Urban runoff as a source of polycyclic aromatic hydrocarbons to coastal waters

Chemical contamination affecting filter-feeding bivalves in no-take marine protected areas from Brazil

Marine protected areas (MPAs) are zones geographically delimited under pre-defined management goals, seeking to reduce anthropogenic threats to biodiversity. Despite this, in recent years reports of MPAs affected by chemical contamination has grown. Therefore, this study addresses this critical issue assessing legacy and current chemical contamination in filter-feeder bivalves obtained in very restrictive no-take MPAs from Brazil. The detected pollutants encompass polycyclic aromatic hydrocarbons (PAHs), linear alkylbenzenes (LABs), and persistent organic pollutants (POPs) like dichlorodiphenyltrichloroethane (DDTs) and polychlorinated biphenyls (PCBs). Despite protective measures, bivalves from nine MPAs exhibited high LABs (13.2-1139.0 ng g-1) and DDTs levels (0.1-62.3 ng g-1). PAHs were present in low concentrations (3.1-29.03 ng g-1), as PCBs (0.7-6.4 ng g-1), hexachlorobenzene (0.1-0.2 ng g-1), and Mirex (0.1-0.3 ng g-1). Regardless of the sentinel species, MPAs and management categories, similar accumulation patterns were observed for LABs, DDTs, PAHs, and PCBs. Based on the limits proposed by Oslo Paris Commission, the measured levels of PAHs, PCBs and were below the environmental assessment criteria. Such findings indicate the no biological effects are expected to occur. However, they are higher considering background conditions typically measured in remote or pristine areas and potential simultaneous exposure. Such findings indicate an influence of anthropogenic sources, emphasizing the urgency for monitoring programs guiding strategic management efforts to safeguard these areas.

Distribution of pyrethroid insecticides in urban storm drain structures: Catch basins, open channels, and outfalls

Surface water runoff can transport contaminants offsite to downstream aquatic ecosystems. The prevalence of impervious surfaces in urban areas enhances surface runoff and contributes to contamination of urban surface streams. Urban areas have complex drainage systems for the conveyance of drainage water, however, there is a dearth of information on the distribution of contaminants within storm drain system structures. Pyrethroid insecticides are among the most used insecticides in urban areas, and trace levels of pyrethroids are known to exert toxicity to aquatic invertebrates. To investigate pyrethroid occurrence and distribution throughout an urban drainage system, samples of water, sediment, algae, and biofilm were collected from catch basins, open channels, and outfalls in Los Angeles County, California, during the dry season. From 3 catch basins, 7 open channels, and 7 outfalls, a total of 28 water samples, 4 sediment samples, 8 algae samples, and 4 biofilm samples were collected and analyzed. Pyrethroid concentrations above the reporting limit were detected in 89% of water samples and all sediment, algae, and biofilm samples, with bifenthrin and cyfluthrin being the most frequently detected compounds. The median total pyrethroid concentrations in water, sediments, algae, and biofilms were 27 ng/L, 88 ng/g, 356 ng/g, and 3556 ng/g, respectively. Bifenthrin concentrations in catch basins were found to be significantly higher than those in open channels or outfalls. Significant correlations were found for various metrics, including between pyrethroid partitioning in water samples and total suspended solids. These findings highlight the role of underground catch basins as a sink as well as a secondary source for contaminants such as pyrethroid insecticides. Prevention of the input of these urban originated contaminants to catch basins is crucial for protecting the water quality of urban surface waters.

Polycyclic aromatic hydrocarbon record in an urban secondary carbonate deposit over the last three centuries (Paris, France)

Preserving water resources and limiting pollution are central environmental issues in the current context of intense anthropization. Among organic pollutants, polycyclic aromatic hydrocarbons (PAHs) are commonly analysed as part of water quality assessments. After being emitted into the atmosphere, these persistent organic pollutants are deposited on the continental surface, where they are transported to the aquatic environment by run-off and infiltration waters. Mainly due to anthropogenic emissions, PAHs can therefore be considered as a proxy for human activities. Urban secondary carbonate deposits (USCDs), similar to cave speleothems, have recently been studied for their potential as natural archives of water quality. However, USCDs have never been used to trace water organic pollution and only a few studies on PAHs in speleothems are available. This study focuses on a well-dated USCD covering the last 300 years from the Great Aqueduct of Belleville (north-east of Paris, France). The aim is to determine the nature and variation of trapped organic compounds over time and to discuss their origin, transport, and link with changes in soil occupation due to human activities. To do so, high-resolution solid-phase UV fluorescence imaging analyses were combined with chemical analyses of PAHs and organic carbon carried out on low-weight samples. The results show that PAHs have been present in urban surface water for 300 years. Over the last few decades, a 7-fold increase is observed, accompanied by a change in the pollution source, enriched in high-molecular-weight PAHs, probably linked to urban dust. This study also reveals modes of transport directly influenced by changes in the soil occupation that are very different from those usually encountered in natural environments. This work thus paves the way for a better long-term understanding of the impact of human activity on the transfer of pollutants to sub-surface waters.

An Assessment of Southeast United States Headwater Tidal Creek Sediment Contamination Over a Twenty-Year Period in Relation to Coastal Development

Headwater tidal creeks are a primary link between estuarine and upland habitats, serving as conduits for runoff. They are sentinel habitats, providing early warning of potential harm, thus ideal systems to evaluate the effects of coastal suburban and urban development on environmental quality. Estuarine sediments have concentrations of metals, polycyclic aromatic hydrocarbons (PAHs), pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) that are associated with human activity. High concentrations of contaminants can impair faunal communities, habitat quality, and ecosystem function. Forty-three headwater creeks were sampled between 1994 and 2006 to assess contaminants, and 18 of these were sampled again in 2014/2015. Watersheds were classified as forested, forested to suburban, suburban, or urban land. These values are based on their percent impervious cover (IC) levels and change in IC from 1994-2014. Analyses of temporal data resulted in significant relationships between IC and select metals, PAHs, pesticides, PCBs, and PBDEs. In addition, 11 of the creeks sampled in 2014/2015 have paired data from 1994/1995, allowing for change analysis over the 20 years. Results indicated increasing chemical contamination occurring with increasing levels of development, although only PAHs and total dichloro-diphenyl-trichloroethane (DDT) exhibited a statistically significant increase over time; PAHs also exhibited significantly higher concentrations in developed creeks. Additionally, several metals were deemed enriched in developed creeks based on reference conditions. These results expand our knowledge of how these systems respond to urban development and can inform managers about how human population growth along coastlines may predict altered tidal creek health.

Functional redundancy in response to runoff input upholds microbial community in hydrocarbon-contaminated land-sea continuum

An experimental approach mimicking the land-sea continuum in microcosms was developed in order to determine the effect of the terrigenous inputs by soil runoff on the microbial functional potential in hydrocarbon (HC) contaminated marine coastal sediment. We hypothesized that the coalescent event increases the functional potential of microbial communities in marine coastal sediments, influencing the fate of HC in marine coastal ecosystems. The microbial functional potential including the HC degradation ability was assessed by DNA-array to compare the sediment receiving or not terrigenous inputs. The removal of HC and the functional gene richness in sediment was unchanged with the terrigenous inputs. However, the gene variants (GVs) composition was modified indicating functional redundancy. In addition, functional indicators including GVs related to sulfite reduction, denitrification and polyaromatic degradation were identified in higher proportion in sediment receiving terrigenous inputs. The terrigenous inputs modified the functional co-occurrence networks, showing a reorganization of the GVs associations with an increase of the network complexity. Different keystone GVs ensuring similar functions were identified in networks with or without terrigenous inputs, further confirming functional redundancy. We argue that functional redundancy maintains the structure of microbial community in hydrocarbon-contaminated land-sea continuum mixing zone. Our results provide helpful functional information for the monitoring and management of coastal environment affected by human land-based activities.

Spatiotemporal variability of PAHs and their derivatives in sediments of the Laizhou Bay in the eastern China: Occurrence, source, and ecological risk assessment

To understand the pollution status and risk levels in the Laizhou Bay, the spatiotemporal distribution, source, and ecological risk of 16 polycyclic aromatic hydrocarbons (PAHs) and 20 substituted PAHs (SPAHs) were studied in surface sediments in 2022. The findings indicated significant seasonal differences in the concentrations of PAHs and SPAHs under the influences of precipitation, temperature, light, and human activities, with higher storage levels in summer than in spring, and there was also a spatial distribution trend of estuary > coast > offshore. 2-Nitrofluorene (2-NF) and 2-methylnaphthalene (2-MN) were the most abundant components of SPAHs in both spring and summer, with levels of 21.44 ng/g and 17.89 ng/g in spring, 43.22 ng/g and 25.51 ng/g in summer, respectively. The results of the diagnostic ratio and principal component analysis - multiple linear regression identified sources of PAHs and SPAHs as combustion sources, including petroleum, coal, and biomass. The risk level of PAHs was low-to-moderate according to the toxicity equivalent quotient (TEQ) and risk quotient. A novel calculation method based on TEQ was proposed to assess the ecological risk of SPAHs, and the results indicated that the risk level of SPAHs was moderate-to-high.

Study of polycyclic aromatic hydrocarbons accumulation in bioretention facilities and its influence on microbial community structure

Bioretention facilities are one of the most widely used measures for urban stormwater control and utilization. In this study, the accumulation characteristics of polycyclic aromatic hydrocarbons (PAHs) in bioretention facilities and the effects of PAHs on the structure of microbial communities were explored by combining on-site monitoring and water distribution simulation experiments. The correlation between pollutant accumulation and dominant microorganisms in the bioretention systems was also clarified. The results showed that all 16 priority PAHs were detected in the bioretention facilities in the sponge city pilot area. The PAH concentrations in the soil during the non-rainy season were higher than those in the rainy season and medium- and high-ring PAHs dominated. PAHs in the study area were mainly derived from coal and biomass combustion. The potential carcinogenic risk of PAHs accumulated in the bioretention facilities in the study area was low. The microbial diversity during the non-rainy season was greater than that during the rainy season. Firmicutes, Bacteroidetes, Bacteroides, and Massilia were strongly correlated with naphthalene (NAP), pyrene (PYR), fluoranthene (FLT), and benzo[a]pyrene (BaP). According to the results of the small-scale water distribution test, the addition of PAHs had little effect on the decline in water quantity, and there was no significant regularity in the reduction of water quality including TP, NH4+-N, NO3-N, and TN. The addition of PAHs had a significant effect on the microbial community structure and an inhibitory effect on enzyme activity.

Biosurfactants: Secondary Metabolites Involved in the Process of Bioremediation and Biofilm Removal

The search for environmentally friendly methods to remove persistent substances such as organic pollutants and sessile communities such as biofilms that severely affect the environment and human health resulted in biosurfactant discovery. Owing to their low level of toxicity and high biodegradability, biosurfactants are increasingly preferred to be used for removal of pollutants from nature. These amphipathic molecules can be synthesized inexpensively, employing cheap substrates such as agricultural and industrial wastes. Recent progress has been made in identifying various biosurfactants that can be used to remove organic pollutants and harmful microbial aggregates, as well as novel microbial strains that produce these surface-active molecules to survive in a hydrocarbon-rich environment. This review focuses on the identification and understanding the role of biosurfactants and the microorganisms involved in the removal of biofilms and remediation of xenobiotics and various types of hydrocarbons such as crude oil, aromatic hydrocarbons, n-alkanes, aliphatic hydrocarbons, asphaltenes, naphthenes, and other petroleum products. This property of biosurfactant is very important as biofilms are of great concern due to their impact on the environment, public health, and industries worldwide. This work also includes several advanced molecular methods that can be used to enhance the production of biosurfactants by the microorganisms studied.

Distribution and source assignments of polycyclic aromatic and aliphatic hydrocarbons in sediments and biota of the Lafayette River, VA

The Lafayette River comprises a tidal sub-estuary constrained by an urban watershed that is bounded by residential areas at its upper reaches and port activity at its mouth. We determined the concentrations and distributions of polycyclic aromatic hydrocarbons (PAHs) and aliphatic n-alkanes across 19 sites from headwaters to river mouth in surface sediments (0-2 cm). Potential atmospheric sources were investigated through the analysis of wet and dry deposition samples and intact coals from a major export terminal nearby. The potential consequences for human consumption were examined through analysis of native oyster (Crassostrea virginica) and blue crab tissues (Callinectes sapidus). A suite of up to 66 parent and alkyl-substituted PAHs were detected in Lafayette sediments with total concentrations ranging from 0.75 to 39.00 µg g^-1 dry wt. Concentrations of aliphatic n-alkanes (n-C₁₆ - n-C₃₁) ranged from 4.94 to 40.83 μg g^-1 dry wt. Source assignment using diagnostic ratios and multivariate source analysis suggests multiple sources contribute to the hydrocarbon signature in this metropolitan system with automotive and atmospheric transport of coal dust as the major contributors. Oyster tissues showed similar trends as PAHs observed in sediments indicating similar sources to water column particles which ultimately accumulate in sediments with crabs showing altered distributions as a consequence of metabolism.

New insights into microbial community coalescence in the land-sea continuum

The land-sea continuum constitutes a mixing zone where soil microbial communities encounter, via runoff, those inhabiting marine coastal sediment resulting in community coalescence. Here, we propose an experimental approach, mimicking the land-sea continuum, to study the microbial community coalescence events in different situations, by 16S and 18S rRNA genes metabarcoding. The microbial community structure of sediment diverged with the soil inputs. For prokaryotes, phylogenetic enrichment and amplicon sequence variants (ASVs) replacements characterized the community changes in sediment receiving soil inputs. For fungi, despite phylogenetic enrichment was not observed, the fungal ASVs richness was maintained by soil inputs. Comparison of microbial communities revealed ASVs specific to sediment receiving soil inputs, and also ASVs shared with soil and/or runoff. Among these specific ASVs, four bacterial and one fungal ASVs were identified as indicators of coalescence. Our study provides evidences that coalescence involves the mixing of microorganisms and of the environment.

Adopting Sustainable Jatropha Oil Bio-Based Polymer Membranes as Alternatives for Environmental Remediation

This study aimed to optimize the removal of Cu(II) ions from an aqueous solution using a Jatropha oil bio-based membrane blended with 0.50 wt% graphene oxide (JPU/GO 0.50 wt%) using a central composite model (CCD) design using response surface methodology. The input factors were the feed concentration (60–140) ppm, pressure (1.5–2.5) bar, and solution pH value (3–5). An optimum Cu(II) ions removal of 87% was predicted at 116 ppm feed concentration, 1.5 bar pressure, and pH 3.7, while the validated experimental result recorded 80% Cu(II) ions removal, with 95% of prediction intervals. A statistically non-significant term was removed from the analysis by the backward elimination method to improve the model’s accuracy. Using the reduction method, the predicted R² value was increased from −0.16 (−16%) to 0.88 (88%), suggesting that the reduced model had a good predictive ability. The quadratic regression model was significant (R² = 0.98) for the optimization prediction. Therefore, the results from the reduction model implied acceptable membrane performance, offering a better process optimization for Cu(II) ions removal.

Planktonic Fiddler Crab (Uca longisignalis) Are Susceptible to Photoinduced Toxicity Following in ovo Exposure in Oiled Mesocosms

Benthic organisms may be exposed to polycyclic aromatic hydrocarbons (PAHs) in marine sediments as the result of oil spills. PAH photoinduced toxicity, which has been documented in a wide range of early life stage (ELS) aquatic biota, is a phenomenon by which ultraviolet (UV) radiation potentiates the toxicity of photodynamic PAHs (often leading to mortality). Fiddler crabs (Uca longisignalis) are important ecosystem engineers that influence biogeochemical cycles via burrowing. As gravid females burrow, their eggs may bioaccumulate PAHs from contaminated sediments, leading to in ovo exposure. Consequently, free-swimming larvae exposed to intense UV may be at risk for photoinduced toxicity. In the present study, mature fiddler crabs were bred on oiled sediments contaminated via simulated tidal flux. Gravid females were transferred to clean water after 10 days, and larvae were collected at hatch. While in ovo exposures to oil alone did not affect survival, offspring that were subsequently exposed to full spectrum sunlight in clean water experienced significant mortality that corresponded with in ovo exposures to sediments containing ≥1455 μg/kg tPAH₅₀. Results presented here provide evidence for the potential of photoinduced toxicity to occur in benthic organisms with free-swimming early life stages.

Spatiotemporal distribution, source, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in the urbanized semi-enclosed Jiaozhou Bay, China

Coastal contamination by polycyclic aromatic hydrocarbons (PAHs) is a worldwide issue. Nevertheless, the spatiotemporal distribution of PAHs in the urbanized semi-enclosed bays in China remains relatively uncharacterized. Here we present measurements of 15 priority PAHs in the water and sediment of the Jiaozhou Bay, as well the assessment of their spatiotemporal distribution, sources and ecological risk. The total PAH (ΣPAH) concentrations ranged from 23.6 to 86.2 ng L ^-1 in the water and from 37.7 to 290.9 ng g^-1 in the sediment. The average ΣPAH concentration in the water was significantly higher in the winter (52.8 ng L ^-1) than in the spring (30.4 ng L ^-1) (α = 0.05 level). Average concentration of phenanthrene in the water was 8.9 ng L^-1 in the spring and 15.7 ng L^-1 in the winter and the highest of PAHs, contributing about 29.4% to ΣPAHs. Compared with three-ring PAHs, four- and five-ring PAHs were more tended to accumulate in the sediment, and the partitioning into sediment was influenced by the water salinity. The spatial distribution of ΣPAH concentrations in the water were controlled by water exchange capability. Organic matter content and sediment texture played important roles in determining the spatial distribution of ΣPAHs in the sediment. Molecular diagnostic ratio analysis indicated that pyrogenic source was the main source for PAHs in the Bay. Specifically, the positive matrix factorization (PMF) model indicated that vehicle emission, biomass combustion, coal combustion, and petrogenic sources contributed for 41.6, 20.2, 20, and 18.2% of ΣPAHs, respectively. The risk assessment by sediment quality guidelines suggested that adverse biological effects are expected to occur rarely in the sediment.

Analysis of origin, change, and distribution of polycyclic aromatic hydrocarbons in the continental shelf of China Sea

The sources and environmental fate of polycyclic aromatic hydrocarbons (PAHs) are closely related with anthropological activities and natural environmental conditions. The continental shelf of China Sea has the most intense land-ocean interactions. The PAHs' distribution in this region is of great significance for revealing the impact of human activities on the marine environment and the environmental fate of terrigenous substances input to the ocean. However, up to now, almost all the studies were confined to relatively small regions, such as estuaries. There was a lack of systematic understanding of PAHs in the whole continental shelf sea. In this study, the relevant research findings of PAHs in the continental shelf of China Sea in recent years were systematically summarized. The spatial and temporal variations of PAHs in sediments of China Sea were comprehensively displayed. The relationships between PAHs' distributions in different seas with regional economic development history were analyzed. These findings will play a guiding significance for improving marine environment research in large-scale areas.

A study of the road sediment build-up process over a long dry period in a megacity of China

The build-up of urban road deposited sediments is the key to study the quality of stormwater and the associated receiving waterbody in urban catchments. In the past, many sediment build-up field studies were conducted between 7 and 20days. It is generally assumed that the cumulative amount of pollutants reaches equilibrium and be represented as a mono-growth curve such as the power function. However, the dry period between two rain events in many areas in Northern China may be much longer than 20days, especially for spring and fall seasons. This research was conducted for 41days during a long dry period in 2017 in Tianjin, a megacity of China. The variability of the road sediment build-up process and the intrinsic and extrinsic factors which influence the process variability were investigated. It has been found that the normally used mono-growth curve (such as the power function) may be suitable for the short-term build-up process in area with less interference (sparse human activity area, R²>0.6). The double-bell shaped curve (sin function) fits better for the 41-day study, a longer period build-up study (R²>0.9). An "unexpected" phenomenon at which the particulate load was rapidly decreased in the first three sampling days was observed. This remarkable phenomenon can undoubtedly be well represented by the sin function instead of the power function. Compared to the power function, the goodness of fit of the sin function is increased by 30%-130%. Particle size, as an important characteristic affecting the behavior of particles, was considered in the build-up model. This research may bring people's attention to study the long-term road sediment build-up process and their impacts on the receiving water quality.

Quantification of azaarenes, hydroxylated azaarene derivatives, and other polar compounds released in urban runoff from two commercial sealcoat products

Sealcoat is an emulsified coating product applied to asphalt to protect against surface weathering. Sealcoat products contain coal-tar (CT) or petroleum-derived residues and are a recognized source of polycyclic aromatic hydrocarbons (PAHs) in urban areas. Although the toxicity of urban runoff from CT-sealed asphalt is established, chemical characterization has focused more on PAHs and alkylated derivatives and less on polar transformation products. In this study, solid-phase extraction (SPE) was used to concentrate dissolved (<0.2 μm) species in runoff collected from asphalt surfaces sealed with CT pitch or steam-cracked petroleum (SCP) residues. CT-sealed surfaces released a 20-fold greater concentration of SPE-extractable compounds in runoff compared to SCP-sealed surfaces. Representative compounds were sorted into four groups: nitrogen heterocycles (azaarenes) and other oxygen- and sulfur-containing species (N HET); hydroxylated N heterocycles (hydroxylated N HET); the nonionic surfactant 2,4,7,9-tetramethyl-5-decyne-4,7-diol (TMDD); and styrene-acrylonitrile polymer byproducts (SAN Trimer). Species concentrations and weathering-related disappearance behavior differed among the four subgroups. While hydroxylated N HET concentrations decreased by 94% in runoff from CT-sealed surfaces 60 h after sealcoat application, SAN Trimer concentrations in CT and SCP runoff increased over time as polymerization progressed, illustrating the complex changes the chemicals in sealcoat undergo as it cures under environmentally-relevant conditions. Overall, this study shows that urban runoff collected from CT-sealed and SCP-sealed asphalt surfaces is a potential source of water-soluble contaminants with unknown long-term ecotoxicological effects to aquatic systems.

Fiproles in urban surface runoff: Understanding sources and causes of contamination

Urban-use pesticides present a unique risk to non-target organisms in surface aquatic systems because impervious pavement facilitates runoff that may lead to serious contamination and ensuing aquatic toxicity. Fipronil is an insecticide used at high rates in urban environments, especially in regions such as California. This compound and its biologically active degradation products have been detected in urban runoff drainage and downstream surface water bodies at concentrations exceeding toxicity thresholds for sensitive aquatic invertebrates, necessitating a better understanding of the runoff sources and causes of this contamination at sites of application. In this study, we evaluated sorption of fipronil, fipronil desulfinyl, fipronil sulfide, and fipronil sulfone in urban dust, soil, and concrete, matrices commonly associated with the perimeter of a residential home. Samples were also collected from five single family homes treated with fipronil in Riverside, California, for five months to determine the occurrence of fipronil and its degradates in runoff water, urban dust, soil, and on concrete surfaces. Statistical analysis was performed to determine which urban matrices contributed more significantly to the contaminant levels in runoff water. Freundlich sorption coefficients for fipronil and its degradation products in dust were 3- to 9-fold greater than their values in soil. Fipronil and its degradates were detected in 100% of runoff samples and their presence was observed in dust, soil, and concrete wipe samples for 153 d after the treatment. Linear regression analysis showed that concrete surfaces were a primary source of all four compounds to runoff, and loose dust on concrete pavement also served as an important contributor. This study represents the first comprehensive investigation of the sources and causes for surface runoff contamination by fipronil and its degradation products. Findings highlight the importance to reduce fipronil residues on concrete surfaces through improved application methods and other mitigation practices.

Assessing the Feasibility of Soil Infiltration Trenches for Highway Runoff Control on the Island of Oahu, Hawaii

The coastal waters of Hawaii are extremely important for recreation as well as for the health of the marine environment. Non-point source pollution from storm runoff poses a great threat to surface water quality in Hawaii. The State of Hawaii Department of Transportation (HDOT) includes infiltration trenches as a best management practice (BMP) option to reduce pollution caused by stormwater runoff. HDOT guidelines state that the implementation of BMPs is needed to reduce sediment and pollutant loads to streams and the ocean. In this study, the suitability of soils adjacent to highways on Oahu for the siting of infiltration trenches was examined. In addition to field surveys and in-situ tests, laboratory investigations on soil properties, infiltration experiments on undisturbed soil columns, and mathematical modeling of hydraulic functioning of the infiltration trench were conducted. Dissolved metal concentrations in highway stormwater runoff were observed to exceed the groundwater environmental action levels for all heavy metals tested, but the soils had high sorption capacity for these metals. The results of the simulations indicated that all the sampled Oahu soils, with one exception, would require less than two hours to drain a filled hypothetical trench. Therefore, these soils are suitable for construction of infiltration trenches as a possible BMP, even when clogging of soil is considered in the simulation.

Comparison and origins of polycyclic aromatic hydrocarbons (PAHs) in the entrance and the exit of the Turkish Straits System (TSS)

Investigations of total petroleum hydrocarbons (TPHs) in water and polycyclic aromatic hydrocarbons (PAHs) in sediments were performed in the entrance and the exit of the Turkish Straits System (TSS) in autumn of 2016 and spring of 2017. TPH and PAH values ranged from 1.7 to 11.6 μg/l and 120 to 2912 ng/g (dw), respectively. On the basis of the given surface fluxes of the TSS, average petroleum flows were calculated as 1631 t/y from the Black Sea to the Marmara Sea and 8484 t/y from the Marmara Sea to the Aegean Sea. Pollution by PAHs ranged from relatively moderate to high. The most polluted sediments were collected from regions affected by shipping, such as Riva and Seddülbahir located at the entrance and the exit of the TSS, respectively. Moreover, origins of PAHs were determined using the ratios of PAH congeners. The main origins of PAHs were found as both pyrolytic and petrogenic at most stations.

Land-use-based sources and trends of dissolved PBDEs and PAHs in an urbanized watershed using passive polyethylene samplers

Narragansett Bay is a temperate estuary on the Atlantic coast of Rhode Island in the north-eastern United States, which receives organic pollutants from urban and industrial activities in its watershed, though detailed knowledge on sources and fluxes is missing. Twenty-four polyethylene passive samplers were deployed in the surface water of the watershed around Narragansett Bay during June-July of 2014, to examine the spatial variability and possible sources of priority pollutants, namely dissolved polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs). Dissolved ∑₂₂PAH concentrations ranged from 3.6 to 340 ng L^-1, and from 2.9 to 220 pg L^-1 for ∑₁₂PBDE. The spatial variability of the concentrations was correlated to land use pattern and population distribution, in particular with human activities within 2 km of sampling sites. River discharges derived from the concentrations of PAHs and PBDEs measured here were 10-20 times greater than their previously measured concentrations in the open waters of Narragansett Bay. These results imply that river waters are the main source of PAHs and PDBEs to the Bay and that major sink terms (e.g., sedimentation, degradation) affect their concentrations in the estuary. Predicted PAH and PBDE toxicity based on dissolved concentrations did not exceed 1 toxic unit, suggested that no toxicity occurred at the sampling sites.

Urban stormwater runoff negatively impacts lateral line development in larval zebrafish and salmon embryos

After a storm, water often runs off of impervious urban surfaces directly into aquatic ecosystems. This stormwater runoff is a cocktail of toxicants that have serious effects on the ecological integrity of aquatic habitats. Zebrafish that develop in stormwater runoff suffer from cardiovascular toxicity and impaired growth, but the effects of stormwater on fish sensory systems are not understood. Our study investigated the effect of stormwater on hair cells of the lateral line in larval zebrafish and coho salmon. Our results showed that although toxicants in stormwater did not kill zebrafish hair cells, these cells did experience damage. Zebrafish developing in stormwater also experienced impaired growth, fewer neuromasts in the lateral line, and fewer hair cells per neuromast. A similar reduction in neuromast number was observed in coho salmon reared in stormwater. Bioretention treatment, intended to filter out harmful constituents of stormwater, rescued the lateral line defects in zebrafish but not in coho salmon, suggesting that not all of the harmful constituents were removed by the filtration media and that salmonids are particularly sensitive to aquatic toxicants. Collectively, these data demonstrate that sub-lethal exposure to stormwater runoff negatively impacts a fish sensory system, which may have consequences for organismal fitness.

Steel slag as low-cost adsorbent for the removal of phenanthrene and naphthalene

This study investigates the removal effectiveness and characteristics of phenanthrene and naphthalene using low-cost steel slag with batch experiments. The adsorption characteristics of steel slag were measured and analysed using X-ray fluorescence, X-ray diffraction, and Fourier transform infrared spectroscopy. The batch experiments investigated the effect of the time gradient, pH, and steel slag dosage gradient on the adsorption of the steel slag. The results show that with time and dosage of steel slag increased, the adsorption capacity of phenanthrene and naphthalene increased and gradually became balanced, but pH had no obvious effect on the adsorption of phenanthrene and naphthalene. The Langmuir isotherm model best describes the phenanthrene and naphthalene removal by the steel slag, which shows the adsorption occurring in a monolayer. The maximum adsorption capacity of the steel slag to phenanthrene and naphthalene is 0.043 and 0.041 mg/g, respectively. A pseudo-first-order kinetic model can better represent the adsorption of phenanthrene and naphthalene by steel slag. The research demonstrates that the steel slag has a certain adsorption capacity for phenanthrene and naphthalene.

Effect of Green Macroalgal Blooms on the Behavior, Growth, and Survival of Cockles (Clinocardium nuttallii) in Pacific NW Estuaries

Nutrient over-enrichment can produce adverse ecological effects within coastal ecosystems and negatively impact the production of ecosystem goods and services. In small estuaries of the U.S. Pacific Northwest, seasonal blooms of green macroalgae (GMA; Family Ulvaceae) are primarily associated with natural nutrient input, rather than anthropogenic sources. This provided us a unique opportunity to investigate the effects of naturally-stimulated macroalgal blooms on intertidal bivalves. Clinocardium nuttallii (heart cockles) are an important species for shellfisheries in the region. In summer population surveys, we found that cockles emerged from the sediment with greater frequency as GMA biomass increased. Experimental manipulation of GMA biomass in the field showed that GMA elicited emergence, evoked above-ground lateral movement, inhibited shell growth, and increased mortality (by 34.0 ± 15.2%) in cockles. Laboratory experiments revealed that the interaction of a weighted barrier at the sediment surface and GMA presence elicited rapid emergence among cockles. Risk assessment of the emergence response in cockles showed that the in situ emergent population experienced 11.0 ± 8.0% mortality due to gull predation, while laboratory exposure to elevated temperatures (≥34 °C) slowed valve-closure, inhibited reburial, and increased mortality, which could have translated to 7.1 ± 1.5% in situ mortality. We found that cockles avoided mortality due to burial below GMA mats by emerging from the sediment, but that behavior consequently put them at risk of mortality due to heat stress or gull predation. Regardless of nutrient source, our research showed that GMA blooms pose a threat to the survival of intertidal bivalves.

Air-sea exchange and gas-particle partitioning of polycyclic aromatic hydrocarbons over the northwestern Pacific Ocean: Role of East Asian continental outflow

We measured 15 parent polycyclic aromatic hydrocarbons (PAHs) in atmosphere and water during a research cruise from the East China Sea (ECS) to the northwestern Pacific Ocean (NWP) in the spring of 2015 to investigate the occurrence, air-sea gas exchange, and gas-particle partitioning of PAHs with a particular focus on the influence of East Asian continental outflow. The gaseous PAH composition and identification of sources were consistent with PAHs from the upwind area, indicating that the gaseous PAHs (three-to five-ring PAHs) were influenced by upwind land pollution. In addition, air-sea exchange fluxes of gaseous PAHs were estimated to be -54.2-107.4 ng m^-2 d^-1, and was indicative of variations of land-based PAH inputs. The logarithmic gas-particle partition coefficient (logK_p) of PAHs regressed linearly against the logarithmic subcooled liquid vapor pressure (logP_L⁰), with a slope of -0.25. This was significantly larger than the theoretical value (-1), implying disequilibrium between the gaseous and particulate PAHs over the NWP. The non-equilibrium of PAH gas-particle partitioning was shielded from the volatilization of three-ring gaseous PAHs from seawater and lower soot concentrations in particular when the oceanic air masses prevailed. Modeling PAH absorption into organic matter and adsorption onto soot carbon revealed that the status of PAH gas-particle partitioning deviated more from the modeling K_p for oceanic air masses than those for continental air masses, which coincided with higher volatilization of three-ring PAHs and confirmed the influence of air-sea exchange. Meanwhile, significant linear regressions between logK_p and logK_oa (logK_sa) for PAHs were observed for continental air masses, suggesting the dominant effect of East Asian continental outflow on atmospheric PAHs over the NWP during the sampling campaign.

The transport of polycyclic aromatic hydrocarbons during rainfall and snowmelt in contrasting landscapes

Though it has been established that stream concentrations of polycyclic aromatic hydrocarbons (PAHs) in urban watersheds can be much greater than those in less developed watersheds, knowledge of transport mechanisms is lacking, particularly in temperate, Northern climates with seasonal snow packs. We combine high-resolution stream water sampling with air, suspended solid and stream flow monitoring to investigate the source to stream transport of PAHs during rainfall and snowmelt in paired watersheds with contrasting land use. Despite similar particle loads, contamination of particles that is 8-48 times higher in the urban watersheds leads to area-normalized loads of PAHs that are 6-82 times greater than in the agricultural watersheds. In the urban watershed, average volumetric storm flow concentrations increase with longer antecedent dry period that allows build-up of PAHs on watershed surfaces. Cluster analysis suggests road dust is a minor source of suspended solid-bound PAHs in more agricultural watersheds during rainfall. During snowmelt, earlier peaks in concentration in the urban watershed are likely due to melt from snow packs and snow banks travelling quickly to the stream network via impervious surfaces and sewer drains. While road-derived inputs also appear to be important during snowmelt in the agricultural watershed, relatively delayed peak concentrations result from delayed inputs from snow packs in more pervious areas of the watershed.

Application of a self-organizing map and positive matrix factorization to investigate the spatial distributions and sources of polycyclic aromatic hydrocarbons in soils from Xiangfen County, northern China

The concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) were measured in 128 surface soil samples from Xiangfen County, northern China. The total mass concentration of these PAHs ranged from 52 to 10,524ng/g, with a mean of 723ng/g. Four-ring PAHs contributed almost 50% of the total PAH burden. A self-organizing map and positive matrix factorization were applied to investigate the spatial distribution and source apportionment of PAHs. Three emission sources of PAHs were identified, namely, coking ovens (21.9%), coal/biomass combustion (60.1%), and anthracene oil (18.0%). High concentrations of low-molecular-weight PAHs were particularly apparent in the coking plant zone in the region around Gucheng Town. High-molecular-weight PAHs mainly originated from coal/biomass combustion around Gucheng Town, Xincheng Town, and Taosi Town. PAHs in the soil of Xiangfen County are unlikely to pose a significant cancer risk for the population.

Vertical distribution, composition profiles, sources and toxicity assessment of PAH residues in the reclaimed mudflat sediments from the adjacent Thane Creek of Mumbai

A study on vertical distribution of magnetic susceptibility, carcinogenic and endocrine disrupting PAHs was performed in the reclaimed mudflat sediments adjacent to the Thane Creek of Mumbai. The 5-rings PAHs and ΣC-PAHs were more dominant at 120cm depth contributing 52.23% and 60.19% respectively to ∑PAHs. The average ratio values of LMW/HMW PAHs (0.58); Fla/(Fla+Pyr) (0.50); Ant/(Ant+Phe) (0.50); BaA/(Chry+BaA) (0.48); BaP/BghiP (2.06), Phe/Ant (1.03) and BaA/Chr (0.93) indicate that the PAH contamination might have raised due to inefficient combustion and pyrogenic emissions during the open burning of solid waste in the vicinity. This was further supported by the anthropogenic ferri(o)magnetic loading over the last 100years influencing the Creek sediments. The PAHs toxicity estimation was performed by calculating the toxic equivalent quantity (TEQ) value of 8.62ng TEQ/g which was below the safe level (600ng TEQ/g) suggested by the Canadian risk-based soil criterion for protection of human health.

Distribution, sources and ecological risk of polycyclic aromatic hydrocarbons in the estuarine-coastal sediments in the East China Sea

Polycyclic aromatic hydrocarbons (PAHs), total organic carbon (TOC) and black carbon (BC) in the estuarine-coastal areas of the East China Sea (ECS) were investigated. The results showed that ∑PAH concentrations ranged from 61 to 355 ng g^-1 with a mean value of 146 ng g^-1. The contents of TOC and BC were in the range of 1.31-7.23 mg g^-1 and 0.52-5.60 mg g^-1, respectively. Data analyses showed that PAH concentrations had a positive linear relationship with TOC and with BC. In addition, the grain size of silts and clays had significant influence on the PAHs of sediments. These physicochemical properties as well as coastal currents, especially the trapping effect of the Taiwan Warm Current and the Zhejiang Fujian Coastal Current, played important roles in determining the spatial distribution of PAHs in the ECS. The estimated deposition flux of PAHs was 106 t per year in the study area. Source apportionment showed that these PAHs mainly originated from oil sources, and the combustion of liquid fossils and coal/wood.

Occurrence and distribution of polycyclic aromatic hydrocarbons in surface sediments of San Diego Bay marinas

Polycyclic aromatic hydrocarbons (PAHs) have garnered much attention due to their bioaccumulation, carcinogenic properties, and persistence in the environment. Investigation of the spatial distribution, composition, and sources of PAHs in sediments of three recreational marinas in San Diego Bay, California revealed significant differences among marinas, with concentrations in one site exceeding 16,000ngg^-1. 'Hotspots' of PAH concentration suggest an association with stormwater outfalls draining into the basins. High-molecular weight PAHs (4-6 rings) were dominant (>86%); the average percentage of potentially carcinogenic PAHs was high in all sites (61.4-70%) but ecotoxicological risks varied among marinas. Highly toxic benzo(a)pyrene (BaP) was the main contributor (>90%) to the total toxic equivalent quantity (TEQ) in marinas. PAHs in San Diego Bay marina sediments appear to be derived largely from pyrogenic sources, potentially from combustion products that reach the basins by aerial deposition and stormwater drainage from nearby streets and parking lots.

Role of environmental factors and microorganisms in determining the fate of polycyclic aromatic hydrocarbons in the marine environment

Polycyclic aromatic hydrocarbons (PAHs) are widespread in marine ecosystems and originate from natural sources and anthropogenic activities. PAHs enter the marine environment in two main ways, corresponding to chronic pollution or acute pollution by oil spills. The global PAH fluxes in marine environments are controlled by the microbial degradation and the biological pump, which plays a role in particle settling and in sequestration through bioaccumulation. Due to their low water solubility and hydrophobic nature, PAHs tightly adhere to sediments leading to accumulation in coastal and deep sediments. Microbial assemblages play an important role in determining the fate of PAHs in water and sediments, supporting the functioning of biogeochemical cycles and the microbial loop. This review summarises the knowledge recently acquired in terms of both chronic and acute PAH pollution. The importance of the microbial ecology in PAH-polluted marine ecosystems is highlighted as well as the importance of gaining further in-depth knowledge of the environmental services provided by microorganisms.

Carcinogenic and endocrine-disrupting PAHs in the aquatic ecosystem of India

The quantification studies of 17 carcinogenic and endocrine-disrupting polycyclic aromatic hydrocarbons (PAHs) in the Mithi River polluting the Mahim Creek near Mumbai were performed to understand their sources and probable ecological risk. The overall concentration level of ΣPAHs was 157.96 ± 18.99 μg L^-1, while that of carcinogenic PAHs (ΣC-PAHs) was 81.31 ± 9.75 μg L^-1, which corresponds to 51.5 % of the ΣPAHs. The source analysis of PAH pollution was made on the basis of different PAH ratios. It was observed that the probable PAH contamination was due to pyrogenic inputs arising due to the combustion of grass, wood, and coal as well as due to the combustion of diesel and gasoline. Toxicity and biological risk assessment was made using toxic equivalent quantity (TEQ) for various C-PAHs. The results of our study showed that the mean BaP concentration in the Mithi River water (8.61 μg L^-1) was above the European Directive 2008/105/EC Environmental Quality Standards (EQS) value of 0.05 μg L^-1, while the levels of benzo(k)fluoranthene (BkF) + benzo(b)fluoranthene (BbF) (21.54 μg L^-1) and benzo(g,h,i)perylene (BghiP) + indeno(1,2,3,-c,d) pyrene (InP) (18.27 μg L^-1) were significantly higher than that set by the EQS (0.03 and 0.002 μg L^-1, respectively), showing that the ecological integrity of the river and the adjoining creek is possibly at risk.

PAH Accessibility in Particulate Matter from Road-Impacted Environments

Snowmelt, surface runoff, or stormwater releases in urban environments can result in significant discharges of particulate matter-bound polycyclic aromatic hydrocarbons (PAHs) into aquatic environments. Recently, more-specific activities such as road-tunnel washing have been identified as contributing to contaminant load to surface waters. However, knowledge of PAH accessibility in particulate matter (PM) of urban origin that may ultimately be released into urban surface waters is limited. In the present study, we evaluated the accessibility of PAHs associated with seven distinct (suspended) particulate matter samples collected from different urban sources. Laboratory-based infinite sink extractions with silicone rubber (SR) as the extractor phase demonstrated a similar pattern of PAH accessibility for most PM samples. Substantially higher accessible fractions were observed for the less-hydrophobic PAHs (between 40 and 80% of total concentrations) compared with those measured for the most-hydrophobic PAHs (<5% of total concentrations). When we focused on PAHs bound to PM from tunnel-wash waters, first-order desorption rates for PAHs with log Kow > 5.5 were found in line with those commonly found for slowly or very slowly desorbing sediment-associated contaminants. PAHs with log Kow < 5.5 were found at higher desorbing rates. The addition of detergents did not influence the extractability of lighter PAHs but increased desorption rates for the heavier PAHs, potentially contributing to increases in the toxicity of tunnel-wash waters when surfactants are used. The implications of total and accessible PAH concentrations measured in our urban PM samples are discussed in a context of management of PAH and PM emission to the surrounding aquatic environment. Although we only fully assessed PAHs in this work, further study should consider other contaminants such as OPAHs, which were also detected in all PM samples.

Active biomonitoring with Corbicula for USEPA priority pollutant and metal sources in the Anacostia River (DC, Maryland, USA)

The freshwater Anacostia River watershed (Maryland, DC, USA) was surveyed for the sources of bioavailable US Environmental Protection Agency (USEPA) Priority Pollutants and toxic metals by active biomontoring (ABM) using the freshwater Asiatic clam Corbicula fluminea. The Anacostia River is a 456 km(2) tributary of the tidal freshwater Potomac River that includes the city of Washington, DC where edible fish are highly contaminated with PCBs and chlordane. From 1999 to 2011, Corbicula were collected for ABM from a Potomac reference site and translocated in cages placed at 45 sites in the tidal and nontidal Anacostia watershed. Minimum clam mortality and maximum contaminant bioaccumulation was with 2-week translocation. The clam tissues (28-50) were combined at sites and analyzed by TestAmerica for 66 USEPA Priority Pollutants plus technical chlordane, benz(e) pyrene, and 6 metals (As, Cd, Cr, Cu, Fe, Pb). Tissue contaminants reflected water, not sediment, levels. To compare sites, all contaminant data above detection or reference were grouped as total metals (TMET), total polycyclic aromatic hydrocarbons (TPAH), total PCB congeners (TPCB), total pesticides (TPEST), and total technical chlordane (TCHL). Tidal Anacostia ABM found highest TPAH and TCHL upstream at Bladensburg Marina (MD) except for TCHL at site PP near the confluence. Five nontidal MD subtributaries (94% of flow) had 17 sites with bioavailable TPAH, TPCB, or TCHL 2 to 3 times higher than found at the toxic-sediment "hotspots" near Washington. The only TMET noted was Fe at 1 site. TPAH in MD subtributaries was highest near industrial parks and Metro stations. A naphthalene spill was detected in Watts Branch. TPCB (low molecular weight) originated upstream at 1 industrial park. Total technical chlordane (80% of TPEST) was 2 to 5 times the US Food and Drug Administration action in 4 nontidal tributaries where heptachlor indicated legacy chlordane dumpsites. Total technical chlordane fell to reference below a stormwater pond, suggesting transport via suspended sediment. Controlling the formation and movement of contaminated TSS in MD should enable the uncontaminated-sediment capping of Washington DC's toxic-sediment "hot-spots" that are presently considered responsible for fish contamination. Integr Environ Assess Manag 2016;12:548-558. © 2015 SETAC.

Spatial and Temporal Examination of Bivalve Communities in Several Estuaries of Southern California and Northern Baja California, MX

A combination of historical bivalve surveys spanning 30–50 years and contemporary sampling were used to document the changes in bivalve community structure over time at four southern California and one northern Baja California estuaries. While there are limitations to the interpretation of historic data, we observed generally similar trends of reduced total bivalve species richness, losses of relatively large and/or deeper-dwelling natives, and gains of relatively small, surface dwelling introduced species across the southern California estuaries, despite fairly distinct bivalve communities. A nearly 50-year absence of bivalves from two wetlands surveyed in a Baja California estuary continued. A combination of site history and current characteristics (e.g., location, depth) likely contributes to maintenance of distinct communities, and both episodic and gradual environmental changes likely contribute to within-estuary temporal shifts (or absences). We highlight future research needed to determine mechanisms underlying patterns so that we can better predict responses of bivalve communities to future scenarios, including climate change and restoration.

Determination of oxygen, nitrogen, and sulfur-containing polycyclic aromatic hydrocarbons (PAHs) in urban stream sediments

Recent studies indicate that PAH transformation products such as ketone or quinone-substituted PAHs (OPAHs) are potent aryl hydrocarbon receptor (AhR) activators that elicit toxicological effects independent of those observed for PAHs. Here, we measured eight OPAHs, two sulfur-containing (SPAH), one oxygen-containing (DBF), and one nitrogen-containing (CARB) heterocyclic PAHs (i.e. ΣONS-PAHs = OPAH8 + SPAH + DBF + CARB) in 35 stream sediments collected from a small (∼1303 km(2)) urban watershed located in south-central Pennsylvania, USA. Combined ΣONS-PAH concentrations ranged from 59 to 1897 μg kg(-1) (mean = 568 μg kg(-1); median = 425 μg kg(-1)) and were 2.4 times higher in urban versus rural areas, suggesting that activities taking place on urban land serve as a source of ΣONS-PAHs to sediments. To evaluate urban land use metrics that might explain these data, Spearman rank correlation analyses was used to evaluate the degree of association between ΣONS-PAH concentrations and urban land-use/land-cover metrics along an urban-rural transect at two spatial scales (500-m and 1000-m upstream). Combined ΣONS-PAH concentrations showed highly significant (p < 0.0001) correlations with ΣPAH19, residential and commercial/industrial land use (RESCI), and combined state and local road miles (MILES), suggesting that ΣONS-PAHs originate from similar sources as PAHs. To evaluate OPAH sources, a subset of ΣONS-PAHs for which reference assemblages exist, an average OPAH fractional assemblage for urban sediments was derived using agglomerative hierarchal cluster (AHC) analysis, and compared to published OPAH source profiles. Urban sediments from the Condoguinet Creek (n = 21) showed highly significant correlations with urban particulate matter (X(2) = 0.05, r = 0.91, p = 0.0047), suggesting that urban particulate matter is an important OPAH source to sediments in this watershed. Results suggest the inclusion of ΣONS-PAH measurements adds value to traditional PAH analyses, and may help elucidate and refine pollutant source identification in urban watersheds.

Anthropogenic waste indicators (AWIs), particularly PAHs and LABs, in Malaysian sediments: Application of aquatic environment for identifying anthropogenic pollution

Polycyclic aromatic hydrocarbons (PAHs) and linear alkylbenzenes (LABs) were used as anthropogenic markers of organic chemical pollution of sediments in the Selangor River, Peninsular Malaysia. This study was conducted on sediment samples from the beginning of the estuary to the upstream river during dry and rainy seasons. The concentrations of ƩPAHs and ƩLABs ranged from 203 to 964 and from 23 to 113 ng g(-1) dry weight (dw), respectively. In particular, the Selangor River was found to have higher sedimentary levels of PAHs and LABs during the wet season than in the dry season, which was primarily associated with the intensity of domestic wastewater discharge and high amounts of urban runoff washing the pollutants from the surrounding area. The concentrations of the toxic contaminants were determined according to the Sediment Quality Guidelines (SQGs). The PAH levels in the Selangor River did not exceed the SQGs, for example, the effects range low (ERL) value, indicating that they cannot exert adverse biological effects.

Studies on polycyclic aromatic hydrocarbons in surface sediments of Mithi River near Mumbai, India: Assessment of sources, toxicity risk and biological impact

This study investigated the levels, sources and potential risks of 17 polycyclic aromatic hydrocarbons in surface sediment samples collected along the Mithi River of Mumbai. The concentration level of ΣPAHs found in the present study was in the range of 1206-4735 ng/g dw. The composition patterns of PAHs by ring size in sediment were surveyed which indicate the dominance of four rings followed by five and three ring PAHs. In the study it was observed that the high molecular weight PAHs (HMW PAHs) made greater contributions of 90.83% as compared to that of low molecular PAHs (LMW PAHs) contributing to 9.17% to the total PAH concentrations. Toxicity and biological risk were assessed using toxic equivalent quantity and sediment quality guideline quotient. It is feared that the pollution level of PAHs in the sediments might increase in coming times resulting in an unconspicuous risks for the environment and humans through food chains.

Organic pollution in surficial sediments of Tripoli harbour, Lebanon

Tripoli harbour is among the most important ports on the Mediterranean Sea eastern basin. The persistent organic pollutants (POPs) were monitored (28 PCBs, 16 PAHs and 18 Me-PAHs) in 15 stations of Tripoli harbour basins, which are influenced by anthropogenic activities. Total PAHs concentrations ranged from 243 to 2965 μg kg(-1)dw, total Me-PAH concentrations ranged from 54 to 1638 μg kg(-1)dw, while total PCB levels ranged from 18 to 302 μg kg(-1)dw. PCBs profiles were dominated by four and six-chlorinated congeners while the PAHs were dominated by four and five rings. For identifying pollution emission sources of PAHs, different ratios were used. The results show that the pollution origin was predominated by pyrogenic process related to the deposition of coal dust and the combustion of biomass and coal. Based on Sediments Quality Guidelines the biological adverse effects on aquatic ecosystems were expected rarely to occasionally for PAHs and PCBs contamination.

Severe intersex is predictive of poor fertilization success in populations of rainbow darter (Etheostoma caeruleum)

Municipal wastewater effluent (MWWE) contains emerging contaminants such as pharmaceuticals and personal care products (PPCPs) that have estrogenic properties. PPCPs are thought to be responsible for feminization of male fish in heavily urbanized areas around the globe. While many observations of feminized male fish have been made, the impact of feminization on reproductive success is not well understood. To address this lack of knowledge of the impacts of feminization, we examined the reproductive fitness of rainbow darter (Etheostoma caeruleum), a fish that is also known to have been feminized in some reaches of the Grand River, Kitchener-Waterloo, Ontario, Canada. In order to assess their reproductive health, somatic indices, gonadal steroid production, fecundity, and histological severity of intersex were measured in male rainbow darter collected through an urban gradient. Reproductive fitness was assessed by stripping milt and eggs from wild spawning fish, fertilizing eggs manually, and rearing embryos to hatch. The fertilization success and survival of embryos to hatch were compared among sites. In this study, it was found that rainbow darter collected at sites near a large municipal wastewater treatment plant (MWWTP) had decreased gonad size, increased severity of intersex, and decreased androgen production relative to other sites. Fish collected near the largest MWWTP also had lower fertilization success and survival to hatch. In contrast, fish collected near a second MWWTP farther upstream had comparable fertilization success, but lower survival to hatch relative to the upstream rural reference site. Intersex severity was negatively correlated with fertilization success, but not survival to hatch, suggesting that intersex is a good indicator of a population's fertilization success. Further investigation is required in order to determine if feminization will impact the sustainability of wild populations of fish.

Street dust: implications for stormwater and air quality, and environmental through street sweeping

Street dust represents a source of dual potential risk to stormwater and air quality. It has been well documented that street dust washes into local watersheds and can degrade water quality. Research has also demonstrated that ambient particulate matter (PM10) , which is associated with adverse health outcomes, can arise from resuspension of accumulated street dust. Furthermore, many contaminants, including metals, are present at higher concentrations in the smallest available particles, which are more likely to be resuspended in air and stormwater runoff. Although street cleaning is listed as a best management practice for storm water quality by the EPA, data are limited on the critical parameters (technology, environment, usage), which determine the effectiveness of any street cleaning program, particularly in the peer-reviewed literature. The purpose of the present study was to develop a comprehensive understanding of the efficacy of various street cleaning technologies and practices to protect both water quality and public health. Few studies have compared the effectiveness of street sweeping technologies to remove street dust. Unfortunately, the dearth of comprehensive data on exposure, contaminant concentrations, and efficacy of various sweeping technologies and strategies precludes developing quantitative estimates for potential risk to humans and the environment. Based on the few studies available, regenerative air street sweepers appear to provide the most benefit with regard to collection of small particles and prevention of re-entrainment. It is also clear from the available data that local conditions, climate, and specific needs are critical determinants of the ideal street sweeping strategy (technology, frequency, speed, targeted areas, etc.). Given the critical need for protection of water and air quality in rapidly expanding urban regions (e.g., megacities), further research is necessary to develop best practices for street dust management. Herein, we provide a framework for future experimental studies to support risk-based assessments of street cleaning technologies.

A combined chemical and biological approach to transforming and mineralizing PAHs in runoff water

The water quality of lakes, rivers and streams associated with metropolitan areas is declining from increased inputs of urban runoff that contain polycyclic aromatic hydrocarbons (PAHs). Our objective was to transform and mineralize PAHs in runoff using a combined chemical and biological approach. Using (14)C-labeled phenanthrene, (14)C-benzo(a)pyrene and a mixture of 16 PAHs, we found that ozone transformed all PAHs in a H2O matrix within minutes but complete mineralization to CO2 took several weeks. When urban runoff water (7.6 mg CL(-1)) replaced H2O as the background matrix, some delays in degradation rates were observed but transforming a mixture of PAHs was still complete within 10 min. Comparing the biodegradability of the ozonated products to the parent structures in unsaturated soil microcosms showed that the 3-ring phenanthrene was more biodegradable (as evidence by (14)CO2 released) than its ozonated products but for the 5-ring benzo(a)pyrene, the products produced by ozone were much more biodegradable (22% vs. 3% mineralized). For phenanthrene, we identified diphenaldehyde as the initial degradation product produced from ozonation. By continuing to pump the ozonated products ((14)C-labeled diphenaldehyde or ozone-treated benzo(a)pyrene) onto glass beads coated with microorganisms, we verified that biological mineralization could be achieved in a flow-through system and mineralization rates improved with acclimation of the microbial population (i.e., time and exposure to the substrate). These results support a combined ozone and biological approach to treating PAHs in urban runoff water.

Coal-tar-based sealcoated pavement: a major PAH source to urban stream sediments

We used land-use analysis, PAH concentrations and assemblages, and multivariate statistics to identify sediment PAH sources in a small (~1303 km(2)) urbanizing watershed located in South-Central, Pennsylvania, USA. A geographic information system (GIS) was employed to quantify land-use features that may serve as PAH sources. Urban PAH concentrations were three times higher than rural levels, and were significantly and highly correlated with combined residential/commercial/industrial land use. Principal components analysis (PCA) was used to group sediments with similar PAH assemblages, and correlation analysis compared PAH sediment assemblages to common PAH sources. The strongest correlations were observed between rural sediments (n = 7) and coke-oven emissions sources (r = 0.69-0.78, n = 5), and between urban sediments (n = 22) and coal-tar-based sealcoat dust (r = 0.94, n = 47) suggesting that coal-tar-based sealcoat is an important urban PAH source in this watershed linked to residential and commercial/industrial land use.

Polycyclic aromatic hydrocarbons (PAHs) in soils from a multi-industrial city, South Korea

We collected soil samples at 25 sites in Ulsan, Korea to investigate the levels, patterns, spatial distribution, and sources of polycyclic aromatic hydrocarbons (PAHs) in the summer 2010. The target compounds were the 16 US-EPA priority PAHs. For the source identification of PAHs, diagnostic ratios and the positive matrix factorization (PMF) model were used. The total concentrations of PAHs ranged from 65 ng/g to 12,000 ng/g (mean: 960 ng/g, median 330 ng/g). The levels and distribution of PAHs indicated that industrial areas were more polluted than rural and urban areas. The diagnostic ratios suggested that the soil samples were contaminated by pyrogenic sources and traffic emission. According to the result of PMF, four factors were identified: gasoline and heavy oil combustion (14%), diesel combustion (54%), coke oven (23%), and coal/biomass burning (9%). Therefore, it was concluded that vehicles and industrial complexes were major sources of PAHs in Ulsan.

Coastal urbanization leads to remarkable seaweed species loss and community shifts along the SW Atlantic

Coastal urbanization is rapidly expanding worldwide while its impacts on seaweed communities remain poorly understood. We assessed the impact of urbanization along an extensive latitudinal gradient encompassing three phycogeographical regions in the SW Atlantic. Human population density, number of dwellings, and terrestrial vegetation cover were determined for each survey area and correlated with diversity indices calculated from seaweed percent cover data. Urban areas had significantly lower calcareous algal cover (-38%), and there was significantly less carbonate in the sediment off urban areas than off reference areas. Seaweed richness averaged 26% less in urban areas than in areas with higher vegetation cover. We observed a remarkable decline in Phaeophyceae and a substantial increase of Chlorophyta in urban areas across a wide latitudinal gradient. Our data show that coastal urbanization is causing substantial loss of seaweed biodiversity in the SW Atlantic, and is considerably changing seaweed assemblages.