Risk assessment and source apportionment of PAHs in surface sediments from Caofeidian Long Island, China

An extensive investigation on human risk associated with PAHs in fish and sediment in Bushehr, Northern of Persian Gulf

Here, a comprehensive study was designed to estimate the human risk assessment attributed to exposure of polycyclic aromatic hydrocarbons (PAHs)in sediment and fish in most polluted shore area in north of Persian Gulf. To this end, a total of 20 sediment and inhabitual Fish, as one of most commercial fish, samples were randomly collected from 20 different stations along Bushehr Province coastline. The 16 different components of PAHs were extracted from sediment and edible parts of inhabitual fish and measured with high-performance liquid chromatography (HPLC) and gas chromatography (GC), respectively. In addition, dietary daily intake (DDI) values of PAHs via ingestion Indian halibut and the incremental lifetime cancer risk (ILCR) attributed to human exposure to sediments PAHs via (a) inhalation, (b) ingestion, and (c) dermal contact for two groups of ages: children (1-11 years) and adults (18-70 years) were estimated. The results indicated that all individual PAHs except for Benzo(b)flouranthene (BbF) and Benzo(ghi) perylene (BgP) were detected in different sediment sample throughout the study area with average concentration between 2.275 ± 4.993 mg.kg-1 dw. Furthermore, Naphthalene (Nap) with highest average concentration of 3.906 ± 3.039 mg.kg-1 dw was measured at the Indian halibut. In addition, the human risk analysis indicated that excess cancer risk (ECR) attributed to PAHs in sediment and fish in Asaluyeh with high industrial activities on oil and derivatives were higher the value recommended by USEPA (10-6). Therefore, a comprehensive analysis on spatial distribution and human risk assessment of PAHs in sediment and fish can improve the awareness on environmental threat in order to aid authorities and decision maker to find a sustainable solution.

Distribution characteristics, source analysis and risk assessment of polycyclic aromatic hydrocarbons in sediments of Kuye River: a river in a typical energy and chemical industry zone

This study systematically analyzed the distribution characteristics, sources, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in Kuye River sediments, located in an energy and chemical industry base in northern Shaanxi, China. The results that revealed the concentrations of 16 PAHs in the sediment ranged from 1090.04 to 32,175.68 ng∙g-1 dw, with the four-ring PAHs accounting for the highest proportion. Positive matrix factorization analysis (PMF) revealed the main sources of PAHs as incomplete fossil fuel combustion, biomass combustion, and traffic emissions. The total toxic equivalent concentration of BaP, risk quotient, and lifetime carcinogenic risk of PAHs suggested moderate to high contamination of PAHs in the area. The higher incremental lifetime carcinogenic risk (ILCR) indicated that PAH ingestion was the primary route of impact on public health, with children potentially being more susceptible to PAH exposure. This study can provide valuable theoretical support for implementing pollution prevention measures and ecological restoration strategies for rivers in energy and chemical industry areas.

Spatiotemporal distributions and ecological risk of polycyclic aromatic hydrocarbons in the surface seawater of Laizhou Bay, China

The spatial-temporal distribution, source, and potential ecological risk of polycyclic aromatic hydrocarbons (PAHs) in surface seawater from Laizhou Bay were investigated. The total PAH (ΣPAH) concentrations ranged from 277 to 4393 ng/L with an average of 1178 ng/L, thereby suggesting a relatively moderate to high PAH exposure level in Laizhou Bay in comparison to other bays in the world. The composition patterns and source apportionment results revealed that the coal, biomass burning, diesel emissions, and petroleum combustion as well as the combination of these processes were the dominant sources of PAHs in the surface water, which were closely associated with sail process and sewage effluents. The ecological risk assessment indicated that benzo(a)pyrene (BaP), phenanthrene (Phe), luoranthene (Flua), and naphthalene (Nap) would exist ecological risks in most of surface seawater sites, but the probabilistic risk assessment (PRA) results showed that the current level of risk is not as severe as the risk quotient (RQ) results revealed.

Assessment of the estuarine shoreline microplastics and mesoplastics of the River Itchen, Southampton (UK) for contaminants and for their interaction with invertebrate fauna

The presence of shoreline microplastics (1-5 mm) and mesoplastics (5-25 mm) in estuarine ecosystems is ubiquitous, but there remains little data on their composition, contamination status and ecological impacts. Chessel Bay Nature Reserve, situated in the internationally protected Itchen Estuary in Southampton, UK, has serious issues with shoreline plastic accumulation. In evaluating potentially adverse ecological impacts, the influence of quantities of shoreline microplastic (mp) and mesoplastic (MeP) material and adsorbed contaminants (PAHs and trace metals) on the biometrics and population dynamics of the burrowing supralittoral amphipod, Orchestia gammarellus, was assessed in this study. mp/MeP concentrations were variable in surface (0-42%: 0-422,640 mg/kg dry sediment) and subsurface horizons (0.001-10%: 11-97,797 mg/kg dry sediment). Secondary microplastics accounted for 77% of the total microplastic load (dominated by fragments and foams), but also comprised 23% nurdles/pellets (primary microplastics). Sorption mechanisms between contaminants and natural sediments were proposed to be the main contributor to the retention of PAHs and trace metal contaminants and less so, by mp/MeP. O. gammarellus populations showed a positive correlation with microplastic concentrations (Spearman correlation, R = 0.665, p = 0.036). Some reported toxicological thresholds were exceeded in sediments, but no impacts related to chemical contaminant concentrations were demonstrated. This study highlights a protected site with the severe plastic contamination, and the difficulty in demonstrating in situ ecotoxicological impacts.

Characteristics and source analysis of polycyclic aromatic hydrocarbons in organisms and manure near Ardley Island, Antarctica

In order to better understand the migration and accumulation behavior of polycyclic aromatic hydrocarbons (PAHs) in biological chains in the cold environment around the Ardley Island, a variety of biological and penguin manure samples during China's 36th Antarctic Scientific expedition have been collected and studied. A certain difference in PAHs concentration was observed in the environmental samples, and the order of size was as follows: fish > limpets > krill > manure > brown alga > mosses. The percentage of PAHs with different ring numbers in brown alga, moss, and krill was in the following order: three rings > two rings > four rings > five rings > six rings. The proportion of HMW-PAHs in limpets and fish samples was higher than that in brown alga, moss, manure, and krill samples. The main source of PAHs in environmental samples near Ardley Island is oil, which may be due to the development of tourism in Antarctica, the number of ships and human activities around the region. Therefore, it is imperative to strengthen the protection of the ecological environment in the area around Ardley Island.

Does marine environmental research meet the challenges of marine pollution induced by the COVID-19 pandemic? Comparison analysis before and during the pandemic based on bibliometrics

The outbreak of the COVID-19 pandemic has brought enormous challenges to the global marine environment. Various responses to the COVID-19 pandemic have led to increased marine pollution. Has the COVID-19 pandemic affected marine pollution research? This work comprehensively reviewed marine pollution publications in the Web of Science database before and during the COVID-19 pandemic. Results show that the COVID-19 outbreak has influenced the marine pollution research by: (i) increasing the number of publications; (ii) reshaping different countries' roles in marine pollution research; (iii) altering the hotspots of marine pollution research. The ranking of countries with high productivity in the marine pollution research field changed, and developed economies are the dominant players both before and after the outbreak of the COVID-19 pandemic in this field. Other high-productivity countries, with the exception of China, have higher international cooperation rates in marine pollution research than those before the pandemic. Microplastic pollution has been the biggest challenge of marine pollution and has been aexplored in greater depth during the COVID-19 pandemic. Furthermore, the mining results of marine pollution publications show the mitigation of plastic pollution in the marine environment remains the main content requires future research. Finally, this paper puts forward corresponding suggestions for the reference of researchers and practitioners to improve the global ability to respond to the challenges posed by the pandemic to the marine environment.

PAHs Source Identification in Sediments and Surrounding Soils of Poyang Lake in China Using Non-Negative Matrix Factorization Analysis

Identifying sources of soil and sediment PAHs and apportioning their contributions are key in building effective pollution abatement strategies, especially for Poyang Lake—the largest freshwater lake in China. PAHs were detected in all the monitored soil and sediment samples under three land use types, with the concentrations varying by area, ranging from moderate to relatively high. The order of PAHs content in different the land use types was as follows: industrial soil > grassland soil > agricultural soil. Although agricultural soil was dominated by LMW PAHs, industrial grassland soils were dominated by HMW PAHs. Based on factor analysis, non-negative matrix factorization analysis was effective in non-negative constrained skew rotation, especially for clear and interpretable source analysis of PAHs.

Dynamics and Mass Balance of Polycyclic Aromatic Hydrocarbons in and Around the Seto Inland Sea, Japan

Polycyclic aromatic hydrocarbons (PAHs) were analyzed to elucidate the distribution, ecological risk, pathways, and fluxes of these pollutants in and around the Seto Inland Sea, an industrialized coastal region of Japan. High molecular weight PAHs (5-6 rings) were primarily found in regions close to the bay estuaries, and their proportions decreased at distances further from the estuaries (offshore areas), where low molecular weight PAHs (2-4 rings) were more ubiquitous. Screening-level risk assessments revealed that the PAHs found in the sediments should have no adverse effects on benthic communities. A mass balance for PAHs in the Seto Inland Sea, calculated based on data collected in the field and published literature findings, showed the PAH flux into the Seto Inland Sea from atmospheric deposition were ca. 6 times higher than that from riverine inflows. Comparison of the amount of the PAH mass flux between the Seto Inland Sea and the sea of the Europe and Asian countries indicated that the Seto Inland Sea is less polluted than the Gulf of Lion, the Mediterranean Sea, and the Bohai Sea, China and more polluted than the Yellow Sea. This paper is the first to determine the fluxes of PAHs in the coastal region of Japan.

Effects of organic matter on polycyclic aromatic hydrocarbons in riverine sediments affected by human activities

Organic matter (OM) is an important component of riverine environments and a major factor in the migration and transformation of hydrophobic organic substances, such as polycyclic aromatic hydrocarbons (PAHs), to sediments. We studied the distributions, sources, and correlations between PAHs and OM in sediments from the Duliujian and the Beiyun rivers in North China. Sixteen PAHs were detected in the surface sediments at total concentrations ranging from 356 to 4652 ng·g^-1 dry weight, which caused a moderate to high level of pollution. The PAH distributions were significantly and positively correlated with OM (p < 0.01) and higher concentrations were detected downstream of areas affected by human activity. Petroleum, coal, and wood combustion were the main sources of PAHs in riverine sediments, and the sources of OM in sediment included terrestrial and aquatic higher plants, soil, and sewage discharge. The OM accumulated and aged along the river, with increases in the degree of aromaticity and condensation, which led to stronger adsorption of PAHs. Our results will help to promote the management and restoration of contaminated riverine sediments.

Review on the contamination and remediation of polycyclic aromatic hydrocarbons (PAHs) in coastal soil and sediments

The rapid economic and population growth in coastal areas is causing increasingly serious polycyclic aromatic hydrocarbons (PAHs) pollution in these regions. This review compared the PAHs pollution characteristics of different coastal areas, including industrial zones, commercial ports, touristic cities, aquacultural & agricultural areas, oil & gas exploitation areas and megacities. Currently there are various treatment methods to remediate soils and sediments contaminated with PAHs. However, it is necessary to provide a comprehensive overview of all the available remediation technologies up to date, so appropriate technologies can be selected to remediate PAHs pollution. In view of that, we analyzed the characteristics of the remediation mechanism, summarized the remediation methods for soil or sediments in coastal areas, which were physical repair, chemical oxidation, bioremediation and integrated approaches. Besides, this review also reported the development of new multi-functional green and sustainable systems, namely, micro-nano bubble (MNB), biochar, reversible surfactants and peracetic acid. While physical repair, expensive but efficient, was regarded as a suitable method for the PAHs remediation in coastal areas because of land shortage, integrated approaches would produce better results. The ultimate aim of the review was to ensure the successful restructuring of PAHs contaminated soil and sediments in coastal areas. Due to the environment heterogeneity, PAHs pollution in coastal areas remains as a daunting challenge. Therefore, new and suitable technologies are still needed to address the environmental issue.

Combined effects of exposure to polycyclic aromatic hydrocarbons and metals on oxidative stress among healthy adults in Caofeidian, China

Exposure to polycyclic aromatic hydrocarbons (PAHs) and metals is associated with many adverse effects on human health, accompanied by oxidative stress. This study aimed to investigate the effects of co-exposure to PAHs and metals on oxidative stress in healthy adults. A preliminary longitudinal panel study was conducted between 2017 and 2018 in 45 healthy college students in Caofeidian, China. Six urinary monohydroxylated-PAHs (OH-PAHs), ten metals, 8-hydroxydeoxyguanosine (8-OHdG), and 8-iso-prostaglandin-F2α (8-iso-PGF2α) were measured. Linear mixed effects (LME) models and Bayesian kernel machine regression (BKMR) models were used to explore the associations of urinary OH-PAHs and metals with 8-OHdG and 8-iso-PGF2α. LME models showed that most urinary OH-PAHs and metals were positively associated with 8-OHdG and 8-iso-PGF2α. For example, a one-unit increase in the ln-transformed level of 1-hydroxypyrene (1-OHPyr) and vanadium (V) was associated with an increase of 143.8% (95% CI: 105.7 - 188.9%) and 105.8% (95% CI: 79.2-136.4%) in 8-OHdG; 8-iso-PGF2α increased by 118.9% (95% CI: 99.2-140.5%) and 83.9% (95% CI: 67.2-102.2%) with a one-unit increase in the ln-transformed level of 3-hydroxyphenanthrene (3-OHPhe) and aluminum (Al). BKMR models indicated the overall positive associations of the mixture of six OH-PAHs, ten metals, or six OH-PAHs and ten metals with 8-OHdG and 8-iso-PGF2α. Urinary 1-OHPyr and V were identified as the major contributors to the increased urinary 8-OHdG levels, while urinary 3-OHPhe and Al were the most vital contributors to the increased urinary 8-iso-PGF2α levels. The results revealed the longitudinal dose-response relationships of urinary OH-PAHs and metals with oxidative stress among healthy adults in Caofeidian; this finding serves as an evidence regarding the early health hazard caused by exposure to PAHs and metals and has implications for the environmental management of PAH and metal emissions in this area.

Remediation of soils and sediments polluted with polycyclic aromatic hydrocarbons: To immobilize, mobilize, or degrade?

Polycyclic aromatic hydrocarbons (PAHs) are generated due to incomplete burning of organic substances. Use of fossil fuels is the primary anthropogenic cause of PAHs emission in natural settings. Although several PAH compounds exist in the natural environmental setting, only 16 of these compounds are considered priority pollutants. PAHs imposes several health impacts on humans and other living organisms due to their carcinogenic, mutagenic, or teratogenic properties. The specific characteristics of PAHs, such as their high hydrophobicity and low water solubility, influence their active adsorption onto soils and sediments, affecting their bioavailability and subsequent degradation. Therefore, this review first discusses various sources of PAHs, including source identification techniques, bioavailability, and interactions of PAHs with soils and sediments. Then this review addresses the remediation technologies adopted so far of PAHs in soils and sediments using immobilization techniques (capping, stabilization, dredging, and excavation), mobilization techniques (thermal desorption, washing, electrokinetics, and surfactant assisted), and biological degradation techniques. The pros and cons of each technology are discussed. A detailed systematic compilation of eco-friendly approaches used to degrade PAHs, such as phytoremediation, microbial remediation, and emerging hybrid or integrated technologies are reviewed along with case studies and provided prospects for future research.

Comprehensive characterization of PAHs profile in Serbian soils for conventional and organic production: potential sources and risk assessment

This study presents a comprehensive characterization of occurrence and levels of 16 polycyclic aromatic hydrocarbons (PAHs) in arable soils used for conventional and organic production in northern and central part of Serbia as well as cross-border region with Hungary. Furthermore, this study includes a characterization of PAH sources and carcinogenic/non-carcinogenic human health risk for PAHs accumulated in analysed arable soils. The total concentration of 16 PAHs varied between 55 and 4584 µg kg^-1 in agricultural soil used for conventional production and between 90 and 523 µg kg^-1 in agricultural soil used for organic production. High molecular weight (HMW) PAHs were dominant compounds with similar contribution in both soil types (86% and 80% in conventional and in organic soil, respectively). Principal component analysis and diagnostic ratios of selected PAHs were used for identification of PAH sources in the analysed soils. Additionally, positive matrix factorization was applied for quantitative assessment. The results indicated that the major sources of PAHs were vehicle emissions, biomass and wood combustion, accounting for ~ 93% of PAHs. Exposure of farmers assessed through carcinogenic (TCR) and non-carcinogenic (THQ) risk did not exceed the acceptable threshold (TCR < 10^-6 and THQ < 1). Oral ingestion was the main exposure route which accounted for 57% of TCR and 80% of THQ. It was followed by dermal contact. This investigation gives a valuable data insight into the PAHs presence in arable soils and reveals the absence of environmental and health risk. It also acknowledges the importance of comprehensive monitoring of these persistent pollutants.

Sediment Contamination by Heavy Metals and PAH in the Piombino Channel (Tyrrhenian Sea)

Sediment contamination is of major concern in areas affected by heavy maritime traffic. The spatial variation and contamination of 11 trace elements and 17 PAHs in surface sediments were studied along a 31 km transect along the seaway from the port of Piombino (Tuscany) to the port of Portoferraio (Elba Island) in the Northern Tyrrhenian Sea. Heavy metal contamination was detected at sites near Piombino (Ni, Pb, Hg, Cu and Zn) and at sites near Portoferraio (Pb, Zn, Hg, Cr and Cd). Each of the 35 sampled sites showed PAH contamination, with the highest concentrations at sites near Portoferraio. The most abundant isomers detected were 2- and 4-ring PAHs. PAH ratio analysis showed a prevalence of PAHs of pyrolytic origin. High values of PAHs and heavy metals were related to high sediment water content, TOC, silt, and clay content. Arsenic increased with increasing depth. The correlation between concentrations of metals and PAHs suggests common anthropogenic sources and is of concern for possible synergistic adverse effects on the biota.

Distribution, sources, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Daya Bay, South China

In this study, the concentrations of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Daya Bay were determined and analyzed. Results showed that 16 PAHs were detected in all the samples, and the total PAH concentration ranged from 70.18 to 128.04 ng g-1, with an average of 103.17 ng g-1. The cyclic number distribution of PAHs in the sediments was mainly 4 and 5 rings. Six classic PAH ratios named Ant/(Ant + Phe), Fla/(Fla + Pyr), [InP/(InP + BghiP)], [BaA/(BaA + Chr)], BaA/BghiP, and LMW/HMW, and principal component analyses showed that the main source of PAHs in this region was combustion (biomass, coal, and petroleum combustion), and the secondary source was petroleum. The ecological risk analysis of PAHs by using effect range low/median method and mean effects range-median quotient method showed that all of PAHs are lower than the effect range low (ERL) level and the effects range-median quotient (M-ERM-Q) value of all stations is 0.0027-0.0067, with an average value of 0.0046. Thus, it can be seen that PAHs are at a low-risk level in surface sediments of Daya Bay.

Polycyclic aromatic hydrocarbon (PAH) distribution in surface sediments from Yazhou Bay of Sanya, South China, and their source and risk assessment

The distribution, source, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in surface sediments were analyzed and discussed at 15 sampling sites in Yazhou Bay, Sanya. Results showed that the total PAH content in the surface sediments of Yazhou Bay ranged from 13.20 ng/g to 40.37 ng/g, and the average content was 31.53 ng/g. Component analysis showed that the distribution of various PAHs in the surface sediments of Yazhou Bay was relatively average, and 3- and 4-ring PAHs were the dominant species. PAHs were traced by characteristic ratio method and principal component analysis. PAHs in the surface sediments mainly came from combustion sources, including incomplete combustion of petroleum, coal, and biomass, which also indicated the existence of petroleum sources. The ecological risk assessment results of surface sediments showed that, compared with effect range low and effect range median (ERM) of the ecological risk of 14 kinds of PAHs detected, no ecological risk existed for PAHs of all sampling sites in Yazhou Bay. The mean ERM quotient analysis also showed that PAHs in the sediments in Yazhou Bay were at a low risk level.

High-sensitive detection of fluorene by ambient ionization mass spectrometry

High sensitive analysis for fluorene at the sub-ng L⁻¹ level in real water samples was achieved by nebulization-dielectric barrier discharge ionization.

Spatial and vertical distribution, composition profiles, sources, and ecological risk assessment of polycyclic aromatic hydrocarbon residues in the sediments of an urban tributary: A case study of the Songgang River, Shenzhen, China

In this study, the Songgang River (SR) was selected as a typical tributary that is heavily polluted by rapid urbanization and industrialization. The polycyclic aromatic hydrocarbon (PAH) distribution at five representative sampling sites from different urban functional areas was studied. The chemical and physical properties and spatial and vertical distribution of PAHs in sediments were investigated. PAH source identification and the ecological risks of the sediments were evaluated. The results suggested that the industrial zone and dense residential and commercial areas were the most contaminated areas of the SR, as the chemical and physical properties of total organic carbon content in sediments was the highest at the dense residential and commercial areas (0.1-4.5%); however, the acid volatile sulfide, total nitrogen, and total phosphorus contents were the highest in the industrial zone, with ranges of 700.0-1618.4 mg/kg dw, 22.4-3543.9 mg/kg dw, and 82.3-4550.7 mg/kg dw, respectively. The spatial distribution of residual PAHs in the sediment cores showed a wide variation among different urban functional areas, and the vertical characterization (0-300 cm) depicted a significant decreasing trend with depth and with an abrupt increase at 180 cm. The concentration of ∑16 PAHs ranged from 208.7 to 7709.8 ng/g dw, with the highest concentrations obtained in the industrial zone. The low molecular weight-PAHs (153-6720 ng/g dw) were predominant in the sediments. Furthermore, there were combined sources (biomass burning: 40.3%; fossil fuel combustion: 25.5%; mixed source: 21.5%; oil pollution: 12.7%) and a long term accumulation effect, with anthropogenic activities and industrial pollution as the major contributing sources. The concentrations of Nap, Acy, Ace, Flu, and Ant exceeded the lower limit of the sediment quality criteria, and higher toxic equivalent concentration values of the total carcinogenic PAHs were observed nearby the midstream of the SR, which may cause adverse biological effects and implies a need for regular monitoring.

Composition, content, source, and risk assessment of PAHs in intertidal sediment in Shilaoren Bay, Qingdao, China

Intertidal sediment samples from Shilaoren Bay, Qingdao, China, were collected to determine the concentrations and compositions of 16 polycyclic aromatic hydrocarbons (PAHs). The sources of PAHs were analyzed, and risk assessment was performed. Results show that the pollution level of PAHs in the investigated area was low. The majority of PAHs are four-ring PAHs. The PAHs in this region were mainly derived from combustion sources, including the incomplete combustion of petroleum, coal, and biomass, such as vegetation, which were affected to some extent by petroleum sources. The highest concentration of PAHs in all sampling sites was lower than that of effects range low, and the mean effects range median quotient was low. Therefore, the PAHs in the study area did not have toxic and side effects on the ecological environment, and ecological risk was low.

Activation of percarbonate by water treatment sludge-derived biochar for the remediation of PAH-contaminated sediments

Sludge from a groundwater treatment plant was used to prepare biochar by pyrolysis. The Fe-Mn rich biochar was used to activate percarbonate for the remediation of polycyclic aromatic hydrocarbons (PAHs) contaminated aquatic sediments. Results showed that the sludge-derived biochar (SBC) produced at a pyrolysis temperature of 700 °C was the most effective in activating percarbonate, which exhibited significant oxidative removal of PAHs. PAHs degradation took place via a Fenton-like oxidation manners, contributed from the Fe³⁺/Fe²⁺ and Mn³⁺/Mn²⁺ redox pairs, and achieved the highest degradation efficiency of 87% at pH₀ 6.0. Reactions between oxygenated functional groups of biochar and H₂O₂ generated of O₂^•- and HO• radicals in abundance under neutral and alkaline pH was responsible for the catalytic degradation of PAHs. Our results provided new insights into the environmental applications of SBC for the green sustainable remediation of organics-contaminated sediments and aided in reduction of associated environmental and health risk.

Improved comprehensive ecological risk assessment method and sensitivity analysis of polycyclic aromatic hydrocarbons (PAHs)

Based on the existing comprehensive ecological risk assessment methods of PAHs, this paper proposed an improved hierarchical Archimedean copula integral assessment (HACIA) model with the optimization in the model selection mechanism and accelerating the calculation speed, and according to which performed the sensitivity analysis of the integrated risk relative to the underlying grouped risk probability. Taihu Lake in China and the Bay of Santander in Spain were taken as study areas, whose samples were obtained and extracted concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs). After briefly analyzing their concentration characteristics and source, their comprehensive ecological risks were evaluated by the improve HACIA model and their sensitivity was also analyzed. The results proved that, for Taihu Lake, pyrogenic sources occupied the dominance, especially grass, coal and wood combustion, while the risk proportion of 5-rings PAHs was the lowest indeed based on the improved HAICA model. For the Bay of Santander, source apportionment indicated both petrogenic and pyrogenic sources, mainly from vehicle emissions including gasoline and diesel engines, and 4-ring PAHs were urgently needed to be managed. However, the sensitivity analysis results of two study areas showed that the most effective control target for reducing integral risk has no obvious relationship with the maximum grouped risk. And a clear linear relationship between the maximum sensitivity range and the logarithm of the initial overall risk only presented in one of study areas, which required further research to clarify. In brief, the improved HACIA model is helpful to evaluate the comprehensive ecological risk of 16 PAHs, and formulate risk management strategies based on grouped risk assessment and sensitivity analysis, with the former points out the admonitory risk and the latter helps to find the most effective mitigation measures.

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

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

Concentration level, distribution model, source analysis, and ecological risk assessment of polycyclic aromatic hydrocarbons in sediments from laizhou bay, China

To master the distribution patterns and environmental risk of 16 USEPA preferential polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Laizhou Bay, 20 samples were collected and investigated in this survey. The average PAH concentration in these sediments ranged from 268.97 ng/g to 895.37 ng/g with an average of 612.52 ng/g, thereby suggesting a relatively low PAH pollution in Laizhou Bay compared with other bays in the world. Tricyclic PAHs account for 79% of the total PAH content and were eventually identified as the most crucial component of these sediments. The PCA-MLR results identify fossil fuel combustion, biomass burning, and coke oven as the main sources of PAHs that account for 26.69%, 67.16%, and 6.15% of the total PAH concentration in the collected sediments, respectively. The effect range low/effect range median (ERL/ERM) reveal the low toxicity of PAHs in these sediments. However, the concentration of Fle at each survey site exceeds the ERL level. Meanwhile, the mean effects range-median quotient (M-ERM-Q) indicates the low level of ecological risk of PAHs in the surface sediments from Laizhou Bay. However, the contingency risk of Fle and Phe cannot be ruled out.