Spatial and temporal distributions of polycyclic aromatic hydrocarbons in sediments from the Canadian Arctic Archipelago

Ecotoxicological and health risks associated with sediment-bound polycyclic aromatic hydrocarbons in peri-urban closed and open coastal lagoons

Coastal urbanisation has ramifications for the sustainable development of developing nations. There are often unquantified ecological and health risks associated with urbanisation. Sixteen polycyclic aromatic hydrocarbons (PAHs) were analysed in surface sediment from three peri-urban coastal lagoons in southern Ghana. We found significant spatial variations of sediment PAHs. These variations were attributed to physiography of the lagoons and diverse anthropogenic activities surrounding them. Total PAHs ranged from 20.81 to 24,801.38 μg/kg (dry weight), underscoring a low to very high pollution level. Diagnostic ratios revealed both pyrogenic and petrogenic origins. Over 50 % of individual PAHs were of moderate ecological risk to benthic organisms, and cancer risk to humans was above the World Health Organisation's recommended safety limit (1 × 10-6). These ecological and health risks should be wake-up call for a more integrated urban planning approach to coastal urbanisation as coastal communities largely depend on natural ecosystems for food and livelihood opportunities.

Occurrence characteristics, environmental trend, and source analysis of polycyclic aromatic hydrocarbons in the water environment of industrial zones

The middle reaches of the Yellow River are rich in energy resources, with the Kuye River, a first-class river in this region, serving as a vital hub for the coal chemical industry within China. This study investigated the occurrence patterns, environmental trends, and ecological risks associated with polycyclic aromatic hydrocarbons (PAHs) in the Kuye River Basin, offering insights into the environmental dynamics of regions. The findings indicated that the river sediments primarily contained PAHs with medium to high-molecular weights, exhibiting levels ranging from 402.92 ng/g dw to 16,783.72 ng/g dw, while water bodies predominantly featured PAHs with low to medium molecular weights, ranging from 299.34 ng/L to 10,930.9 ng/L. The source analysis of PAHs indicated that industrial and traffic exhaust emissions were the primary contributors to PAHs in the Kuye basin, with sediments serving as a secondary release source based on fugacity fraction. The content of PAHs in sediment correlated closely with the environmental factors, and the PAHs inventory of the basin was 19.97 tons. The increased overall PAH concentration in the basin posed significant ecological and public health concerns, necessitating urgent attention.

Sedimentary records of contaminant inputs in Frobisher Bay, Nunavut

Contaminants, such as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), heavy metals, and per and polyfluoroalkyl substances (PFASs), primarily reach the Arctic through long-range atmospheric and oceanic transport. However, local sources within the Arctic also contribute to the levels observed in the environment, including legacy sources and new sources that arise from activities associated with increasing commercial and industrial development. The City of Iqaluit in Frobisher Bay, Nunavut (Canada), has seen rapid population growth and associated development during recent decades yet remains a site of interest for ocean protection, where Inuit continue to harvest country food. In the present study, seven dated marine sediment cores collected in Koojesse Inlet near Iqaluit, and from sites in inner and outer Frobisher Bay, respectively, were analyzed for total mercury (THg), major and trace elements, PAHs, PCBs, and PFASs. The sedimentary record in Koojesse Inlet shows a period of Aroclor 1260-like PCB input concurrent with military site presence in the 1950-60s, followed by decades of input of pyrogenic PAHs, averaging about ten times background levels. Near-surface sediments in Koojesse Inlet also show evidence of transient local-source inputs of THg and PFASs, and recycling or continued slow release of PCBs from legacy land-based sources. Differences in PFAS congener composition clearly distinguish the local sources from long-range transport. Outside Koojesse Inlet but still in inner Frobisher Bay, 9.2 km from Iqaluit, sediments showed evidence of both local source (PCB) and long-range transport. In outer Frobisher Bay, an up-core increase in THg and PFASs in sediments may be explained by ongoing inputs of these contaminants from long-range transport. The context for ocean protection and country food harvesting in this region of the Arctic clearly involves both local sources and long-range transport, with past human activities leaving a long legacy insofar as levels of persistent organic pollutants are concerned.

Polycyclic aromatic hydrocarbons in the sediments of highly polluted coastal area in the Red Sea: levels, spatial distribution, and risk assessment

The southern part of the Jeddah coast faces a range of pollution challenges that can impact the water quality and ecosystem in the area. Pollution sources are represented mainly by treated wastewater (TWW), harbor activities, and atmospheric deposition from vehicle exhaust emissions. Polycyclic aromatic hydrocarbons (PAHs) are among the persistent organic pollutants that interfere with all environmental matrices and could cause humane mutagenic and carcinogenic effects. In the present study, 16 priority parent and 21 methylated PAHs (∑37PAHs) were assessed in the sediments of three hot spot coastal sites (Islamic Jeddah port, Al-Arbaeen, and Al-Shabab lagoons) to evaluate the factors affecting their spatial distribution, examine their probable sources and potential adverse effects. The total detected concentrations of ∑37PAHs ranged from 785.9 to 8359.8 ng/g dw (average: 2296.3 ± 2017.3 ng/g dw). The highest levels of ∑37PAHs were detected near TWW stations. The highest individual PAH congeners observed were phenanthrene, anthracene, and pyrene. PAH molecular diagnostic ratios pointed out different pyrogenic sources. In some specific stations, there was an overlap of petrogenic origin. The sediment samples contained high concentrations of methylated PAHs, with concentrations ranging from 558.42 to 6321.21 ng/g dw and an average concentration of 1679.1 ± 1430.7 ng/g dw. The sediment quality guidelines indicated that adverse biological effects are likely to occur at least at the two TWW disposal stations and the sediments in these stations are at risk. The values of the mutagenic equivalence quotient (MEQ) and toxic equivalence quotient (TEQ) of carcinogenic PAHs were recorded at 39.88 and 33.17 ng/g, respectively.

Distribution, sources, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in Kaokaowusu river sediments near a coal industrial zone

This study systematically analyzed the contents, compositions, and sources of polycyclic aromatic hydrocarbons (PAHs) in river sediments near an important energy and chemical base in northwest China. In addition, their possible adverse effects on the ecology and human health were assessed. The PAH concentrations in this study area ranged from 2641.28 to 16783.72 (ng/g dw). PAHs of medium molecular weight (3-ring and 4-ring) showed the largest proportion, followed by PAHs of higher molecular weight (5-ring and 6-ring). The results of molecular diagnostic ratios and principal component analysis revealed that PAHs in the region have complex sources, with incomplete combustion of local fossil fuels and traffic exhaust factors being the main sources. The total toxic equivalent concentration of PAHs varied from 10.05 to 760.26 ng/g, and according to the sediment quality guidelines, PAHs have high potential ecological risk in the lower reaches of the river. The mean effect range-median quotient for the region was 0.46, and the combined ecological risk was at moderate to high levels (21% probability of toxicity). The lifetime carcinogenic risks for adults and children exposed to PAHs were 2.95 × 10-3 and 1.87 × 10-2, respectively, which are much higher than the limit of 10-4, indicating moderate to high potential cancer risks. Therefore, the local government should consider taking some environmental remediation measures. This study can provide theoretical support for pollution prevention measures and ecological restoration strategies for rivers in resource-rich areas.

Distribution, sources, and ecological risk assessment of polycyclic aromatic hydrocarbons in sediments from Baiyang Lake, China

The issue of polycyclic aromatic hydrocarbons (PAHs) has been an environmental focus worldwide. In this study, the contents, sources, and ecological risks of sixteen PAHs in the sediment of Baiyang Lake were estimated, and a list of priority pollutants was established. The total PAH contents ranged from 114 to 1010 ng·g-1. The composition of PAHs indicated that 4- to 6-ring PAHs predominated in the sediment samples. The diagnostic ratio analysis showed that combustion sources were predominant for PAHs in Baiyang Lake. Specifically, the positive matrix factorization model indicated that diesel engine emissions, gasoline engine emissions, wood combustion sources, and coal combustion sources contributed 22, 32, 24, and 22% of ∑PAHs, respectively. Based on the sediment quality guidelines, mean effects range median quotient, ecological risk quotient, and toxicity equivalent quotient methods, the comprehensive assessment results of PAHs in Baiyang Lake sediments indicated that the ecological risks were at medium and low levels. The priority pollutant list showed that benzo[b]fluoranthene and benzo[a]pyrene were the highest-priority pollutants and thus should be given more attention.

Priority Organic Pollutants and Endocrine-Disrupting Compounds in Arctic Marine Sediments (Svalbard Islands, Norway)

The present study investigated the occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) and phenolic endocrine-disrupting compounds (PEDCs), including bisphenol A (BPA), 4-nonylphenol (4-NP), and its monoethoxylate (NP1EO) and diethoxylate precursors in marine sediments in an Arctic fjord (Svalbard, Norway). The contribution of different local sources of contamination was also evaluated, together with a risk assessment for the marine environment. Samples were collected during two consecutive summer seasons (2018 and 2019), and target contaminants were analyzed with gas chromatography-mass spectrometry (MS) and high-performance liquid chromatography-MS/MS. The results showed no statistical differences between total PAH concentrations measured in 2018 (mean value 53.7 ± 54.3 ng/g) and 2019 (mean value 58.1 ± 63.6 ng/g). Low-ring (three or four rings) PAHs were the most abundant congeners, and single PAH ratios indicated a predominance of petrogenic sources (i.e., coal and liquid fossil fuel combustion). Nonylphenols and BPA showed a significant decrease in 2019 compared to 2018; 4-NP and NP1EO prevailed in both years, particularly in sediments close to the Ny-Ålesund research village. Overall, the results indicate that local anthropic activities are the major source of contamination in the Kongsfjorden ecosystem, but also melting waters from glaciers in the summer season can play an important role as a secondary source of pollutants previously trapped in ice. Comparison between our data and empirical and mechanistic indices derived from sediment quality guidelines suggests that the occurrence of PAHs and PEDCs in sediments does not currently pose a risk for this Arctic ecosystem, but further investigation is needed on the spread of hazardous contaminants and their effects on these fragile environments. Environ Toxicol Chem 2023;42:953-965. SETAC.

Distributions and potential sources of polychlorinated biphenyls and polycyclic aromatic hydrocarbons in the glacimarine sediments of Arctic Svalbard

Distribution and sources of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in the glacimarine sediments (35 sites) of Svalbard were investigated. PCBs (32 congeners), traditional PAHs (15 homologs), emerging PAHs (11 homologs), and alkylated PAHs (16 homologs) were widely distributed in the Svalbard sediments (ranges: below method detection limit to 20, 21 to 3600, 1.0 to 1400, and 31 to 15,000 ng g^-1 dry weight, respectively). Compositional analysis indicated that PCBs mainly originated from combustion sources, with PAHs being strongly influenced by local sources. Positive matrix factorization analysis showed that PAHs were associated with vehicle and petroleum combustion, coal, and coal combustion. Coal-derived PAHs contributed significantly to the sediments of Van Mijenfjorden. Remnants of coal mining activity trapped in the permafrost appear to enter the coastal environments as ground ice melts. Consequently, PAHs are currently emerging as the most significant contributors to potential risks in the Svalbard ecosystems.

Baseline levels and characterization of hydrocarbons in surface marine sediments along the transportation corridor in Hudson Bay: A multivariate analysis of n-alkanes, PAHs and biomarkers

Hudson Bay is a small arctic inland shelf sea which receives large amounts of freshwater from riverine discharges, with marine flow from the north and the Atlantic. A warming climate has resulted in an expanded open water season which will result in an increase in shipping of fuel oil and petroleum to communities and mines on the western shore, increasing the risk of hydrocarbon releases. To evaluate the status of hydrocarbons, surface sediments were collected at 34 locations in the transportation route and offshore and analysed for several types of hydrocarbons. Total hydrocarbons varied by over 25 times between sites, reaching a maximum of 1116 μg/g OC (organic carbon basis) in Hudson Strait due to low molecular weight n-alkanes from marine primary production. The gross mean for all sites was 344 μg/g OC (GSD = 173-682), roughly equivalent to other remote sites in the Canadian Arctic with no known local hydrocarbon source. n-alkanes accounted for >90 % of residues. Diagnostic ratios (e.g., Carbon Preference Index (CPI), Odd-Even Predominance (OEP)) indicated mixed sources of n-alkanes, likely due to the input from vascular plants and ombrotrophic peat in northern and western watersheds, and primary production within the Bay. The elevated proportion of high molecular weight n-alkanes at deep water sites is consistent with lotic particulate organic matter deposited in the nearshore environment and redeposited offshore. Ʃ₃₆PAHs were a small fraction (1.9 %) of hydrocarbons, with a gross mean of 5.68 μg/g OC (GSD = 3.30-9.79). PCA separated deep water sediments from nearshore and community samples due to 4 alkylated naphthalenes which usually indicate a petrogenic source but probably indicates a natural source due to the lack of other petrogenic markers. Priority PAHs (i.e., Ʃ₁₆PAH) varied from 31.5 % to 56.6 % of the Ʃ₃₆PAH residues. The concentrations of individual PAHs were well below the Interim Sediment Quality Guidelines recommended by the Canadian Council of Ministers of the Environment.

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

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

Occurrence, spatial patterns, air-seawater exchange, and atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) from the Northwest Pacific to Arctic Ocean

Numerous studies have elucidated the characteristics of polycyclic aromatic hydrocarbons (PAHs) in the Arctic; however, their behavior in different environments has not been studied at a large scale. To investigate the occurrence, spatial trends, air-seawater exchange and atmospheric deposition of 16 polycyclic aromatic hydrocarbons (PAHs), this study takes sample from the Northwest Pacific Ocean. to the Arctic Ocean.The concentrations of 16 PAHs in air and seawater ranged from 27 to 5658 pg/m³ and 34-338 ng/L, respectively. The air-seawater exchange flux of the region was calculated with a Whitman two-film model to be -82681-24613 ng/m²/day. Meanwhile, low-ring PAHs were transported from seawater to the air, while high-ring PAHs were transported from air to seawater. A correlation analysis between multiple environmental factors and particle phase ratio suggested that temperature might be the major driving factor for PAHs in the long-range atmospheric transport (LRAT) process. Moreover, the dry atmospheric deposition fluxes in the region were analyzed by considering environmental factors and the physicochemical properties of each PAHs monomer, these fluxes ranged from 0.001 to 696 ng/m²/day and were greater inshore than offshore and at higher latitudes. This study highlights that PAHs are affected by LRAT during their transport from Asia to Northwest Pacific and further to the Arctic Ocean, while emphasizing that air-seawater exchange plays an important role in air-sea interactions in the open ocean.

Pre- and post-industrial levels of polycyclic aromatic hydrocarbons in sediments from the Estuary and Gulf of St. Lawrence (eastern Canada)

The concentrations of 23 polycyclic aromatic hydrocarbons (PAHs; 16 parent PAHs and 7 alkyl-PAHs) were determined in 45 surface sediment and 7 basal sediment box core samples retrieved from the Estuary and Gulf of St. Lawrence in eastern Canada. The concentration sums of 16 priority PAHs (Σ₁₆PAHs) in the surface sediments (representing modern times or at least younger than the last decade) ranged from 71 to 5672 ng g^-1. Σ₁₆PAHs in the basal sediments ranged from 93 to 172 ng g^-1 among the pre-industrial samples (pre-1900 common era or CE) and from 1216 to 1621 ng g^-1 among the early post-industrial samples (~1930s and ~1940s CE). The highest Σ₁₆PAH values occurred in samples retrieved from the Baie-Comeau-Matane area, an area affected by intense industrial anthropogenic activities. Source-diagnostic PAH ratios suggest a predominance of pyrogenic sources via atmospheric deposition, with a minor contribution of petrogenic seabed pockmark sources. The PAH concentrations in the sediments from the study areas reveal low ecological risks to benthic or other organisms living near the water-sediment interface.