Organic contamination of surface sediments in the metropolitan coastal zone of Athens, Greece: sources, degree, and ecological risk

Association between exposure to water sources contaminated with polycyclic aromatic hydrocarbons and cancer risk: A systematic review

The recent scientific focus on polycyclic aromatic hydrocarbons (PAHs) has stemmed from their recognized genotoxic, mutagenic, and carcinogenic properties. This systematic review seeks to evaluate the nexus between exposure to water sources contaminated with PAHs and the associated cancer risk among global populations, encompassing both children and adults. Web of Science (WoS), Cochrane Library, PubMed, ProQuest, Scopus, and Google Scholar, were searched following the PRISMA guidelines, until December 31, 2023. Quality assessment of the selected studies was performed using the Newcastle-Ottawa Scale. The increased lifetime cancer risk (ILCR) attributed to PAH exposure through ingestion and dermal absorption was thoroughly examined across diverse age groups. After extensive searching, screening, and eligibility, 30 articles were included in this review, which was conducted in different parts of the world, including Nigeria (n = 11), China (n = 7), India (n = 4), Iran (n = 3), South Africa (n = 2), Italy (n = 1), Colombia (n = 1), and Iraq (n = 1). Our analysis underscores Nigeria's alarming prevalence of PAH contamination in its rivers, groundwaters, and seawater. Remarkably, the highest cancer risk was identified among children and adults, notably in proximity to the Atlas Cove jetty (seawater) and various Nigerian rivers. This elevated risk is primarily attributed to the combined effects of ingestion and dermal absorption. Furthermore, our findings emphasize the prominent role of combustion-derived and pyrogenic sources of PAH in the examined aquatic ecosystems. This study unequivocally establishes that PAH-contaminated water sources significantly amplify the risk of cancer among both children and adults. The extent of risk variation is influenced by the specific water source, duration of exposure, and age group. Consequently, proactive identification of contaminated water sources and their pollution origins, coupled with targeted educational campaigns, holds promise for reducing the global burden of PAH-related cancer.

Ecotoxicological risk assessments and components of persistent organic pollutants and metals in the historical settlement area (Iznik (Nicea) lake) large water resource sediments

The main objectives of this study are to measure permanent organic and inorganic pollutants in detail in an area that hosts historical structures underneath and feeds the huge ecosystem with water, to reveal risk values. Total PAH concentrations in the samples ranged from 43.41 to 202.7 ng/g. Total OCP concentration ranged from 5.15 to 17.98 ng/g, while total PCB concentration ranged from 0.179 to 0.921 ng/g. PCB 28/31, 138, and 153 are the highest detected PCBs. It was found that the lake sediment reached toxic equivalent quotient (TEQ) values of 29.21 for total PAHs and 28.90 for carcinogenic PAHs. Negligible concentration risk quotient had a low to moderate ecological and toxicological risk between 12.91 and 64.42. Highest pollution index value was found 3.81 and the risk index value reached 417.4. It has been revealed that toxicologically risky components accumulate over many years even in the best-protected water resources.

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

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

Polycyclic aromatic hydrocarbons in the surface water and sediment along Euphrates River system: Occurrence, sources, ecological and health risk assessment

This study presented for the first time a comprehensive measurement campaign of 16 PAHs along the Euphrates River for five months, in both water and sediment samples. Our study revealed that the PAHs contamination increased along the flow direction due to the increasing non-point pollution and the return flows of agriculture. The 5-6 rings PAHs were dominant in water and sediment samples with an average of 42 % and 50 %, respectively. The diagnostic ratios of PAHs suggest that the pollution of these compounds originated mainly from petroleum product combustions. The carcinogenic PAHs formed 46 % and 55 % of the total measured compounds in water and sediment samples, respectively, which highlights potential ecological and human health risks. Based on sediment quality guidelines (SQGs), most sites exhibit an effect range between low and medium. The calculated incremental lifetime cancer risk (ILCR) for adult and children were in the 10^-2-10^-3 range, which is 3-6-fold higher than what was reported in the literature. These observations call for urgent attention from environmental authorities of countries sharing this key water source in Western Asia.

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

Purpose

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

Methods

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

Results

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

Conclusion

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

Supplementary Information

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

Response of Living Benthic Foraminifera to Anthropogenic Pollution and Metal Concentrations in Saronikos Gulf (Greece, Eastern Mediterranean)

The Saronikos Gulf, including the industrial zone of Elefsis Bay, is subjected to a variety of urban and industrial impacts that significantly contribute to environmental degradation. Benthic foraminifera comprise a significant component of meiobenthic communities and they are widely used as reliable indicators for the determination of the natural environmental and anthropogenic impact in shallow coastal systems. The present study analyses the living benthic foraminifera composition and its relation to environmental parameters such as grain size, organic carbon content, and heavy metal concentrations, from the surficial sediment layer collected in the Elefsis Bay and the Inner Saronikos Gulf in February 2016. Canonical correspondence analysis and Spearman’s rho correlation show that the foraminiferal species composition is significantly influenced by the increase of organic carbon and Cu, Pb, Zn content. In particular, a relatively low diversity fauna dominated by the stress-tolerant species Ammonia tepida, Bulimina elongata, Bulimina marginata, and Nonionella turgida occurs in the restricted environment of the Elefsis Bay, demonstrating the negative environmental impact caused by the relatively elevated organic carbon and heavy metal contents.

Trace metals, polycyclic aromatic hydrocarbons and polychlorinated biphenyls in the surface sediments from Sanya River, China: Distribution, sources and ecological risk

The urban inland river ecosystems are now facing comprehensive pollution and governance pressures. Up to now, few works related to the multiple pollution assessment of trace metals, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) for the urban inland river sediments have been reported in China. Our study investigated the spatial distribution, ecological risk and potential sources of trace metals, PAHs and PCBs in surface sediment collected from 20 sampling sites of Sanya River, Hainan Province, China. The pollution status and potential ecological risk of trace metals were evaluated using the contamination indexes including geoaccumulation index (I_geo), individual potential ecological risk (E_rⁱ), potential ecological risk index (RI) and pollution load index (PLI). Considering the carcinogenicity and toxicity of PAHs and PCBs to human health and the ecological environment, we also analyzed the distributions, sources and adverse biological effects of PAHs and PCBs according to the sediment quality guidelines (SQGs), principal component analysis (PCA) and other source analysis. This study revealed that the surface sediments in Sanya River were extremely slight pollution and showed a very low ecological risk according to I_geo, E_rⁱ, PLI and RI results for trace metals. Besides, PAHs and PCBs pollution detected may not pose considerable adverse biological effect to ecological environment in a foreseeable period on the basis of comprehensive research results. The overall surface sediments quality of the Sanya River not seem to pose a serious pollution and ecological risk based on the evaluation results of multiple pollution factors. The study provided detailed information on the multiple pollution status and location of surface sediments, one of the key environmental indicators of international tourism cities, in the Sanya River, which would be useful for the water quality improvement of Sanya River and the environmental remediation of the other coastal ecosystems from different regions.

Ecological status assessment and non-indigenous species in industrial and fishing harbours of the Gulf of Gabès (central Mediterranean Sea)

Port Biological Baseline Surveys (PBBS) are standardized surveys of the indigenous and non-indigenous marine biodiversity within harbour activities. They provide a baseline for monitoring changes in the structure and function of harbour communities. This study conducted in 12 fishing and industrial harbours from January to December 2018 was the first initiative of a Port Baseline Survey aimed to assess the impact of biological invasions in harbours of the Gulf of Gabès (GG), Tunisia. A total of 174 macrobenthos species were recorded, belonging to eight phyla, with a dominance of crustaceans (32%), molluscs (31%) and polychaetes (20%). Among these species, 57 were non-indigenous species (NIS) for Tunisian waters, while 27 species were recorded for the first time in GG harbours, and three decapods (Dyspanopeus sayi, Hippolyte prideauxiana and Pilumnus minutus) and one amphipod (Hamimaera hamigera) were newly recorded from Tunisian waters. Two main categories of harbours are distinguished according to their macrobenthic communities and environmental conditions. The industrial harbours yield higher richness and abundance of NIS than the fishing harbours. The ALEX metric is used to evaluate the biological invasion status of the Gulf of Gabès harbours and shows that their status ranges from unaffected in fishing harbours to extremely affected in industrial harbours. Three biotic indices (AMBI, BO2A and BENTIX) are applied to assess the ecological status of harbours, which varies from moderate to good. ALEX and the other biotic indices are significantly correlated with harbour characteristics, maritime traffic and edaphic factors (organic matter and chemical contamination). The present study provides a data baseline for the implementation of environmental policies and management plans in the future.

Spatiotemporal occurrence, sources and risk assessment of polycyclic aromatic hydrocarbons in a typical mariculture ecosystem

The spatiotemporal variations, influencing factors and potential sources, as well as the ecological/health risks of polycyclic aromatic hydrocarbons (PAHs) were systematically investigated in seawater, sediment, and fish from Xiangshan Bay, China, one of the most important and oldest domestic marine aquaculture bases. The average concentrations of Σ_PAHs in seawater, sediment and fish were 150 ± 70.0 ng/L, 276 ± 271 μg/kg (dry weight, dw), and 434 ± 151 μg/kg (dw), respectively. Naphthalene, phenanthrene, fluoranthene, benzo(b)fluoranthene and pyrene were the dominant contaminants in all samples. The highest PAH concentrations in the seawater and sediment samples occurred in the inner bay where the mariculture and industry are clustered. Seasonal differences were observed in the seawater samples but not in the sediment samples. Among all 15 fish species, large yellow croaker (Larimichthys crocea) (775 μg/kg (dw)), red drum (Sciaenops ocellatus) (749 μg/kg (dw)), and flathead grey mullet (Mugil cephalus) (637 μg/kg (dw)) had relatively high PAH accumulation concentrations in muscle tissue. According to the molecular diagnostic ratio method, the PAHs in seawater mainly originated from a mixed source of petroleum and combustion, whereas biomass/coal combustion sources were identified for sediment. The results obtained from the risk quotient (for seawater), sediment quality guidelines and toxic equivalence quotients (for seawater and sediment) methods showed that the ecological risks posed by PAHs were generally at a low to moderate level. Potentially toxic effects existed from PAH-contaminated fish consumption, and the resulting potential carcinogenic risk was also slightly higher than the recommended guidelines (10^-6).

Fate and Occurrence of Polycyclic Aromatic Hydrocarbons and Their Derivatives in Water and Sediment from Songhua River, Northeast China

The Songhua River is one of the most populated and oldest industrial areas in Northeast China. To understand the sources and distribution of polycyclic aromatic hydrocarbons and their derivatives, such as 16 priority (PAHs), 33 methylated (Me-PAHs), and 12 nitrated (NPAHs) in river water and sediment, were noticed. The concentrations of ∑PAHs, ∑Me-PAHs, and ∑NPAHs in river water scaled from 135 to 563, 9.36 to 711, and 1.26 to 64.7 ng L−1, with mean values of 286, 310, and 17.9 ng L−1, and those in sediments were from 35.8 to 2000 ng g−1, 0.62 to 394 ng g−1, and 0.28 to 176 ng g−1 (dry weight) with mean values of 283, 103, and 21.7 ng g−1. The compositions proved that two-ring and three-ring compounds of PAHs, NPAHs, and four-ring, six-ring of Me-PAHs were prevalent in water samples; in contrast, four-ring dominated in sediments. Principal components analysis (PCA) and diagnostic ratios confirmed that pollutant source was mixed petrogenic and pyrogenic origin. The fugacity fraction (ƒƒ) was also calculated to explain the trend of sediment–water exchange, high ƒƒ values found in summer, for most HMW PAHs and Me-PAHs that these substances acted as a secondary source of emissions from sediment to water. The risk assessment for water was categorized as high.

Polycyclic aromatic hydrocarbons in surface sediments of the Aegean Sea (eastern Mediterranean Sea)

In this study, we provide baseline data on the composition, major sources and mechanisms driving the distribution of polycyclic aromatic hydrocarbons (PAHs) mixtures in surficial sediments collected from 43 offshore and open/deep sea locations across the north, central and south Aegean Sea. The determined total concentrations of the considered PAH compounds were generally low, comparable to those reported in relatively non-polluted coastal and open/deep Mediterranean marine sites. Their molecular profile and diagnostic indices reveal mixed contributions from both pyrolytic and petrogenic sources across the study area. Organic carbon exerts an important control on the transport and ultimate accumulation of PAHs, however, the presented results highlight a significant variability in sedimentary PAHs concentrations and compositional patterns within the studied Aegean Sea sub-regions. This could be likely attributed to a combination of distinct hydrological and biogeochemical characteristics, surface and near bottom water mass circulation patterns and the relative importance of PAH sources.

Imprint and short-term fate of the Agia Zoni II tanker oil spill on the marine ecosystem of Saronikos Gulf

In this study we investigate the spatial and temporal imprint of the September 2017 Agia Zoni II tanker heavy fuel oil spill on the marine ecosystem of Saronikos Gulf (Greece). Based on the chemical fingerprinting approach, by means of gas chromatography - flame ionization detector, gas chromatography-mass spectrometry and the use of various diagnostic ratios, we characterize changes in the composition of the spilled oil at various sampling sites and evaluate major mechanisms affecting its fate i.e. dissolution/dispersion, evaporation, biodegradation, photo-oxidation and sedimentation during the first six months from the spill. Overall, the main effects of the incident were confined to the coastal zone during the first three months after the spill, where an extended petroleum imprint was recorded in many cases, with the determined concentrations of the total petroleum hydrocarbons and polycyclic aromatic hydrocarbons falling within the highest range of concentrations previously reported for similar oil spill incidents worldwide. In the first three months following the spill the oil was affected by a combination of volatilization, rapid biodegradation and photodegradation, the later playing a role in its early days weathering. Concerning sediments, an imprint related to the incident was recorded in a few cases, being, however, mild in respect to the high chronic petroleum-associated anthropogenic background of the impacted area.

Macrozoobenthos in the Adriatic Sea ports: Soft-bottom communities with an overview of non-indigenous species

The present paper is a contribution to the first initiative of the Port Baseline Survey (PBS) for Non-indigenous species (NIS) in the Mediterranean Sea. It presents a report on the soft-bottom macrobenthos from the five Adriatic ports: Bari, Ancona (Italy), Koper (Slovenia), Pula, Rijeka (Croatia), with a focus on the presence and contribution of NIS to native assemblages. Out of 451 species identified, only four were common to all ports. A total of eight NIS were recorded, five in surveyed ports and three in the lagoon connected to the Port of Koper. The highest number of NIS was recorded in Bari, and the highest abundance in Ancona and Bari. Generally, the number, abundance and contribution of NIS seems too low to cause a substantial impact on native communities in surveyed ports. The suitability of methods adopted for PBS for soft-bottom NIS was discussed and suggestion for methodological improvement is provided.

Distributions and Sources of PAHs and OCPs in Surficial Sediments of Edremit Bay (Aegean Sea)

In this study, levels, distributions, and sources of polycyclic aromatic hydrocarbons (18 compounds) and organochlorine pesticides (19 compounds) in surface sediments of 14 stations from Edremit Bay (Aegean Sea) were investigated in April and November 2015. ΣPAH concentrations (0.65-175 ng/g) in Edremit Bay sediments indicated low pollution. ΣPAH levels were decreased in the order of inner (81.1 ± 47.0 ng/g), northern (48.4 ± 15.9 ng/g), and southern (19.0 ± 15.8 ng/g) bays. p,p'-DDE was the only organochlorine pesticide detected in Edremit Bay sediments and found between nd to 1.16 ng/g dw. According to sediment quality guidelines, PAHs and p,p'-DDE levels in Edremit Bay were below the threshold effect level, effect range low, and threshold effect concentration limits and the sediments have no potential ecological risks. Two- to 3-ring PAHs were found at higher levels than 4- to 5-ring PAHs. Molecular PAHs ratios and Principal Component Analysis-Multiple Linear Regression analyses indicated combustion of wood-coal and vehicle emissions might have contributed to PAH levels in the bay.

Polycyclic aromatic hydrocarbons (PAHs) in water and sediment of Hoor Al-Azim wetland, Iran: a focus on source apportionment, environmental risk assessment, and sediment-water partitioning

The concentration, source, and ecological risk of 16 polycyclic aromatic hydrocarbons (PAHs) in water and sediment samples in Hoor Al-Azim wetland, a significant freshwater wetland in Lower Mesopotamia, were evaluated. Total PAHs concentrations varied from 15.3 to 160.15 ng/L, and 15.78 to 410.2 μg/Kg in water and sediment, respectively. PAHs pollution levels in sediments compared with sediment quality guidelines (SQG) were found to be moderate in two stations and low in water and the rest of sediment stations. Based on the diagnostic ratio analysis, cluster analysis (CA), and principal component analysis-multiple linear regression (PCA-MLR), the mean percentage contributions were 62.62% for mixed pyrogenic and petrogenic sources (e.g., unburned and combusted fossil fuels from fishing boats and vehicle engines, incomplete combustion, oil leakage), 20.68% for auto emission, and 16.7% for pyrogenic sources (fossil fuels and biomass combustion). According to the sediment risk assessment indices such as mean effects range-median quotient (M-ERM-Q), the ecological risk of multiple PAHs was low. Risk quotient (RQ) calculation of water samples suggested high ecological risk level for Benzo[a]anthracene (BaA), and low to moderate for other individual PAHs and ΣPAHs. The result of PAHs partitioning between sediment and water phases revealed that most PAHs prefer to accumulate in sediment. Sediments probably act as a secondary source for some PAHs in the oil collection and pumping station.

The effect of land use configurations on concentration, spatial distribution, and ecological risk of heavy metals in coastal sediments of northern part along the Persian Gulf

In the present study, a total of 41 sediment samples were collected from the areas with different land uses: industrial (IS), urban (US), agricultural (AGS), and natural field (NS) in the northern coasts along the Persian Gulf from November 2016 to January 2017. Samples were analyzed to determine the concentration of heavy metals (Zn, Cu, Pb, Cd, Cr, and Ni). The mean concentration of Ʃ6 heavy metals in the samples taken from IS, US, AGS, NS were 2300.24, 251.02, 553.21, and 40.93 mg/kg, respectively. The predominant metals were Zn, Cu, and Pb and the mean concentrations of Ʃ3 metals (Zn, Cu, and Pb) in IS, US, AGS, NS areas were 2245.6, 241.44, 529.61, and 36.98 mg/kg, respectively. The results indicated that the mean concentrations of Ʃ6Metals/Ʃ3 metals in the IS and AGS samples were significantly higher than US and NS samples (p < 0.05). Heavy metal levels (mg/kg. dry weight) in all four land uses were as follows: industrial region: Pb (1347.44) > Cu (465.00) > Zn (427.16) > Cr (34.20) > Cd (19.45) > Ni (7.09); urban region: Zn (97.45) > Cu (79.90) > Pb (64.09) > Cr (5.30) > Ni (2.55) > Cd (1.73); agricultural region: Zn (247.88) > Pb (164.89) > Cu (116.84) > Cr (11.09) > Ni (7.45) > Cd (5.06); and natural fields: Zn (27.43) > Cu (6.34) > Pb (3.18) > Cr (1.94) > Ni (1.18) > Cd (0.83). According to geo-accumulation index (I-geo), the IS, US, and AGS were classified into "highly-extremely polluted", "unpolluted-moderately polluted" and "highly polluted", respectively. Similarly, in accordance with the ecological risk index (ERI), the IS and AGS fell into the very high and considerable categories, respectively, while US land uses area was categorized as low risk. Based on the results obtained from the present study, it can be concluded that the sediments of Asalouyeh coasts in the northern part of the Persian Gulf are heavily contaminated with heavy metals, causing serious negative effects on both the human being and environment.

Spatio-temporal variability, distribution and sources of n-alkanes and polycyclic aromatic hydrocarbons in reef surface sediments of Kharg and Lark coral reefs, Persian Gulf, Iran

Environmental pollution, particularly oil pollution, has been a long-standing problem in marine areas. With the aim to assess the pollution status in the Persian Gulf, Iran, herein surface sediments were collected from Kharg and Lark coral reefs, in summer (dry season) and winter (wet season), to evaluate the spatio-temporal variations of n-alkanes and PAHs. The mean total organic carbon (TOC⁾ contents of sediments showed a significantly dramatic variation (p < 0.05) in both seasons at both Islands, with high values recorded at sites located near pollutant inputs. The total mean percent of clay grain-sized sediments at Kharg were 26.57% and 28.86% in dry and wet seasons, respectively, while in Lark were 26.73% in summer and 24.57% in winter. Additionally, at Kharg the mean ∑25n-alkanes and ∑30PAHs ranged from 81.35 to 573 µg g^-1 dw and 60.25-491 ng g^-1 dw in dry season, and 171-754 µg g^-1 dw and 41.61-693 ng g^-1 dw in winter, respectively. At Lark, the average ∑25n-alkanes and ∑30PAHs varied from 31.18 to 272 µg g^-1 dw and 41.25-196 ng g^-1 dw in summer, whilst oscillated from 57.99 to 332 µg g^-1 dw and 16.56-487 ng g^-1 dw in wet season, respectively. The lowest mean level of the examined pollutants were spanned in offshore sites, while the highest average concentrations indicated that contaminated sediments were at onshore stations at both Islands in both seasons. Significant seasonal variations (p < 0.05) were observed at most sampling sites for all pollutants. Molecular Diagnostic Ratio (MDR) and Principal Component Analysis (PCA) indicated that n-alkanes and PAHs had mostly a petrogenic source. The compositional profile of PAHs showed that 2 and 3-ring PAHs were abundant at both sampling sites. Significant positive correlation (r > 0.76) was observed between ∑25n-alkanes and ∑30PAHs at Kharg and Lark sediments with TOC content, especially for the sites with high total pollutant concentrations. Based on the potential impact and ecological risk of n-alkanes and PAHs in surface sediments, it is, therefore, necessary in future studies to focus on their effects on corals and other marine organisms within this ecosystem.

Marine pollution in the Libyan coastal area: Environmental and risk assessment

A comprehensive assessment of the potential adverse effects on environment and human health generated by the inputs of chemicals from the most important Libyan petrochemical plant is presented. Ecotoxicological risk associated with the presence of As, Hg, Ni, Zn and PAHs in marine sediments is low or moderate, with a probability of toxicity for ecosystem <9% and <20% for heavy metals and PAHs respectively. However, surface sediments result strongly enriched in Hg and As of anthropogenic origin. Investigation of metals in fish allowed to assess potential risks for human populations via fish intake. Target hazard quotients values indicate potential risk associated to toxic metals exposure by fish consumption and lifetime cancer risk (TR) values highlight a potential carcinogen risk associated to As intake. Noteworthy, the presented results provide an unprecedented environmental dataset in an area where the availability of field data is very scant, for a better understanding of anthropogenic impacts at Mediterranean scale.

Comprehensive and comparative ecotoxicological and human risk assessment of polycyclic aromatic hydrocarbons (PAHs) in reef surface sediments and coastal seawaters of Iranian Coral Islands, Persian Gulf

The concentration and spatial distribution along with ecotoxicological risk of 30 polycyclic aromatic hydrocarbons were investigated in the reef surface sediments (RSSs) and coastal seawater (CSW) of ten coral Islands from the Persian Gulf, Iran, in January 2015. For all sampling sites, assessment of ecological risk was undertaken using several approaches. Mean concentration of ∑30PAHs varied between 70 and 884ngL^-l with an overall mean value of 464ngL^-l in the CSW, while the RSS ranged from 274 to 1098ngg^-1dw with a total average of 619ngg^-1dw. The results showed a gradient in PAH concentration and toxicity estimates from the northern Hormoz site increasing to the eastern Kharg site. Most of the toxicity estimates were in the moderate range or less than risk values for damage to the marine environment. The calculated Dermal Hazard Quotient (HQs), the sum of HQs (HI) and other cancer risk values of most compounds were less than safety values at most sites. It means that the possibility of negative effects of PAHs via dermal absorption from sediments for children and adults is low. Some sampling sites studied have already been impacted with hazardous pollutants for an extended period of time and evidence from this investigation demonstrates that mixtures of PAHs may be carcinogenic to humans, especially in the western part of the Gulf.

Influence of land use configurations on river sediment pollution

Land use is an influential factor in river sediment pollution. However, land use type alone is found to be inadequate to explain pollutant contributions to the aquatic environment since configurations within the same land use type such as land cover and development layout could also exert an important influence. Consequently, this paper discusses a research study, which consisted of an in-depth investigation into the relationship between land use type and river sediment pollution by introducing robust parameters that represent configurations within the primary land use types. Urban water pollutants, namely, nutrients, total carbon, polycyclic aromatic hydrocarbons and metals were investigated in the study. The outcomes show that higher patch density and more diverse land use development forms contribute relatively greater pollutant loads to receiving waters and consequently leading to higher sediment pollution. The study outcomes are expected to contribute essential knowledge for creating robust management strategies to minimise waterway pollution and thereby protect the health of aquatic ecosystems.

Origin and distribution of hydrocarbons and organic matter in the surficial sediments of the Sfax-Kerkennah channel (Tunisia, Southern Mediterranean Sea)

We investigated the origin and distribution of aliphatic and polycyclic aromatic hydrocarbons (AHs and PAHs) and organic matter (OM) in surficial sediments of the Sfax-Kerkennah channel in the Gulf of Gabès (Tunisia, Southern Mediterranean Sea). TOC, AH and PAH concentrations ranged 2.3-11.7%, 8-174μgg^-1sed.dw and 175-10,769ngg^-1sed.dw, respectively. The lowest concentrations were recorded in the channel (medium sand sediment) and the highest ones in the Sfax harbor (very fine sand sediment). AHs, PAHs and TOC were not correlated for most of the stations. TOC/N and δ¹³C values revealed a mixed origin of OM with both marine and terrestrial sources. Hydrocarbon molecular composition highlighted the dominance of petrogenic AHs and the presence of both petrogenic and pyrogenic PAHs, associated with petroleum products and combustion processes. This work underscores the complex distribution patterns and the multiple sources of OM and hydrocarbons in this highly anthropogenized coastal environment.

Polycyclic aromatic hydrocarbons in the soil profiles (0–100 cm) from the industrial district of a large open-pit coal mine, China

Mining and industrial activities are the primary sources of soil pollution in the open-pit coal mine.

Aliphatic and polycyclic aromatic hydrocarbons risk assessment in coastal water and sediments of Khark Island, SW Iran

The potential sources and ecotoxicological risks of 26 aliphatic hydrocarbons (AHs), 16 polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPHs) were investigated in coastal water and sediments of Khark Island, SW Iran. The major sources of the contamination were petroleum and petroleum combustion based on the PCA analysis and diagnostic indices of AHs and PAHs, and also ring classification of PAHs. The ecological risk of both individual and multiple PAHs was quite low in sediments compared with screening benchmarks. Likewise, the low concentration of TEQ, MEQ and TEQ(carc) of sediments suggest low toxicity of PAHs in the study area. However, environmental control is recommended to reduce the pollution burden of PAHs in seawater. The human health risk assessment for PAHs through dermal adsorption indicated that the possibility of negative adverse effects of PAHs in sediments is rare but swimming in the vicinity of industrial facilities should be done cautiously.

Benthic ecosystem functioning in the severely contaminated Mar Piccolo of Taranto (Ionian Sea, Italy): focus on heterotrophic pathways

The benthic ecosystem functioning is a rarely applied holistic approach that integrates the main chemical and biological features of the benthic domain with the key processes responsible for the flux of energy and C through the system. For the first time, such conceptual model, with an emphasis on the heterotrophic pathways, has been applied to the sediments at four stations within one of the most polluted coastal areas in Italy: the Mar Piccolo of Taranto. The functioning of the benthic ecosystem was different according to the investigated site. Nearby the military arsenal, i.e., the main source of organic contaminants and heavy metals, the system seemed inhibited at all the investigated structural and functional levels. Slow microbial processes of C reworking together with very limited densities of benthic fauna suggested a modest transfer of C both into a solid microbial loop and to the higher trophic levels. On the other hand, the ingression of marine water through the "Navigabile" channel seemed to stimulate the organic matter degradation and, consequently, the proliferation of meiofauna and macrofauna. In the innermost part of the basin, the system functioning, to some extent, is less impacted by contaminants and more influenced by mussel farms. The organic matter produced by these bivalves fueled faster C reworking by benthic prokaryotes and enhanced the proliferation of filter feeders.