US Environmental Protection Agency Priority Research Articles

Size Distributions and Health Risks of Particulate Polycyclic Aromatic Hydrocarbons in the Atmosphere at Coastal Areas in Ningbo, China.

Most current research focusing on the health risk assessments of particulate polycyclic aromatic hydrocarbons (PAHs) have not analyzed the size distributions and human respiratory deposition rates. In the present study, size-separated particulate matter (PM) was collected in the coastal area of Ningbo using an Anderson eight-stage air sampler over a 1-year period (2014-2015). The 16 US Environmental Protection Agency priority PAHs associated with PM were pretreated with rapid solvent extraction and analyzed by gas chromatography-mass spectrometry. The respiratory exposure assessment was determined using the multiple-path particle dosimetry (MPPD) model. The results show that all PAHs exhibited bimodal distribution with one mode peak in accumulation mode (0.43-0.65 µm) and another mode peak in coarse mode (4.7-5.8 µm). In addition, a low coefficient of divergence of PAHs between PM2.1 and PM2.1-10 indicated a high spatial heterogeneity in source factor contribution and formation mechanism. The deposition fluxes (tracheobronchial + pulmonary) of PM were highest for children in the size range of 3.3 µm < particle diameter (Dp) < 9 µm, while for males and females the highest fluxes occurred in the size range of 1.1 µm < Dp < 2.1 µm. The depositions of coarse PM in children were significantly higher than those in adults. The benzo[a]pyrene equivalent (BaPeq) depositions of dibenz[a,h]anthracene ranged from 1.4e-04 to 0.015 ng h-1, which were highest among the PAHs. The PAHs on particles with Dp >4.7 µm contributed approximately three times more to children than to males and females. Therefore, the toxicity of coarse PM to children needed attention. The incremental lifetime cancer risks (ILCR) for children, males, and females were estimated to be 2.92 × 10-7, 1.82 × 10-7, and 2.38 × 10-7, respectively, which were below the cancer risk guideline value (10-6). These ILCR values were much lower than the risks calculated without considering particle size distributions and respiratory depositions. The combination of the size-segregated sampling technique and the MPPD model can effectively avoid the overestimation of human respiratory exposure. Environ Toxicol Chem 2024;43:1364-1377. © 2024 SETAC.

Determination of sediment sources following a major wildfire and evaluation of the use of color properties and polycyclic aromatic hydrocarbons (PAHs) as tracers

PurposeThis research aimed to determine if a severe wildfire caused changes in the source of sediment being delivered to downstream aquatic systems and evaluate the use of polycyclic aromatic hydrocarbons (PAHs) and color properties as tracers.MethodsSediment samples were collected from 2018 to 2021 in three tributaries impacted by the 2018 Shovel Lake wildfire and from two sites on the mainstem of the Nechako River, British Columbia. Source samples were collected from burned and unburned soils as well as from channel banks and road-deposited sediment. Samples were analyzed for color properties and for the 16 US Environmental Protection Agency priority PAHs. After statistical tests to determine the conservatism and ability to discriminate between sources by the tracers, the MixSIAR unmixing model was used, and its outputs were tested using virtual mixtures.ResultIn the tributaries, burned topsoil was an important contributor to sediment (up to 50%). The mainstem Nechako River was not influenced as significantly by the fires as the greatest contributor was banks (up to 89%). The color properties provided more realistic results than those based on PAHs.ConclusionIn smaller watersheds, the wildfire had a noticeable impact on sediment sources, though the impacts of the fire seemed to be diluted in the distal mainstem Nechako River. Color tracers behaved conservatively and discriminated between contrasting sources. Due to their low cost and reliability, they should be considered more widely. While PAHs did not work in this study, there are reasons to believe they could be a useful tracer, but more needs to be understood about their behavior and degradation over time.

Soil PAH Concentrations Decrease in China in Response to the Adjustment of the Energy Structure During the Past Two Decades

China has made great efforts to fight environmental contamination along with rapid development and industrialization over the past few decades. However, the effects of these nationwide measures, such as energy restructuring, on pollutant residuals in soil have not been well quantified. Polycyclic aromatic hydrocarbon (PAH) pollution is a major concern around the world, and PAH emissions are associated with the energy structure. Therefore, we speculated that the adjustment of the energy structure in China may reduce the content of PAHs in soil. To test this hypothesis, we measured the concentrations of sixteen US Environmental Protection Agency (US EPA) priority PAH compounds (Σ16PAHs) at 54 soil sampling sites in Beijing in 2008 and 2019 and compiled nationwide data for 1704 soil sampling sites in the past two decades. The results showed that the Σ16PAH concentrations descended along the urban–suburban–rural–background gradient, and they first increased with increasing gross regional production (GRP) and plateaued when the GRP reached a certain level. The average Σ16PAH concentrations showed a decreasing trend across China over the past 20 years, and they decreased significantly from 22.7 μg·g−1 total organic carbon (TOC) in 2008 to 10.0 μg·g−1 TOC in 2019 in Beijing. The source identification analyses inferred that the decreasing trend of soil PAHs was due to the declines in the consumption of coal, coke, and some oils and the rising consumption of clean energy, such as electricity and natural gas, in China. This study demonstrates the important role of adjusting the energy structure in decreasing soil PAH concentrations and improving soil environmental quality.

Primary Sources of Polycyclic Aromatic Hydrocarbons to Streambed Sediment in Great Lakes Tributaries Using Multiple Lines of Evidence.

Polycyclic aromatic hydrocarbons (PAHs) are among the most widespread and potentially toxic contaminants in Great Lakes (USA/Canada) tributaries. The sources of PAHs are numerous and diverse, and identifying the primary source(s) can be difficult. The present study used multiple lines of evidence to determine the likely sources of PAHs to surficial streambed sediments at 71 locations across 26 Great Lakes Basin watersheds. Profile correlations, principal component analysis, positive matrix factorization source‐receptor modeling, and mass fractions analysis were used to identify potential PAH sources, and land‐use analysis was used to relate streambed sediment PAH concentrations to different land uses. Based on the common conclusion of these analyses, coal‐tar–sealed pavement was the most likely source of PAHs to the majority of the locations sampled. The potential PAH‐related toxicity of streambed sediments to aquatic organisms was assessed by comparison of concentrations with sediment quality guidelines. The sum concentration of 16 US Environmental Protection Agency priority pollutant PAHs was 7.4–196 000 µg/kg, and the median was 2600 µg/kg. The threshold effect concentration was exceeded at 62% of sampling locations, and the probable effect concentration or the equilibrium partitioning sediment benchmark was exceeded at 41% of sampling locations. These results have important implications for watershed managers tasked with protecting and remediating aquatic habitats in the Great Lakes Basin. Environ Toxicol Chem 2020;39:1392–1408. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Polycyclic Aromatic Hydrocarbon Gaseous Emissions from Household Cooking Devices: A Kenyan Case Study.

In developing countries, household energy use is highly variable and complex, yet emissions arising from fuel combustion indoors are typically poorly quantified. Polycyclic aromatic hydrocarbons (PAHs) are emitted during the combustion of organic fuels such as charcoal and biomass. In the present study, multichannel polydimethylsiloxane rubber traps were used for gas-phase PAH sampling and extracted using a low-solvent volume plunger-assisted solvent extraction method. Sixteen US Environmental Protection Agency priority PAHs, primarily in the gas phase, were investigated in indoor air of rural and urban residential homes in coastal Kenya (Mombasa and Taita Taveta Counties) using typical combustion devices of each area. Average gaseous PAH concentrations per household were higher in rural (ranging 0.81-6.09 µg m-3 ) compared to urban (ranging 0-2.59 µg m-3 ) homes, although ambient PAH concentrations were higher in urban environments, likely attributable to traffic contributions. The impact of fuel choice and thereby combustion device on PAH emissions was very clear, with the highest concentrations of PAHs quantified from wood-burning emissions from 3-stone stoves (total PAH averages 46.23 ± 3.24 µg m-3 [n = 6]). Average benzo[a]pyrene equivalent total concentrations were evaluated for the priority PAHs and ranged from not detected to 43.31, 88.38, 309.61, and 453.88 ng m-3 for gas, kerosene, jiko, 3-stone, and improved 3-stone stoves, respectively. Environ Toxicol Chem 2020;39:538-547. © 2019 SETAC.

Source patterns and contamination level of polycyclic aromatic hydrocarbons (PAHs) in urban and rural areas of Southern Italian soils

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants. They have been identified as a type of carcinogenic substance and are relatively widespread in environment media such as air, water and soils, constituting a significant hazard for human health. In many parts of the world, PAHs are still found in high concentrations despite improved legislation and monitoring, and it is therefore vital defining their profiles, and assessing their potential sources. This study focused on a large region of the south of Italy, where concentration levels, profiles, possible sources and toxicity equivalent quantity (TEQ) level of sixteen PAHs were investigated. The survey included soils from five large regions of the south of Italy: 80 soil samples (0-20cm top layer) from urban and rural locations were collected and analysed by gas chromatography-mass spectrometry. Total PAHs and individual molecular compounds from the US Environmental Protection Agency priority pollutants list were identified and measured. Results showed that 16 PAHs varied significantly in urban and rural areas, and different regions presented discordant characteristics. Urban areas presented concentrations ranging from 7.62 to 755ngg-1 (mean = 84.85ngg-1), whilst rural areas presented ranges from 1.87 to 11,353ngg-1 (mean = 333ngg-1). Large urban areas, such as Rome, Naples and Palermo, exhibited high PAHs total concentration, but high values were also found in rural areas of Campania region. Different PAHs molecular ratios were used as diagnostic fingerprinting for source identification: LWMPAHs/HWMPAHs, Fluo/(Fluo + Pyr), BaA/(BaA + Chr), Ant/(Ant + Phe) and IcdP/(IcdP + BghiP). These ratios indicated that PAHs sources in the study area were mainly of pyrogenic origin, i.e. mostly related to biomass combustion and vehicular emission. On the other hand, values in Sicilian soils seemed to indicate a petrogenic origin, possibly linked to emissions from crude oil combustion and refineries present in the region. Finally, results allowed to calculate the toxicity equivalent quantity (TEQBAP) levels for the various locations sampled, highlighting that the highest values were found in the Campania region, with 661 and 54.20ngg-1, in rural and urban areas, respectively. These findings, which could be linked to the presence of a large solid waste incinerator plant, but also to well-documented illegal waste disposal and burning, suggest that exposure to PAH may be posing an increased risk to human health in some of the studied areas.

Semi volatile organic compounds in the snow of Russian Arctic islands: Archipelago Novaya Zemlya

Environmental contamination of the Arctic has widely been used as a worldwide pollution marker. Various classes of organic pollutants such as pesticides, personal care products, PAHs, flame retardants, biomass burning markers, and many others emerging contaminants have been regularly detected in Arctic samples. Although numerous papers have been published reporting data from the Canadian, Danish, and Norwegian Arctic regions, the environmental situation in Russian Arctic remains mostly underreported. Snow analysis is known to be used for monitoring air pollution in the regions with cold climate in both short-term and long-term studies. This paper presents the results of a nontargeted study on the semivolatile organic compounds detected and identified in snow samples collected at the Russian Artic Archipelago Novaya Zemlya in June 2016. Gas chromatography coupled to a high-resolution time-of-flight mass spectrometer enabled the simultaneous detection and quantification of a variety of pollutants including those from the US Environmental Protection Agency (EPA) priority pollutants list, emerging contaminants (plasticizers, flame retardants-only detection), as well as the identification of novel Arctic organic pollutants, (e.g., fatty acid amides and polyoxyalkanes). The possible sources of these novel pollutants are also discussed.GC-HRMS enabled the detection and identification of emerging contaminants and novel organic pollutants in the Arctic, e.g., fatty amides and polyoxyalkanes.

Distribution, sources, and toxicity assessment of polycyclic aromatic hydrocarbons in surface soils of the Gwangju City, Korea

Twenty-three individual polycyclic aromatic hydrocarbons (PAHs) including sixteen US Environmental Protection Agency (EPA) priority pollutants were analyzed in soil samples collected from twenty sites in the metropolitan city of Gwangju, Korea to investigate the levels of concentration, profiles, possible sources of PAHs, and a probabilistic human health risk. Soil samples (0–15cm top layer) were collected, and the sampling sites were classified into two groups, including a school area and a residential area. Regardless of the sampling site, the concentrations of ∑23 PAHs ranged from 120 to 273ng/g with an average value of 164ng/g. The molecular distribution of PAHs reflected the similarity between school and residential areas in soil PAHs profile, and the PAHs could be from the same emission sources. High molecular weight PAHs (5- and 6-ring) were predominant in the soil samples, followed by 4-ring PAHs, while the fraction of 2-ring PAHs was the lowest. The total concentration of carcinogenic PAHs accounted for 54% of ∑16-EPA PAHs. Considering the different diagnostic ratios of PAHs, such as Flt/(Flt+Pyr), BaA/(BaA+Chr), Ant/(Ant+Phe), and IcdP/(IcdP+BghiP) and the principal component analysis results, the soil samples were likely attributed to mixed pyrogenic sources (coal and fossil fuel combustion, regardless of fuel types). The cancer risks for two age groups were <10−4, indicating no potential cancer risk.

Spatio\u2013Temporal Distribution of Polycyclic Aromatic Hydrocarbons in Urban Soils in Cape Town, South Africa

The spatial and seasonal distribution of eight US Environmental Protection Agency priority poly aromatic hydrocarbons (PAHs); namely benzo(b)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, benzo(k)fluoranthene, chrysene, benzo(a)anthracene, dibenz(a,h)anthracene and fluoranthene were investigated in 35 soil samples. Gas chromatography with flame ionization detection was used for the quantification of the PAHs in the residential, roadside and industrial soil samples collected in proximity to an industrial area, including a petrochemical plant, in Cape Town. The sum of the concentrations of the detected PAHs (ΣPAHs) in winter ranged between nd (not detected) and 13.88 mg/kg, with a mean concentration of 4.08 mg/kg and a standard deviation of distribution of 2.64 mg/kg, while in summer, ΣPAHs ranged between nd and 10.43 mg/kg, with a mean concentration of 0.50 mg/kg and standard deviation of distribution 1.83 mg/kg. The presence and concentration level of the PAHs detected in the soil samples vary significantly under climatic change (p < 0.05). The maximum concentrations of individual PAHs in the soil samples were higher in winter compared to the maximum concentrations of the PAHs detected in summer. The diagnostic ratios of selected PAH compounds showed that petrogenic processes were the most likely sources of the PAH compounds in the soil samples. In summer and winter, the total PAH concentration increased in order of residential soil < industrial soil ≤ roadside soil.

Characterization, source apportionment, and risk assessment of polycyclic aromatic hydrocarbons in urban soil of Nanjing, China

Polycyclic aromatic hydrocarbons (PAHs) are widespread in the urban environment, particularly in urban soil, which are affected by intensive human activities. The purpose of this study was to determine the levels of PAHs in urban areas of Nanjing, China, apportion their sources, and evaluate their health risk. One hundred eighty topsoil samples (0–10 cm) were collected from 180 grids of 1 km × 1 km in the main urban area of Nanjing, China, which was divided into four different land use classes. All the soil samples were analyzed for 16 US Environmental Protection Agency (US EPA) priority PAHs by HPLC. Source of PAHs was explained by isomer ratios and principal component analysis, and health risk of PAHs was assessed by benzo[a]pyrene (BaP) toxic equivalency factors. The average concentration of PAHs ranged from 41.19 to 7016.65 μg kg−1, with an average of 979.59 μg kg−1. PAHs in soil characterized by different land uses, in decreasing order, were as follows: university (UN) > traffic area (TA) > forest park (FP) > residential area (RA). PAHs in FP soils were mainly attributed to biomass combustion, while TA soils exhibited clear traffic emission characteristics. PAHs for UN and RA came from mixed sources. A principle component analysis (PCA) and ordinary kriging map indicated coal combustion and vehicle emissions as the major contributors to PAHs in Nanjing urban soils, respectively. A health risk assessment based on the BaP toxic equivalency approach indicated a potential risk level of PAHs. The mean value of PAH concentrations in UN was the highest. However, the maximum was detected in TA. The PAHs in soil samples originated mainly from coal combustion and petroleum combustion sources. There was a potential health risk level of PAHs in Nanjing urban areas.

Soil Polycyclic Aromatic Hydrocarbons Across Urban Density Zones in Shenzhen, China: Occurrences, Source Apportionments, and Spatial Risk Assessment

Urbanization may cause increased exposure levels to polycyclic aromatic hydrocarbons (PAHs) and associated health risks for over half of the world's population living in cities, but little evidence has shown a direct spatial relationship between urbanization and soil PAH pollution. Based on the monitored PAH concentrations in 188 topsoil (0–5 cm) samples in Shenzhen, the most rapidly developing city in China, in recent decades, we applied geographical demarcation to determine the occurrences, source apportionments, and spatial ecological risks of soil PAHs across five zones of varying urban densities. Mean concentrations of the 16 US Environmental Protection Agency (EPA) priority PAHs (∑16PAHs) and the 7 carcinogenic PAHs (∑7CarPAHs) both followed the order: Zone D (60%–80% constructive land density (CLD)) > Zone E (80%–100% CLD) > Zone C (40%–60% CLD) > Zone B (20%–40% CLD) > Zone A (0%–20% CLD), suggesting that the highest PAH levels occurred in the suburban-urban center transitional zone (Zone D) rather than the urban center zone (Zone E) in Shenzhen. There were significant correlations of ∑16PAHs to TOC and sampling altitude across all samples but not within highly-urbanized regions (Zones D and E), implying a considerable disturbance of urbanization to the soil PAH pool. Source apportionments suggested that soil PAHs of all zones were mainly derived from fossil fuel combustion, with Zone E showing the highest contribution from oil sources among different zones. Spatial ecological risk analysis showed that the contaminated area (467 km2; 23.9% of total area; toxic equivalency quotients > 33 ng g−1) had a higher contribution from the highly-urbanized regions (Zones D and E) than the uncontaminated area (42.3% vs. 18.1%). Overall, our study highlighted a strong spatial relationship between urbanization and soil PAH pollution.

Phthalate esters in water and surface sediments of the Pearl River Estuary: distribution, ecological, and human health risks.

The Pearl River Estuary (PRE) is vulnerable due to the increasingly serious environmental pollution, such as phthalate esters (PAEs) contaminants, from the Pearl River Delta (PRD). The concentrations of six US Environmental Protection Agency (USEPA) priority PAEs in water and surface sediments collected from the PRD's six main estuaries in spring, summer, and winter 2013 were measured by GC-MS. Total PAEs (∑6PAEs) concentrations were from 0.5 to 28.1μg/L and from 0.88 to 13.6μg/g (dry weight (DW)) in water and surface sediments, respectively. The highest concentration was detected in summer. Higher concentrations of PAEs were found in Yamen (YM) and Humen (HM) areas than the other areas. Bis(2-ethylhexyl)phthalate (DEHP) and dibutyl phthalate (DBP) were the dominant PAEs in the investigated areas, contributing between 61 and 95% of the PAEs in water and from 85 to 98% in surface sediments. Based on risk quotients (RQs), DEHP posed greater ecological risks to the studied aquatic environments than other measured compounds. Little human health risk from the target PAEs was identified.

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.

Vertical profile, source apportionment, and toxicity of PAHs in sediment cores of a wharf near the coal-based steel refining industrial zone in Kaohsiung, Taiwan.

Three sediment cores were collected from a wharf near a coal-based steel refining industrial zone in Kaohsiung, Taiwan. Analyses for 16 polycyclic aromatic hydrocarbons (PAHs) of the US Environmental Protection Agency priority list in the core sediment samples were conducted using gas chromatography-mass spectrometry. The vertical profiles of PAHs in the core sediments were assessed, possible sources and apportionment were identified, and the toxicity risk of the core sediments was determined. The results from the sediment analyses showed that total concentrations of the 16 PAHs varied from 11774 ± 4244 to 16755 ± 4593 ng/g dry weight (dw). Generally, the vertical profiles of the PAHs in the sediment cores exhibited a decreasing trend from the top to the lower levels of the S1 core and an increasing trend of PAHs from the top to the lower levels of the S2 and S3 cores. Among the core sediment samples, the five- and six-ring PAHs were predominantly in the S1 core, ranging from 42 to 54 %, whereas the composition of the PAHs in the S2 and S3 cores were distributed equally across three groups: two- and three-ring, four-ring, and five- and six-ring PAHs. The results indicated that PAH contamination at the site of the S1 core had a different source. The molecular indices and principal component analyses with multivariate linear regression were used to determine the source contributions, with the results showing that the contributions of coal, oil-related, and vehicle sources were 38.6, 35.9, and 25.5 %, respectively. A PAH toxicity assessment using the mean effect range-median quotient (m-ERM-q, 0.59-0.79), benzo[a]pyrene toxicity equivalent (TEQ(carc), 1466-1954 ng TEQ/g dw), and dioxin toxicity equivalent (TEQ(fish), 3036-4174 pg TEQ/g dw) identified the wharf as the most affected area. The results can be used for regular monitoring, and future pollution prevention and management should target the coal-based industries in this region for pollution reduction.

Atmospheric concentration and carcinogenic risk of polycyclic aromatic hydrocarbons including benzo[c]fluorene, cyclopenta[c,d]pyrene, and benzo[j]fluoranthene in Japan

The atmospheric concentrations of both gas-phase and particulate-phase polycyclic aromatic hydrocarbons (PAHs) including 16 US Environmental Protection Agency priority PAHs (16 PAHs) were measured in eleven cities across Japan. Using the measured average concentrations and toxic equivalency factors (TEF) of the 16 PAHs, the benzo[a]pyrene (BaP)-toxic equivalent for eight major PAHs was obtained: the ratio of BaP to the eight major PAH toxicities ranged from 0.23 to 0.47. Among the target PAHs, from the viewpoint of carcinogenicity, we focused on benzo[c]fluorene (BcFE), which was detected in both the gas and particulate phase in contrast to BaP. The relative potency factor (RPF) of BcFE was evaluated as 6.46 based on its cancer slope factor relative to that of BaP determined in the benchmark dose calculations for mice. The relative carcinogenic risk of BcFE to BaP was obtained by multiplying the averaged concentrations of BaP and BcFE by the RPF value: the risk of BcFE was 6.8 and 5.1 times higher than that of BaP in summer and winter, respectively. These results show that the collection of atmospheric samples including the gas phase is important when assessing the carcinogenic risk of atmospheric PAHs.

Accumulation and risks of polycyclic aromatic hydrocarbons and trace metals in tropical urban soils

The study deals with the combined contribution of polycyclic aromatic hydrocarbons (PAHs) and metals to health risk in Delhi soils. Surface soils (0-5 cm) collected from three different land-use regions (industrial, flood-plain and a reference site) in Delhi, India over a period of 1 year were characterized with respect to 16 US Environmental Protection Agency priority PAHs and five trace metals (Zn, Fe, Ni, Cr and Cd). Mean annual ∑16PAH concentrations at the industrial and flood-plain sites (10,893.2 ± 2826.4 and 3075.4 ± 948.7 μg/kg, respectively) were ~15 and ~4 times, respectively, higher than reference levels. Significant spatial and seasonal variations were observed for PAHs. Toxicity potentials of industrial and flood-plain soils were ~88 and ~8 times higher than reference levels. Trace metal concentrations in soils also showed marked dependencies on nearness to sources and seasonal effects. Correlation analysis, PAH diagnostic ratios and principal component analysis (PCA) led to the identification of sources such as coal and wood combustion, vehicular and industrial emissions, and atmospheric transport. Metal enrichment in soil and the degree of soil contamination were investigated using enrichment factors and index of geoaccumulation, respectively. Health risk assessment (incremental lifetime cancer risk and hazard index) showed that floodplain soils have potential high risk due to PAHs while industrial soils have potential risks due to both PAHs and Cr.

Polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Bizerte Lagoon, Tunisia: levels, sources, and toxicological significance

To assess the status of polycyclic aromatic hydrocarbon (PAH) contamination in sediments from the Bizerte Lagoon (northern Tunisia), 18 surface sediment samples were collected in March 2011 and analyzed for 14 US Environmental Protection Agency priority PAHs by high-performance liquid chromatography. The total concentrations of the 14 PAHs (ΣPAHs) ranged from 16.9 to 394.1 ng g(-1) dry weight (dw) with a mean concentration of 85.5 ng g(-1) dw. Compared with other lagoons, coasts, and bays in the world, the concentrations of PAHs in surface sediments of the Bizerte Lagoon are low to moderate. The PAHs' composition pattern was dominated by the presence of four-ring PAHs (45.8 %) followed by five-ring (26.8 %) and three-ring PAHs (12.7 %). The PAH source analysis suggested that the main origin of PAHs in the sediments of the lagoon was mainly from pyrolytic sources. According to the numerical effect-based sediment quality guidelines of the USA, the levels of PAHs in the Bizerte Lagoon should not exert adverse biological effects. The total benzo[a]pyrene toxicity equivalent values calculated for the samples varied from 3.1 to 53.7 ng g(-1) dw with an average of 10.6 ng g(-1) dw.

Polycyclic Aromatic Hydrocarbons, Heavy Metals, and Genotoxicity of the Suburban Soils from Guangzhou, China

During the past few decades, urban and suburban developments have grown at unprecedented rates and extents with unknown consequences for ecosystem function. The problem of soil pollution as a result of the accelerating development of Guangzhou in China is becoming great concerns. In the present study, gas chromatograph coupled mass spectrometry (GC-MS), inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) were employed to determine the 16 US Environmental Protection Agency (EPA) priority polycyclic aromatic hydrocarbons (PAHs) and the heavy metals (As, Cr, Cu, Pb, Cd, Hg, and Se) of soils collected from suburban areas of Guangzhou. The genotoxicity of these soils was screened with micronucleus (MN) assay in Vicia faba root cells. The concentrations of the pollutants in the soils were (dried weight): ΣPAHs (230.6–1263 ng·g−1), As (2282.6–36064 μg·kg−1), Cr (7109–64699 μg·kg−1), Cu (7047–56388 μg·kg−1), Pb (9675.9–93739 μg·kg−1), Cd (68.5–847.3 μg·kg−1), Hg (85.4–549.2 μg·kg−1), and Se (219.2–968 μg·kg−1), which fell in the moderately polluted range. However, six out of nine soil-exposed groups had a significant increases of MN frequencies observed in the V. faba root cells compared with the negative group (P < 0.05, P < 0.01), indicating that they had potential genotoxic risks. Bringing together the chemical analyses with the biological effects observed in this study, the genotoxic response could at a certain degree be explained by both the soil PAHs and heavy metals. Our results suggested that apart from chemical analysis, bioassays like the MN assay of V. faba root cells should also be included in a battery of tests to assess the eco-environmental risks of urban and/or urbanization in the developing areas on the soils.

Determination of heavy polycyclic aromatic hydrocarbons of concern in edible oils via excitation–emission fluorescence spectroscopy on nylon membranes coupled to unfolded partial least-squares/residual bilinearization

Seven heavy polycyclic aromatic hydrocarbons (PAHs) of concern on the US Environmental Protection Agency priority pollutant list (benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene, and indeno[1,2,3-c,d]-pyrene) were simultaneously analyzed in extra virgin olive oil. The analysis is based on the measurement of excitation-emission matrices on nylon membrane and processing of data using unfolded partial least-squares regression with residual bilinearization (U-PLS/RBL). The conditions needed to retain the PAHs present in the oil matrix on the nylon membrane were evaluated. The limit of detection for the proposed method ranged from 0.29 to 1.0μgkg(-1), with recoveries between 64 and 78%. The predicted U-PLS/RBL concentrations compared favorably with those measured using high-performance liquid chromatography with fluorescence detection. The proposed method was applied to ten samples of edible oil, two of which presented PAHs ranging from 0.35 to 0.63μgkg(-1). The principal advantages of the proposed analytical method are that it provides a significant reduction in time and solvent consumption with a similar limit of detection as compared with chromatography.

Decontamination of polycyclic aromatic hydrocarbons and nonylphenol from sewage sludge using hydroxypropyl-β-cyclodextrin and evaluation of the toxicity of leachates

A decontamination technique based in cyclodextrin extraction has been developed to eliminate nonylphenol (NP) and 16 polycyclic aromatic hydrocarbons (PAHs; the US Environmental Protection Agency priority pollutants list) from sewage sludge. In a first step, PAHs and NP were characterised in six sludges to determine contamination levels according to limit values proposed by the European Union Sludge Directive draft. There were few variations in the total PAHs content with levels of 1.88 to 3.05 mg kg(-1). Three-ring PAHs predominated, but fluoranthene and pyrene were also present. None of the sludge exceeded the PAHs limit proposed by the European Union's draft Directive. On the contrary, NP content in four of the six sludges was over the recommended limits of 50 mg kg(-1) for NP ethoxylates. With the aim of obtaining NP values below the concentration limits proposed to use the sewage sludge as agricultural amendments, a preliminary study using hydroxypropyl-β-cyclodextrin (HPBCD) extractions as a decontamination technique was carried out. About 90% of NP content was removed with only one extraction with HPBCD, whereas after three sequential extractions using an aqueous solution without HPBCD, the NP extraction percentage was less than 1%. Simultaneously, PAHs extraction percentages obtained with HPBCD were also much higher than when aqueous solution was used, especially in the case of two- and three-ring PAHs. Finally, the potential environmental hazard of HPBCD leachates to aquatic organisms (Daphnia magna) was tested. These results indicate that the treatment of sewage sludge with cyclodextrin could allow their safe use as fertiliser in agriculture.