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The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in water and sediment samples collected from 12 locations in Gao-ping River, Taiwan were analyzed. Molecular ratios and principal component analysis (PCA) were used to characterize the possible pollution sources. Concentrations of total 16 PAHs (SigmaPAHs) in water samples ranged from below method detection limits (

This study investigated a pressing environmental concern: the presence, distribution, sources, and ecological implications of sixteen polycyclic aromatic hydrocarbons (PAHs) in the left-bank canals of Kotri barrage-Akram, Pinyari, and Phuleli of the Indus River in Pakistan. These vital waterways, crucial for industrial, domestic, and agricultural activities, are experiencing contamination threats from anthropogenic sources, particularly PAHs. The study collected three water and two sediment samples from each canal in pre-monsoon and post-monsoon seasons. Then the EPA's liquid-liquid extraction method and gas chromatography determined the concentrations of PAHs. The findings of this study reveal alarming contamination levels, with pre-monsoon concentrations ranging from 22.256 to 836.455 ng/L in water and 1,459.941 to 43,179.243 ng/g in sediments. The post-monsoon concentrations ranged from 60.352 to 5663.058 ng/L in water and 2976.770 to 15,238.335 ng/g in sediments. The diagnostic ratios and principal component analysis (PCA) identified multiple sources of contamination, including industrial and domestic wastewater discharge, solid waste burning, vehicular emissions, biomass combustion, and petroleum residues. Furthermore, the assessment of the toxic equivalency factor (TEF) underscored the heightened carcinogenic potential of certain PAHs, notably benzo(a)pyrene and benzo(a)anthracene. Thus, the high levels of PAH contamination pose severe health risks to both human populations and aquatic ecosystems, emphasizing the urgency of addressing this issue. Stricter regulations governing industrial and domestic waste discharge, advocacy for cleaner fuel technologies, and the implementation of effective waste management practices must be initiated as crucial strategies in safeguarding the environmental integrity of the left-bank canals and the health of the surrounding communities., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

We evaluated spatial distribution and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in water and sediments at four selected sites of the Ganga River. Also, we measured PAHs in muscle tissues of Rohu (Labeo rohita), the most common edible carp fish of the Ganga River and potential human health risk was addressed. Total concentration of PAHs (∑PAHs) in water was highest at Manika Site (1470.5 ng/L) followed by Knuj (630.0 ng/L) and lowest at Adpr (219.0 ng/L). A similar trend was observed for sediments with highest concentration of ∑PAHs at Manika (461.8 ng/g) and lowest at Adpr Site (94.59 ng/g). Among PAHs, phenanthrene (Phe) showed highest concentration in both water and sediment. Of the eight major carcinogenic contributors (∑PAH 8C ), Indeno (1,2,3-C,D) pyrene (InP) did appear the most dominant component accounting for 42% to this group at Manika Site. Isomer ratios indicated vehicular emission and biomass combustion as major sources of PAHs. The ∑PAHs concentrations in fish tissue ranged from 117.8 to 758.0 ng/g (fresh weight basis) where low molecular weight PAHs assumed predominance (above 80%). The risk level in fish tissues appeared highest at Manika Site and site-wise differences were statistically significant (p < 0.05). The ILCR (> 10 -4 ) indicated carcinogenic risk in adults and children associated with BaP and DBahA at Manika Site and with BaP at Knuj Site. Overall, the concentrations exceeding permissible limit, carcinogenic potential and BaP equivalent all indicated carcinogenic risks associated with some individual PAHs. This merits attention because the Ganga River is a reservoir of fisheries., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

In this study, we observed that four congeners, including naphthalene (Nap), acenaphthylene (Acy), phenanthrene (Phe), and benz(a)anthracene (BaA), are the characteristic congeners for predicting the emission and the sediment concentrations of polycyclic aromatic hydrocarbons (PAHs). A novel multiple relationship of the total PAHs concentrations (C ∑PAHs ) in sediments with the concentrations of four congeners was established (p < 0.01, R 2  = 0.95) using published data over the past 30 years. Moreover, the multiple linear relationship of the total PAHs emission factors with the emission factors of four congeners was also established (p < 0.01, R 2  = 0.99). Interestingly, the ratio of multicomponents coefficient from the multiple linear relationship in sediments to that from the multiple linear relationship in emission sources correlated positively with octanol-water partition coefficient (logK ow ) (p < 0.01, R 2  = 0.88) of the four PAHs congeners. Therefore, a novel model was established to predict C ΣPAHs in sediments using the emissions and logK ow of the four characteristic PAHs congeners. The percent sample deviation between calculated C ∑PAHs and their observed values was 54%, suggesting the established model can accurately predict C ΣPAHs in sediments., (© 2022. The Author(s).)

The resource, environment, and ecological value of drinking reservoirs have received widespread concerns due to the pollution of persistent organic pollutants such as polycyclic aromatic hydrocarbons (PAHs). Therefore, we comprehensively studied the occurrence, source, distribution, and risk assessment of representative PAHs in Fengshuba Reservoir (FSBR) (large drinking reservoir, China). The total concentrations of 16 USEPA PAHs in the water phase, porewater phase, sediment phase, and soil phase were in ranges of 109.72-393.19 ng/L, 5.75-35.15 μg/L, 364.4-743.71 μg/kg, and 367.81-639.89 μg/kg, respectively. The naphthalene (Nap) was the dominant PAHs in the water phase, while it was Nap and phenanthrene (Phe) in porewater, sediment, and soil phase. The main sources of PAHs in FSBR were biomass combustion. Redundancy analysis indicated that the NTU, NO 2 - , NH 4 + , Chl-α, and IC were the dominant factors influencing the PAH distribution in water phase, and the PAHs in sediment phase was affected by T and NO 3 - . Pseudo-partitioning coefficients indicated that the PAHs in the porewater phase were more likely to migrate to the sediment phase. Risk assessment indicated that the PAHs both in the water and sediment phases were generally in a low-risk state, while the PAHs in the soil phase were in a moderate-risk state, and the Nap was in a high-risk state, and exposure to the PAHs in FSBR through drinking and skin exposure had little impact on consumers' health. In summary, Nap could be used as a key indicator to evaluate the existence and potential risk of PAHs in FSBR., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This paper assesses the concentrations, spatial distribution, compositional patterns, and sources of polycyclic aromatic hydrocarbons (PAHs) in the dissolved aqueous phase along the Abou Ali River course. The 16 priority PAHs, listed by the USEPA, were investigated in surface- and groundwater samples for 2 years starting August 2015 and ending in March 2017. Statistical analysis was done by using the ANOVA test at p < 0.05. The spatial distribution analysis and illustration were done using the ARC GIS software. The total PAHs concentration in surface and groundwater samples varied between not detected to 15.162 ng mL -1 and not detected to 0.635 ng mL -1 , respectively. The highest concentration of PAHs in surface water was observed at site S16, downstream of the river. However, the absence of PAHs was noticed at sites S1 and S2 of the upstream. The contamination levels of PAHs were found to be high in surface water samples, and low in groundwater samples. The 5- and 6-ring PAHs were the most abundant species among others in surface water samples, whereas the 3-ring PAHs were the most abundant in groundwater. Pyrogenic inputs deriving from fuel combustion, incineration, and miscellaneous burning were found to be the main PAH sources in surface and groundwater without ignoring the contribution of petrogenic inputs in some areas., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

PAH contamination in water environment has become an important water quality problem in China. In this study, groundwater PAHs were monitored in September 2019 at 48 groundwater sites, and statistical analysis and positive matrix factorization (PMF) model were used to analyze the characteristic of PAHs in groundwater and to identify the pollution sources of PAHs in the Hutuo River Basin, Hebei Province, China. The results showed that the concentration of the PAHs in groundwater was low and the total PAHs (∑PAHs) ranged from below detection limit to 260.6 ng/L and with a mean value of 17.7 ng/L. The concentration of PAHs in groundwater was obviously affected by the land use. Based on molecular ratio method, the main source of PAHs in groundwater is the biomass combustion, while the results of PMF source analysis were more accurate and the results showed that the primary sources and contribution rate of PAHs in groundwater were wood, coal, and gasoline sources (41.4%), followed by oil and diesel sources (39.4%), and natural gas combustion (19.2%). There was obvious spatial variation in the contribution of pollution sources to PAHs at the sites of different land uses in this region. The highest contribution of nature gas combustion, oil and diesel sources, and wood, coal, and gasoline combustion to PAHs was found in the urban area (0.617 ng/L), industrial area (0.380 ng/L), and village area (0.379 ng/L), respectively. The results can provide scientific basis for the prevention and control of PAH contamination in groundwater in this area.

A class of hazardous chemical molecules known as polycyclic aromatic hydrocarbons (PAHs) are frequently detected in environmental samples such as soil, water, and air. Because of their carcinogenic and mutagenic qualities, PAHs pose a significant threat to both human health and the environment. Therefore, the identification and extraction of PAHs from environmental samples is crucial for monitoring and assessing their presence and potential risks. An overview of these recent advancements is given in this review, which includes the use of sophisticated analytical methods for the identification and measurement of PAHs in environmental samples, such as high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). The limitations of conventional extraction techniques such as Soxhlet extraction and liquid-liquid extraction, which are frequently labour-intensive, solvent-intensive, and prone to low selectivity, are highlighted in this review. In contrast, modern techniques such as Solid-Phase Microextraction (SPME) and Accelerated Solvent Extraction (ASE) offer significant advantages, including reduced solvent use, faster processing times, and enhanced sensitivity and selectivity for PAHs. This review highlights the benefits of these advancements in facilitating faster, more accurate, and environmentally friendly PAH extraction and identification processes, focusing on overcoming the limitations of traditional methods such as chromatographic separation and detection. To improve our comprehension of PAH contamination and provide practical mitigation methods for their effects on the environment and human health, this field needs ongoing research and development. [ABSTRACT FROM AUTHOR]

Most studies have concentrated on the distribution of polycyclic aromatic hydrocarbons (PAHs) in air, water, and soil; however, little is known about their behavior during urban wet deposition. During frequent urban rainstorms, surface runoff carries large amounts of organic pollutants into water, which has a significant impact on the quality of the water environment. "Poseidon" made landfall in Jilin Province on 27 August, 3 September, and 7 September 2020, respectively, causing some impact on the surface water. Gas chromatography–mass spectrometry (GC–MS) was used to measure the concentrations of 16 major PAHs in stormwater and water samples from the Yitong River. The PAH concentrations in rainwater runoff gradually decreased with increasing rainfall duration. The PAHs in the Yitong River water samples were mainly composed of two to three rings, with total concentrations ranging 279.19–756.37 ng/L. Ratio characterization and principal component analysis of the sources of PAHs in the water samples revealed that some water bodies had also been contaminated by oil spills in addition to combustion emissions from coal and motor vehicle oil. Health and environmental risks were assessed for PAHs in water bodies from the Yitong River, and health risk assessment showed that exposure to PAHs in the water is not a health risk for human beings; however, the risk for children is higher than that for adults and requires attention. Although the environmental risk is moderate, the risk from Benzo(a)anthracene(BaA) alone is high and requires ongoing attention. In terms of the sustainability of drinking water sources, consideration should be given to taking necessary regulatory and protective measures to prevent further contamination. These results serve as a guide for managing PAHs in urban water bodies and managing water pollution. [ABSTRACT FROM AUTHOR]

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Simple Summary: The multiple impacts of polycylic aromatic hydrocarbon on the aquatic invertebrates were rarely assessed in a chronic way and multiple-species experiments, despite the clear advantage of better mimicking natural conditions compared to traditional acute and single-species-focused toxicological experiments. The application of such an approach is essential to lower the health risks for populations that regularly consume seafood. The data presented herein supported the use of Mytilus galloprovincyalis and Ruditapes decussatus as bioindicators of phenanthrene in water and/or sediment and proved the efficacy of the biomarkers' assessment and molecular modelling in determining environmental thresholds and policies for governments. The aim of the current study was to assess the multifaceted effects of the polycylic aromatic hydrocarbon phenanthrene, mainly used in the colouring, explosive, and pharmaceutical industries, on the physiology of two bivalve species with economic value as seafood, namely, the Mediterranean mussel Mytilus galloprovincyalis and the European clam Ruditapes decussatus. The current study assessed how the phenanthrene affected several biomarkers and biometric endpoints in both bivalves, based on an in vivo experiment in silico approach. The bivalves were exposed during four time slots (i.e., 7, 15, 21, and 28 days) to two concentrations of phenanthrene in water (50 µg/L and 100 µg/L). For the clam R. decussatus, an additional contamination of sediment was applied due their typical benthic lifestyle (50 µg/kg and 100 µg/kg). The phenanthrene significantly reduced the ability of bivalves to tolerate desiccation and their Median Lethal Time, and also inhibited the activity of the enzyme acetylcholinesterase in a time-dependent manner. The activity of catalase indicated that bivalves also experienced oxidative stress during the first 21 days of the experiment. The significant decline in catalase activity observed during the last week of the experiment for the mussel M. galloprovincyalis supported a depletion of enzymes caused by the phenanthrene. The phenanthrene has also toxicokinetic and toxicodynamic properties, as assessed by the in silico approach. Overall, the results obtained suggest that the bivalves Ruditapes decussatus and M. galloprovincyalis can be used as a sentinel species in monitoring studies to assess the environmental impact of phenanthene in marine ecosystems. The significance of our findings is based on the fact that in ecotoxicology, little is known about the chronic effects, the simultaneous use of multiple species as bioindicators, and the interactions molecular modelling. [ABSTRACT FROM AUTHOR]

Profile assessment of the behavior of total polycyclic aromatic hydrocarbons (TPAH – sum of 16 US EPA priority PAHs) in water and suspended particulate matter (SPM) from Cross River estuary, SE Nigeria in response to hydrological cycles and human-induced activities as well as their sources were undertaken using gas chromatography-flame ionization detector (GC-FID). TPAH concentrations in water were in the range 0.23–3.98 ng/L, with a minimum and maximum values found in April and December, respectively (mean = 0.97 ± 0.65 ng/L) having higher concentrations in the dry season. The low PAHs levels recorded in water for the wet season were linked to dilution effect. On the other hand, TPAH concentrations in SPM (suspended particulate matter) ranged between 5.16 ng/g in February and 40.52 ng/g in June (mean = 17.77 ± 8.48 ng/g). Higher PAHs levels found in the wet season were associated with greater wash-in of terrigenous materials occasioned by intense rainfall events via river discharges/wet precipitation coupled with the high adsorption capacity of PAHs toward solid matrix as well as proximity to fish settlement. Seasonal changes in salinity, temperature and suspended sediment concentration (SSC or SPMC) somewhat influenced the PAH phase association. Higher SSC in the wet season accounted for the higher PAHs levels in SPM (r = 0.9295), whereas lower salinity aided desorption from SPM in the wet season, temperature did not show regular trend with PAHs levels in both seasons. Application of principal component analysis (PCA) and multiple linear regression (MLR) to both water and SPM data indicated a scenario predominated by petroleum and wood combustion PAHs with a moderate vehicular exhaust emission and coal tar inputs (11%). [ABSTRACT FROM AUTHOR]

The past several decades have seen increasing concern regarding the wide distribution of polycyclic aromatic hydrocarbons (PAHs) in environmental matrices. Primary toxicological data show PAHs' persistent characteristics and possible toxicity effects. Because of this pressing global issue, electroanalytical methods have been introduced. These methods are effective for PAH determination in environmental waters, even outclassing sophisticated analytical techniques such as chromatography, conventional spectrophotometry, fluorescence, and capillary electrophoresis. Herein, the literature published on PAHs is reviewed and discussed with special regard to PAH occurrence. Moreover, the recent developments in electrochemical sensors for PAH determination and the challenges and future outlooks in this field, are also presented. [ABSTRACT FROM AUTHOR]

This study presents the results for the determination of the concentrations and distribution patterns of polycyclic aromatic hydrocarbons (PAHs) in urban street dusts from the Nigerian megacity, Lagos, in order to provide information on their sources, and the potential environmental and human health risks arising from exposure to PAH contaminated dust. Gas chromatography-mass spectrometry was used for the quantification of the levels of PAHs in the dust samples after they were extracted with n-hexane/dichloromethane by ultrasonication. The PAH concentrations in the urban street dusts ranged from 545 to 10785 μg kg−1, 289 to 17943 μg kg−1 and 616 to 13174 μg kg−1 for industrial, commercial, and residential areas, respectively. The risk quotient (RQ) values indicated a moderate to high ecosystem risk for organisms in contact with PAHs in dust from these functional areas. The BaPTEQ and BaPMEQ values indicated potential carcinogenic and mutagenic risks to residents of the megacity. The hazard index (HI) values signify that there is a substantial non-carcinogenic risk relating to exposure of children to PAHs in dusts from the commercial areas, while the lifetime cancer risk factors indicate a considerable cancer risk for human exposure to PAHs via oral ingestion and dermal contact with the dust particles. The source diagnosis, determined from PAH isomeric ratios and multivariate analysis, showed that PAHs in the urban street dust originated from vehicular traffic emissions, burning of biomass, volatilization of petroleum products, and domestic cooking gas. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs), one of the major chemical constituents of petroleum, are widely used and are largely present in all environmental matrices, including aquatic environment. Polycyclic aromatic hydrocarbons are made of fused aromatic rings with no heteroatoms carrying substituents. Polycyclic aromatic hydrocarbons are produced naturally from various resources that include volcanic emission and forest fires. , They are present in tar deposits, coal, and oil, and are also produced as byproducts of fuel burning. Polycyclic aromatic hydrocarbons can also be present in foods. PAHs are highly lipophilic. They are strongly absorbed from gastrointestinal tract and rapidly distributed in various tissues with great tendency to localize fat. In the marine environment, fish and other animal groups can easily pick up residues of PAHs either directly from the water column or indirectly through their food. In this respect, PAHs are transported through the blood stream ending up in body tissues. Fish easily accumulate PAHs either through food and water ingestion, through their gills, and also from sediment. Hydrocarbon residues in Egyptian aquatic environment have been reported by several studies. This study portrays some of the major impacts of PAHs on marine ecosystem with special reference to studies conducted in Egypt. [ABSTRACT FROM AUTHOR]

Dust deposited on leaves of trees can be effectively used as monitors of polycyclic aromatic hydrocarbons (PAHs). Sixteen EPA priority PAHs concentrations in deposited dust on leaves of the street trees (leaves dust) at 14 sampling sites at traffic and residential areas in Cairo, Egypt were measured. The health risk of the 16 PAHs to humans were estimated and calculated. Results indicate that the predominant PAHs were high molecular weight-PAHs, with higher contribution 83%, whereas low molecular weight-PAHs were the less lower contribution 17%. Higher concentrations of ΣPAHs recorded at traffic areas (18,223 ± 4,172) mg/kg, whereas lower levels were found in residential areas (8,261 ± 2,006) mg/kg. The diagnostic ratios and total indexes of PAHs compounds indicate that traffic emissions and incomplete combustion were the major sources of PAHs in deposited dusts on leaves of street trees of Greater Cairo. The health risk assessment focused on ΣPAHs in leave dust, which were related to health impacts. The results recorded higher exposure doses at traffic areas than residential areas. In the current study, hazard quotient and hazard indices values were less than 1 at all sampling sites, indicating that there were no health effects for noncarcinogen. The cancer risk values for inhalation of PAHs in traffic areas > residential areas for child and adult. The current results showed that the cancer risk values were within the safe levels set by United States Environmental Protection Agency. These results indicate that cancer risk values for Greater Cairo were within the acceptable range, implying negligible carcinogenic risk. [ABSTRACT FROM AUTHOR]

The concentrations, composition, sources, and risks of polycyclic aromatic hydrocarbons (PAHs) in topsoil and surface water of the Liuxi River basin, south China were analyzed in this study. The total concentrations of 16 PAHs ranged from 296.26 to 888.14 ng/g in topsoil and from 156.73 to 422.03 ng/L in surface water, indicating mild pollution. The PAHs in topsoil exhibited an even spatial distribution, suggesting that they originated primarily from dry and wet deposition of transported pollutants. The concentration of PAHs in surface water did not differ significantly geographically, but the concentrations of total, three-, and four-ring PAHs were significantly lower in the Liuxi River than in its tributaries. Three- and two-ring PAHs predominated in topsoil and surface water, respectively. A correlation analysis suggested that the total organic carbon content and pH exerted a negligible effect on the spatial distribution of PAHs in topsoil, and they may have common sources. Fossil fuel combustion (particularly vehicle emissions) and coking production were the dominant sources of PAHs in topsoil, whereas those in surface water were derived from a variety of sources. The total toxic equivalent concentrations of 16 PAHs in topsoil ranged from 3.73 to 105.66 ng/g (mean, 30.93 ng/g), suggesting that exposure to the basin's topsoil does not pose a risk to the environment or public health according to the Canadian soil quality guidelines. A risk assessment revealed that the total PAH concentrations in surface water posed a low ecological risk. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) represent an important group of pollutants, which are known to be mutagenic, teratogenic, carcinogenic and relatively unwavering in the environment. The photocatalytic decomposition employing nano-based semiconductor photocatalyst has been a promising method for the elimination of organic pollutants in water and atmosphere. Photocatalytic remediation of pyrene (Py) and phenanthrene (Phe) by TiO2 in aqueous solutions was investigated under UV light irradiation along with chemical oxygen demand (COD) measurements. Moreover, UV–vis spectrophotometry and gas chromatography (GC) techniques were used to monitor the degradative reaction process. Fast and effective removal of pyrene and phenanthrene was achieved in this system. Catalyst TiO2 accelerated the photoremediation of Py and Phe significantly, with their half-lives being 40.005 and 60.0086 min−1, respectively. Statistical analysis showed high correlation coefficient and significant negative relation with COD and concentration of PAHs with time. All results indicated that the photocatalytic method in the presence of TiO2 nanoparticles is an advisable choice for the treatments of PAHs polluted wastewaters in nature. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) occur in the surface water of the Taizi River, China. The levels and composition patterns were studied by high-performance liquid chromatography and PAHs sources were analyzed using the isomer ratios of selected PAH compounds. In the flood period, concentrations of PAHs ranged from 1562.52 to 4176.15 ng/L with a mean of 2562.56 ng/L. In the dry period, concentrations ranged from 498.09 to 3218.27 ng/L with a mean of 1389.30 ng/L. The levels of ΣPAHs in the study area were higher than in other locations. The dominant PAHs were Baa in the flood period and Phe, Flu and Pyr in the dry period. The composition of PAHs was dominated by four-ring PAHs (51.72–82.69%) in the flood period and three-ring (28.25–50.10%) and four-ring PAHs (38.28–56.28%) in the dry period. The isomer ratios of Ant/(Ant + Phe), Flu/(Flu + Pyr) and compositional analysis were selected to identify the sources of PAHs. Coal combustion and traffic emission were the sources of PAHs in the surface water of the Taizi River, and the major source of PAHs was from combustion of coal. [ABSTRACT FROM AUTHOR]

The concentrations of the 16 US EPA polycyclic aromatic hydrocarbons (PAHs) were determined in the floodplain soils of the lower parts of the River Niger, Nigeria in 2013 and 2014 after recent flood waters had receded completely into the river channels. The aim of the research was to provide data on the spatiotemporal changes in the contamination levels, compositional patterns, sources and human health risks linked with exposure to PAHs in these soils through non-dietary ingestion, inhalation and dermal contact pathways. The PAHs in the soil samples were extracted by ultrasonication with hexane/dichloromethane, followed by clean-up on a silica gel/alumina column, and gas chromatography-mass spectrometry was used for their separation, detection and quantification. The concentrations of the 16 PAHs varied from 812 to 10,700 µg kg−1 in 2013 after an extreme flooding event, and from 12.2 to 2630 µg kg−1 in 2014 after a natural flooding event. The benzo[a]pyrene (BaP) potency factors and incremental life cancer risks (ILCR) were used to evaluate the risks of human exposure to PAHs in these soils. The average total ILCR values obtained for 2014 (a year after the extreme flooding) indicated that there was a probability of 443 children and 308 adults in a population of one million equally exposed individuals at risk of developing cancer or cancer-related illnesses in their lifetime as opposed to 6450 children and 4480 adults in 2013 immediately after the extreme flooding event. This study has shown that flooding events can cause significant variations in pollutant concentrations of floodplain soils that markedly alter human health risks. [ABSTRACT FROM AUTHOR]

Gas flaring is a major activity in oil exploration processes in Nigeria with concerns on its effects on the oil communities. This study investigated the contribution of flare gases to pollution burden of Anieze and Okwuibome communities. Water samples were displayed at 10-m, 50-m, and 100-m locations from gas-flaring stations, and control samples were taken in another location. After a month, the water samples were examined for heavy metals, polycyclic aromatic hydrocarbons, and physico-chemical parameters. Pb was found only in the 50-m location and above the WHO standard. Fe, Zn, and Cr were detected in the order 10 m > 50 m > 100 m > control whereas Cd was detected in the order 100 m > 50 m > 10 m > control. Fe, Zn, Cr, and Cd were linked to gas-flaring activities. The total PAHs were found in the order 10 m (1929.43 μg/L) > 100 m (1759.64 μg/L) > 50 m (620.27 μg/L) > control (389.37 μg/L). The signature ratio related the PAH sources to combination of petroleum and combustion sources. The sources of the PAHs were linked to the flare gas. The study implicates gas-flaring activities for the increased pollution burden in the communities and suggests policies that guide its reduction in petroleum explorations. [ABSTRACT FROM AUTHOR]

In Chennai city, India, the industrial outfalls, port activities and anthropogenic activities dump a significant amount of waste in the riverine belts of two major rivers, viz. Cooum and Adayar. Hence, this paper aims to study the occurrences and sources of 16 priority polycyclic aromatic hydrocarbons (PAHs) enlisted in United States Environmental protection Agency. Gas chromatography–mass spectrometry analysis showed that total PAHs in surface riverine sediment ranged from 136 to 2063 ng/g (Average ± SD, 654 ± 801 ng/g dw) for Cooum and 105–1710 ng/g (Average ± SD, 380 ± 593 ng/g) for Adayar. Generally, high molecular weight PAHs were higher than low molecular weight PAHs. A prevalence of high molecular weight carcinogenic PAHs was suspected due to incomplete combustion. Principal component analysis and diagnostic ratios revealed that emission sources were from pyrogenic (vehicular emissions), as well as significant contribution was from petrogenic inputs. Principal component analysis also revealed that for both riverine sediments in PC1 65% of high molecular weight compounds were from informal e-waste recycling area and industrial corridor possibly associated with industrial effluents and recycling activities. The ecological risk assessment using probable effect level estimation suggested that PAHs are likely to cause no adverse effect or slightly adverse in all the sites of Cooum and Adayar excluding in residential sites (CR-03, AD-02) and e-waste site (CR-16) which were under heavy and moderate ecological impact. Further toxic equivalent factor also showed that residential site (AD-02) was affected by moderate level loading of benzo[a]pyrene. [ABSTRACT FROM AUTHOR]

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in surface water samples collected from three locations along the downstream of river Nile in Alexandria, Egypt were analyzed using gas chromatography–mass spectrometry. To the best of knowledge, this investigation represents one of the very few extensive studies investigating the distribution and sources of PAHs in water of river Nile in Egypt. Total concentrations of the 16 PAHs in water samples ranged from 235.92 ng L−1 at Abbis site (an agricultural area), which were predominated by three- and four-ring PAHs (about 90%) to 10367.60 ng L−1 at Al-Max area (a residential area with heavy traffic and fishing activities), which were predominated by five- to six-ring PAHs (about 94%). PAH concentrations were one to two orders of magnitude higher in comparison with those reported for riverine/estuaries systems around the world. Molecular indices, such as ratios of specific PAH compound including Phenanthrene/Anthracene (Phe/Ant) and Fluoranthene/Pyrene (Flua/Pyr), were calculated to evaluate the possible sources of PAHs and their relative importance. These ratios indicated that the major PAH input was from combustion of fuel, wood and grasses in the area under study (i.e. a pyrogenic source). The concentrations recorded in this investigation were higher than that recorded in the rivers of the USA and Europe and even higher than the levels established for drinking water in the USA. [ABSTRACT FROM AUTHOR]

Soil is an important environmental matrix to support the life of all organisms directly or indirectly. Despite being the ultimate sink for all pollutants, it has been neglected for long, which has negatively affected the quality of the soil. Disposal of pollutants has resulted in changes in properties of soils and introduction of toxicity into it. The presence of heavy metals, pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons (PAHs) affects all forms of life since these chemicals have associated toxicity, mutagenicity, and carcinogenicity. PAHs are typical pollutants of soil which result in alteration in grain size, porosity and water-holding capacity of soil and affect diversity/population of microbes adversely. Significant changes in permeability, volume, plasticity, etc., are also brought about resulting in poor quality of contaminated soils. Considering the toxicity and global prevalence of PAHs, remediation of contaminated soils has become a challenge. Therefore, it is important to understand the detailed mechanism of physical, chemical or biological changes in soil. Simultaneously, it becomes pertinent to identify the environmentally sustainable treatment options for remediation of contaminated sites. Whereas physical and chemical treatment methods are either cost, chemical, or energy prohibitive, the biological treatment is emerging as an efficient and effective option which employs microorganisms for mitigation. Microorganisms are known for their enzyme-catalyzed catabolic activity when degradation/mineralization of a pollutant is aimed at and can prove useful in degradation of PAHs. Therefore, the present study reviews the effects of PAHs on soil properties, different remediation techniques and the role of microorganisms in remediating contaminated sites. [ABSTRACT FROM AUTHOR]

This paper has investigated the concentration and distribution of polycyclic aromatic hydrocarbons in shallow groundwater from an alluvial-diluvial fan of the Hutuo River in North China. Results show that the concentration levels of 16 priority polycyclic aromatic hydrocarbons range from 0 to 92.06 ng/L, do not conform to drinking water quality standards in China (GB 5749- 2006). However, the concentration figures of priority polycyclic aromatic hydrocarbons are much lower than that of other studies conducted elsewhere in China. In addition, highly-concentrated polycyclic aromatic hydrocarbons (50-92 ng/L) are fragmentarily distributed. The composition of polycyclic aromatic hydrocarbons from this study indicates that low molecular polycyclic aromatic hydrocarbons are predominant in groundwater samples, medium molecular compounds occur at low concentrations, and high molecular hydrocarbons are not detected. The polycyclic aromatic hydrocarbon composition in groundwater samples is basically the same as that of gaseous samples in the atmosphere in this study. Therefore, the atmospheric input is assumed to be an important source of polycyclic aromatic hydrocarbons, no less than wastewater discharge, adhesion on suspended solids, and surface water leakage. Ratios of specific polycyclic aromatic hydrocarbons demonstrate that they mainly originate from wood or coal combustion as well as natural gas and partially from petroleum according to the result of principal component analysis. On the whole, conclusions are drawn that the contamination sources of these polycyclic aromatic hydrocarbons are likely petrogenic and pyrolytic inputs. Future investigations by sampling topsoil, vadose soil, and the atmosphere can further verify aforementioned conclusions. [ABSTRACT FROM AUTHOR]

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The aim of this study was to determine the sources and contamination characteristics of polycyclic aromatic hydrocarbons (PAHs) in various environmental media in a karst underground river system. For this purpose, air, underground river water, sediment, and soil samples were collected from a typical underground river in southern China in the dry and wet seasons of 2013-2014, and the compositional spectra, distribution, and ratio characteristics of 16 PAHs were determined for comparative analysis. The results show that three 2-3-ring PAHs (naphthalene, phenanthrene, and fluoranthene) mainly occur in air and underground river water. In sediments and soils, 4-6-ring PAHs are the main components. The PAH concentrations in the air in the wet season are clearly greater than those in the dry season, while it is the opposite in the underground water. Seasonal differences in the concentration of PAHs in the sediments and soils are minor. The concentrations of PAHs in the environmental media overall showed variation in the following order: upstream < midstream < downstream, and this is related to pollutant discharge, adsorption, etc. The main source of PAHs in the upstream area is the combustion of grass, wood, and coal, while it is petroleum in the midstream area, and combustion of grass, wood, coal, and petroleum near the outlet of the underground river. It is necessary to change the energy structure in the study area, improve the efficiency of environmental protection facilities, reduce the emission in vehicle exhaust, and control pollution by PAHs at their sources. [ABSTRACT FROM AUTHOR]

In this study, the characteristics, probable source, and potential carcinogenic risk of 16 polycyclic aromatic hydrocarbons (PAHs) in surface water of the Liaohe River were investigated. Twelve sampling points were selected, and water samples were collected in both dry and flood periods of 2011. Sample analysis indicated that the concentration of total PAHs varied from 840.50 ng/L to 4274.73 ng/L in the flood period, and from 387.76 ng/L to 1997.83 ng/L in the dry period. The representative PAHs in the flood period were benz[a]anthracene (Baa), naphthalene (Nap), and chrysene (Chr), whereas Phenanthrene (Phe), fluoranthene (Flu), and pyrene (Pyr) were the representative PAHs in the dry period. The compositional pattern of PAHs indicated that four-ring PAHs were predominant in the flood period, whereas three-ring and four-ring PAHs dominated in the dry period. The different PAH congener ratios indicated that PAHs in surface water of the Liaohe River mainly originated from a mixed source in the flood period, and from combustion in the dry period. Based on the methods of Incremental Lifetime Cancer Risk (ILCR) and the benzo[a]pyrene toxic equivalent (TEQ), the potential cancer risk was quantitatively assessed, and the results suggested that there was a potential cancer risk in surface water of the Liaohe River and more attentions must be paid to the PAHs contamination. The cancer risk in the teenager group was the most, followed by the children group, adult group, and infant group, and toddler group was the least. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants, entering into various water and wastewater systems through various natural and anthropogenic activities. The aim of the work is to convert vehicular tires, a highly available waste material, into potential adsorbent for the removal of PAHs from aqueous solutions. The BET surface area of the prepared vehicular tire activated carbon is 643.86 m2/g. Removal of PAHs using activated carbons and the effect of various parameters such as contact time, adsorbent dose, temperature, and pH on the adsorption have been evaluated. The data were fitted to Freundlich and Langmuir isotherms and values of various constants were evaluated. In all the cases, Freundlich model was found to be better fitted. The equilibrium time for adsorption of PAHs was 120 min. The values of thermodynamic parameters, such as Gibb's free energy change ΔG°, enthalpy change ΔH°, and entropy change ΔS°, were calculated using adsorption equilibrium constants obtained from Langmuir isotherm. The thermodynamic data for adsorption of PAHs revealed spontaneity and endothermic nature of the adsorption process. The samples were analyzed using a UV-vis spectrophotometer for PAH determination. Mixture of sodium hydroxide and ethanol in different proportions was tried for desorption of PAHs and 50% ethanolic NaOH solution was most effective. The developed activated carbon demonstrates good adsorption and desorption capabilities for PAHs, indicating towards its suitability for use in the treatment processes of various industrial effluents or water streams containing PAHs. [ABSTRACT FROM AUTHOR]

Sixteen priority polycyclic aromatic hydrocarbons (PAHs) were investigated in the water dissolved phase (DP), suspended particulate matter (SPM), and sediment collected from the water source zone of the Pearl River Delta region. The sum of 16 PAH concentrations ranged from 92.8 to 324 ng/L in the water DP, from 28.8 to 205 ng/L in the SPM, and from 55.7 to 381 ng/g (d.w.) in the sediment. Compared with other areas globally, the PAH levels were considerably moderate in the DP and SPM and relatively low in the sediment. Spatial distribution of PAHs was site-specific, and relatively higher PAH levels were found in the areas with dense population and heavy traffic. The PAH profile was dominated by two- and three-ring PAHs, and PAH pollution was identified of pyrolytic origins. Based on risk quotient, the ecological risk in water was ranked as moderate, but the adverse health risk associated with water ingestion was minimal. Naphthalene and fluorene of the sediment samples showed potential biological impairment in some locations; nevertheless, the mean effects range median quotient suggested that the ecological risk of multiple PAHs was quite low (less than 10% incidence of adverse effects). [ABSTRACT FROM AUTHOR]

The composition of polycyclic aromatic hydrocarbons (PAHs) in Lake Baikal water and adjacent air layer and PAH emission composition profiles of possible sources were investigated. Analysis of emission composition data showed that the source profiles could not be grouped by fuel type or pyrogenic/petrogenic origin. Because of the similarity of source PAH profiles, the drawing of 3D mixing diagrams was the only way to check whether some of the potential PAH sources were the true sources. The mixing diagrams showed that the sources of air pollution were paper mills and wood burning and that the sources of water pollution were coal-fired and oil-fired boilers. The common source for both air and water was only oil and petroleum products. To determine the locations of PAH sources, their contributions to air and water pollution were calculated and mapped. Based on the results, air and water were polluted from both local and regional sources. The location of the zone influenced by a particular source was conditioned by physical properties of source emission, direction of air/water flows that transfer PAHs and temperature differences between mixing air/water flows. [ABSTRACT FROM AUTHOR]

Surface sediments were collected from the Watershed of Wadi El Bey in Tunisia to evaluate the degree of polycyclic aromatic hydrocarbons (PAHs) contamination. Sediments were collected during different seasons in 14 sites that received wastes from domestic effluent, industrial discharge, and agricultural drainage wastes. Twenty-six individual PAHs were analyzed. The total PAH contents (Σ PAHs) in surface sediments showed wide variability, ranging from 6.89 ± 0.05 to 340 ± 0.1 ng g. The 4-, 5-, and 6-ring compounds were the most abundant PAHs detected at the majority of sites. Diagnostic concentration ratios between pairs of PAHs and molecular indices, calculated with the purpose of drawing information about pollution sources, indicated that PAHs were of both petrogenic and pyrolytic origins. Toxic contaminants concentrations were determined according to the numerical effect-based sediment quality guidelines (SQGs). PAH levels did not exceed the SQGs, indicating that PAHs seem to pose low and occasional toxicity risks. Total carcinogenicity and mutagenicity (TEQ and MEQ) ranged from 0.08 to 65 ng and from 0.02 to 135.0 ng g of dry weight, respectively. Among the seven carcinogenic PAHs, BaP accounted for the majority of the potency and could potentially be used as a unique indicator of PAH toxicity. This study provides a baseline to promote environmental protection programs and pollution monitoring/control in Watershed and coastal areas. [ABSTRACT FROM AUTHOR]

The concentration characteristics, sources, and potential ecological risk assessment of 16 PAHs were investigated in the surface water from the Songhua River Basin, Northeast China. A total of 48 river water samples, including 16 from the main streams and 32 from the tributaries, were collected. Samples were separated into dissolved phases and suspended particle matter (SPM) via filtration with 0.47 μm glass fiber filters. Each phase was analyzed for PAHs. The total PAH concentration in the dissolved phase in the water ranged from 32.5 to 108 ng L and from 0.3 to 62.3 μg g (dry weight) in the suspended particle matter (SPM). The total PAH concentration in the main stream was lower than in the tributaries; the volume of annual runoff of rivers had a significant effect on the ƩPAH in the rivers. The 2- and 3-ring PAHs dominated in both the dissolved phase and SPM, indicating a relatively recent local source of PAHs in the study area. The concentrations of PAHs in the Songhua River Basin are lower when compared with the values previously reported in the literature from other rivers around the world. The sources of PAHs were assessed by diagnostic ratios and principal component analysis (PCA), and the ecological risk of the PAHs was assessed based on the risk quotient (RQ). The diagnostic ratios and PCA indicated that the main sources of PAHs originated from pyrogenic and petrogenic sources, and pyrogenic sources had a greater impact. The ecological risk assessment indicated that the PAHs presented low ecosystem risk in the Songhua River Basin. [ABSTRACT FROM AUTHOR]

Historical distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) and their carriers (i.e., organic matter and mineral particles) in the sediment cores of the Yangtze Estuary were investigated, with emphasis laid on the role of the Yangtze River. Grain size component of sediments (clay, silt, and sand) and organic carbon (black carbon and total organic carbon) in the sediment cores were markedly affected by water flux and sediment discharge of the Yangtze River. Qualitative and quantitative analysis results showed that sands and black carbon acted as the main carriers of PAHs. The sedimentation of two-ring to three-ring PAHs in the estuary had significant correlations with water flux and sediment discharge of the Yangtze River. The relative lower level of the four-ring and five-ring to six-ring PAHs concentrations appeared around the year 2003 and remained for the following several years. This time period accorded well with the water impoundment time of the Three Gorges Reservoir. The decreased level of two-ring to three-ring PAHs occurred in the year 1994, and the peak points around the year 2009 indicated that PAHs sedimentation in the estuary also had close relationship to severe drought and flood in the catchments. The findings presented in this paper could provide references for assessing the impacts of water flux and sediment discharge on the historical deposition of PAHs and their carriers in the Yangtze Estuary. [ABSTRACT FROM AUTHOR]

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 dry weight in sediments, from 51.0 to 559.1 ng L in water, and from 4528 to 51,080 ng g 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. [ABSTRACT FROM AUTHOR]

Waste water treatment plants (WWTP) have attracted attention in numerous studies in their impact on receiving surface waters because of the presence of varied contaminants in their effluents. This study investigated the relevance of particle-bound contaminants using suspended particulate matter (SPM) to monitor the temporal variability of the impact of a WWTP discharge in a chalk stream (Loue River) in France. We performed five sampling campaigns of SPM and sediment during a year at different seasons and analyzed polycyclic aromatic hydrocarbons (PAHs) and phosphorus in both matrix. PAH contents in SPM ranged from 675 to 3709 μg kg dry weight (dw) and in sediment from 668 to 7712 μg kg dw. Levels of phosphorus ranged from 364 to 1380 mg kg dw in SPM and from 315 to 523 mg kg dw in sediment. The WWTP increased significantly PAH levels in SPM to the Loue River. However, our results did not allow to evidence significant differences on particulate phosphorus concentration in SPM. Nevertheless, we evidenced significant seasonal variations of PAH and phosphorus concentrations in SPM. Besides sediment sampling, the collection of SPM allowed to monitor changes in contamination from the WWTP and highlighted impact of WWTP on PAH concentrations and changes of PAH and phosphorus concentrations over time. Contamination of SPM of the Loue River was driven by mixed inputs from point source like WWTP and from diffuse sources in the catchment like runoff from impervious and pervious surfaces. Combining monitoring of SPM and sediment proved to be an improved approach to assess contamination of local and diffuse sources in chalk streams. [ABSTRACT FROM AUTHOR]

Based on the available toxicity data and the concentrations of polycyclic aromatic hydrocarbons (PAHs) in 16 surface sediments from upper reach of Huaihe River, overlapping areas of probability density curves and margin of safety (MOS10) were used to estimate the ecological risk of eight PAHs to aquatic organisms. The results indicated that the overlapping areas of Pyr, Nap, Fla, Ant, Phe, Ace, BaP, and Flu were 0.38, 0.29, 0.16, 0.11, 0.07, 0.03, 0.03, and 0.01, respectively. The risk of Pyr was the highest while that of Flu was the lowest. The overlapping area of ΣPAH8was 0.72, higher than that of any individual PAHs due to their joint effect. The calculated MOS10for Nap, Ace, Flu, Phe, Ant, Fla, Pyr, and BaP were 6.86, 5.42, 19.0, 2.72, 0.93, 0.75, 0.03, and 63.0, respectively. The probabilities of Nap, Ace, Flu, Phe, and BaP surpassing the 10th percentile value of the toxicity data were 0.07%, 0.30%, 0.05%, 1.97%, and 0.01%, respectively, suggesting minimal risk to aquatic organisms. However, the probabilities of Ant, Fla, and Pyr exceeding this value were 11.3%, 12.9%, and 64.8%, indicating potential risks. Among the individual PAHs, the ecological risk from Pyr was the highest, followed by Fla, Ant, Phe, Ace, Nap, Flu, and BaP. Additionally, the combined ecological risk of ΣPAH8in the upper reach of Huaihe River was significantly higher than that of any individual PAH alone, which the probabilities of ∑PAH8in excess of the 10th percentile of the toxicity data were 99.4%. [ABSTRACT FROM AUTHOR]

Samples were collected from the middle and lower reaches of the Yangtze River, China, to study the concentrations, distributions, and compositions of 16 US-EPA priority polycyclic aromatic hydrocarbons (PAHs) in water and suspended particulate matter (SPM). We also evaluated sources of the PAHs and their potential toxicity. Total concentrations of the PAHs (ΣPAHs) in water ranged from 17.33 to 77.12 ng L, and in SPM, the levels ranged from 595.91 to 2473.74 ng g. Total concentrations of seven carcinogenic PAHs (ΣCPAHs) ranged from 7.63 to 13.02 ng L in water and 276.55 to 1216.89 ng g in SPM. PAH levels in water samples were relatively low, and those in the lower reaches were higher than in the middle reaches. SPM samples had higher levels of PAHs, especially in the lower reaches and in Dongting Lake and Poyang Lake. Principal component analysis (PCA) with multiple linear regression analysis (MLR) was performed to quantitatively characterize the PAH sources. Two factors and their contributions were identified from water samples. Coal and wood combustion accounted for 74.1 % of the PAHs, and petroleum emissions explained 25.9 % of the PAHs. Three source factors were identified from SPM samples: these were vehicular emissions (46.3 % of PAHs), wood and coal combustion (40.4 % of PAHs), and petrogenic sources (13.3 %). Ecological risk assessment indicated that a moderate undesirable impact will be caused by PAHs, and some control measures and remedial actions should be conducted. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) have received increasing attentions owing to their carcinogenicity, teratogenicity and environmental toxicity. The studies on the spatial variations, sources identification and potential ecological risk assessment of PAHs in the reservoir sediments after dam construction are becoming new hotpots. Sixteen PAHs contamination levels were investigated from 15 sample sections in the sediments of Manwan Reservoir in the middle of Lancang River, China. Total concentrations of 16 PAHs ranged from 14.4 to 137.7 ng g dw with a mean concentration of 70.68 ng g dw. The areas with residential settlement at large tributaries and near dam had higher PAHs concentrations. In the sight of classification of PAHs pollution levels, the sediments of Manwan Reservoir could be considered as low to moderate PAHs polluted levels. One-way analysis of variance for spatial analysis revealed that there were no significant differences ( P < 0.05) for 16 PAHs at the reservoir head, centre and tail. Moreover, no significant differences ( P < 0.05) were found for most individual PAH at the mainstream and tributaries except that BaP showed significant differences ( P < 0.05) in the mainstream and tributaries. According to the diagnostic ratios, the possible pollution sources of PAHs in Manwan Reservoir might be mixed, primarily including the petroleum source and coal combustion. As compared with sediment quality guidelines, the observed concentrations of PAHs in all sample sections did not exceed the effects range low (ERL) and the threshold effect level (TEL) values, suggesting that there were little harmful biological toxic effects on the aquatic organisms in Manwan Reservoir. The study provided a comprehensive overview on the PAHs contaminations on the reservoir sediments in the middle Lancang River, which may have an important significances on the international river management. [ABSTRACT FROM AUTHOR]

The sources of polycyclic aromatic hydrocarbons (PAHs) and sources of water that deliver PAHs to an investigated river were apportioned using an end-member mixing approach. The identification of sources and tracers was based on bounding the samples by end-member sources on the mixing diagram using coordinates of source tracer concentrations. The sums of PAHs with the same molecular weight were used as PAH source tracers, and the dissolved organic carbon to base cations ratio was used as a tracer for water sources. The source contributions were evaluated by solving systems of linear equations. Most of the water samples were bound by a triangle formed by wood combustion, oil-fired boilers, and aluminum smelters in the mixing space defined by the concentrations of the principal mass 178 and 228 PAHs. There were notable seasonal variations in the PAH source contributions at each sampling site due to different contributions of groundwater, surface flow, and interflow to stream water. The differences in the PAH source contributions among sites were due to both different proportions of the flow components and different positions of the sites relative to the emission sources. Most of the bottom sediment samples were bound by a triangle formed by the same sources, but in the mixing space defined by the principal mass 252 and 276 PAHs. There were no spatial or temporal differences in the PAH source proportions among the samples because the PAH composition of the bottom sediments at each location represents the time- and space-weighted average of all the sediment loads from upstream. [ABSTRACT FROM AUTHOR]

Karoon is the longest river in Iran and provides water for industries located along its banks, such as metal, petrochemical, and oil industries. It is also the source of drinking water for cities such as Ahwas, Abadan, and Khorramshahr. In this study, 34 and 18 surface sediment samples were collected and analyzed for heavy metals (Al, As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and polycyclic aromatic hydrocarbons (PAHs). The measured concentrations of heavy metals were compared with US EPA sediment quality guidelines, and the results showed that Cu concentration was above the threshold effect level (TEL) in 65.67 % of the samples and Hg concentration was above the effect range median (ERM) in some samples. The results revealed that Hg was severely enriched (5 < enrichment factor < 20) and classified in very high ecological risk index category. It is the major metallic contaminant in the study area. The total PAH concentrations ranged from 11.54-117,730 μg/kg, with the mean value of 7034.55 μg/kg dominated by lower molecular weight (LMW) PAHs. The total potentially carcinogenic PAHs (∑cPAHs) in sediment samples ranged from 2.09 to 31,930 μg/kg, indicating high carcinogenic potential of sediments in the study area. The total toxic equivalent (TEQ) values ranged from 1.06 to 7228.7 μg/kg. Maximum TEQ occurred in Abadan oil refinery station followed by Khorramshahr soap factory and Abadan petrochemical complex. Principal component analysis and cluster analysis also revealed the relationships between the studied parameters and identified their probable sources. [ABSTRACT FROM AUTHOR]

This study investigates the variations of polycyclic aromatic hydrocarbon (PAH) levels in surface water, suspended particulate matter (SPM) and sediment upstream and downstream of the discharges of two wastewater treatment plant (WWTP) effluents. Relationships between the levels of PAHs in these different matrices were also investigated. The sum of 16 US EPA PAHs ranged from 73.5 to 728.0 ng L in surface water and from 85.4 to 313.1 ng L in effluent. In SPM and sediment, ∑PAHs ranged from 749.6 to 2,463 μg kg and from 690.7 μg kg to 3,625.6 μg kg, respectively. Investigations performed upstream and downstream of both studied WWTPs showed that WWTP discharges may contribute to the overall PAH contaminations in the Loue and the Doubs rivers. Comparison between gammarid populations upstream and downstream of WWTP discharge showed that biota was impacted by the WWTP effluents. When based only on surface water samples, the assessment of freshwater quality did not provide evidence for a marked PAH contamination in either of the rivers studied. However, using SPM and sediment samples, we found PAH contents exceeding sediment quality guidelines. We conclude that sediment and SPM are relevant matrices to assess overall PAH contamination in aquatic ecosystems. Furthermore, we found a positive linear correlation between PAH contents of SPM and sediment, showing that SPM represents an integrating matrix which is able to provide meaningful data about the overall contamination over a given time span. [ABSTRACT FROM AUTHOR]

Many epidemiological studies from all over the world have reported that populations of rural and urban environments differ in their health issues due to the differences in the countrywide pollution pattern. In developing countries, various occupational cohorts and subsections of the population in urban and rural areas are routinely exposed to several environmentally widespread contaminants. Polycyclic aromatic hydrocarbons (PAHs) are a group of over hundred different compounds and have ubiquitous presence in rural and urban environments. Smoke from the combustion of biomass fuel contains a high concentration of carcinogenic PAHs, which are related with several human morbidities. The sources and types of biomass fuel are diverse and wide in distribution. Limited numbers of literature reports have focused the significant impact of PAHs on several components of blood, both in human and wildlife. The toxicity of PAHs to rapidly dividing cells (e.g., bone marrow cells) and other tissues is largely attributed to their reactive oxygenated metabolites, potential of causing oxidative stress, and the adducts of their metabolites with DNA. This review aims to encompass the blood-related effects of PAHs and associated human health risks-an aspect that needs further research-on the population of developing countries of the world in particular. [ABSTRACT FROM AUTHOR]

Farmland soil and leafy vegetables accumulate more polycyclic aromatic hydrocarbons (PAHs) in suburban sites. In this study, 13 sampling areas were selected from vegetable fields in the outskirts of Xi’an, the largest city in northwestern China. The similarity of PAH composition in soil and vegetation was investigated through principal components analysis and redundancy analysis (RDA), rather than discrimination of PAH congeners from various sources. The toxic equivalent quantity of PAHs in soil ranged from 7 to 202 μg/kg d.w., with an average of 41 μg/kg d.w., which exceeded the agricultural/horticultural soil acceptance criteria for New Zealand. However, the cancer risk level posed by combined direct ingestion, dermal contact, inhalation of soil particles, and inhalation of surface soil vapor met the rigorous international criteria (1×10−6). The concentration of total PAHs was (1052±73) μg/kg d.w. in vegetation (mean±standard error). The cancer risks posed by ingestion of vegetation ranged from 2×10−5 to 2×10−4 with an average of 1.66×10−4, which was higher than international excess lifetime risk limits for carcinogens (1×10−4). The geochemical indices indicated that the PAHs in soil and vegetables were mainly from vehicle and crude oil combustion. Both the total PAHs in vegetation and bioconcentration factor for total PAHs (the ratio of total PAHs in vegetation to total PAHs in soil) increased with increasing pH as well as decreasing sand in soil. The total variation in distribution of PAHs in vegetation explained by those in soil reached 98% in RDA, which was statistically significant based on Monte Carlo permutation. Common pollution source and notable effects of soil contamination on vegetation would result in highly similar distribution of PAHs in soil and vegetation. [ABSTRACT FROM AUTHOR]

Surface water and sediments were collected from eleven locations on the middle region of Huaihe River to evaluate the environmental effects of urban and industrial activities. The concentrations of sixteen polycyclic aromatic hydrocarbons (PAHs) in water and sediments were between 1.2–5.1 µg/L and 72–139 ng/g, respectively. High levels of PAHs in water were recorded in comparison to those of other countries, while the concentrations in sediments were low to moderate levels. A weak positive correlation was observed (R2 = 0.49, P = 0.13) between PAHs and total organic carbon in water. However, a significant positive correlation (R2 = 0.79, P = 0.004) was found in sediments, which indicated that total organic carbon was a factor in PAH levels in sediments but not in water. The parent ratios were studied by principal component analysis that showed the PAHs from water were predominantly derived from coal combustion (34%), oil spills (49%), and vehicular emissions (17%), while the major PAH sources to sediments were coal combustion. Using the ecological toxic equivalency factor index, it was concluded that the PAHs levels may provide a potential risk in water but not in sediments. [ABSTRACT FROM PUBLISHER]

Liaohe River Basin is an important region in northeast China, which consists of several main rivers including Liao River, Taizi river, Daliao River, and Hun River. As a highly industrialized region, the basin receives dense waste discharges, causing severe environmental problems. In this study, the spatial and temporal distribution of aqueous polycyclic aromatic hydrocarbons (PAHs) in Liaohe River Basin from 50 sampling sites in both dry (May) and level (October) periods in 2012 was investigated. Sixteen USEPA priority PAHs were quantified by gas chromatography/mass selective detector. The total PAH concentration ranged from 111.8 to 2,931.6 ng/L in the dry period and from 94.8 to 2766.0 ng/L in the level period, respectively. As for the spatial distribution, the mean concentration of PAHs followed the order of Taizi River > Daliao River > Hun River > Liao River, showing higher concentrations close to large cities with dense industries. The composition and possible sources of PAHs in the water samples were also determined. The fractions of low molecular weight PAHs ranged from 58.2 to 93.3 %, indicating the influence of low or moderate temperature combustion process. Diagnostic ratios, principal component analysis, and hierarchical cluster analysis were used to study the possible source categories in the study area, and consistent results were obtained from different techniques, that PAHs in water samples mainly originated from complex sources, i.e., both pyrogenic and petrogenic sources. The benzo[a]pyrene equivalents (EBaP) characterizing the ecological risk of PAHs to the aquatic environment suggested that PAHs in Liaohe River Basin had already caused environmental health risks. [ABSTRACT FROM AUTHOR]

To assess the status of polycyclic aromatic hydrocarbon (PAH) contamination in sediments from the Bizerte Lagoon (northern Tunisia), 18 surface sediment samples were collected in March 2011 and analyzed for 14 US Environmental Protection Agency priority PAHs by high-performance liquid chromatography. The total concentrations of the 14 PAHs (ΣPAHs) ranged from 16.9 to 394.1 ng g dry weight (dw) with a mean concentration of 85.5 ng g dw. Compared with other lagoons, coasts, and bays in the world, the concentrations of PAHs in surface sediments of the Bizerte Lagoon are low to moderate. The PAHs' composition pattern was dominated by the presence of four-ring PAHs (45.8 %) followed by five-ring (26.8 %) and three-ring PAHs (12.7 %). The PAH source analysis suggested that the main origin of PAHs in the sediments of the lagoon was mainly from pyrolytic sources. According to the numerical effect-based sediment quality guidelines of the USA, the levels of PAHs in the Bizerte Lagoon should not exert adverse biological effects. The total benzo[ a]pyrene toxicity equivalent values calculated for the samples varied from 3.1 to 53.7 ng g dw with an average of 10.6 ng g dw. [ABSTRACT FROM AUTHOR]

The spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) in the Songhua River, Harbin, China, were investigated. Seventy-seven samples, 42 water and 35 sediment samples, were collected in April and October of 2007 and January of 2008. The concentrations of total PAHs in water ranged from 163.54 to 2,746.25 ng/L with the average value of 934.62 ng/L, which were predominated by 2- and 3-ring PAHs. The concentrations of total 16 PAHs in sediment ranged from 68.25 to 654.15 ng/g dw with the average value of 234.15 ng/g dw, which were predominated by 4-, 5- and 6-ring PAHs. Statistical analysis of the PAH concentrations shown that the highest concentrations of the total PAHs were found during rainy season (October of 2007) and the lowest during snowy season (January of 2008). Ratios of specific PAH compounds, including fluoranthene/(fluoranthene + pyrene) (Flu/(Flu + Pyr)) and phenanthrene/(phenanthrene + anthracene) (An/(Ant + PhA)), were calculated to evaluate the possible sources of PAH contaminations. These ratios reflected pyrolytic inputs of PAHs in Songhua River water and a mixed pattern of pyrolytic and petrogenic inputs of PAHs in the Songhua River sediments. Ecotoxicological risk levels calculated for PAHs suggested that there were individual PAHs, which can less frequently cause biological impairment in some samples, but no samples had constituents that may frequently cause biological impairment. Total toxic benzo[a]pyrene equivalent of ΣcPAHs varied from 10.03 to 29.7 ng/g dw and from 0.36 to 1.92 ng/g dw for total toxic tetrachlorodibenzo-p-dioxin equivalent. The level of PAHs indicated a low toxicological risk to this area. [ABSTRACT FROM AUTHOR]