PAH related effects on fish in sedimentation ponds for road runoff and potential transfer of PAHs from sediment to biota

Distribution of helminth eggs in environmental and stool samples of farming households along Akaki River in Addis Ababa, Ethiopia

BACKGROUND

Helminth infections are a public health issue in countries with poor sanitation facilities. However, there little information on the epidemiological association between helminths in wastewater and soil samples and rates of helminth infection among farming households along the Akaki River in Addis Ababa, Ethiopia.

METHODS

A cross-sectional study was conducted between November 2021 and February 2022. A stratified random sampling technique was used to select farming households. The sample size for each district was determined by a proportionate allocation to the number of households. From wastewater-irrigated farms, 70 wastewater samples, 28 soil samples, and 86 farmers' stool samples were collected and analyzed for helminths. A questionnaire was used to gather ethnographic data, about farming households, whereas wastewater and soil sample analysis was used to generate quantitative data on helminth loads. The data were systematically analysed by developing themes, and bias evaluated using triangulation validation methodologies. Potential pathways to helminth infection were evaluated by measuring. Total number of helminth eggs in wastewater, soil samples and farmer's stools was investigated using Poisson regression.

RESULTS

In this study, 82.9% of wastewater samples, 57.1% of soil samples, and 18.6% of farmers' stool samples contained helminth eggs. The most prevalent helminth was Ascaris lumbricoides in all samples (wastewater 67%, soil 25%, and stool 10.5%), followed by hookworm (wastewater 10%, soil 21.4%, and stool 6.9%) and Trichuris trichiura eggs (wastewater 5.7%, soil 10.7%, and stool 1.2%). There was a positive association between the total number of helminth eggs in wastewater and soil samples with counts in farmers' stool. The Poisson regression coefficients for wastewater and soil were, 1.63 (95% CI = 1.34-1.92) and 1.70 (95% CI = 1.39-2.01), (p < 0.05).

CONCLUSIONS

This research has shown a clear association between the total helminth eggs in wastewater and soil samples and farmer stools along the Akaki River. Therefore, an integrated approach is essential to address the issue in this area and prevent the spread of further helminth infections.

Genotoxic effects of polycyclic aromatic hydrocarbons (PAHs) present in vehicle-wash wastewater on grass carp (Ctenopharyngodon idella) and freshwater mussels (Anodonta cygnea)

Vehicle-wash wastewater (VWW) contains high levels of various petrochemicals such as polycyclic aromatic hydrocarbons (PAHs), a carcinogenic category of organic substances. However, the genotoxic effects of PAHs present in VWW remain largely unknown. We explored the genotoxic effects of PAHs present in VWW on fish grass carp (Ctenopharyngodon idella) and freshwater mussels (Anodonta cygnea). Fish and freshwater mussels were divided into control and exposed groups, the prior groups were treated at weekly intervals with clean water, and the latter with Σ16PAHs contaminated VWW for up to four weeks. The samples of blood from fish and haemolymph from freshwater mussels were collected and analyzed using the comet assay technique. Results exhibited that in control fish and freshwater mussel groups the genotoxicity decreased with every week passing following the order of W1 > W2 > W3 > W4, ranging from 8.33 ± 3.06 to 25.3 ± 4.62 and from 46.0 ± 6.93 to 7.67 ± 3.79, respectively. The exposed fish and freshwater mussel groups indicated an increase in genotoxicity with increasing week intervals with an order of W4 > W3 > W2 > W1, ranging from 55.7 ± 11.9 to 128.3 ± 10.0 and from 112.7 ± 8.50 to 183.3 ± 10.1, respectively. The genotoxic effect of Σ16PAHs on fish was comparatively lower than on freshwater mussels. This study elucidates that VWW is highly genotoxic and should be treated before discharging into aquatic ecosystems.

Responses of Wild Finescale Dace (Phoxinus neogaeus) to Experimental Spills of Cold Lake Blend Diluted Bitumen at the International Institute for Sustainable Development-Experimental Lakes Area, Northwestern Ontario

Pipelines carrying diluted bitumen (dilbit) traverse North America and may result in dilbit release into sensitive freshwater ecosystems. To better understand the potential effects of a freshwater oil release, the Boreal-lake Oil Release Experiment by Additions to Limnocorrals project at the International Institute for Sustainable Development-Experimental Lakes Area (Ontario, Canada) modeled seven dilbit spills contained within a 10-m diameter of littoral limnocorrals in a boreal lake. Wild finescale dace (Phoxinus neogaeus) were released in the limnocorrals 21 days after oil addition and remained there for 70 days. Dilbit volumes covered a large range representing a regression of real spill sizes and total polycyclic aromatic compounds (TPAC) between 167 ng L^-1  day^-1 and 1989 ng L^-1  day^-1 . We report the effects of chronic exposure on reproductive potential as well as physiological responses in the gallbladder and liver. In exposures >1000 ng L^-1  day^-1 , there was a significant decrease in fish retrieval, culminating in zero recapture from the three highest treatments. Among the fish from the limnocorrals with lower levels of TPAC (<500 ng L^-1  day^-1 ), effects were inconsistent. Gallbladder bile fluorescence for a naphthalene metabolite was significantly different in fish from the oil-exposed limnocorrals when compared to the lake and reference corral, indicating that fish in these lower exposures were interacting with dilbit-derived polycyclic aromatic compounds. There were no significant differences in condition factor, somatic indices, or hepatocyte volume indices. There were also no significant changes in the development of testes or ovaries of exposed dace. The results from the present study may serve to orient policymakers and emergency responders to the range of TPAC exposures that may not significantly affect wild fish. Environ Toxicol Chem 2022;41:2745-2757. © 2022 SETAC.

Polycyclic aromatic hydrocarbons (PAHs) in gas, PM2.5, and frost samples in a severely polluted rural site of the North China Plain: Distribution, source, and risk assessment

The process of frost formation has been studied as an important deposition pathway for removing atmospheric pollutants. However, the removal of organic species during frost formation remains unknown. Gas, PM_2.5 and frost samples were collected in Wangdu, a severely polluted rural site in the North China Plain, during the winter of 2018. The concentrations, distributions, sources, and ecological and health risks of the 16 PAHs in the samples were determined. The 24 h-averaged concentrations of PAHs in the air (gas + PM_2.5) reached 719 ng m^-3, indicating that the local atmosphere was heavily contaminated by PAHs in winter. The average concentrations of PAHs in the frost insoluble reached 27.5 μg g^-1, indicating the strong ambient PAHs deposition during the frost process. The distribution patterns of individual PAH species indicated that the PAHs in the gas influenced the frost samples, and the sources of PAHs in frost samples were highly similar to those in PM_2.5 samples. The calculated lifetime lung cancer risk (LLCR) via inhalation of ambient PAHs was classified as high risks. The average total Benzo(a)pyrene toxic equivalent quotient (TEQ) of PAHs in the frost samples was estimated as 2.50 μg TEQ g^-1, posing a high threat to the ecological environment and health. After the melting of frost, the PAHs are released into the soil. Although the concentrations are diluted, the PAH concentrations could adversely affect the growing vegetation or agricultural activities. The extremely high PAH concentrations and their ecological and health risks require special attention and strict regulation.

Extensive rain events have a more substantial impact than advanced effluent treatment on the endocrine-disrupting activity in an effluent-dominated small river

Wastewater treatment plants (WWTPs) remain an important primary source of emission for endocrine-disrupting compounds in the environment. As an advanced wastewater treatment process, ozonation is known to reduce endocrine-disrupting activity. However, it remains unclear to which extend improved wastewater treatment may reduce the endocrine-disrupting activity in the receiving water body. The present study investigated possible factors for the endocrine-disrupting activity in a small receiving water body, the Wurm River (North-Rhine Westphalia, Germany), up- and downstream of a local WWTP. The cell-based reporter gene CALUX® assay was applied to identify the endocrine-disrupting activity in the water, sediment, and suspended particulate matter. The water phase and the effluent sampling were primarily driven by applying the full-scale effluent ozonation (sampling campaigns in June 2017 and March 2019). In contrast, the sediment sampling aimed to compare the particle-bound endocrine-disrupting activity during dry (June 2017) and rainy summer (June 2018) seasons. The water phase showed low to moderate estrogenic/antiandrogenic activity. Advanced effluent treatment by ozonation led to a complete reduction of the endocrine-disrupting activity according to the limit of detection of the CALUX® assays. The suspended particulate matter originated from the water phase of the second sampling campaign revealed antiandrogenic activity only. Sediments at the sampling sites along the local WWTP revealed higher estrogenic and antiandrogenic activity after extensive rain events and were not affected by the ozonated effluent. Fluctuation patterns of the endocrine-disrupting activity in sediments were in line with fluctuated concentrations of polycyclic aromatic hydrocarbons. Rainwater overflow basin release was suggested as a vector for particle-bound and dissolved endocrine-disrupting activity in the receiving water body. The present study underlined the necessity for monitoring both water and sediment phases to achieve reliable profiling of the endocrine-disrupting activity. The receptor-mediated CALUX® assays were proven to be suitable for investigating the endocrine-disrupting activity distribution in different river compartments and WWTP effluents.

Distribution, sources, and ecological risk assessment of polycyclic aromatic hydrocarbons in the sediments of Daihai Lake in Inner Mongolia, China

Polycyclic aromatic hydrocarbons (PAHs) are typical toxic organic pollutants that can accumulate in sediments and may be toxic to aquatic organisms. In the present study, the contamination level, composition pattern, and sources of sixteen PAHs listed by the United States Environmental Protection Agency were investigated in surface sediments and a sediment core from Daihai Lake, which is located in a typical semiarid area of Inner Mongolia, China, and the ecological risk of these PAHs was assessed. The results show that the total concentration of PAHs in the surface sediments ranged from 204.6 to 344.5 ng/g with an average value of 287.2 ng/g and that compared with other aquatic systems, the level of PAHs in the sediments from Daihai Lake was low. However, a general upward trend was observed for the concentrations of PAHs in the sediment core, which might be related to the increase in human activities in the area. Moreover, the PAH concentrations were significantly positively correlated with the total organic carbon (TOC) content in the sediments, and it is thus inferred that TOC regulates the distribution of PAHs in Daihai Lake. Three-ring and four-ring PAHs were found to be predominant in all the sediment samples, and phenanthrene (Phe) was the most abundant compound. According to the composition of PAHs and the anthracene (Ant)/(Ant+Phe) or fluoranthene (Flt)/(Flt+pyrene (Pyr)) ratios, the PAHs in Daihai Lake mainly originated from the combustion of domestic coal, grass, and wood, and petroleum cannot be ignored as a source considering the growth of industry. Risk assessment based on a comparison of PAH concentrations and the effect range low (ERL) and effect range median (ERM) values demonstrated that acenaphthene (Ace) at 11 sites and fluorene (Flu) at 7 sites had occasional adverse biological effects.

Levels, distributions, and seasonal variations of polycyclic aromatic hydrocarbons (PAHs) in ambient air and pine components

Pine tree (Pinus pinea) components have been used as passive air samples for determining atmospheric polycyclic aromatic hydrocarbon (PAH) concentrations. Our results indicated that pine needles and branches were found to be statistically successful in describing the ambient air. Monthly pine needles, branches (1- and 2-year-old) and ambient air samples were collected for 1 year to identify molecular distributions and temporal concentrations of PAHs in a suburban-industrial area. Annual average Σ₁₄PAH concentrations for pine needles, 1- and 2-year-old branches, and ambient air were 756 ± 232 ng/g DW, 685 ± 350 ng/g DW, 587 ± 361 ng/g DW, and 28.29 ± 32.33 ng/m³, respectively. The order of average Σ₁₄PAH concentrations in the pine tree components was determined as needle > 1-year-old branch > 2-year-old branch. In general, concentrations increased with the rise in the surface area of tree components. In the samples, 3- and 4-ring PAHs were dominant compounds in the ambient air, pine needles, and branches. The annual total fraction of 3- and 4-ring PAHs in the air was 98.5%, while the fraction of 5- and 6-ring PAHs was 1.5%. On the other hand, 3- and 4-ring PAHs in pine needles and branches were 30% or more. The fraction and level of PAHs change with the season. Although needle samples did not show any seasonal trend, PAH levels in other tree components changed with the air temperature. Generally, lower values were observed in warmer seasons in the branch samples. Similarly, ambient air PAH concentrations were higher in the winter season due to heating and adverse meteorological conditions.

Occurrence and trophic transport of organic compounds in sedimentation ponds for road runoff

Sedimentation ponds have been shown to accumulate several groups of contaminants, most importantly polycyclic aromatic compounds (PACs) and metals. But also, other urban organic pollutants have shown to be present, including polybrominated diphenyl ethers (PBDEs), organophosphate compounds (OPCs) and benzothiazoles (BTs). This investigation aimed at determining the occurrence of these four groups of contaminants in sedimentation ponds and determine their transport from water/sediment to organisms. PACs, including alkylated PACs, PBDEs; OPCs and BTs were determined in water, sediment, plants, dragonfly larvae and fish from two sedimentation ponds and one reference site. Fish were analysed for PAC metabolites. Overall, higher concentrations of all four pollutant groups were detected in water and sediment from sedimentation ponds compared to two natural lakes in rural environments (reference sites). The concentration difference was highest in sediments, and >20 higher concentration was measured in sedimentation ponds (3.6-4.4 ng/g ww) compared to reference (0.2 ng/g ww) for sum BDE6. For PACs and PBDEs a clear transport from water/sediment to organisms were observed. Fish were the highest trophic level organism (3.5-5) in our study, and all four pollutant groups were detected in fish. For PBDEs a trophic biomagnification (TMF) was found both in sedimentation ponds and reference, but higher concentrations in all matrices were measured in sedimentation ponds. TMF was not calculated for PACs since they are metabolised by vertebrates, but a transfer from water/sediment to organisms was seen. For BTs and OPCs, no consistent transfer to plants and dragonfly larvae could be seen. One OPC and two BTs were detected in fish, but only in fish from sedimentation ponds. It is therefore concluded that sedimentation ponds are hotspots for urban and traffic related contaminants, of which especially PACs and PBDEs are transferred to organisms living there.

A comparative study of macroinvertebrate biodiversity in highway stormwater ponds and natural ponds

The use of stormwater ponds along the highways is shown to be an effective alternative to conventional systems, which are usually sewers. These ponds have the potential to combine their primary function of pollution and peak flow control with the promotion of biodiversity. The present study focuses on comparing natural and highway stormwater ponds in terms of environmental conditions and biodiversity of macroinvertebrate communities. Twelve highway stormwater ponds and nineteen natural ponds (located within or in the vicinity of cultivated landscape) were explored for the number of taxa, community composition, and selected environmental variables: pH, conductivity, pond surface area, the number of ponds within 1 km radius, and the distance to nearest neighboring pond. Highway stormwater ponds showed much higher conductivity, which is a good proxy for chloride concentration and highway pollutants. In addition, the surface area of stormwater ponds was almost twice as big as that of natural ponds. The biological community composition was very different between the two types of ponds, and the number of taxa was slightly higher in the highway stormwater ponds. The most important variables responsible for the variation in the biological community composition were conductivity, pond surface area, and the number of ponds within 1 km radius. This study supports that, in addition to their role in pollution and peak flow control, stormwater ponds have the potential to provide a habitat that may otherwise be unavailable along the highway.

Polycyclic aromatic hydrocarbons: bioaccumulation in dragonfly nymphs (Anisoptera), and determination of alkylated forms in sediment for an improved environmental assessment

Road runoff carries a mixture of contaminants that threatens the quality of natural water bodies and the health of aquatic organisms. The use of sedimentation ponds is a nature-based solution for the treatment of road runoff. This study assessed the concentration of polycyclic aromatic hydrocarbons (PAHs) and their alkylated homologues in sediment from seven highway sedimentation ponds and three natural urban ponds. In addition, the study explored the bioaccumulation of PAHs in dragonfly nymphs (Anisoptera). Finally, biota-sediment accumulation factors (BSAFs) were estimated. The results revealed a significant difference in the concentrations of 16 priority PAHs in sediment, with overall higher levels in sedimentation ponds (2,911 µg/kg on average) compared to natural urban ponds (606 µg/kg on average). PAH levels increased substantially once alkylated homologues were considered, with alkylated comprising between 42 and 87% of the total PAH in sediment samples. These results demonstrate the importance of alkylated forms in the environmental assessment of PAHs. The bioaccumulation assessment indicates that dragonfly nymphs bioaccumulate PAHs to a certain degree. It is not clear, however, whether they metabolize PAHs. BSAF results ranged from approx. 0.006 to 10 and indicate that BSAFs can be a powerful tool to determine the functionality of sedimentation ponds.

Bisphenol A (BPA) and polycyclic aromatic hydrocarbons (PAHs) in the surface sediment and bivalves from Hormozgan Province coastline in the Northern Persian Gulf: A focus on source apportionment

This study investigates Polycyclic Aromatic Hydrocarbons (PAHs) and Bisphenol-A (BPA) pollution in coastal sediments and bivalves of Hormozgan Province coastline. The results indicated that the BPA concentration in some bivalves reached up to 340.16 ng g^-1. The mean BPA concentration in the sediment samples was also 787.01 ng g^-1. The ∑PAHs content in sediments ranged from 14.54 to 85.00 ng g^-1, while values for bivalves ranged from 5.37 to 16.40 ng g^-1. Individual PAH concentrations in sediments exceeded those in bivalves for which only LMW PAHs were detected. A combination of techniques including Self-Organizing Maps (SOM), Positive Matrix Factorization (PMF), and Cluster Analysis (CA) were applied and both petrogenic and pyrogenic sources were identified. The risk of PAHs in the sediments was relatively low according to the sediment quality guidelines. The health risk indices suggest that exposure to PAHs through bivalve consumption does not impose harmful health effects upon consumers.

Toxicities of Polycyclic Aromatic Hydrocarbons for Aquatic Animals

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds that are widely distributed in the air, water, and soil. Recently, the amount of PAHs derived from fuels and from incomplete combustion processes is increasing. In the aquatic environment, oil spills directly cause PAH pollution and affect marine organisms. Oil spills correlate very well with the major shipping routes. Furthermore, accidental oil spills can seriously impact the marine environment toxicologically. Here, we describe PAH toxicities and related bioaccumulation properties in aquatic animals, including invertebrates. Recent studies have revealed the toxicity of PAHs, including endocrine disruption and tissue-specific toxicity, although researchers have mainly focused on the carcinogenic toxicity of PAHs. We summarize the toxicity of PAHs regarding these aspects. Additionally, the bioaccumulation properties of PAHs for organisms, including invertebrates, are important factors when considering PAH toxicity. In this review, we describe the bioaccumulation properties of PAHs in aquatic animals. Recently, microplastics have been the most concerning environmental problem in the aquatic ecosystem, and the vector effect of microplastics for lipophilic compounds is an emerging environmental issue. Here, we describe the correlation between PAHs and microplastics. Thus, we concluded that PAHs have a toxicity for aquatic animals, indicating that we should emphasize the prevention of aquatic PAH pollution.

Road related pollutants induced DNA damage in dragonfly nymphs (Odonata, Anisoptera) living in highway sedimentation ponds

Nowadays, stormwater sedimentation ponds are popular in stormwater management because of their ability to mitigate flooding and treat polluted runoff from e.g. roads. In addition, they may provide other ecosystem services such as biodiversity. These man-made habitats will inevitably be polluted and the organisms living therein may be negatively affected by the chemical cocktail present in both the water and sediment compartments. The present study explored DNA damage in dragonfly nymphs (Odonata, Anisoptera) living in highway sedimentation ponds in comparison with natural ponds. The concentrations of Polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs and metals were also determined in sediment samples from the different ponds. The results showed that DNA damage was significantly higher in dragonfly nymphs living in sedimentation ponds compared to nymphs living in natural ponds. DNA damage was also highly and significantly correlated with the pollution levels in the sediment, i.e., PAH and Zinc. Finally, we report the concentrations of various alkylated PAHs which appeared to be very dominant in the sedimentation ponds. Our results show that there may be a conflict between the sedimentation ponds’ primary function of protecting natural water bodies from polluted runoff and their secondary function as habitats for organisms. Overall, we suggest that this must be considered when planning and designing stormwater measures.

Impact of environmental factors on aquatic biodiversity in roadside stormwater ponds

Constructed stormwater ponds mitigate runoff volumes and pollution, and provide other ecosystem services, such as supporting biodiversity, but these services attracted relatively less attention. The impacts of the pollution levels in the water column and sediments, the physical characteristics of ponds, and the presence of amphibians on the macroinvertebrate community composition and biodiversity were explored in twelve stormwater ponds in Norway. Also, the similarities between macroinvertebrate, zooplankton and plant communities were explored. Most of the taxa displayed in the ordination diagram were positively correlated with the pond size and the number of neighbouring ponds, and negatively correlated with the pollution levels in the water column and sediments. However, no statistically significant impacts on the number of taxa and Shannon index were observed. There were low similarities between the macroinvertebrate and zooplankton community compositions as well as between the plant and macroinvertebrate community compositions in the stormwater ponds. We observed a significant positive correlation between the number of plant and of zooplankton taxa, and a weak non-significant positive correlation between the number of plant and of macroinvertebrate taxa. Overall, the explanatory variables had a significant impact on the community composition, but not on the number of taxa nor Shannon index.

Erythrocyte Nuclear Abnormalities in Astyanax lacustris in Response to Landscape Characteristics in Two Neotropical Streams

The objective of this research was to evaluate land use and occupation in the landscape surrounding two neotropical streams of the Upper Paraná River in Brazil and to investigate if the water from these streams induces erythrocyte nuclear abnormalities in Astyanax lacustris. We observed that the areas surrounding the streams are predominantly used for agricultural purposes (73.46% of the total area), followed by buildings (15.21%). Only 8.78% of the area consisted of forest fragments. We observed higher frequencies of micronuclei in erythrocytes of A. lacustris exposed to water from impacted sites (IMP) compared with less impacted sites and the negative control (NC) (p < 0.05). Analysis of nuclear alterations in A. lacrustis erythrocytes showed significant differences in the frequency of notched nuclei and nuclear pyknosis only between the NC and the IMP sites (p < 0.05). Our results indicate that water from the most impacted sites of the microbasin can induce mutagenic and genotoxic effects in A. lacustris.

Occurrence and Risk Assessment of PAHs in Surface Sediments from Western Arctic and Subarctic Oceans

In the fourth Chinese National Arctic Research Expedition (from July to September, 2010), 14 surface sediment samples were collected from the Bering Sea, Chukchi Sea, and Canadian Basin to examine the spatial distributions, potential sources, as well as ecological and health risk assessment of polycyclic aromatic hydrocarbons (PAHs). The ∑PAH (refers to the sum of 16 priority PAHs) concentration range from 27.66 ng/g to 167.48 ng/g (dry weight, d.w.). Additionally, the concentrations of ∑PAH were highest in the margin edges of the Canadian Basin, which may originate from coal combustion with an accumulation of Canadian point sources and river runoff due to the surface ocean currents. The lowest levels occurred in the northern of Canadian Basin, and the levels of ∑PAH in the Chukchi Sea were slightly higher than those in the Being Sea. Three isomer ratios of PAHs (Phenanthrene/Anthracene, BaA/(BaA+Chy), and LMW/HMW) were used to investigate the potential sources of PAHs, which showed the main source of combustion combined with weaker petroleum contribution. Compared with four sediment quality guidelines, the concentrations of PAH are much lower, indicating a low potential ecological risk. All TEQ_PAH also showed a low risk to human health. Our study revealed the important role of the ocean current on the redistribution of PAHs in the Arctic.

Characteristics of PAHs in street dust of Beijing and the annual wash-off load using an improved load calculation method

A significant amount of polycyclic aromatic hydrocarbons (PAHs) adsorbed in street dust ends up in runoff. Accordingly, evaluating the content, possible wash-off load and constituent risks associated with street dust is critical for urban runoff usage. Based on the PAH concentrations examined in this study, different risk assessment methods were applied and the differences among results were analyzed. An improved PAH wash-off calculation method was established and the annual PAH wash-off load was obtained. In addition, emission sources were diagnosed based on isomer ratios and PMF methods. The overall mean ΣPAHs (sum of 16 individual PAHs) concentration in the street dust was 3.70μg/g, with the highest mean concentrations found for main roads (5.18μg/g). Adjacent anthropogenic activities had a greater effect on pollution characteristics of street dust than land use types. The toxic risk order was park (0.64μg/g)>main road (0.57μg/g)>residence (0.32μg/g)>street (0.29μg/g)>commerce (0.23μg/g), while that of the ecological risk index was main road (1278)>street (920)>residence (904)>commerce (713)>park (195). Although the park sites had a high level of toxic risk, they showed low ecological risk because they had less dust mass per unit area, indicating a great difference in the risk evaluation results and the difference methods. Using different values for different magnitudes of the antecedent dry days, rainfall event amounts, and dust mass fraction of different size ranges, the average wash-off load of ΣPAHs from street dust was calculated to be 23kg per year in Beijing from 2000 to 2014 with an improved wash-off load calculation method. The main sources of PAHs in the street dust of Beijing's center were identified as gasoline emissions, diesel emissions, coal combustion and unburned petroleum.

In vivo and in vitro effects of tunnel wash water and traffic related contaminants on aquatic organisms

In order to maintain the construction and safety of road tunnels, they are routinely washed. The wash water appears to be highly polluted with a plethora of contaminants in elevated concentrations. In addition, new and emerging compounds are likely to occur. The discharge water has shown acute toxic and sub-lethal effects in several organisms. In this study, ecotoxicity tests with algae (Pseudokirchneriella subcapitata) and in vitro tests with primary rainbow trout (Oncorhynchus mykiss) hepatocytes were used to characterize the effect of TWW from three different tunnels. In addition, selected N- and Cl-PAHs were tested for cytotoxicity, EROD activity and CYP1A protein production. TWW samples and/or extracts from two tunnels reduced the algal growth and induced cytotoxicity, EROD activity and CYP1A protein production in vitro. Four of the eight tested Cl- and N-substituted PAHs induced EROD activity and CYP1A protein production at micro-molar concentrations. N-PAHs were detected in samples from the tunnel wash, highlighting substituted PAHs as potentially important traffic-related contaminants.