Polycyclic Aromatic Hydrocarbons Profiles Research Articles

Influence of rice straw open burning on levels and profiles of semi-volatile organic compounds in ambient air.

Semi-volatile organic compounds (SVOCs) of polycyclic aromatic hydrocarbons (PAHs) and organo-chlorinated pesticides (OCPs) were sampled (24h, Hi-Vol XAD-2) in dry and wet season, and separately analyzed for particulate and gaseous phases. To reveal the influence of rice straw open burning (RSOB), SVOC levels and profiles were comparatively analyzed between two areas, rice plantation area (KL) with intensive RSOB activities and remote national park (KY), and with fresh RSOB smoke. PAHs were significantly higher in KL than KY in both seasons. PAHs levels in KL during burning season were ∼10 times above the wet season indicating RSOB influence. In KY, however, PAHs levels in wet season were 2 times above dry season suggesting impacts of local emission transport. OCPs levels were not statistically different between 2 seasons and between 2 sites in each season. RSOB smoke contained 5880ng/m3 of 14 PAHs and 13.5ng/m3 of 16 OCPs which were respectively 14 and 7 times above those in KL during burning period. The 4-ring compounds, most remarkably fluoranthene, and 5-ring (BbF and BaP) were dominant PAHs species in RSOB smoke. Similarity in PAH profiles and diagnostic ratios between KL dry season and RSOB smoke suggested its strong influence on the local air quality. Elevated OCPs levels in RSOB smoke may be associated with re-emission of the compounds accumulated in the paddy soil during the burning. RSOB in Southeast Asia has a serious implication on exposure to the toxic air pollutants hence should be eliminated with priority.

Analysis of polycyclic aromatic hydrocarbons (PAHs) and their polar derivatives in soils of an industrial heritage city of Australia

Knowledge about polar derivatives of polycyclic aromatic hydrocarbons (PAHs) in soils is limited despite the extensive study of the environmental presence and persistence of non-polar parent PAHs. Polar PAHs have greater potential to be more toxic at low environmental concentrations compared to their homocyclic analogues. For both polar and non-polar PAHs, combustion of fossil fuels is often the main source especially in industrialised environments. This study investigated the concentration profiles of PAHs and its associated polar PAHs such as nitrated PAHs (NPAHs), oxygenated PAHs (oxy-PAHs) and nitrogen, sulphur and oxygen heterocyclic PAHs (N/S/O-heterocyclic PAHs) in a well-known industrial heritage city of Australia. The most abundant polar PAHs were 9-fluorenone (oxy-PAHs), 2-nitrofluorene (NPAHs) and carbazole (heterocyclic-PAHs). A positive correlation (r = 0.5, p < 0.01) between ∑13PAHs and ∑19 polar PAHs was observed, implying a possible spatial association between parent and polar PAHs. The concentrations of polar PAHs in soil samples, across various landuse patterns, were used to calculate the excess lifetime cancer risk (ELCR) from incidental ingestion of soils. The computed ELCR values ranged from 8.2*10−7 (industrial soils) to 2.3*10−6 (residential soils), indicating negligible cancer risks. This is the first known study on the occurrence and concentrations of polar and non-polar PAHs in any Australian city, and the results may serve a baseline purpose for improved risk assessment of contaminated sites.

Polycyclic aromatic hydrocarbons (PAHs) in indoor air and dust samples of different Saudi microenvironments; health and carcinogenic risk assessment for the general population

In this study, the presence of polycyclic aromatic hydrocarbons (PAHs) was studied in indoor air (PM10) and settled dust collected from different indoor microenvironments of Saudi Arabia. Limited data is available on the indoor quality of Saudi Arabia and to the best of our knowledge, this is the first study reporting PAHs in indoor air from Saudi Arabia. The main objectives were to study the levels and profile of selected PAHs in indoor dust and PM10 samples from different microenvironments of Saudi Arabia and to estimate health risk assessment to the local population via inhalation, dust ingestion and dermal contact. To study PAHs, indoor dust and PM10 samples were collected from different households, offices and hotel roomsPM10.Pyrene, benz(a)anthracene, chrysene, and phenanthrene were the major PAHs in both settled dust and PM10 samples. Profile of PAHs in dust samples was dominated by 3 and 4 ring PAHs while in PM10 sample 5–6 aromatic ring PAHs also contributed significantly. PM10 collected from kitchens and AC filter dust samples were the most contaminated with PAHs. PM10Health risk assessment was made for adults and young based on benzo(a)pyrene equivalent carcinogenic power (BaPE) and incremental lifetime cancer risk (ILCR). BaPE revealed major toxicity threat associated with PAHs is all microenvironments samples (dust and PM10) is from 5 and 6 aromatic rings PAHs. ILRC calculated using ingestion, inhalation and dermal contact was within the limits set by USEPA and although using max concentration it was up to 8.0E-05, which can have significant impact long term if other exposure pathways such as food and outdoor exposure, etc. are considered.

Implementing standardized desorption extraction into bioavailability-oriented bioremediation of PAH-polluted soils

We applied a standardized desorption extraction method (Tenax extraction), to assess the bioavailability of native polycyclic aromatic hydrocarbons (PAHs) present in contaminated soils. Single-time point Tenax extraction at 20 h has been recently proposed by the International Organization for Standardization as one of the chemical methods to measure environmental bioavailability of nonionic pollutants (ISO/TS 16751). This work is one of the first ones that use this ISO method systematically in the field of bioremediation, and shows its advantages when used in combination with total concentrations determined with conventional, exhaustive solvent extraction. This method has been applied to different PAHs contaminated soils which had a different level of total PAHs (66–4370 mg kg−1) and which were from different contaminated sites and dissimilar bioremediation approaches. In most samples the study was focused on phenanthrene and benzo(a)pyrene as representative pollutants, although the profile of total PAHs was also studied in some samples. The results from this study show that the pollutant fractions extracted with Tenax during 20 h (D20) decreased after traditional bioremediation (biostimulation and phytoremediation), but they often increased in bioavailability-oriented treatments involving either biosurfactants or bioaugmentation with specialized microbial inocula. Therefore, D20-based assessments provided information on the bioremediation performance, not directly evident through the measurement of total PAH concentrations.

Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in small craft harbor (SCH) surficial sediments in Nova Scotia, Canada.

Multiple source apportionment approaches were employed to investigate PAH sources which contribute to small craft harbor (SCH) sediments in Nova Scotia (NS), Canada. A total of 580 sediment samples were analyzed using PAH diagnostic ratios, Unmix Optimum receptor modeling, and by assessment of the composition of the PAH profile. PAH diagnostic ratios suggest PAHs are primarily of pyrogenic (thermal) origin, while UnmixO modeling identifies four individual sources which best describe surficial sediments and suggests contributions from both pyrogenic and petrogenic origins. These include coal combustion, automobile exhaust, and biomass incineration. PAH profile assessment determined an overwhelming contribution of high molecular weight PAHs, which exhibited a strong correlation with total PAH concentrations.

Looking at Organic Pollutants (OPs) Signatures in Littoral Sediments to Assess the Influence of a Local Urban Source at the Whole Lake Scale

Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are organic pollutants (OPs) that can originate from both the watershed (i.e. local sources) and long-range emissions. Even when local sources are identified, the propagation of OPs in aquatic systems remains poorly known. The southern part of Lake Bourget (France) is known to be impacted by PAHs and PCBs from local urban sources and surficial sediments exhibit OP concentrations higher than in the North. However, little is known about the propagation of this pollution within the lake. We propose a dual approach to assess the propagation of 13 PAHs and 7 PCBs in 10 littoral sites. The first method quantifies the similarities between the OP profiles of the sites and that of a local urban signature used as a reference of the southern watershed, and the second method is based on concentration ratios. The two independent methods provided convergent results and supported a south–north gradient of the OPs propagation. Southern sediments exhibited the highest OP contents, similarities in profiles with the local signatures, and abundance of heavy molecular weight congeners. PAH contents and profiles seemed to be more variable than for the PCBs. Changes in the littoral OP profiles with tributary distance illustrated the spread from tributary outlets that may act as contamination pathways. Two littoral sites did not match this north–south gradient for PAH contamination, indicating another potential point sources. These results furthermore underline the relevance of focusing on the littoral zone in the prospect of assessing propagation of pollution within a lake.

Characterization of polycyclic aromatic hydrocarbon (PAHs) source profiles in urban PM2.5 fugitive dust: A large-scale study for 20 Chinese cites

Polycyclic aromatic hydrocarbons (PAHs) in road dust (RD) and construction dust (CD) in PM2.5 were quantified in the samples collected in 20 Chinese cities. The PAHs profiles in urban PM2.5 fugitive dusts were determined and their potential health risks were evaluated. Seven geographical regions in China were identified as northwest China (NWC), the North China Plain (NCP), northeast China (NEC), central China (CC), south China (SC), southwest China (SWC), and east China (EC). The overall average concentrations of total quantified PAHs (ΣPAHs) were 23.2 ± 18.9 and 22.8 ± 29.6 μg·g−1 in RD and CD of PM2.5, indicating that severe PAHs pollution to urban fugitive dusts in China. The differences of ΣPAHs between RD and CD were minor in northern and central regions of China but much larger in southern and east regions. The ƩPAHs for RD displayed a pattern of “high in northern and low in southern”, and characterized by large abundance of high molecular weights (HMWs) PAHs, indicating that vehicle emission was the predominant pollution origin. Additionally, higher diagnostic ratios of fluoranthene/(fluoranthene + pyrene) in NCP, CC, and SWC suggest critical contributions of biomass burning and coal combustion for RD in these areas. In comparison, gasoline combustion was the major pollution source for CD PAHs in NWC, NCP, NEC, and CC, whereas industrial emissions such as cement production and iron smelting had strong impacts in the heavy industrial regions. The total benzo[a]pyrene (BaP) carcinogenic potency concentrations (BaPTEQ) for RD and CD both showed the lowest in SC (0.05 and 0.07, respectively) and the highest in NCP (10.99 and 7.67, respectively). The highest and lowest incremental life cancer risks (ILCR) were found in NCP and SC, coinciding with the spatial distributions of ambient PAHs levels. The total CD-related cancer risks for adults and children (~10−4) suggest high potential health risks in NCP, SWC, and NWC, whereas the evaluated values in EC and SC indicate virtual safety (≤10−6).

Seasonal profiles of atmospheric PAHs in an e-waste dismantling area and their associated health risk considering bioaccessible PAHs in the human lung

Due to the development of the economy, electronic waste (e-waste) has become a new global problem and e-waste dismantling processes are an important source of air pollution. Among the pollutants emitted, polycyclic aromatic hydrocarbons (PAHs) are a severe concern because of their carcinogenic and mutagenic properties. However, few studies have investigated the atmospheric PAHs generated by e-waste dismantling in a specific region, especially the PAH levels throughout the year. Thus, we assessed the effects of PAHs on the local air quality by sampling the total suspended particulates (TSP), PM10, PM2.5, and gaseous phase from an e-waste dismantling area and a control site during four seasons. The TSP, PM10, and PM2.5 concentrations were measured as 84.8–414, 70.7–302, and 57.1–204 μg m−3, respectively, in this area, and those of three types of particulate bound-PAHs and gaseous phase PAHs were 2.6–16.1, 2.2–15.1, 1.9–14.6, and 20.1–72.8 ng m−3, respectively. The pollutant levels were higher in the spring and winter than those in the summer and autumn. The PAH sources were identified by diagnostic ratio approaches and principal component analysis. E-waste dismantling was identified as the major source of PAH pollution within this area, where approximately 82.4% of the PAHs was attributed to e-waste dismantling at an industrial park (EP site). Among the sites sampled, the pollutant levels and cancer risk were highest at the EP site, and they could pose a cancer risk for humans, although only the bioaccessible PAHs in human lungs were considered. In particular, infants had a higher health risk than adults, thereby suggesting that air pollution with PAHs is a concern in this area. This study provides clear evidence of the requirement for control measurements of e-waste dismantling processes.

Particulate matter bound polycyclic aromatic hydrocarbons: Toxicity and health risk assessment of exposed inhabitants

In the present study, the toxicological profile of 13 polycyclic aromatic hydrocarbons (PAHs) associated with airborne particulate matter (PM) was assessed. The average concentration of both PM10 and PM2.5 exceeded the Indian National Ambient Air Quality Standards. Amongst 13 analyzed PAHs, Naphthalene (Nap) was found to be the most dominant in both size fraction of PM whereas Indeno (1, 2, 3-cd) pyrene (IP) exhibited the least concentration. The relative % distribution of Low molecular weight (LMW) three ring PAHs were found to be predominant in both sized PM. The combined results derived from diagnostic ratios and factor analysis suggested that the vehicular emission (Diesel + gasoline) and coal combustion in the vicinity of study province are probable sources of PM bound PAHs. Maximum contribution towards the carcinogenicity has been found for Benzo (a) pyrene [B(a)p] for both size PM. The cytotoxic profile of PAHs determined by MTT assay demonstrated significant decrease in cell viability and PAHs associated with PM10 samples exhibited higher cytotoxic response. The redox activity measured by DTT assay exhibited the oxidative nature of PAHs associated with both sized PM. The interaction study between the PAHs and BSA resulted in substantial decrease in fluorescence intensity of BSA, indicating that PM bound PAHs could quench intrinsic fluorescence of the protein through successive molecular interaction and further conformational changes of protein was confirmed by circular dichroism spectra. Results obtained in the present study provide a valuable approach to evaluate the toxicological profile of PAHs encountered in the atmosphere of Pune.

Carbon dioxide as a carrier gas and biomass addition decrease the total and bioavailable polycyclic aromatic hydrocarbons in biochar produced from sewage sludge

Organic-solvent extractable (Ctot) and freely dissolved (Cfree) polycyclic aromatic hydrocarbons (PAHs) (US EPA 16 PAHs) were determined in biochars produced from the mixture of sewage sludge and sewage sludge and willow (8:2 or 6:4, w/w). The pyrolysis was carried out at 500, 600, and 700 °C using two different carrier gases (N2 or CO2). Addition of willow and the change of carrier gas from N2 to CO2 reduced Ctot PAHs (from 7.0 to 52%) and Cfree PAHs (15–29%) content. Co-application of willow and SSL and the use of CO2 as a carrier gas also beneficially affected the PAHs profile. The biochars produced with willow addition and/or in a CO2 atmosphere were characterized by a lower (from 9.0 to 62.8%) percentage of 3-6-ring PAHs (Ctot) than the biochars derived from sewage sludge alone in N2 atmosphere. The contribution of individual Cfree PAHs did not differ significantly between biochars. The presence of willow during pyrolysis influenced the direction of the changes in the Ctot PAH content depending on the pyrolysis temperature. For SSL alone, regardless of the carrier gas used, the content of Ctot PAHs was observed to decrease with increasing temperature, whereas in the presence of willow temperature did not affect significantly (P ≥ 0.05) the Ctot PAHs content. The change of carrier gas from N2 to CO2 increased the affinity of the biochars to PAHs as confirmed by the distribution coefficients log KTOC.

Establishing the occurrence and profile of polycyclic aromatic hydrocarbons in marine sediments: The eastern Mediterranean coast of Spain as a case study

Sampling, cost-effective analysis, diagnosis of sources of pollution and assessment of potential toxicological effects were included in the case study. Marine sediments collected from 24 points along the eastern Mediterranean coast of Spain (Comunitat Valenciana region) in 2010, 2011, 2012 and 2015 have been analysed for polycyclic aromatic hydrocarbons. Fluoranthene, pyrene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene were the most found. An analysis of the relative abundance of selected PAHs revealed that petrogenic and mixed petrogenic/pyrogenic sources are predominant in the area. The total concentrations of the target compounds ranged from 14.7 to 615.3 ng/g dry weight. The effects range-low (ERL) guideline values were used to assess potential toxicological effects. Rarely adverse biological effects can be expected in the tested area. The level of pollution by PAHs in the area can be considered low, although occasionally high values can be found, particularly in areas with high population or ship traffic.

Multivariate Analysis for Assessing Sources, and Potential Risks of Polycyclic Aromatic Hydrocarbons in Lisbon Urban Soils

Urban soils quality may be severely affected by polycyclic aromatic hydrocarbons (PAHs) contamination, as is the case of Lisbon (Portugal). However, to conduct a risk assessment analysis in an urban area can be a very difficult task due to the patchy nature and heterogeneity of these soils. Thus, the present study aims to provide an example on how to perform the first tier of a risk assessment plan in the case of urban soils using a simpler, cost effective, and reliable framework. Thus, a study was conducted in Lisbon to assess the levels of PAH, their potential risks to the environment and human health, and to identify their major sources. Source apportionment was performed by studying PAHs profiles, their relationship with potentially toxic elements, and general characteristics of soil using multivariate statistical methods. Results showed that geostatistical tools are useful for evaluating the spatial distribution and major inputs of PAHs in urban soils, as well as to identify areas of potential concern, showing their usefulness in risk assessment analysis and urban planning. Particularly, the prediction maps obtained allowed for a clear identification of areas with the highest levels of PAHs (close to the airport and in the city center). The high concentrations found in soils from the city center should be a result of long-term accumulation due to diffuse pollution mostly from traffic (through atmospheric emissions, tire debris and fuel exhaust, as well as pavement debris). Indeed, most of the sites sampled in the city center were historical gardens and parks. The calculation of potential risks based on different models showed that there is a high discrepancy among guidelines, and that risks will be extremely associated with the endpoint or parameters used in the different models. Nevertheless, this initial approach based on total levels was useful for identifying areas where a more detailed risk assessment is needed (close to the airport and in the city center). Therefore, the use of prediction maps can be very useful for urban planning, for example, by crossing information obtained with land uses, it is possible to define the most problematic areas (e.g., playgrounds and schools).

Effects of large aromatic precursors on soot formation in turbulent non-premixed sooting jet flames

In this paper, we computationally study the effects of large Polycyclic Aromatic Hydrocarbons (PAH) (more than two aromatic rings) on soot yield and distribution in turbulent flames, when they are considered as nucleating species for soot formation. This is examined in two turbulent non-premixed sooting jet flames using ethylene and a jet fuel (JP-8) surrogate as fuels. For each flame, two Large-Eddy Simulations (LES) are performed with two different soot nucleation strategies. In the first strategy, a range of PAH from naphthalene to cyclopenda[cd]pyrene are considered as nucleating species, while in the second strategy, naphthalene is considered as the only soot nucleating species and the effects of larger PAH are represented entirely by naphthalene. Flamelet-based chemistry-tabulation is used for the major thermochemical quantities, such as density, temperature, and major species mass fractions. Turbulence-chemistry interactions for PAH are accounted for by transporting their mass fractions and using a recently developed PAH relaxation model for their source term closure. The effects of large PAH on soot are highlighted by comparing the PAH profiles, soot nucleation rate, and soot volume fraction distributions obtained from both simulations for each test flame. These results are also compared against experimental measurements, when available. From these comparisons, it is first shown that naphthalene is predominantly formed along the flame centerline, and larger PAH species with more than two aromatic rings are primarily formed away from the centerline. Further, it is found that these larger PAH species only contribute to around of the overall soot nucleation rate along the flame centerline but their contributions are more substantial (up to ) away from the centerline. Finally, it is shown that representing the effects of these large PAH species by naphthalene leads to an under-prediction of around for the soot volume fraction magnitude along the flame centerline. Away from the centerline, this under-prediction can be as much as 100

Occurrence, composition profiles and risk assessment of polycyclic aromatic hydrocarbons in municipal sewage sludge in China

A nationwide survey, including 75 sludge samples and 18 wastewater samples taken from different wastewater treatment plants (WWTPs) from 23 cities, was carried out to investigate the occurrence and composition profiles of polycyclic aromatic hydrocarbons (PAHs) in China. In total, the concentrations of ∑16PAHs in sludge ranged from 565 to 280,000 ng/g (mean: 9340 ng/g) which was at a moderate level in the world. The composition profiles of PAHs were characterized by 3- and 4-ring PAHs in textile dyeing sludge and 4- and 5-ring PAHs in domestic sludge. Significant variations in regional distribution of PAHs were observed. Both the principal components analysis and diagnostic ratios revealed that vehicle exhaust, coal and natural gas combustion were the main sources of PAHs in China. The estimated concentrations of PAHs were 3820 ng/L and 1120 ng/L in influents and effluents of the WWTPs, respectively. The high toxic equivalent quantity (TEQ) values of PAHs are ascribed to the high PAH levels. Risk quotient values (RQs) in sludge indicated that there was low potential risk to soil ecosystem after sludge had been applied one year except for indeno [1,2,3-cd]pyrene (IcdP) detected in Huaibei, Anhui province.

PM and PAHs emissions of ship auxiliary engine fuelled with waste cooking oil biodiesel and marine gas oil

Clean fuels are recommended for ships at berth to reduce air pollutant emissions. This study aimed to evaluate the feasibility of waste cooking oil (WCO) biodiesel application on board with regard to particle matter (PM) and polycyclic aromatic hydrocarbon (PAH) emissions. An experiment was conducted on a marine auxiliary engine for three different fuels: WCO biodiesel, formulation blends with marine gas oil (MGO) and neat MGO. Results revealed that WCO biodiesel could reduce PM and PAHs emissions. WCO exhaust also exhibited differences in PAH profile and phase distribution as compared to MGO, depending on the operation modes and the proportion of biodiesel in the formulation blends. Consequently, WCO biodiesel could dramatically reduce the total carcinogenic potencies related to PAHs of exhausts. Moreover, PAH source recognition pair ratios of tested fuels were observed to deviate from the widely accepted values. This study highlights that WCO biodiesel is a cleaner fuel for operating ship auxiliary engines with respect to PM and PAHs emissions and has the potential to moderate the severe effects of PM and PAHs on an air of coastal areas.

Assessing the level and sources of Polycyclic Aromatic Hydrocarbons (PAHs) in soil and sediments along Jhelum riverine system of lesser Himalayan region of Pakistan

Lesser Himalayan Region (LHR) is an important mountain ecosystem which supports a wide range of biodiversity for native flora and fauna. Human population in this region is largely dependent upon local sources for their livelihood. Surface soil (n = 32) and sediment (n = 32) were collected from four different altitudinal ranges of LHR and analyzed for priority Polycyclic Aromatic Hydrocarbons (PAHs) recommended by USEPA. Level, sources and distribution pattern of PAHs were assessed in soil and sediments samples collected from four altitudinal zones in LHR. Total PAHs concentration level of PAHs in soil and sediments ranged from 62.79 to 1080 ng g−1 and 14.54–437.43 ng g−1, respectively. Compositional profile of PAHs in both soil and sediment were dominated by low and medium molecular weight PAHs, ranged from 18.02 to 402.18 ng g−1in soil and 0.32–96.34 ng g−1in sediments. In the context of spatial distribution trend, highest mean concentrations of PAHs in soil were recorded in zone D (sites from the rural region) and for sediments highest concentrations were detected at zone A, which includes dam sites. In all four zones, no altitudinal trend of PAHs in soil and sediments was observed. Source apportionment through receptor modelling by positive matrix factorization (PMF) revealed that local sources such as biomass combustion and vehicular emissions are important sources of PAHs in this region. The prevalence of monsoon atmospheric circulation system in LHR implicated that this region is also influenced by medium and long range atmospheric transportation of PAHs from neighboring countries where potential sources and high level of PAHs has been reported.

Carcinogenic profile, toxicity and source apportionment of polycyclic aromatic hydrocarbons accumulated from urban road dust in Tokyo, Japan

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in urban environments. Urban road dust (URD) generated by traffic is an important PAH accumulator. Twelve priority PAHs in < 2000 µm fraction of ten URD samples from Tokyo, Japan were characterized based on profile distributions, carcinogenicity, toxicity, and source apportionment by cluster analysis, biplot and diagnostic ratios. PAH concentrations (mg/kg dry weight) in arterial roads, highways, highway parking, highway drainage pit and residential area URD samples were 2.06–4.24, 0.25–3.37, 3.44, 4.94, and 5.26 respectively, dominated by the ∑4 rings (average 46%) and ∑5 + 6 rings (average 41%) PAHs. Biplot analysis revealed that the antecedent dry weather period, vehicle frequency and organic matter content were the dominant environmental factors governing PAH profiles of different road types. The total amount of carcinogenic PAHs in the residential URD (2.12 mg/kg) was higher than those in the arterial road (0.60–2.00 mg/kg) and highway (0.10–1.84 mg/kg) URD. Toxic equivalent concentrations (TECs) of residential, arterial road and highway URD were 0.54, (0.12–0.57), and (0.02–0.51) mg/kg, respectively. The dominant PAH sources were found to be petrogenic combustion in arterial road and highway URD, and pyrogenic combustion consisting of a mix of biomass, petroleum and traffic-related sources in the residential and highway drainage pit samples. This is also the first study to find that TEC-based toxicity should not be taken as a measure of URD toxicity.

Crude oil cardiotoxicity to red drum embryos is independent of oil dispersion energy

The potential bioavailability of toxic chemicals from oil spills to water column organisms such as fish embryos may be influenced by physical dispersion along an energy gradient. For example, a surface slick with minimal wave action (low energy) could potentially produce different toxic effects from high energy situations such as pressurized discharge from a blown wellhead. Here we directly compared the toxicity of water accommodated fractions (WAFs) of oil prepared with low and high mixing energy (LEWAFs and HEWAFs, respectively) using surface oil samples collected during the 2010 Deepwater Horizon spill, and embryos of a representative nearshore species, red drum (Sciaenops ocellatus). Biological effects of each WAF type was quantified with several functional and morphological indices of developmental cardiotoxicity, providing additional insight into species-specific responses to oil exposure. Although the two WAF preparations yielded different profiles of polycyclic aromatic hydrocarbons (PAHs), cardiotoxic phenotypes were essentially identical. Based on benchmark thresholds for both morphological and functional cardiotoxicity, in general LEWAFs had lower thresholds for these phenotypes than HEWAFs based on total PAH measures. However, HEWAF and LEWAF toxicity thresholds were more similar when calculated based on estimates of dissolved PAHs only. Differences in thresholds were attributable to the weathering state of the oil samples.

Sedimentary polycyclic aromatic hydrocarbons record recent anthropogenic activities near high-elevation Lake Sayram, northwest China

Mountain lakes are sensitive to natural perturbations and human activities. Profiles of anthropogenic polycyclic aromatic hydrocarbons (PAHs) in lake sediments serve as a natural archive from which human impacts on lakes can be reconstructed. Two parallel sediment cores (34 cm long) were extracted from Lake Sayram in the Tianshan Mountains of arid northwest China and dated using 210Pb and 137Cs. PAHs in the sediments were used to infer the past ∼150 years of anthropogenic impact on the lake. Results showed that PAH concentrations in the lake sediments were generally low, but nevertheless reflect some human activity. Benzo(ghi)perylene (BghiP) and indeno(1, 2, 3-cd)pyrene (IcdP) are typical markers of vehicular traffic, so significant correlations between PAH (especially BghiP and IcdP) and metal concentrations suggest that PAHs in sediments are effective proxies for anthropogenic activities. Furthermore, constrained cluster analysis revealed that the vertical profile of PAHs was characterized by three periods that correspond to changes in human activities. Prior to the 1960s, low PAH concentrations in the sediments generally indicate that the lake was virtually unaffected by human impact. BghiP and IcdP concentrations, however, displayed a minor peak in the 1950s, possibly reflecting transport from a remote polluted region via prevailing westerly winds. From the 1960s through the 1990s, relatively high values of PAHs, especially high molecular weight (HMW) PAHs BghiP and IcdP, and heavy metal enrichment factors (EFs), were related to increasing anthropogenic activities. After the 1990s, maxima of PAHs, HMW PAHs, BghiP, IcdP, EFs, together with highest total phosphorus (TP) and total organic carbon (TOC) values, reflect intensive human-related impact on the lake. The coincidence of limnological changes and local socio-economic development suggest that sedimentary PAHs record recent anthropogenic impact on Lake Sayram.

PAH and PCB contamination in the sediments of the Venice Lagoon (Italy) before the installation of the MOSE flood defence works.

Contamination from polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the shallow water areas of the Venice Lagoon (415km2) was investigated in the surface (0-5cm) and sub-surface (5-10cm) sediments by collecting cores from 380 sites. The concentrations of 14 PAHs (USEPA priority pollutants) and seven PCB indicator congeners were analysed with high-performance liquid chromatography (HPLC) and capillary gas chromatography (GC), respectively. PAH and PCB concentrations ranged from 2.75 to 9980ngg-1 d.w. and from 0.01 to 60.1ngg-1 d.w., respectively. Their concentrations never exceeded the probable effect level (PEL) stipulated in the respective quality guidelines. In addition, the average total PAH levels expressed as B[a]P toxicity equivalents (total TEQ) were lower in the sediments of the Venice Lagoon than in other literature-reported zones in the Mediterranean. PAH profiles and ratios showed that they originated not only largely from high-temperature pyrolytic processes attributable primarily to the burning of fossil fuels but also partly from petroleum spillage. Comparison of tetra-to-hepta PCB congeners enabled the PCB profiles observed in the lagoon environment to be characterised as Aroclor 1254 and 1260 (1:1). Compared to other marine coastal areas and harbours in the Mediterranean, the Venice Lagoon sediments showed a low mean value but a wide range of concentrations. The estimation of PAH and PCB inventories indicated the low contribution of atmospheric deposition relative to local sources.