Polycyclic Aromatic Hydrocarbons In Surface Water Research Articles

Anthropogenic and natural hydrocarbons in water and sediments of the Kara Sea.

The results on the content and composition of aliphatic (AHСs) and polycyclic aromatic hydrocarbons (PAHs) at the geochemical barrier between the Kara Sea and the Ob and Yenisei Rivers are discussed in comparison with those in the mouth areas of the Lena, Khatanga, Indigirka and Kolyma. It has been established that hydrocarbon concentrations sharply decrease in the river-sea mixing zones, and their composition, and the ratio of their dissolved and suspended forms change. Besides, the research season plays a great role, as the highest content of hydrocarbons and particulate matter was found in the Ob Gulf during the flood, when the concentrations of AHCs in surface waters reached 325μg/L, PAHs -15ng/L, particulate matter-15.5mg/L. In the Kara Sea itself, AHC concentrations increased on average from 20 to 59μg/L, that is most likely associated with the melting of seasonal ice and floods. Anthropogenic influence was found in river waters, where the proportion of naphthalenes, which marks oil products, and pyrene, which marks pyrogenic PAHs, is increased. In the Ob Gulf is linked to an increase in navigation along the Northern Sea Route and the functioning of the port of Sabetta. In the mouth area of the Yenisei, the concentrations of both AHC and PAH in surface waters and sediments varied in a smaller range than in the mouth area of the Ob, which is due to the nature of the rocks that make up the catchment areas of these rivers, as well as the regulation of the Yenisei runoff. The hydrological features of the estuarine areas can lead to increased AHC concentrations (the mouth of the Khatanga, up to 189μg/L, 2.6μg/mg SPM). The minimum AHC content in SPM and sediments in the river transects was established in the East Siberian rivers (Indigirka, Kolyma), associated with the decreasing productivity in waters from the Western Arctic seas to the Eastern.

Polycyclic aromatic hydrocarbons in surface water and sediment from Shanghai port, China: spatial distribution, source apportionment, and potential risk assessment.

The spatial distribution, sources, and potential risk of polycyclic aromatic hydrocarbons (PAHs) were systematically investigated in Shanghai port, one of the most important hubs in international trade. The 16 priority PAHs in surface water and sediment were determined. Total concentrations of 16 PAHs (Σ16PAHs) ranged from 140.6 to 647.4ng/L in surface water and from 12.7 to 573.2ng/g (dry weight, dw) in sediment, respectively. The 2-ring and 3-ring PAHs with low molecular weight were main components in water, while the 3-ring and 4-ring PAHs were abundant in sediment. Flu was the main component of the Σ16PAHs in water and sediment. According to the source apportionment, the PAHs in water mostly originated from combustion of fossil fuels and petroleum and petroleum combustion were the main contributors to the PAHs in sediment. The results obtained from potential risk assessment indicate that the PAHs in surface water present a moderate ecological risk, whereas the PAHs in sediment show low ecological risk indicating a less possibility of toxic pollution.

Polycyclic Aromatic Hydrocarbons (PAHs) in the Dissolved Phase, Particulate Matter, and Sediment of the Sele River, Southern Italy: A Focus on Distribution, Risk Assessment, and Sources.

The Sele River, located in the Campania Region (southern Italy), is one of the most important rivers and the second in the region by average water volume, behind the Volturno River. To understand the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in the Sele River, water sediment samples were collected from areas around the Sele plain at 10 sites in four seasons. In addition, the ecosystem health risk and the seasonal and spatial distribution of PAHs in samples of water and sediment were assessed. Contaminant discharges of PAHs into the sea were calculated at about 1807.9 kg/year. The concentration ranges of 16 PAHs in surface water (DP), suspended particulate matter (SPM), and sediment were 10.1–567.23 ng/L, 121.23–654.36 ng/L, and 331.75–871.96 ng/g, respectively. Isomeric ratio and principal component analyses indicated that the PAH concentrations in the water and sediment near the Sele River were influenced by industrial wastewater and vehicle emissions. The fugacity fraction approach was applied to determine the trends for the water-sediment exchange of 16 priority PAHs; the results indicated that fluxes, for the most part, were from the water into the sediment. The toxic equivalent concentration (TEQ) of carcinogenic PAHs ranged from 137.3 to 292.6 ngTEQ g−1, suggesting that the Sele River basin presents a definite carcinogenic risk.

Characteristics of Microplastics and Their Affiliated PAHs in Surface Water in Ho Chi Minh City, Vietnam.

Microplastic pollution has become a worldwide concern. However, studies on the distribution of microplastics (MPs) from inland water to the ocean and their affiliated polycyclic aromatic hydrocarbons (PAHs) are still limited in Vietnam. In this study, we investigated the distribution of MPs and PAHs associated with MPs in canals, Saigon River, and Can Gio Sea. MPs were found at all sites, with the highest average abundance of MPs being 104.17 ± 162.44 pieces/m3 in canals, followed by 2.08 ± 2.22 pieces/m3 in the sea, and 0.60 ± 0.38 pieces/m3 in the river. Fragment, fiber, and granule were three common shapes, and each shape was dominant in one sampling area. White was the most common MP color at all sites. A total of 13 polymers and co-polymers were confirmed, and polyethylene, polypropylene, and ethylene-vinyl acetate were the three dominant polymers. The total concentration of MPs-affiliated PAHs ranged from 232.71 to 6448.66, from 30.94 to 8940.99, and from 432.95 to 3267.88 ng/g in Can Gio sea, canals, and Saigon River, respectively. Petrogenic sources were suggested as a major source of PAHs associated with MPs in Can Gio Sea, whereas those found in Saigon River and canals were from both petrogenic and pyrogenic sources.

PAHs in the surface water and sediments of the middle and lower reaches of the Han River, China: Occurrence, source, and probabilistic risk assessment

Polycyclic aromatic hydrocarbons (PAHs) pose versatile risks to the environment and human health. However, studies on their occurrences, spatial distributions, seasonal variations, possible sources and potential risks of the Han River are still not clear. In this study, 16 PAHs were investigated in the surface water and sediments from 15 sampling sites of the Middle and Lower Reaches of the Han River during the dry, normal, and flood seasons. It was found that the sum concentration of PAHs (ΣPAHs) determined by GC-MS ranged from 18.3 to 146.8 ng/L (mean 77.4 ng/L) in surface water, while it was 137.1–1478.4 ng/g (mean 679.6 ng/g) in sediments. The two to three rings PAHs in surfer water and four-five-ring in sediments PAHs comprised the majority of the detected compounds. The level of PAHs in dry season was higher than that in the flood and normal seasons, and the distributions of PAHs varied substantially along the river without clear trend in surface water and sediments. The sources of PAHs in surface water and sediments were mainly from biomass and coal combustion, followed by petroleum combustion. The human health risk of PAHs were evaluated using the risk entropy method of Kalf in surface water, and the mean effects range-median quotient method in sediments, respectively. Overall, the potential health risks caused by PAHs are still acceptable with special concerns about certain specific issues.

Spatial distribution of polycyclic aromatic hydrocarbons in the Philippine Sea, Western Pacific and the impact factors analysis

Knowing the polycyclic aromatic hydrocarbons (PAHs) pollution properties in ocean is highly needed to protect the open sea. In July to August of 2020, twenty surface water samples were obtained from the East China Sea to the Philippine Sea. The ranges of Σ15PAHs concentrations were 3.188–5.29 ng L−1 in dissolved phase, 0.455–1.305 ng L−1 in particulate phase in the Philippine Sea. 3, 4-Ring PAHs were the most abundant PAHs. Their spatial differences in dissolved phase were mainly caused by human activities, the summer monsoon from the Philippine Islands and the Northern Equatorial Current, and the Kuroshio Current and Subtropical Countercurrent. The source analysis showed that PAHs in surface water in the Philippine Sea may come from coal combustion. It is the first time to analyze the occurrence and distribution of PAHs in the Philippine Sea.

Environmental occurrence, spatial distribution, and source identification of PAHs in surface and groundwater samples of Abou Ali River-North Lebanon

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 2years 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 15.162ngmL-1 and not detected to 0.635ngmL-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.

Wildfires as a Source of PAHs in Surface Waters of Background Areas (Lake Baikal, Russia)

Polycyclic aromatic hydrocarbons (PAHs) were detected in different types of PAH-containing samples collected in Lake Baikal during wildfires in the adjacent areas. The set of studied samples included the following: (i) water from the upper layer (5 m); (ii) water from the surface microlayer; (iii) water from the lake tributaries; (iv) water from deep layers (400 m); and (v) aerosol from the near-water layer. Ten PAHs were detected in the water samples: naphthalene, 1-methylnaphthalene, 2-methylnaphthalene acenaphthylene, acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene, and chrysene. The total PAH concentrations (ƩPAHs) were detected in a wide range from 9.3 to 160 ng/L, characterizing by seasonal, intersessional, and spatial variability. In September 2016, the ƩPAH concentration in the southern basin of the lake reached 610 ng/L in the upper water layer due to an increase in fluorene, phenanthrene, fluoranthene, and pyrene in the composition of the PAHs. In June 2019, ƩPAHs in the water from the northern basin of the lake reached 290 ng/L, with the naphthalene and phenanthrene concentrations up to 170 ng/L and 92 ng/L, respectively. The calculation of back trajectories of the atmospheric transport near Lake Baikal, satellite images, and ƩPAH concentrations in the surface water microlayer of 150 to 960 ng/L confirm the impact of wildfires on Lake Baikal, with which the seasonal increase in the ƩPAH concentrations was associated in 2016 and 2019. The toxicity of PAHs detected in the water of the lake in extreme situations was characterized by the total value of the toxic equivalent for PAHs ranging from 0.17 to 0.22 ng/L, and a possible ecological risk of the impact on biota was assessed as moderate.

Presence of polycyclic aromatic hydrocarbons among multi-media in a typical constructed wetland located in the coastal industrial zone, Tianjin, China: Occurrence characteristics, source apportionment and model simulation

In-depth understanding and accurately predicting the occurrence and fate of polycyclic aromatic hydrocarbons (PAHs) in constructed wetlands (CWs) is extremely crucial for optimizing the CWs construction and strengthening the risk control. However, few studies have focused on the PAHs among sediment-water-plant and model simulation in CWs. In this study, sediment, surface water and reed samples were gathered and analyzed from a typical CW. The concentrations of 16 PAHs (Σ16PAHs) in sediments, surface water and reeds ranged from 620 to 4277 μg/kg, 114 to 443 ng/L and 74.5 to 362 μg/kg, respectively. The coefficients of variation (CV) were calculated as 0.796, 0.431 and 0.473 for the above three media respectively, indicating that the spatial distribution variation was medium intensity. The fugacity fraction (ff) suggested that sediments might act as the secondary release source of most PAHs. According to the diagnostic ratios and principal component analysis-multiple linear regression (PCA-MLR), PAHs in this CW mainly come from fossil fuels combustion and petroleum leakage. PAHs in sediments showed high ecological risk at water inlet and moderate risk at the other functional zones, while low risks for surface water at all functional zones. Although the human health risk assessment indicated relatively low cancer risk, the health risk still cannot be ignored with the continuous input and accumulation of exogenous PAHs. A mathematical model covering the hydraulics parameters and composition characteristics of the wetland was established, and its reliability was verified. The simulated results obtained by the established model were basically consistent with the measured values. In addition, the total remove efficiency of PAHs in surface water was 40.2%, which calculated by the simulated model. This work provides helpful insight into the comprehension of occurrence and fate of PAHs among multi-media in CWs.

Predicting polycyclic aromatic hydrocarbons in surface water by a multiscale feature extraction-based deep learning approach

Accurate and effective prediction of polycyclic aromatic hydrocarbons (PAHs) in surface water remains a substantial challenge due to the limited understanding of the dynamic processes. To assist integrated surface water management, a novel hybrid surface water PAH prediction model based on a two-stage decomposition approach and deep learning algorithm was proposed. Specifically, a two-stage decomposition technique consisting of complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and variational mode decomposition (VMD) was first introduced to decompose the data into several subsequences to extract the main fluctuations and trends of the PAH sequence. Subsequently, the deep learning algorithm long short-term memory (LSTM) was employed to explore the latent dynamic characteristics of each subsequence. Finally, the predicted values of the subsequences were integrated to obtain the final predicted results. An empirical study was conducted based on PAH data of eight major rivers in Saxony, Germany. The empirical results proved that the CEEMDAN-VMD-LSTM model outperformed other benchmark data-driven methods in predicting PAHs in surface water because it combined the advantages of two-stage decomposition and deep learning methods. The mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2) of the model were 27.89, 37.92 and 0.85, respectively. The proposed hybrid method can achieve effective and accurate water quality prediction and is an effective tool for surface water management.

Toxicity and health risk assessment of polycyclic aromatic hydrocarbons in surface water, sediments and groundwater vulnerability in Damodar River Basin

Ingestion of polycyclic aromatic hydrocarbons (PAHs) contaminated water has potential human-health and ecological consequences. A comprehensive investigation of PAHs' occurrence and distribution in the surface water and sediment samples of the Damodar River Basin was conducted using the Agilent 7890B Gas Chromatograph (GC-FID) coupled with 5977A Mass Spectrometry. The results showed that concentrations of the individual PAHs in surface water and sediments ranged from ND to 36 μg/L and ND to 582 ng/g with the highest detected levels of 3-ring PAH Acenapthylene (ACY) and 4-ring PAH Benzo(a)Anthracene (BaA) with a mean concentration of 6.12 ± 6.06 μg/L and 2.79 ± 4.5 μg/L, respectively. The concentration of 4-ring PAHs such as Fluoranthene (Flur), Pyrene (Pye), Benzo(a)Anthracene (BaA), and Chrysene (Chry) in sediment samples has mean levels of 43 ± 41 ng/g, 32 ± 29 ng/g, 52 ± 50 ng/g, and 83 ± 105 ng/g, respectively. The 4-ring PAH Chry was frequently detected in all sediment samples, while the 3-ring PAH ACY was dominant in surface water samples. The principal component analysis (PCA) and diagnostic ratios suggested that the PAHs contamination in surface water was due to petrogenic and fuel combustion. In sediments, PAHs' primary sources were coal burning, fuel combustion, petrogenic, and pyrolysis. The incremental lifetime cancer risk (ILCR) for children and adults due to ingestion of surface water ranged from ND to 4.25 × 10−5 and ND to 7.21 × 10−5, respectively. In contrast, the Risk index (RI) values ranged from 4.3 × 10−5 and 7.3 × 10−5. For sediment samples, higher toxic equivalent quotient (TEQ = 1865 ng/kg) and mutagenic equivalent quotient (MEQ = 1665 ng/kg) for eight carcinogenic PAHs indicate extremely high toxicity. Improper management of mine drainage, frequent flooding of open cast mines, and hydraulic connection between the surface water, sediments, and groundwater significantly deteriorated overall water quality in the DRB.

Characterizing the Variation of Dissolvable PAHs in Receiving Water in a Reclaimed Water Irrigation Region

Long-term wastewater and reclaimed water irrigation systems constitute the major processes in local water circulation, which concomitantly introduce plenty of undesirable substances that can threaten water quality, ecosystem functions and human health. At the Southeast Reclaimed Water Irrigation Region (SRWIR) of Beijing, wastewater irrigation was adopted from 1969 to 2002, and second-treated effluents (reclaimed water) has been used thereafter. Polycyclic aromatic hydrocarbons (PAHs) were the most ubiquitously detected contaminant in wastewater and reclaimed water and are reported to be carcinogenic. Hence, we measured the concentrations of dissolved sixteen United States Environmental Protection Agency (USEPA) priority PAHs in surface water and groundwater at the SRWIR to characterize their spatial and temporal variations, and to clarify the role of reclaimed water to natural water. The concentration of 16 individual PAHs in reclaimed water, rivers and groundwater varied from 339.4 to 636.2 ng/L, 359.1 to 3,435.0 ng/L and 216.5 to 488,205.2 ng/L, respectively. The lower aromatic rings of PAHs prevailed in aquatic environments rather than the higher ones. Thereinto, naphthalene was the predominant isomer within the highest concentration reached to 486,600 µg/L. The groundwater samples had higher PAHs concentrations at Tongzhou district which attributed to the higher vulnerability of aquifer. Additionally, strong correlations between PAHs and total nitrogen, nitrate, dissolved oxygen and electrical conductivity suggested those potential factors affecting the photo degradation and/or biodegradation of PAHs. The relationship identified between PAHs concentrations and physical and chemical indices would help us to enhance the understanding migration and transformation of PAHs spatially and temporally, enable us to assess the potential risks of the environmental pollutants to aquatic organisms and human water supplies.

Health and ecotoxicological risk assessment for human and aquatic organism exposure to polycyclic aromatic hydrocarbons in the Baiyangdian Lake.

Seasonal and regional distributions of 17 polycyclic aromatic hydrocarbons (PAHs) in surface waters from four different main water functional regions of the Baiyangdian Lake were analyzed through GC/MS/MS during spring and summer season. The aim was to identify their possible pollution sources and evaluate their health risk for human and ecotoxicological risk for aquatic organisms. Results showed that the range of total PAH concentration is 35.38-88.06 ng/L (average 46.57 ng/L) in spring and 25.64-301.41 ng/L (average 76.23 ng/L) in summer. PAH contamination was observed slightly lower in the summer season from the pollution characteristics of water bodies in most areas of the Baiyangdian Lake, and the levels of PAH pollution in the water body of urban residential regions and rural residential regions were relatively higher than those in tourist regions and low human disturbance regions. Source analysis based on diagnostic ratios confirmed that combustion sources and petroleum sources were two main sources for PAHs entering into the waters of the Baiyangdian Lake. Human health risk assessment showed that PAHs in surface waters from the Baiyangdian Lake will not cause a potential non-carcinogenic risk to local residents and the carcinogenic risk could mostly be accepted, but the potential lifetime carcinogenic risk for infants in rural residential regions should be concerned about. Urban residential regions and rural residential regions were subject to higher cumulative non-carcinogenic and carcinogenic risk when compared to the other functional regions. Ecotoxicological risk assessment found a moderate risk to aquatic organisms presented by individual PAH and a low risk by total PAHs, and PAHs in the water body of urban residential regions and rural residential regions also have relatively higher harm effects to aquatic organisms compared with the other two functional regions. This study revealed the pollution characteristics of PAHs and their possible sources in waters of the Baiyangdian Lake, clarified its correlation to regional anthropogenic activities, and provided corresponding risk management strategies for human and aquatic organisms.

Polycyclic Aromatic Hydrocarbons in Surface Water from Wuhai and Lingwu Sections of the Yellow River: Concentrations, Sources, and Ecological Risk

In this study, concentrations, sources, and ecological risk of 16 polycyclic aromatic hydrocarbons (PAHs) in 41 surface water samples collected from Wuhai and Lingwu sections of the Yellow River were investigated. The results showed that total PAH concentrations varied from 27.5 ng/L to 234 ng/L and from 135 ng/L to 265 ng/L in surface water of Wuhai and Lingwu sections, respectively. Source identification was performed by using principal component and multiple linear regression analysis. PAHs in Wuhai section of the Yellow River were mainly from coal combustion (35%) and vehicle exhausts (34%). Ecological risk of PAHs to aquatic organisms was assessed by applying the probabilistic risk assessment method. The results showed that the probabilities of exceeding the chronic toxicity for 5% of the species were 28% and 32% for PAHs in surface water from Wuhai and Lingwu sections, respectively. It has been demonstrated that there is an urgent need for environmental managers to take measures to reduce the ecological risk of PAHs in the aquatic environment in both Wuhai and Lingwu sections of the Yellow River.

Characteristics, Sources, and Risks of Polycyclic Aromatic Hydrocarbons in Topsoil and Surface Water from the Liuxi River Basin, South China.

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 888.14ng/g in topsoil and from 156.73 to 422.03ng/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 105.66ng/g (mean, 30.93ng/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.

Specific polycyclic aromatic hydrocarbons identified as ecological risk factors in the Lagos lagoon, Nigeria

The ecological risk assessment (ERA) of polycyclic aromatic hydrocarbons (PAHs) is imperative due to their ubiquity and biological effects in aquatic organisms. We evaluated the seasonal levels and ERA of 16 priority PAHs in surface water, sediment and fish from four (4) anthropogenic-impacted zones of the Lagos lagoon, Nigeria. PAHs were analysed using GC-FID and standard guidelines were utilized for the ERA. Also, we developed a sediment to water-PAHs ratio and ranking of PAHs for the ERA. The dominant fish species were Sarotherodon melanotheron (Black-Jawed Tilapia), Gerres melanopterus (Gerres), Liza falcipinnis (Sicklefin Mullet) and Pseudotolithus elongatus (Bobo Croaker) at Ilaje, Iddo, Atlas cove and Apapa zones respectively. The range of sum PAHs was 195–1006 μg L−1, 302–1290 μg kg−1 and 8.80–26.1 μg kg−1 in surface water, sediment and fish species respectively. Naphthalene was dominant in the surface water and sediment samples while 3-ring to 4-ring PAHs were predominant in fish species across the zones and seasons. The sediment to water-PAHs ratio was greater than 1 for sum PAHs and significantly higher (p < 0.05) in the wet season for specific PAHs across the zones and seasons. On the basis of the sediment PAHs level, Apapa zone was highly polluted with frequent biological effects while the other zones were moderately polluted with occasional biological effects across the zones and seasons. Fish species from all zones were minimally contaminated in both seasons except S. melanotheron which was not contaminated. The specific PAHs identified as ecological risk factors in the lagoon and ranking based on 50–75% recurrence in the ERA were; naphthalene, acenaphthene > acenaphthylene, fluorene, pyrene and benzo[a]anthracene. We recommend that the specific PAHs identified should form the basis for the establishment of environmental quality standards for individual PAHs in coastal waters based on the UN sustainable development goal 14 (life below water).

Contribution of soil erosion to PAHs in surface water in China

In China, the total annual atmospheric emission of 16 polycyclic aromatic hydrocarbons (PAHs) reach up to approximate 100 thousand tons, part of which is preserved in soils. In this study, the contribution of soil erosion to PAHs in surface water nationwide was quantified. The results indicate that a major portion of the annual PAHs emission is lost from soils via rainfall erosivity and subsequently transported to the ocean. The national annual flux of PAHs from soil to surface water by the natural physical forces of water measures up to ~70 thousand tons, which accounts for ~62% of the annual emission of PAHs with 19% entering the sea directly. In general, both the soil erosion intensity and flux of PAHs for the regions located in the Southeast of China are over those in the Northwest of China, with the regions being divided into two different parts by the famous geographic “Hu Huanyong line”, reflecting the intensive impact of human activities on environmental degradation. Comparative analysis suggested that there must be a big fraction of PAHs lost during transmission due to the river sedimentation and lake dispersion. This study closes a major gap in the national budget of PAHs and provides critical information in the context of regional environment risk assessment.

Monitoring And Distribution Of Organochlorine Pesticides, Polychlorinated Biphenyls And Polycyclic Aromatic Hydrocarbons In Surface River Water And Suspended Particulate Matter

The monitoring results of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in Ukranian and world surface river waters were summarized. Total concentrations of OCPs, PCBs and PAHs in surface waters of Ukrainian rivers (Dnieper and Dniester) were 1.4–17.1; 2.8–57.2; 7.5–378.6 ng/dm3 , respectively. These pollution levels are medium on a global scale. Higher concentrations were recorded in the surface water of China, India and other Asian countries. Distribution of these organic ecotoxicants between water and suspended particulate matter (dispersionphase distribution) was analyzed and it was shown that in the majority of river waters ≥50% of them are associated with suspended particles. By the case of River Dnieper antibate correlations between watersoluble parts of individual OCPs, PCBs and PAHs and coefficient of their hydrophobicity were recorded. These correlations were presented graphically. In addition, relevant correlation coefficients and criterions of probability were calculated. The clearest correlation was established for PCBs.

Polycyclic aromatic hydrocarbons in two polluted lagoons, eastern coast of the Red Sea: Levels, probable sources, dry deposition fluxes and air-water exchange

The air-water exchange of polycyclic aromatic hydrocarbons (PAHs) is an important process in determining the fate, transport and chemical loadings of these contaminants in the atmosphere and water bodies. Concentration levels of PAHs in air (gaseous and particulate) and surface water were investigated in the environments of two polluted lagoons along the eastern coast of the Red Sea to study air water exchange and dry deposition fluxes. Nine priority parent PAHs and nine methylated PAHs were identified and quantified by GC-MS. The range of total PAHs in surface water was from 120.29 ng L−1 to 524.45 ng L−1 (average: 308.7 ng L−1, n = 19). The PAHs levels in air recorded significant rise form the previous study. The probable sources of dissolved PAHs in water were found predominantly to be of petrogenic origin in one lagoon and of pyrogenic origin in the other lagoon. The dry deposition fluxes for individual congeners ranged between 0.01 ng m−2d−1 to 2.82 μg m−2d−1. After Henry's law constant corrections for temperature and salinity; the air-water exchange fluxes were found in the range of −9.7 × 104 to 8.6 × 106 ngm−2d−1 with an average of 6.8 × 105 ngm−2d−1. Beside the other sources of PAHs in the studied lagoons, high temperature and wastewater dumping might affect the magnitude and direction of air-water exchange fluxes.

Seasonal Distribution, Composition, and Source Apportionment of Polycyclic Aromatic Hydrocarbons and Organochlorine Pesticides in the Main Stream of the Luanhe River

Occurrence of 17 polycyclic aromatic hydrocarbons (PAHs) and 15 persistent organochlorine pesticides (OCPs) were analyzed by gas chromatography coupled to tandem mass spectrometry (GC/MS/MS) during the spring and summer of 2015 in surface water at 14 sampling sites in the mainstream of the Luanhe River to elucidate their seasonal distribution, composition, and potential sources. Results showed that total PAH concentrations in the surface water of the Luanhe River ranged from 33.33 ng·L-1 to 90.65 ng·L-1(52.64 ng·L-1 in average) in spring and 147.68 ng·L-1 to 252.68 ng·L-1 (169.88 ng·L-1 in average) in summer, respectively, and total concentrations of OCPs ranged from <0.08 ng·L-1 to 3.48 ng·L-1 (1.19 ng·L-1 in average) in spring and <0.08 to 5.47 ng·L-1(1.02 ng·L-1 in average) in summer, respectively. Seasonal pollution characteristics of PAHs in surface water during two different seasons showed that total PAH concentrations were much higher in summer than in spring at each sampling site on the Luanhe River. While seasonal pollution characteristics of OCPs showed that total OCP concentrations were much lower in spring than in summer at six sites including Luanxian, Daheiting reservoir dam, Panjiakou Village, Guojiatun, Qujiawan, and Baichengzi, and were higher in spring than in summer at the remaining eight sites. From the perspective of spatial and temporal variations in the composition patterns of PAHs and OCPs in surface water of the Luanhe River, the low and middle ring species of PAHs were dominant in spring and summer and the proportion of PAHs with different rings showed significant differences. Three-ring PAHs dominated the samples with 51.18% and 67.55% (61.39% on average) of total PAHs in spring, and four-ring and two-ring PAHs accounted for 11.78%-33.94% (20.97% on average) and 13.31%-27.12% (16.94% on average), respectively. In the summer, In the summer, naphthalene(Nap) was the main component of total PAHs at each sampling site and PAHs were predominated by two-ring compounds with 77.08% and 90.62% (83.34% on average) of the total, and by three-ring and four-ring compounds with 7.09%-15.22% (12.40% on average) and 2.23%-7.49% (3.97% on average), respectively. Only the residues of hexachlorocyclohexanes(HCHs) and dichlorodiphenyltrichloroethanes(DDTs) were detected in surface water of the Luanhe River at different degrees and HCHs were the dominant compounds. β-HCH was the main pollutant at most sampling sites with 43.78% and 70.09% (56.25% on average) of total HCHs in the spring and with 53.63% and 64.31% (58.37% on average) in the summer. α-HCH and γ-HCH were abundant at other sampling sites. Source analysis based on the isomer ratios indicated that PAHs in the Luanhe River mainly originated from combustion sources and also likely from petroleum processes. Ratios of OCPs confirmed that historical residues and long-range atmospheric transport were the major sources of HCHs in the study area, and new sources of lindane or γ-HCH existed at Wulongji and Sandaohezi in the spring and Daheting reservoir dam in the summer. Fresh inputs at the Panjiakou reservoir dam, Sandaohezi, Waigoumenzi, Baichengzi, Zhenglanqi, and the Shandianhe reservoir, and environmental residues at Jianggezhuang and Guojiatun were the major sources of DDTs. Concentrations of single PAHs in surface water of the Luanhe River did not exceed the water quality standards of China and other countries except that chrysene(Chr) exceeded the United States national water quality standard. Individual PAHs did not exceed any safety guidelines for aquatic organisms that are exposed to PAHs in water but total concentrations of PAHs exceeded the threshold limits set by the United States Environmental Protection Agency (EPA) and the European Union. This result indicated that consuming fish and other aquatic animals might pose a potential threat to human health due to the bioaccumulation of PAHs in aquatic organisms. The concentrations of OCPs in surface water of the Luanhe River did not exceed any water quality standards or the aquatic life threshold limits for freshwater developed by the EPA. However, the concentrations of α-HCH at Jianggezhuang, Wulongji, Qujiawan, and Baichengziand sites in the spring and at the Panjiakou reservoir dam, Panjiakou village, Qujiawan, and Baichengzi sites in the summer, and concentrations of p,p'-DDD at the Shandianhe reservoir and p,p'-DDE at Jianggezhuang, Sandaohezi, Guojiatun, and Shandianhe reservoir in the spring exceeded the human health ambient water quality criteria limit developed by the EPA. This result suggests that α-HCH, p,p'-DDE, and p,p'-DDD pose a potential health risk to the residents who live near the sampling sites on the Luanhe River.