater than those for children (5.27E-4). Pyrene is the significant soil PAH from the depth of 3 cm downwards, while phenanthrene and fluorene are the major constituents of PAHs between the depth of 3 and 10 cm. Also, low molecular weight PAHs significantly decrease in soil layers over the time frame, and maximum PAHs concentrations belong to high molecular weight PAHs over 20 years.

Conclusion

Using an appropriate monitoring system, as well as sound management decisions to reduce the emission of environmental pollution are needed. Also, it seems that the use of constant values for soil physicochemical parameters such as moisture and porosity, despite seasonal variations, may result in uncertainty for fate and transport modelling. Therefore, seasonal sampling and analysis of soil parameters, would be helpful.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40201-022-00809-y.

Polycyclic aromatic hydrocarbons (PAHs) in the Bohai Sea: A review of their distribution, sources, and risks

The distribution, risks, and sources of polycyclic aromatic hydrocarbons (PAHs) observed in seawater and sediments in the Bohai Sea were reviewed. The ecological risk of total PAHs in seawater was low, but the ecological risks of several individual PAHs (Pyr, BbF, and IcdP) were high. Detected PAHs in sediments rarely had adverse biological effects. High PAH concentrations were identified in Bohai Bay, in the sea area near Qinhuangdao, in Jinzhou Bay, and in Bohai Strait. Low PAH concentrations were found in the central Bohai, in Laizhou Bay, and in the sea area with more intensive ocean currents near Caofeidian. PAH concentrations in the Bohai Sea present a seaward-decreasing trend. Their spatial distribution could be attributed to the influence of human activities (population, industrial activities, and shipping activities), which determined PAH emissions. The PAHs were characterized by local sources, indicating that coal consumption and vehicle emissions were important sources of PAHs. Integr Environ Assess Manag 2022;18:1705-1721. © 2022 SETAC.

Potential sources and toxicity risks of polycyclic aromatic hydrocarbons in surface sediments of commercial ports in Taiwan

The accumulation of pollutants in the semi-enclosed waters of ports has long been a concern. This study assessed the pollution status, sources, and toxicity risks of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments of 7 major ports in Taiwan. Total PAHs concentrations in sediments ranged between 8.4 and 572.5 ng/g dw, with an average of 112.4 ± 136.5 ng/g dw. The 3- and 4-ring PAHs (63 %) were the major constituents of PAHs in the sediments. Diagnostic ratios and positive matrix factorization analyses indicated that PAHs in sediments were mainly contributed by biomass combustion (45.0 %), coal combustion (31.5 %), and vehicle emissions and related fossil fuels (23.5 %). The results of ecological risk assessment showed a low-medium risk of PAHs in the sediments outside the port, whereas most of the sediments within the port presented a medium-high risk. An assessment of the possible human health risks indicated that PAHs were present at acceptable levels.

Prediction of •OH-Initiated and •NO3-Initiated Transformation Products of Polycyclic Aromatic Hydrocarbons by Electronic Structure Approaches

The abiotic reaction products of polycyclic aromatic hydrocarbons (PAHs) with hydroxyl radicals (^•OH) and nitrate radicals (^•NO₃) are nitro-, oxygen-, and hydroxyl-containing PAHs (NPAHs, OPAHs, and OHPAHs). Four methods of the highest occupied molecular orbital (HOMO), Fukui function (FF), dual descriptor (DD), and population of π electrons (PP-π) are selected to predict the chemical reactivity of PAHs attacked by ^•OH and ^•NO₃ in this study. The predicted ^•OH-initiated and ^•NO₃-initiated transformation products are compared with the main PAH transformation products (PAH-TPs) observed in the laboratory. The results indicate that PP-π and DD approaches fail to predict the transformation products of fused PAHs containing five-membered rings. By predicting the PAH-TPs of 13-14 out of the 15 parent PAHs accurately, HOMO and FF methods were shown to be suitable for predicting the transformation products formed from the abiotic reactions of fused PAHs with ^•OH and ^•NO₃.

Biodegradation potential of polycyclic aromatic hydrocarbons in Taihu Lake sediments

ABSTRACTTo assess the biodegradation potential of polycyclic aromatic hydrocarbons (PAHs) in sediments, sediment microcosms were constructed with sediments collected from six lake zones with different trophic statuses in Taihu Lake. The presence and concentration of PAH-degrading bacteria (PDB) were estimated by the most probable number (MPN) method. After 85 d of aerobic and anaerobic incubation, spiked PAHs (phenanthrene, pyrene, and benzo[a]pyrene) were partially degraded by indigenous sediment microorganisms. Large differences in PAH degradation were observed depending on the molecular size of the PAHs. The PAH removal efficiency in sediments under aerobic conditions was higher than that under anaerobic conditions. MPN analyses showed a higher abundance of degrading microflora in the high PAH-contaminated sites than in the low PAH-contaminated sites. Moreover, the anaerobic PDB populations in the sediments from the six different sites were much higher than those of aerobic PDB. The PAH biodegradation capability in sediments was associated with the geochemical conditions and bacterial populations. PDB showed a broad spatial distribution, thereby implying that they played an important role in the natural attenuation and cycling of PAHs in Taihu Lake. This work indicates that PAHs remain a concern in Taihu Lake sediments and can provide useful information for further bioremediation of PAH-contaminated sediments.

Formation and weathering assessment of oil-suspended sediment aggregates through a laboratory investigation

Formation of oil-suspended sediment aggregates (OSAs) is believed to be one of the natural cleaning processes in the marine environment. In this study, we have investigated the formation processes of OSAs under different mixing periods (continuous mixing and with the addition of sediments in between), oil-sediment ratios (1:1, 1:2 and 2:1) and crude oils (Arabian Light (AL), Kuwait (KW) and Murban (MB)). The results revealed that size of OSAs significantly increased (up to ≈ 1.41 mm) with the addition of sediments. Aggregates (total 36) were extracted for n-alkanes and polycyclic aromatic hydrocarbons to quantify and assess their weathering and toxic levels. The maximum n-alkane depletion was 84% (111-02), 94% (212-02) and 84% (321-02) and PAH depletion was ≈ 72% (111-02), 79% (212-02) and 81% (311-03) for the OSAs of AL, KW and MB crude oils, respectively, for the different samples considered, indicating that n-alkanes were depleted relatively higher than the PAHs. The highest depletion of both n-alkane and PAHs has occurred in OSAs of 10-h continuous mixing. The depletion of both n-alkane and PAHs reduced after the addition of sediments, however, escalated the growth of OSAs, resulting in bigger size OSAs. The concentration of PAHs of all 36 OSAs is greater than 5000 ng/g, indicating very high PAH pollution. Though the formation of OSAs helps in cleaning the spill sites, the carcinogenic threat to the marine ecosystem caused by these OSAs cannot be ignored.

Polycyclic Aromatic Hydrocarbons in Sediments from Typical Algae, Macrophyte Lake Bay and Adjoining River of Taihu Lake, China: Distribution, Sources, and Risk Assessment

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants in sediments and pose a serious risk for freshwater ecosystems. In this study, sediment samples from 24 sites were collected from the cyanobacterial bloom-occurring, macrophyte-growing lake bay and adjoining river of Taihu Lake. Here, the concentration levels, sources, and risk assessment of 16 priority PAHs in the surface sediments from typical algae, macrophyte lake bay and adjoining river of Taihu Lake, were investigated, and the results were compared with those of previous studies. The total PAH (ΣPAH) concentrations ranged from 4900 to 16,800 ng·g−1 in sediments of the Taihu Lake bay and from 5736.2 to 69,362.8 ng·g−1 in sediments of the adjoining river. The level of PAHs in riverine sediments was significantly higher than those of the Taihu Lake bay, and that of the Dongshan River was significantly higher than that of the Mashan River, while there was no significant difference in the concentrations of PAHs between the cyanobacterial bloom-occurring and macrophyte-growing lake zone. The results indicated petroleum contamination was dominated in the cyanobacterial bloom-occurring, macrophyte-growing lake bay, while PAHs of the riverine sediments derived from petroleum contamination and the combined combustion including wood, coal combustion, and petroleum combustion according to the identification by the molecular diagnostic ratio and principal component analysis (PCA). Sediment risk assessment based on sediment quality guidelines (SQGs) suggested that partial regions of the Taihu Lake bay were subjected to the potential ecological risk of the 3-ring and 5-ring PAHs, and there existed negative effects related to naphthalene pollutant in all survey regions. The adjoining riverine sediments showed a high ecological risk.

Potentially toxic elements and polycyclic aromatic hydrocarbons in street dust of Yazd, a central capital city in Iran: contamination level, source identification, and ecological-health risk assessment

Contamination level, source, and ecological-health risk of potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs) in the street dust of Yazd, a central capital city in Iran, were investigated for the first time regarding samples collected from 21 sites. Geochemical indices pointed out an enrichment trend of [Formula: see text] and an ecological risk trend of [Formula: see text]. The ecological risk indices of PAHs reflected high ecological risk for pyrene (Pyr). The statistical approach along with the isomeric ratios of PAHs suggested that the traffic-related sources, such as wearing of tires and brake pads, and the vehicular exhaust emissions were greatly responsible for the elevated concentrations of Pb, Cu, Sb, and PAHs, while Al, Ni, Co, V, Mn, As, and, to a lesser extent, Fe, Zn, Mo, and Cr were mainly influenced by geogenic sources. The human health risk assessment of PTEs and PAHs reflected that As, Cr, and Pb pose the highest non-carcinogenic risk in adults and children, compared with other PTEs and also PAHs. The carcinogenic health risk of Pb in the children and PAHs in both subpopulations was high for cancer development.

Distribution, sources, and behavior of PAHs in estuarine water systems exemplified by Salt River, Taiwan

Water, suspended particulate matter (SPM), and sediment samples were collected from Salt River in Taiwan and analyzed the concentrations of 16 types of polycyclic aromatic hydrocarbons (PAHs). The analysis results were used to examine the distribution, source, partition behavior, and potential ecological risks of PAHs in the estuarine water systems. The mean concentration of total PAHs in water, SPM, and sediment samples was 0.485-10.2 μg/L, 26.7-169 mg/kg dw, and 0.343-29.4 mg/kg dw, respectively. The highest concentration was found at the river mouth and decreased toward the river and sea with the tide. The distribution of the diagnostic ratios of PAHs showed that the combustion of coal and petroleum products are the main sources of PAHs in Salt River. The in site organic carbon normalized partition coefficients for SPM-water (K'_oc(SPMW)) and sediment-water (K'_oc(SedW)) were 2.8-4.5 and 4.6-6.0 (log units), respectively, increasing with the number of rings in PAHs. The values log K'_oc(SedW) and log K'_oc(SPM-W) showed a significant linear correlation with their octanol-water partition coefficients (p < 0.01), and their slopes were 0.427 and 0.316, respectively. The fugacity fraction was used to evaluate the exchange of PAHs in water-SPM-sediment systems. Results showed that in SPM, 2-4-ring PAHs tend to be released into water, whereas 5-6-ring PAHs in water tend to be adsorbed onto SPM. The exchange of PAHs between water and sediment occurs in the direction of adsorption onto sediment from water. The assessment of the mean risk quotient, total toxicity equivalence, and mean effect range-median quotient of PAHs showed that the PAHs in the water and SPM of Salt River may have moderate to high ecological risk. In sediment, PAHs in the lower reaches and estuary may pose moderate to high ecological risk, whereas PAHs in the middle and upper reaches show low to moderate ecological risk.

Oil pollution in the Eastern Arabian Sea from invisible sources: A multi-technique approach

The Eastern Arabian Sea (EAS) is affected by oil pollution, as often evidenced by the presence of tarballs along the West Coast of India (WCI). Tarball samples collected during May 2017 along the Goa coast were subject to biomarker fingerprints, and the results matched with Bombay High (BH) oil fingerprints. The present study primarily aims at identifying the potential minor spill areas using Sentinel-imagery. Interestingly, repeated occurrence of oil spills detected at two locations, perfectly matched with BH platforms. The simulated Lagrangian trajectories also depict that tarball particles have originated from those detected locations. In 2017 alone, the quantity of spilled oil was estimated to be 129,392 l. However, spills detected offshore regions of Kachchh and Mangalore were found to be caused by ships. This is the first comprehensive study, tracking the oil pollution sources in the EAS through multi-technique approach - chemical, remote sensing and numerical modeling.

Source identification of total petroleum hydrocarbons and polycyclic aromatic hydrocarbons in PM10 and street dust of a hot spot for petrochemical production: Asaluyeh County, Iran

Total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs) are important pollutants that affect public health in urban areas, especially in developing and oil-rich countries such as Iran. This assesses the relationship between TPH and PAHs in street dust and suspended dust, and investigates toxicity level in the urban environment of the most important petrochemical center in Iran. For this purpose, 21 and 48 street dust samples were collected for TPH analysis and PAH analysis, respectively, in Asaluyeh County. Moreover, seven air dust samples were taken for PAH analysis. TPH concentrations ranged between 240 and 4400 mg kg-1, with a mean of 1371.43 mg kg-1. The maximum ∑PAH concentration (6016.3 mg kg-1) was detected in a petrochemical complex while the minimum ∑PAHs content (16.93 mg kg-1) was measured in an urban area. The mean concentrations of total PAHs in street dust particles were 491.35 mg kg-1 in summer and 304.04 mg kg-1 in winter. The results indicated that PAH concentration in summer was higher. PAH sources were identified using both PAHs ratios and robust statistical methods such as Generalized Estimating Equations (GEE), backward GEE, logistic regression, principal components analysis (PCA) in conjunction with multiple linear regression (MLR) and positive matrix factorization (PMF). The results showed that PAH species generally originate from pyrogenic sources and about 0.08% of TPH was typically PAHs. However, petrogenic sources of PAHs in the industrial areas were 11.2 times more abundant than in urban areas. Also, backward GEE model demonstrated that TPH is more influenced by HMW PAHs, particularly indene. Estimated incremental lifetime cancer risk (ILCR) was higher than 10-4, showing that Asaluyeh inhabitants (especially children and indoor workers) are probably exposed to cancer risk, particularly through dermal contact and dust ingestion.

From headwaters to estuary: distribution, sources, and ecological risk of polycyclic aromatic hydrocarbons in an intensively human-impacted river, China

Located in the Shandong Province, North China, the Xiaoqing River is heavily contaminated by industrial wastewater and domestic sewage. However, it plays a significant role with regard to irrigation for agriculture in the river basin. In this study, spatial distribution, sources, and the ecological risk of aqueous polycyclic aromatic hydrocarbons (PAHs) in the Xiaoqing River Basin were investigated from the headwaters to the estuary. Fifteen USEPA priority PAHs (except naphthalene) were quantified in water particulate and soluble phases and in sediment samples. Σ₁₅PAHs concentrations in the sediment varied from 17.15 to 3808.01 ng/g dry weight (dw), with an average of 988.72 ng/g dw, suggesting severe pollution of the Xiaoqing River in comparison with other rivers worldwide. The composition of PAHs was characterized by the high abundance of 4-ring and 5-ring PAHs in sediments and 2-ring and 3-ring PAHs in water. Industrial wastewater is a significant source of PAHs. In the river section, point source was the main factor affecting the distribution of PAHs, while in the estuary region, estuarine turbidity maximum zone (ETM), riverine flow and discharge, and its hydrodynamic parameters play more key roles on PAH levels. Molecular diagnostic ratios have proved that PAHs in sediments were derived from mixed sources, primarily a combination of several combustion processes. Toxicity equivalency concentrations (TEQs) and Ecological risk assessment by Sediment Quality Guidelines indicated that PAHs in sediments might have certain unfavorable effects on ecosystems in certain sites.

Characterization of polycyclic aromatic hydrocarbons (PAHs) in small craft harbour (SCH) sediments in Nova Scotia, Canada

Polycyclic aromatic hydrocarbons (PAHs) have been widely studied in sediments due to their ubiquity and persistence in aquatic environments and potential for impairment to biota. Small craft harbour (SCH) sediments in Nova Scotia (NS), Canada, have yet to be studied comprehensively. SCHs are essential to the fishing industry, which is important for the Canadian economy. This spatiotemporal characterization study evaluated thirty-one SCHs across NS between 2001 and 2017 by analyzing sediment reports (secondary data). Sediment PAH concentrations varied widely across all SCHs. Few SCHs exhibited sediment PAH concentrations likely to impair biota based on comparison to sediment quality guidelines. Sediments in the Gulf region of NS were least impacted by PAHs, while the Southwest region was most impacted. Distribution of individual PAHs in sediments follows global trends, with high molecular weight PAHs dominating samples.

Ecotoxicological and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Short-Neck Clam (Paphia undulata) and Contaminated Sediments in Malacca Strait, Malaysia

The distribution, sources, and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediment and the edible tissue of short-neck clam (Paphia undulata) from mudflat ecosystem in the west coast of Malaysia were investigated. The concentrations of ∑₁₆ PAHs varied from 347.05 to 6207.5 and 179.32 to 1657.5 ng g^-1 in sediment and short-neck clam samples, respectively. The calculations of mean PEL quotients (mean-PELQs) showed that the ecological risk of PAHs in the sediment samples was low to moderate-high level, whereas the total health risk through ingestion and dermal contact was considerably high. The PAHs biota sediment accumulation factors data for short-neck clam were obtained in this study, indicating a preferential accumulation of lower molecular weight PAHs. The source apportionment of PAHs in sediment using positive matrix factorization model indicated that the highest contribution to the PAHs was from diesel emissions (30.38%) followed by oil and oil derivate and incomplete coal combustion (23.06%), vehicular emissions (16.43%), wood combustion (15.93%), and natural gas combustion (14.2%). A preliminary evaluation of human health risk using chronic daily intake, hazard index, benzo[a]pyrene-equivalent (BaP_eq) concentration, and the incremental lifetime cancer risk indicated that PAHs in short-neck clam would induce potential carcinogenic effects in the consumers.

Distribution, sources, and ecological risk assessment of polycyclic aromatic hydrocarbons in surface sediments from the Haihe River, a typical polluted urban river in Northern China

The distribution, sources, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) were investigated in surface sediments from the Haihe River. Total PAH concentrations varied from 171.4 to 9511.2 ng g^-1 with an average of 2125.4 ng g^-1, suggesting serious pollution of the Haihe River in comparison with other reported rivers worldwide. PAH contaminants differed significantly among 17 sampling locations with high values occurring in industrial areas and densely populated areas. The composition of PAHs was characterized by high abundance of 4-ring and 5-ring PAHs, and benzo[a]anthracene, chrysene, and benzo[a]pyrene were the predominant components. Molecular diagnostic ratios have confirmed that PAHs in Haihe River sediments resulted from mixed sources, primarily including various combustion processes. Ecological risk assessment using the Sediments Quality Guidelines indicated that PAHs in sediments could cause certain negative effects on aquatic organisms in most survey regions.

Composition profiles, levels, distributions and ecological risk assessments of trihalomethanes in surface water from a typical estuary of Bohai Bay, China

To characterize the spatiotemporal distribution and potential ecological risk for trihalomethanes (THMs) in the surface water of a river estuary, surface water samples were collected over five consecutive months (from March to July 2016) from four sites in the Haihe River estuary of Bohai Bay. The potential ecological risks of THMs were evaluated quantitatively based on a species sensitivity distribution (SSD) model. The results demonstrate that trichloromethane (TCM) was the predominant THM in surface water of the Haihe River estuary (2.93±1.98μg/L) followed by tribromomethane (TBM) (0.42±0.33μg/L), bromodichloromethane (BDCM) (0.14±0.06μg/L) and dibromochloromethane (DBCM) (0.09±0.10μg/L). The concentration of TCM was higher in summer than that in spring, while TBM displayed the opposite trend. The TCM concentration decreased from the estuary to the adjacent sea. However, the levels of TBM and DBCM in the adjacent sea were higher than those in the estuary. The ecological risks of THMs in surface water of Haihe River were notably low, and the ecological risks of THMs in freshwater were generally higher than those in seawater. Compared with other contaminants in water and surface sediment from rivers and coastal areas, the ecological risk levels of THMs in surface water can be considered low. This study is a contribution to the progress of ecological risk assessment of THMs.

Congener profiles, distribution, sources and ecological risk of parent and alkyl-PAHs in surface sediments of Southern Yellow Sea, China

Congener profiles, distribution and sources of parent and alkyl-polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Southern Yellow Sea (SYS), China were investigated. The ecological risk of parent-PAHs to aquatic organisms were evaluated based on sediment quality guidelines (SQGs), risk quotient (RQ), organic carbon (OC)-normalized analysis and mean effects range-median quotient (M-ERM-Q). The concentrations of 33 PAHs were analyzed, including 14 parent PAHs (without naphthalene and acenaphthylene), 16 alkyl-PAHs (7 methylphenanthrenes, 3 methylanthracenes, 3 methylfluoranthenes, and 3 methylpyrenes), dibenzothiophene, retene and perylene. Total concentrations of PAHs (TPAHs) ranged from 200.8 to 3629.0ng/g dry weight (d.w.), with a mean value of 1035.4ng/g d.w., and mainly contributed by fluorene, phenanthrene, methylphenanthrene, retene, fluoranthene and pyrene. Analysis of a broad variety of diagnostic ratios suggested that combustion was the key source of PAHs. Principal component analysis-multiple linear regression (PCA-MLR) indicated that combustion of coal, softwood and nature gas, coke oven, petroleum and vehicle emission were the main sources of PAHs in sediments of SYS, contributing 41.5%, 30.6%, 18.8%, and 9.0% to TPAHs, respectively. Ecological risk assessment of individual parent-PAHs suggested that fluorene, phenanthrene and fluoranthene may cause some risk to aquatic organisms in some stations. OC-normalized analysis and M-ERM-Q indicated that risk of multiple parent-PAHs was quite low in the studied area.

Risk assessment and uncertainty analysis of PAHs in the sediments of the Yangtze River Estuary, China

To better explore the concentration of polycyclic aromatic hydrocarbons (PAHs) in the sediments of the Yangtze River Estuary (YRE), 16 priority PAHs were analyzed based on sampling data obtained in February 2011. The results showed that the total concentrations of PAHs in sediments of the YRE varied from 65.07 to 668.98ng·g^-1. The results of toxic equivalent quantities of benzo[a]pyrene and the sediment quality guideline quotient suggested that PAHs had little or no adverse effects on the environment. The cancer risk results showed that the cancer risk at all sites exceeded 10^-6, with 73% of sites exceeding 10^-4, suggesting that people remain at risk of cancer as a result of their exposure to carcinogenic PAHs. However, the result of hazard index results showed that the non-cancer risks were substantially lower than one, indicating that PAHs in these sediments likely pose little or no adverse health threats to local inhabitants.

Basin-Scale Study on the Multiphase Distribution, Source Apportionment and Risk Assessment of PAHs in the Hai River Water System

As a systematic research at basin scale, this study explored the composition and concentration characteristics of 16 priority polycyclic aromatic hydrocarbons (PAHs) in sediments, water, and suspended particulate matter (SPM) in the water systems (rivers, lakes, and reservoirs) in the Hai River Basin through literature review. The sources and the ecosystem risks of PAHs in the sediments in the entire basin were specially discussed with diagnostic ration, PAHs composition, and an improved risk quotient method. Results showed that the total concentration of PAHs varied from 99.65 to 25,303 ng g(-1) dry weight in sediments, from 51.0 to 559.1 ng L(-1) in water, and from 4528 to 51,080 ng g(-1) dry weight in SPM, respectively. The dominant PAHs in the three examined phases were 2-3 rings in most waterbodies. PAHs in the rivers were from mixed sources (petrogenic and pyrolytic inputs), whereas those in lakes and reservoirs were mainly from biomass combustion and petroleum combustion. PAHs in the entire basin exhibited moderate to high ecological risk, and the rivers (especially Hai River, Jiyun River, Chaobai River, and Beiyun River) suffered higher ecological risk than reservoirs and lakes. Most of the rivers with higher PAHs risk flow through or around megacity Beijing and Tianjin.

Distribution, sources and ecological risk assessment of PAHs in historically contaminated surface sediments at Bhavnagar coast, Gujarat, India

The concentration, distribution and ecological risk of polycyclic aromatic hydrocarbons (PAHs) have been investigated in surface sediments near Bhavnagar coast. The concentration of ∑PAHs ranged from 5.02 to 981.18 μg g(-1) dry weight, indicating heavy pollution compared to other historically polluted study sites. It was found to be introduced via mixed origins such as burning of gas, oil, coal, production of petrochemicals, cement, and rubber tires. Domestic fuel burning and motor vehicles are also culprits for air pollution. Industrial effluents and accidental oil spillage can also be considered. PAHs can be exposed through air, water, soil and food sources including ingestion, inhalation, and dermal content in both occupational and non-occupational levels by single or sometimes multiple exposures routes concomitantly. Furthermore, diagnostic ratios, statistical principal component analysis (PCA) and hierarchical cluster analysis (HCA) models have confirmed that the sources of PAHs were both - petrogenic and pyrogenic. For both the sites, assessment of ecological risk of the elevated levels of these pollutants has been exercised based on toxic equivalency factors (TEFs) and risk quotient (RQ) methods. The composite results indicated accurately that both the sites, bears potentially acute and chronic health hazards such as decreased immune functionality, genotoxicity, malignancy and developmental malfunctions in humans. The sites studied here and the workers have been exposed to hazardous pollutants for a longer period of time. Evidences indicate that mixtures of PAHs are carcinogenic to humans, based on occupational studies on workers, exposed to these pollutants. Hence, the present study and statistical approaches applied herein clearly indicate the historic mix routes of PAHs that resulted in magnified concentrations leading to high ecosystem risk. Thus, the scientific communities are urged to develop strategies to minimize the concentrations of PAHs from the historically impacted coastlines, thereby concerning for the future investigations and restoration of these sites.

Sources appointment and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in sediments of Erhai Lake, a low-latitude and high-altitude lake in southwest China

Sixteen polycyclic aromatic hydrocarbons (PAHs) were analyzed from the surficial sediments in Erhai Lake, a plateau lake in China. The results showed that except for acenaphthylene (Ace) Ace and Dibenz(a,h)anthracene (DBA), the central region contained individual PAHs at concentrations lower than those in other lake regions. Total concentration of the PAHs (ΣPAHs) in the sediments from Erhai Lake ranged from 32.42 to 558.53 mg/kg with a mean value of 256.70 mg/kg. The maximum value of ΣPAHs was observed in the north region of the lake and more than 10-fold higher than the minimum values. Moreover, high molecular weight (HMW) PAHs, especially 5-ring PAHs, accounted for higher ratios up to 76 % relative to other PAHs compound in almost all sampling sites. Molecular diagnostic ratios including anthtacene (Ant)/(Ant + phenanthrene (Phe)), fluoranthene (Flt)/(Flt + pyrene (Pyr)), benz(a)anthracene (BaA)/(BaA + chrysene (Chr)), and indeno(1,2,3-cd)pyrene (IPY)/(IPY + benz(g,h,i)perylene (BPE)) were recorded at all sampling sites and indicated that the origin of PAHs in Erhai Lake was predominately pyrolytic. Furthermore, principal component analysis with component dominating by HMW PAHs showed that combustion origins were the primary contamination sources of PAHs in the sediments of Erhai Lake. Finally, ecological risk assessment indicated that the sediments from Erhai Lake are exposed to potential low risk for ΣPAHs, and the ecological risk decreases in the order of northern region > southern region > central region.

Environmental risk assessments and spatial variations of polycyclic aromatic hydrocarbons in surface sediments in Yangtze River Estuary, China

In this study, based on sampling data from 30 sites in August 2010, the environmental risks associated with 16 priority PAHs were estimated in surface sediments from the Yangtze River Estuary (YRE). The results indicated that the toxic equivalent quantities of the benzo[a]pyrene (TEQBap) from 30 sites were in the range of 1.93-75.88ngg(-1), and the low-molecular-weight PAHs were the dominated species with higher potential toxicity. The results of the Incremental Lifetime Cancer Risk (ILCR) model indicated that the ILCR values of dermal contact were higher than 10(-6) in the northeast region, suggesting that there were significant potential carcinogenic health risks for fishermen exposure to sedimentary PAHs via dermal contact in these areas. RQ values of PAHs indicated the various distributions of ecological risk levels in the study area. These variations might be caused by the natural and anthropogenic inputs and currents in the YRE.

Sources and ecological risk assessment of PAHs in surface sediments from Bohai Sea and northern part of the Yellow Sea, China

Sources and ecological risk of sixteen priority PAHs in surface sediments from Bohai Sea (BS) and northern part of the Yellow Sea (NPYS) were investigated. The total concentrations of PAHs varied in ranges 149.24-1211.81 and 148.28-907.47 ng/g for BS and NPYS, respectively. Principal component analysis-multiple linear regression (PCA-MLR) suggested that coal combustion, vehicular emission and coke oven could be the primary PAH contributors, accounting for 56.6%, 29.2% and 14.2% of PAH concentrations, respectively. Analysis with sediment quality guidelines (SQGs) indicated that acenaphthylene, fluorene, phenanthrene, fluoranthene, pyrene and dibenzo(a,h)anthracene may occasionally cause adverse biological effects in some stations. Organic carbon (OC)-normalized analysis and mean effects range-median quotient (M-ERM-Q) suggested that the combined ecological risk of PAHs was generally low. The toxic equivalent concentrations of carcinogenic PAHs were 12.87-64.6 ng/g-BaP(eq) and 5.95-68.80 ng/g-BaP(eq) in BS and NPYS, respectively, suggesting low carcinogenic risk for both BS and NPYS.

The levels of PAHs and aryl hydrocarbon receptor effects in sediments of Taihu Lake, China

A total of 16 priority polycyclic aromatic hydrocarbons (PAHs) in sediment samples from Taihu Lake were analyzed by instruments, and sediment extracts were assayed for aryl hydrocarbon receptor (AhR)-mediated ethoxyresorufin-o-deethylase (EROD) induction using a rat hepatoma cell line (H4IIE). The cause-effect relationship between the observed EROD activity and chemical concentrations of PAHs was examined. Our results showed that sediment extracts could induce significant AhR effects, and the bioassay-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents of raw extracts (TEQ(bio)s) ranged from 2.7 to 39.8 pg g(-1) dw. Chemical analysis showed that 16 PAHs were all detected in all samples, and their total concentrations (Σ16PAHs) ranged from 179.8 to 1,669.4 ng g(-1) dw. The abundance of sedimentary PAHs in the three regions (Meiliang Bay, Gonghu Bay, and Xukou Bay) showed a decreasing trend from the inflow region to the outflow region. Chemical analysis-derived TEQs (TEQ(cal)s) contributed by PAHs ranged from 1.6 to 20.7 pg g(-1) dw. The mean contribution rates (CRs) of PAHs to TEQ(bio)s were 48.9%. In Meiliang Bay, EROD effects of 60% samples were caused by PAHs whose CRs were more than 60%, while in most sampling sites of Gonghu Bay and Xukou Bay, the CRs of PAHs to TEQ(bio)s were basically below 40%. In addition, preliminary ecological risk assessment found that PAHs in sediments have very low ecological impact based on the chemical data of PAHs, while the sediments might pose an unacceptable risk to aquatic organisms and their predators based on the data of TEQ(bio). These findings showed that EROD effects of sediment extracts from Taihu Lake were also caused by other compounds, such as dioxins, polychlorinated biphenyls, etc., together.