Historical sedimentary deposition and flux of PAHs, PCBs and DDTs in sediment cores from the western Adriatic Sea

Historical sedimentary and evolutionary characteristics of POPs and EDCs in typical regions of the three Gorges reservoir, China

The historical sedimentary and evolutionary characteristics of persistent organic pollutants and endocrine disruptors in typical regions of the Three Gorges Reservoir are scarcely studied. Herein, the 96-year data on contaminated sediment history were reconstructed using Caesium 137 isotope dating. Polychlorinated biphenyl concentrations in the involved sediment cores ranged from non-detected (ND) to 11.39 ng/g. The concentrations of polycyclic aromatic hydrocarbons ranged from ND to 2075.20 ng/g and peaked in the 1970s owing to natural, agricultural and human activities. Further, phthalate esters (PAEs) and heavy metals (HMs) were detected at concentrations ranging from ND to 589.2 ng/g and 12.10-93.67 μg/g, respectively, with highest values recorded in the 1980s owing to rapid industrialisation and insufficient management during China's early reform and development stages. PAE and HM concentrations have increased in recent years, suggesting the need to focus on industrial and agricultural activities that have caused this impact. Although current pollutant concentrations in sediments do not pose a risk to the aquatic ecosystem, they should be continuously monitored.

Occurrence, sources and risk assessment of polycyclic aromatic hydrocarbons in the coral reef waters of the Lakshadweep Archipelago, Arabian Sea

The compound effects of anthropogenic disturbances on global and local scales threaten coral reef ecosystems of the Arabian Sea. The impacts of organic pollutants on the coral reefs and associated organisms have received less attention and are consequently less understood. This study examines the background levels, sources, and ecological implications of polycyclic aromatic hydrocarbons (PAHs) in the coral reef ecosystems of Lakshadweep Archipelago. Water and particulate matter were collected from four coral Islands (Kavaratti, Agatti, Bangaram and Perumal Par) of Lakshadweep Archipelago during January and December 2022 and analysed for 15 PAHs priority pollutants. The 15 PAHs congeners generally ranged from 2.77 to 250.47 ng/L in the dissolved form and 0.44 to 6469.86 ng/g in the particulate form. A comparison of available data among the coral reef ecosystems worldwide revealed relatively lower PAHs concentrations in the Lakshadweep coral ecosystems. The isomeric ratios of individual PAH congeners and principal component analysis (PCA) indicate mixed sources of PAHs in the water column derived from pyrogenic, low-temperature combustion and petrogenic. The risk quotient (RQ) values in the dissolved form indicate moderate risk to the aquatic organisms, while they indicate moderate to severe risk in the particulate form.

Anthropogenic contribution, transport, and accumulation of Polycyclic Aromatic Hydrocarbons in sediments of the continental shelf and slope in the Mediterranean Sea

A multidisciplinary approach, involving geochemical, sedimentological and oceanographic analyses, was employed to examine the distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in a strongly anthropized area of the marginal Adriatic Sea (Mediterranean basin). The investigation into PAH distribution considered the grain size and biogeochemical properties of the sediments, as well as in relation to the main oceanographic processes and river inputs. Both biogeochemical and hydrographical inputs regulated the sedimentation of organic particles, influencing the distribution of PAHs. The results indicated PAH levels in 116 marine surface sediments ranging from 4 to 235 ng g-1 (average 55 ng g-1). The distribution of PAHs in Adriatic Sea surface sediments aligned with a higher clayey sedimentation in the deeper basin areas of the Middle Adriatic Depression.

How did a tailings spill change the distribution of legacy organochlorine compounds in a Southeast Atlantic inner shelf area: Is a hidden danger being transferred to the ocean?

Polychlorinated biphenyls (PCBs) and dichloro-diphenyl-trichloroethane (DDT) were evaluated in water and sediments from the Espírito Santo Inner Shelf (ESIS), Brazil, three years after the Fundão dam failure (FDF). We discuss the levels, sources, fate, and current environmental risks of these contaminants on temporal and spatial scales. In addition, the associated coastal dispersion patterns, water-sediment exchange trends, and environmental alterations were also discussed. Low contributions and no environmental risks were verified for PCBs after FDF. However, the low concentrations and frequency of occurrence in the samples did not allow for further reliable conclusions regarding the source of this contaminant. In contrast, hazard risk has been detected for DDTs in water and sediments. In sediments, there were a significant increase in level (up to 13.42 ng g-1; outlier = 369.6 ng g-1), inventory (maximum = 35.98 ng cm-2) and mean total mass (21.1 ± 39.4 kg) of DDTs after FDF. The integrated assessment of the spatial distribution in water and sediment suggests that DDTs was released from the Doce River, travelled south by the water column, and returned to the mouth region by northward sediment transport, where it accumulated. However, intense rainfall increased the input of DDTs to the ESIS and may have also altered its spatial distribution. Fugacity fraction analysis (ƒƒ) indicated a net flux of DDTs from water to sediment, suggesting that vertical sinking was an important transport process in this area. Finally, the findings indicate that FDF contributed to DDTs input on ESIS by remobilizing contaminated past sediments and soils from the Doce River drainage basin. This contribution is expected to continue since a large amount of tailings is still stored in the river basin and estuary. These results highlight the importance of assessing the indirect impacts of large-scale land disasters on marine environments, and may be helpful in future interpretations of additional local trends and global inventories of legacy pollutants.

Chlorinated pesticides and PCB residues in the Egyptian Western Desert oases sediments

This preliminary investigation aimed to detect concentrations of chlorinated pesticides and PCBs in 40 sediment samples from three desert oases located in Kharga, Dakhla and Farafra in western Egypt. The residues of 18 PCBs and 16 chlorinated pesticides were measured by GC-MS/MS (SRM) method. The results showed that PCBs and pesticides were present in all studied samples. The concentrations of individual PCBs ranged from undetected to 3.99 ng/g dw in all these sediment samples. The total residue of pesticides (ng/g, dry weight) in sediment samples also varied from 5.18 to 25.92, 5.41 to 29.49, and 5.93 to 24.19 ng/g dw for the Kharga, Dakhla and Farafra Oases, respectively. The concentrations of PCBs and chlorinated pesticides detected in these oasis sediments were lower than that reported for other worldwide locations. According to the recorded concentrations in this baseline study of PCBs and total DDTs, the results revealed the minimal risks to organisms and people in the studied area according to the Effects Range-Low (ERL) and Effects Range-Median (ERM) guideline values.

Chronology of PAH and PCB pollution using sediment core in the Golden Horn estuary (Sea of Marmara)

The sources and depositional history of 16 polycyclic aromatic hydrocarbons (PAHs) and 18 polychlorinated biphenyl (PCBs) congeners in the Golden Horn estuary (İstanbul) were investigated using a dated sediment core for the period between 1880 and 2012. The concentrations of PAHs and PCBs were calculated for every 4 cm slices of the sediment core and ranged from 1203.5 to 3441.4 ng/g and 5.4 to 41.4 ng/g, respectively. The diagnostic ratios indicated that the maximum PAH values correspondence to combustion after a crude oil-carrying Romanian tanker (Independenta) accident in the İstanbul Strait in 1979. The historical deposition of PAHs and PCBs in the Golden Horn was influenced by municipal effluent and heavy industrial dischargers approximately 50 years. When the Silahtarağa thermal power plant (TPP) was operating, PCB pollution rose; however, after a thorough rehabilitation effort and the outlawing of PCB use in the 1990s, pollution levels significantly tended to decrease.

The last 50 years of organic contamination of a highly anthropized tributary of the Po River (Italy)

We examined the temporal profiles of many organic micropollutants analysed in a sediment core sampled from a highly anthropized tributary of the Po River, the Lambro River. Analysed for extractable organic halogens (EOX), total petroleum hydrocarbons (C₁₀-C₄₀TPH), polycyclic aromatic hydrocarbons (PAHs), common legacy pollutants (DDTs, PCBs), halogenated flame retardants (PBDEs, DBDPE, TBBPA-bis, TCBPA, TBBPA, HBCDs), organotins (TBT, TPhT), antimicrobials (TCS, TCC), fragrances (AHTN, HHCB) and phthalates (DMP, DEP, DnBP, BBP, DEHP, DnOP), the dated sediment core revealed the historical record of 50 years of chemical contamination discharged into the Lambro and thereby the Po River. In this regard, the peak levels of PCBs and DDTs found in Lambro sediments were also identified in other sediment cores collected from the Po River prodelta in the Adriatic Sea, thus hundreds of kilometres downstream (Combi et al., 2020). The highest risk to aquatic organisms was associated with decades of high levels of C₁₀-C₄₀ TPH, PBDEs, PCBs, PAHs, DDTs, EOX, TCC, AHTN and DEHP, which in different periods of the contamination history, showed exceedances of guideline/threshold values. C₁₀-C₄₀ TPH and TCC, for example, were very high in the 1960s, whereas PCBs, DDTs, and PBDEs, peaked from the 1980s onward. The corresponding sums of PEC quotients ranged between 0.48 and 28.63, with a mean value (±SD) for the entire recording period of 10.62 ± 9.83. Environmental legislations and improved wastewater treatments were the main drivers of the recent downward trends observed for most of the chemicals investigated. Floods in turn resulted in macroscopic yet temporary improvements in the chemical quality of the tributary, conveying contaminated sediments into the Po River.

Trace metals and polycyclic aromatic hydrocarbons in the Eastern Mediterranean sediments: Concentration ranges as a tool for quality control of large data collections

Assessing the status of marine pollution at regional and sub-regional scales requires the use of comparable and harmonized data provided by multiple institutions, located in several countries. Standardized data management and quality control are crucial for supporting a coherent evaluation of marine pollution. Taking the Eastern Mediterranean Sea as a case study, we propose an approach to improve the quality control procedures used for sediment pollution data, thus supporting a harmonized environmental assessment. The regional ranges of contaminant concentrations in sediments were identified based on an in-depth literature review, and the lowest measured concentrations were evaluated to determine the "background concentrations" of chemical substances not yet targeted in the Mediterranean Sea. In addition, to verify the suitability of the approach for validating large data collections provided by multiple sources, the determined ranges were used to validate a regional dataset available through EMODnet data infrastructure.

Spatial distribution and ecological risks of polychlorinated biphenyls in a river basin affected by traditional and emerging electronic waste recycling in South China

With development of e-waste related legislation in China, formal recycling activities are designated in some areas while informal ones are illegally transferred to emerging areas to avoid supervision. However, the resulting environmental impact and ecological risks are not clear. Here, we investigated the discharge of polychlorinated biphenyls (PCBs) to soil and aquatic environments by e-waste recycling activities in the Lian River Basin, China. The study area included a designated industrial park in the traditional e-waste recycling area (Guiyu, known as the world's largest e-waste center), several emerging informal recycling zones, and their surrounding areas and coastal area. A total of 27 PCBs were analyzed, and the highest concentration was found in an emerging site for soil (354 ng g^-1) and in a traditional site for sediment (1350 ng g^--1) respectively. The pollution levels were significantly higher in both the traditional and emerging recycling areas than in their respective upstream countryside areas (p = 0.0356 and 0.0179, respectively). Source analysis revealed that the traditional and emerging areas had similar PCB sources mainly associated with three PCB technical mixtures manufactured in Japan (KC600) and the USA (Aroclor 1260 and Aroclor 1262). The PCB pollution in their downstream areas including the coastal area was evidently affected by the formal and informal recycling activities through river runoff. The ecological risk assessments showed that PCBs in soils and sediments in the Lian River Basin could cause adverse ecotoxicological consequences to humans and aquatic organisms.

Assessing the chemical anthropocene - Development of the legacy pollution fingerprint in the North Sea during the last century

The North Sea and its coastal zones are heavily impacted by anthropogenic activities, which has resulted in significant chemical pollution ever since the beginning of the industrialization in Europe during the 19th century. In order to assess the chemical Anthropocene, natural archives, such as sediment cores, can serve as a valuable data source to reconstruct historical emission trends and to verify the effectiveness of changing environmental legislation. In this study, we investigated 90 contaminants covering inorganic and organic pollutant groups analyzed in a set of sediment cores taken in the North Seas' main sedimentation area (Skagerrak). We thereby develop a chemical pollution fingerprint that records the constant input of pollutants over time and illustrates their continued great relevance for the present. Additionally, samples were radiometrically dated and PAH and PCB levels in porewater were determined using equilibrium passive sampling. Furthermore, we elucidated the origin of lead (Pb) contamination utilizing non-traditional stable isotopic analysis. Our results reveal three main findings: 1. for all organic contaminant groups covered (PAHs, OCPs, PCBs, PBDEs and PFASs) as well as the elements lead (Pb) and titanium (Ti), determined concentrations decreased towards more recent deposited sediment. These decreasing trends could be linked to the time of introductions of restrictions and bans and therefor our results confirm, amongst possible other factors, the effectiveness of environmental legislation by revealing a successive change in contamination levels over the decades. 2. concentration trends for ΣPAH and ΣPCB measured in porewater correspond well with the ones found in sediment which suggests that this method can be a useful expansion to traditional bulk sediment analysis to determine the biologically available pollutant fraction. 3. Arsenic (As) concentrations were higher in younger sediment layers, potentially caused by emissions of corroded warfare material disposed in the study area after WW II.

Low levels of persistent organic pollutants in sediments of the Doce River mouth, South Atlantic, before the Fundão dam failure

The Doce River mouth (DRM) was severely impacted by the rupture of the Fundão Dam in 2015, considered the greatest Brazilian environmental tragedy in terms of tailings volume released (>40 million m³) and traveled distance (~600 km until the Atlantic Ocean). Environmental monitoring has been performed since then, but background levels are scarce or absent to Persistent Organic Pollutants (POPs), making impact assessments difficult. In the current study, we presented the baseline levels, inventories, and risk assessment of the POPs polychlorinated biphenyl (PCBs) and organochlorinated pesticides (OCPs), in surface sediment of the DRM. Samples were collected in December 2010 and July 2011, i.e., four years before the Fundão dam failure. The total PCBs and the OCPs (Aldrin, HCHs, and Chlordanes) were detected in both sampling campaigns, with levels up to 9.50 and 1.64, 0.28, and 0.63 ng g^-1, respectively. The decrease of the Doce River flow was the main factor contributing to seasonal variations in the spatial distribution, and to a slight decline in the levels and frequency of the analyzed POPs in sediments collected in the dry season (July 2011). Environmental risk assessment, inventories, and total mass results suggest a low potential of PCBs and OCPs accumulation before the dam failure. This is the first POPs assessment in the study area that helped identify some unexpected impacts of the Fundão dam failure and contributed to the understanding of POPs cycles in the Southern Atlantic, data that are still scarce in the region.

Assessment of seasonal relationship between polycyclic aromatic hydrocarbon accumulation and expression patterns of oxidative stress-related genes in muscle tissues of red mullet (M. barbatus) from the Northern Adriatic Sea

In this study, we examined the seasonal association between Polycyclic Aromatic Hydrocarbon (PAH) concentrations and mRNA expression profiles of some antioxidant genes (i.e. CAT, GST and SOD), as well as lipid peroxidation (LPO), in muscle of sexually inactive females of red mullet (Mullus barbatus). Fish were captured in a fishery area of the Northern Adriatic Sea during both winter and summer. We found significantly (p < 0.05) higher ∑HMW-PAHs concentrations in muscle of specimens caught during winter than summer. On the basis of sampling season, red mullets exhibited different gene expression profiles of antioxidant enzymes showing lower levels of both CAT and GST in winter than in summer. Accordingly, CAT was found to be negatively associated with ∑PAH concentrations, especially ∑LMW-PAH, in individuals collected during winter. Seasonal-related downregulation of some oxidative stress biomarker expression is suggestive of greater susceptibility of red mullets to PAHs during winter.

Organic pollutants in deep sea: Occurrence, fate, and ecological implications

The deep sea - an oceanic layer below 200 m depths - has important global biogeochemical and nutrient cycling functions. It also receives organic pollutants from anthropogenic sources, which threatens the ecological function of the deep sea. In this Review, critically examined data on the distribution of organic pollutants in the deep sea to outline the role of biogeochemical and geophysical factors on the global distribution and regional chemodynamics of organic pollutants in the deep sea. We found that the contribution of deep water formation to the influx of perfluorinated compounds reached a maximum, following peak emission, faster in young deep waters (< 10 years) compared to older deep waters (> 100 years). For example, perfluorinated compounds had low concentrations (< 10 pg L^-1) and vertical variations in the South Pacific Ocean where the ocean currents are old (< 1000 years). Steep geomorphologies of submarine canyons, ridges, and valleys facilitated the transport of sediments and associated organic pollutants by oceanic currents from the continental shelf to remote deep seas. In addition, we found that, even though an estimated 1.2-4.2 million metric tons of plastic debris enter the ocean through riverine discharge annually, the role of microplastics as vectors of organic pollutants (e.g., plastic monomers, additives, and attached organic pollutants) in the deep sea is often overlooked. Finally, we recommend assessing the biological effects of organic pollutants in deep sea biota, large-scale monitoring of organic pollutants, reconstructing historical emissions using sediment cores, and assessing the impact of deep-sea mining on the ecosystem.

Historical deposition of PAHs in mud depocenters from the Southwestern Atlantic continental shelf: The influence of socio-economic development and coal consumption in the last century

Polycyclic aromatic hydrocarbon (PAH) concentrations were determined in four dated sediment cores collected in mud depocenters of the southern Brazilian continental shelf. Core dating results covered the interval between 1925 and 2017. The total PAH concentrations (ΣPAHs) ranged from 44.69 ng g^-1 to 305.43 ng g^-1 and were similar between the analysed cores. Fine-grained sediments and total organic carbon (TOC) results did not correlate with the ΣPAHs, indicating that the variations in PAH concentrations are mostly related to variations in sources and emissions. PAH source appointment indicated a high input of a natural compound (perylene) and the predominance of anthropogenic PAHs from coal, biomass, and fuel combustion. Alkylated PAHs presented high contributions throughout all cores. The historical deposition of PAHs was associated with different periods of the socio-economic and industrial development of near coastal cities and reflected very well the history of coal production and consumption in the southern region of Brazil. The low levels of ΣPAHs before 1945 in all analysed cores may be related to the beginning of the industrialization process and the lower urbanization degree in the region. Between 1945 and 1965, the gradual ΣPAHs increase reflects the establishment and enlargement of the southern Brazilian industrial sector. The interval between 1965 and 1990 corresponded to the highest ΣPAHs in three of the four analysed cores. After 1990, a relative decrease in the ΣPAHs was observed in most cores and may be related the multiple cuts of incentives to the industrial usage of coal, as well as to Brazil's efforts in environmental regulation for coal extraction and consumption.

Sedimentary evolution of PAHs, POPs and ECs: Historical sedimentary deposition and evolution of persistent and emerging organic pollutants in sediments in a typical karstic river basin

Knowledge on the occurrence and distributions of organic compounds, especially PAHs, POPs and ECs, in karstic river basins is limited. This study aims to determine the depositional history and sources of PAHs, PCBs, OCPs, antibiotics, EDCs and phenolic compounds and the ecological risk they have in the Panyang River Basin, an area with a typical karstic landscape and a high-longevity population. Sediment core analysis was adopted, correlation and principal component analyses were conducted to analyze pollution sources, and lead isotope technology was implemented for dating analysis. The sediment core covered 108 years. PCBs were detected with concentrations ranging from 3.80 to 16.18 μg/kg in the core with two concentration peaks in 1950 and 2005 that were related to anthropogenic effects. Eight of the 20 targeted phenolic compounds were detected, with concentrations ranging from 0.42 to 1.10 mg/kg. All PAHs were detected in the cores, with concentrations from 12.91 to 37.80 μg/kg. They were mainly related to natural diagenetic processes and domestic and agricultural sources. The concentrations of different OCP compounds ranged from undetected to 213.43 μg/kg and were mainly related to agricultural activities and long-range transportation. These key findings can assist environmental planning and management in this river basin.

Century-long record of polycyclic aromatic hydrocarbons from tree rings in the southeastern Tibetan Plateau

Limited studies have been carried out on the historical variations of atmospheric polycyclic aromatic hydrocarbons (PAHs), especially in remote regions of the world. In this study, century-long record of PAHs (1916-2018) were reconstructed from tree rings in the remote southeastern Tibetan Plateau (TP). The total concentrations of 15 PAHs varied from 27.5 to 6.05 × 10² ng/g dry weight (dw), with a mean value of 1.40 × 10² ng/g dw. Higher levels of PAHs were observed during World War Ⅱ and the Peaceful Liberation of Tibet, and increasing trends were observed starting from rapid industrialization in India. Both the isomer ratios and the positive matrix factorization model results indicated biomass and coal combustion were the dominant sources of PAHs. The carcinogenic risk of PAHs to local residents was assessed, which might have been negligible in most past periods and lower than in other regions of the world. Nevertheless, since the beginning of the 21st century, the cancer risk has been increasing year by year, indicating more actions are needed to reduce emissions of PAHs. This study provides an idea for reconstructing the pollution history of PAHs at the global scale.

Emerging POPs-type cocktail signatures in Pusa caspica in quantitative structure-activity relationship of Caspian Sea

The Caspian seal Pusa caspica is the only endemic mammalian species throughout the Caspian Sea. This is the first report on risk assessment of persistent organic pollutants (POPs) in Caspian seals by age-sex and tissue-specific uptake, and their surrounding environment (seawater, surface sediments, and suspended particulate matters, SPMs) in the Gorgan Bay (Caspian Sea, Iran). Among the quantified 70 POPs (∑₃₅PCBs, ∑₃HCHs, ∑₆CHLs, ∑₆DDTs, ∑₁₇PCDD/Fs, HCB, dieldrin, and aldrin), ∑₃₅PCBs were dominant in abiotic matrices (48.80% of ∑₇₀POPs), followed by HCHs > CHLs > DDTs > PCDD/Fs > other POPs in surface sediments > SPMs > seawater, while the toxic equivalent quantity (TEQ_WHO) exceeded the safe value (possible risk in this area). In biota, the highest levels of ∑₇₀POPs were found in males (756.3 ng g^-1 dw, p < 0.05), followed by females (419.0 ng g^-1 dw) and pups (¹91.6 ng g^-1 dw) in liver > kidney > muscle > blubber > intestine > fur > heart > spleen > brain. The positive age-related POPs declining correlation between mother-pup pairs suggested the possible maternal transfer of POPs to offspring. The cocktail toxicity assessment revealed that Caspian seals can pose a low risk based on their mixed-TEQ values. Self-organizing map (SOM) indicated the non-coplanar PCB-93 as the most over-represented functional congener in tissue-specific POPs bioaccumulation. Quantitative toxicant tissue-profiling is valuable for predicting the state of mixture toxicity in pinniped species.

Accumulation of PAHs in the tissues and algal symbionts of a common Mediterranean coral: Skeletal storage relates to population age structure

Polycyclic aromatic hydrocarbons (PAHs) are widespread and harmful environmental pollutants that threaten marine ecosystems. Assessing their level and source is crucial to estimate the potential risks for marine organisms, as PAHs represent an additional threat to organism resilience under ongoing climatic change. Here we applied the QuEChERS extraction method to quantify four PAHs (i.e. acenaphthene, fluorene, fluoranthene, and pyrene) in three biological compartments (i.e. skeleton, tissue, and zooxanthellae symbiotic algae) of adult and old specimens of a scleractinian coral species (Balanophyllia europaea) that is widespread throughout the Mediterranean Sea. A higher concentration of all four investigated PAHs was observed in the zooxanthellae, followed by the coral tissue, with lowest concentration in the skeleton, consistently with previous studies on tropical species. In all the three biological compartments, the concentration of low molecular weight PAHs was higher with respect to high-molecular weight PAHs, in agreement with their bioaccumulation capabilities. PAH concentration was unrelated to skeletal age. Observed PAHs were of petrogenic origin, reflecting the pollution sources of the sampling area. By coupling PAH data with population age structure data measured in the field, the amount of PAHs stored in the long term (i.e. up to 20 years) in coral skeletons was quantified and resulted in 53.6 ng m^-2 of acenaphthene, 69.4 ng m^-2 of fluorene, 2.7 ng m^-2 of fluoranthene, and 11.7 ng m^-2 of pyrene. This estimate provides the basis for further assessments of long-term sequestration of PAHs from the marine environment in the whole Mediterranean, given the widespread distribution of the investigated coral species.

Pollution status of PAHs in surface sediments from different marginal seas along China Mainland: A quantitative evaluation on a national scale

China is one of the largest coastal countries in the world, which have all kinds of marginal systems. Studies have reported the sedimentary Polycyclic aromatic hydrocarbons (PAHs) pollution status, including their concentrations, sources and risks, in localized marginal systems, which showed significant differences. Thus, a comprehensive understanding of their pollution in marginal systems along China Mainland is urgently needed on a national scale. In the present study, the concentrations of 16 priority PAHs in surface sediments from 62 different marginal systems along China Mainland were reviewed. Their sources were identified and apportioned, and the health risks and ecological risks were also evaluated. As a result, the total sedimentary PAHs varied in a wide range of 4-3700 ng/g, with the lowest values observed in Kenting National Park in East China Sea and the highest values observed in Daliao River estuary in Bohai Sea. Their concentrations suggested that they were not contaminated-weakly contaminated in most study areas, but were contaminated-heavily contaminated in some pollution hot-spots. Source identification and apportion suggested that the sedimentary PAHs were mainly originated from coal combustion, vehicular emission, natural gas combustion and petrogenic source, but the coal combustion and vehicular emission contributed most to their emission (>90%). Risk assessment suggested that the carcinogenic risks were lower than the upper limit of the acceptable range (10^-4), which were acceptable at a large spatial scale. However, for sediments from Qinhuangdao coastal wetland, Daliao River estuary and Yangpu Bay, their carcinogenic risks were higher than 10^-4, which will pose high carcinogenic risks for adults. The non-carcinogenic risks were acceptable in all marginal systems with values lower than the safety guideline (<1). In the ecological risk assessment, their concentrations in some pollution hot-spots were higher than the safety guidelines (effects range low, ERL), suggesting a higher potential ecological risk.

Background concentrations of polycyclic aromatic hydrocarbons (PAHs) in deep core sediments from the Norwegian Sea and the Barents Sea: A proposed update of the OSPAR Commission background values for these sea areas

Geochemical studies of 174 sediment cores collected by the MAREANO mapping program in Norwegian waters of the North Atlantic Ocean give new sets of values of background concentrations (BCs) for polycyclic aromatic hydrocarbons (PAHs) for the studied regions. The study is based on deep core sediment samples representing background levels of PAHs. The samples selected were only from the deeper parts of undisturbed sediment cores with low, stable concentrations of petrogenic and pyrogenic PAHs, with low variation for individual PAH compounds between the samples within the same core, and from below the parts of the cores dated with ²¹⁰Pb to approximately the last 100-150 years. The results show that the main part of the studied area has BCs different from those previously established by OSPAR Commission (OSPAR) for the North-East Atlantic. Another area in central Barents Sea has a separate set of BCs of pyrogenic PAHs, apparently due to the influence from marginal ice zone mechanisms. A third area with its own set of BCs has been established for north-western Barents Sea off the coast of Svalbard, due to high natural contents of PAHs in this area. BCs for several PAHs not included in the present OSPAR list are also provided.

Organic contaminants and trace metals in the western South Atlantic upper continental margin: Anthropogenic influence on mud depocenters

Trace metals, dichloro-diphenyl-trichloroethane (DDTs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) were quantified in surface sediments from mud depocenters located in the western South Atlantic upper continental margin. There was no anthropogenic trace metal pollution observed, and the higher As values were attributed to high CaCO3 content in the area. The results indicate PCB sources associated with long-range atmospheric transport in addition to past DDT use for agriculture and pest control. PAHs were mainly originated from biomass and fossil fuel combustion, and their distribution is in alignment with the riverine runoff influence in southern region, which is transported towards the northern regions by coastal currents. Higher concentrations of 2-3 ring PAHs and DDTs in shallow and northern stations indicate a coastal influence. This work presents baseline information on the extent of anthropogenic influence in mud depocenters located in the western South Atlantic upper continental margin, showing these locations as potential source to sink of anthropogenic contaminants.