Influence of sugarcane burning on indoor/outdoor PAH air pollution in Brazil

Distribution, sources and ecological risks of PAHs and n-alkanes in water and sediments of typically polluted estuaries: Insights from the Xiaoqing River

Seasonal water and sediment samples were collected from the Xiaoqing River estuary and the neighboring sea to study the spatial and temporal distributions, sources and ecological risks of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes. The results showed significant spatial and temporal differences in the concentrations of PAHs and n-alkanes under the influence of precipitation, temperature, and human activities. The concentrations of PAHs in water were lower in the wet season than in the dry season, and those in sediments were higher in the wet season than in the dry season. The concentrations of n-alkanes were higher in the rainy season than in the dry season for both water and sediments. The spatial distributions of PAHs and n-alkanes were estuarine > offshore. The concentration ranges of ∑PAHs in water and sediments were 230.66-599.86 ng/L and 84.51-5548.62 ng/g, respectively, in the wet season and 192.46-8649.55 ng/L and 23.39-1208.92 ng/g, respectively, in the dry season. The proportion of three-ring PAHs in water (57.03% and 78.27% in the wet and dry seasons, respectively) was high, followed by two-ring PAHs (27.31% and 13.59% in the wet and dry seasons, respectively). The proportion of four-ring PAHs was higher in sediments (24.79% and 32.20% in the wet and dry seasons, respectively). The ecological risk of PAHs assessed using the toxicity equivalent quotient and risk quotient was at moderate to moderately high risk levels. The high concentration of n-alkane fraction C16 (611.65-75594.58 ng/L) in the water is indicative of petroleum or other fossil fuel inputs. The main peaks of n-alkanes in river sediments were C27, C29 and C31, indicating higher inputs of plant sources. The sediments in the estuary showed dominance of both short-chain C16 and long-chain C25-C31, indicating a combined input of higher plants and petroleum. The diagnostic ratios of PAHs and n-alkanes indicated that their sources were mainly oil/coal/biomass combustion and petroleum spills attributed to frequent vehicular, vessel and mariculture activities. Given the potential ecological risks of PAHs and n-alkanes in water and sediments, future studies should focus on their bioaccumulation and biotoxicity.

Health burden of sugarcane burning on agricultural workers and nearby communities

Sugarcane is the most widely cultivated crop in the world, with equatorial developing nations performing most of this agriculture. Burning sugarcane is a common practice to facilitate harvest, producing extremely high volumes of respirable particulate matter in the process. These emissions are known to have deleterious effects on agricultural workers and nearby communities, but the extent of this exposure and potential toxicity remain poorly characterized. As the epidemicof chronic kidney disease of an unknown etiology (CKDu) and its associated mortality continue to increase along with respiratory distress, there is an urgent need to investigate the causes, determine viable interventions to mitigate disease andimprove outcomes for groups experiencing disproportionate impact. The goal of this review is to establish the state of available literature, summarize what is known in terms of human health risk, and provide recommendations for what areas should be prioritized in research.

Lung Cancer in the French West Indies: Role of Sugarcane Work and Other Occupational Exposures

OBJECTIVE

Our aim was to study the role of occupational exposures in lung cancer risk in the French West Indies, with special attention to some specific activities, such as sugarcane work, that can only be studied in a limited number of populations.

METHODS

We used data from a population-based case-control study that included 147 incident lung cancer cases and 405 controls. Smoking histories and detailed occupational histories with descriptions of tasks and substances were collected by questionnaire during face-to-face interviews. Odds ratios (OR) adjusted for sex, age, region, smoking status, and cigarette pack-years and 95% confidence intervals (95% CI) were estimated by unconditional logistic regression.

RESULTS

Significantly increased risks of lung cancer were found in sugarcane farm workers (OR = 2.7; 95% CI 1.1-6.6) and more generally in the sugarcane-growing sector (OR = 2.5; 95% CI 1.0-6.3) and to a lesser extent in rum production. Elevated risks of lung cancer were also observed among other agricultural workers, painters, warehouse porters, labourers, and maintenance and motor vehicle repair workers. Exposure to herbicides in sugarcane cultivation was associated with an increased risk of lung cancer (OR = 2.6; 95% CI 0.9-7.6).

CONCLUSION

These results show that occupational exposures contributed to lung cancer risk in the French West Indies, and highlighted the role of exposures related to sugarcane work.

Polycyclic aromatic hydrocarbons in road dusts of a densely populated African city: spatial and seasonal distribution, source, and risk assessment

Road dust is a principal source and depository of polycyclic aromatic hydrocarbons (PAHs) in many urban areas of the world. Hence, this study probed the spatial and seasonal pattern, sources, and related cancer health risks of PAHs in the road dusts sampled at ten traffic intersection (TIs) of a model African city. Mixed PAHs sources were ascertained using the diagnostic ratios and positive matrix factorization (PMF) model. The results showed fluctuations in mean concentrations from 36.51 to 43.04 µg/g. Three-ring PAHs were the most abundant PAHs with anthracene (Anth) ranging from 6.84 ± 1.99 to 9.26 ± 4.42 µg/g being the predominant pollutant in Ibadan. Benzo(k)Fluoranthene (BkF) which is a pointer of traffic emission was the most dominant among the seven carcinogenic PAHs considered, varying from 2.68 ± 0.43 to 4.59 ± 0.48 µg/g. Seasonal variation results showed that PAH concentrations were 20% higher during dry season than rainy season. The seven sources of PAHs identified by PMF model include the following: diesel vehicle exhausts, gasoline combustion, diesel combustion, coal tar combustion, gasoline vehicle exhausts, coal and wood (biomass) combustion, and emissions from unburnt fossil fuels. Employing the incremental lifetime cancer risk (ILCR) model, the city's cancer risk of 5.96E-05 for children and 6.60E-05 for adults were more than the satisfactory risk baseline of ILCR ≤ 10^-6 and higher in adults than in Children.

Trace metals, polycyclic aromatic hydrocarbons and polychlorinated biphenyls in the surface sediments from Sanya River, China: Distribution, sources and ecological risk

The urban inland river ecosystems are now facing comprehensive pollution and governance pressures. Up to now, few works related to the multiple pollution assessment of trace metals, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) for the urban inland river sediments have been reported in China. Our study investigated the spatial distribution, ecological risk and potential sources of trace metals, PAHs and PCBs in surface sediment collected from 20 sampling sites of Sanya River, Hainan Province, China. The pollution status and potential ecological risk of trace metals were evaluated using the contamination indexes including geoaccumulation index (I_geo), individual potential ecological risk (E_rⁱ), potential ecological risk index (RI) and pollution load index (PLI). Considering the carcinogenicity and toxicity of PAHs and PCBs to human health and the ecological environment, we also analyzed the distributions, sources and adverse biological effects of PAHs and PCBs according to the sediment quality guidelines (SQGs), principal component analysis (PCA) and other source analysis. This study revealed that the surface sediments in Sanya River were extremely slight pollution and showed a very low ecological risk according to I_geo, E_rⁱ, PLI and RI results for trace metals. Besides, PAHs and PCBs pollution detected may not pose considerable adverse biological effect to ecological environment in a foreseeable period on the basis of comprehensive research results. The overall surface sediments quality of the Sanya River not seem to pose a serious pollution and ecological risk based on the evaluation results of multiple pollution factors. The study provided detailed information on the multiple pollution status and location of surface sediments, one of the key environmental indicators of international tourism cities, in the Sanya River, which would be useful for the water quality improvement of Sanya River and the environmental remediation of the other coastal ecosystems from different regions.

Distribution, sources, and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the tidal creek water of coastal tidal flats in the Yellow River Delta, China

The concentrations, distribution, sources and ecological risk levels of polycyclic aromatic hydrocarbons (PAHs) in tidal creek water from coastal tidal flats of the Yellow River Delta were investigated. The concentrations of 16 PAHs ranged from 0.113 to 1.533, with a mean value of 0.496 ± 0.035 μg L^-1, which indicated a moderate level of pollution. The main long-term sources of PAHs in the coastal tidal flats of the Yellow River Delta were petroleum combustion and petroleum pollution. The ecological risk assessment showed that the levels of PAHs in tidal creek water of the coastal tidal flats in the Yellow River Delta corresponded to medium to high ecological risk levels, and a high probability of potential ecological risk, posing harm to aquatic organisms. Among the 7 sampling sites, site 5, site 6, and site 7 were at high ecological risk, and the other sites were at moderate ecological risk. PAH pollution in the tidal creek water near the Yellow River Estuary and farther south, in the coastal tidal wetland of Laizhou Bay, deserves special attention, especially with respect to the prevention and control of benzo[a]pyrene (BaP) pollution in the water.

A crucial review on polycyclic aromatic Hydrocarbons - Environmental occurrence and strategies for microbial degradation

Over the last century, contamination of polycyclic aromatic hydrocarbons (PAHs) has risen tremendously due to the intensified industrial activities like petrochemical, pharmaceutical, insecticides and fertilizers applications. PAHs are a group of organic pollutants with adverse effects on both humans and the environment. These PAHs are widely distributed in various ecosystems including air, soil, marine water and sediments. Degradation of PAHs generally occurs through processes like photolysis, adsorption, volatilization, chemical degradation and microbial degradation. Microbial degradation of PAHs is done by the utilization of diverse microorganisms like algae, bacteria, fungi which are readily compatible with biodegrading/bio transforming PAHs into H₂O, CO₂ under aerobic, or CH₄ under anaerobic environment. The rate of PAHs degradation using microbes is mainly governed by various cultivation conditions like temperature, pH, nutrients availability, microbial population, chemical nature of PAHs, oxygen and degree of acclimation. Several microbial species including Selenastrum capricornutum, Ralstonia basilensis, Acinetobacter haemolyticus, Pseudomonas migulae, Sphingomonas yanoikuyae and Chlorella sorokiniana are known to degrade PAHs via biosorption and enzyme-mediated degradation. Numerous bacterial mediated PAHs degradation methods are studied globally. Among them, PAHs degradation by bacterial species like Pseudomonas fluorescence, Pseudomonas aeruginosa, Rhodococcus spp., Paenibacillus spp., Mycobacterium spp., and Haemophilus spp., by various degradation modes like biosurfactant, bioaugmentation, biostimulation and biofilms mediated are also investigated. In contrarily, PAHs degradation by fungal species such as Pleurotus ostreatus, Polyporus sulphureus, Fusarium oxysporum occurs using the activity of its ligninolytic enzymes such as lignin peroxidase, laccase, and manganese peroxidase. The present review highlighted on the PAHs degradation activity by the algal, fungal, bacterial species and also focused on their mode of degradation.

Influencing factors and health risk assessment of polycyclic aromatic hydrocarbons in groundwater in China

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants. This study investigated the occurrence of 16 PAHs in groundwater of representative regions of China (the cities of Lanzhou, Shijiazhuang, and Golmud and in Du'an County) using a gas chromatograph mass spectrometer. The total concentrations of 16 PAHs (∑PAHs) were in the range 0-29.06 μg/L (average: 594.8 ng/L). Acenaphthylene (Acy) and Naphthalene (Nap) had the highest detected frequency (74.56 %) and highest average concentration (632.7 ng/L), respectively. The average concentration of ∑PAHs in each study area exhibited the following trend: Lanzhou > Golmud > Du'an dry season > Du'an wet season > Shijiazhuang. The dominant PAHs in the study areas comprised mainly 2-4-ring PAHs, i.e., Nap (38.71 %; Shijiazhuang), BaA (40.09 %; Du'an wet season), Ace (16.84 %; Du'an dry season), Nap (43.51 %; Lanzhou), and BaA (57.43 %; Golmud). Overall, the PAHs of 101 samples were derived primarily from combustion and a small number of samples of PAHs originated from petroleum sources. Owing to strong adsorption in the vadose zone, the concentrations of PAHs in Shijiazhuang groundwater were lower than those in the groundwater of Golmud and Du'an. The groundwater in Du'an, Lanzhou and Golmud exhibits potential carcinogenic risk if consumed without further treatment.

COVID-19 lockdowns reduce the Black carbon and polycyclic aromatic hydrocarbons of the Asian atmosphere: source apportionment and health hazard evaluation

ABSTRACT

The entire world is affected by Coronavirus disease (COVID-19), which is spreading worldwide in a short time. India is one of the countries which is affected most, therefore, the Government of India has implemented several lockdowns in the entire country from April 25, 2020. We studied air pollutants (i.e., PM_2.5, Black Carbon (BC), and Polycyclic Aromatic Hydrocarbons (PAHs) level, and observed significantly sudden reduced. In India, most of the anthropogenic activities completely stopped. Therefore, we studied the levels of BC, PAHs and PM_2.5 concentrations, their sources apportion, and health risk assessment during normal days, lockdown (from lockdown 1.0 to lockdown 4.0) and unlock down 1.0 situation at Sakchi, Jamshedpur city. It was observed that lockdowns and unlock down situations BC, PAHs and PM_2.5 concentrations were significantly lower than regular days. We applied the advanced air mass back trajectory (AMBT) model to locate airborne particulate matter dispersal from different directions to strengthen the new result. The diagnostic ratio analyses of BC shows that wood burning contribution was too high during the lockdown situations. However, during normal days, the PAHs source profile was dedicated toward biomass, coal burning, and vehicle emission as primary sources of PAHs. During the lockdown period, emission from biomass and coal burning was a significant contributor to PAHs. The summaries of health risk assessment of BC quantified an equal number of passively smoked cigarettes (PSC) for an individual situation was studied. This study focuses on the overall climate impact of pandemic situations.

Emission reduction of black carbon and polycyclic aromatic hydrocarbons during COVID-19 pandemic lockdown

The global pandemic COVID-19 necessitated various responses throughout the world, including social distancing, use of mask, and complete lockdown. While these measures helped prevent the community spread of the virus, the resulting environmental benefits of lockdown remained mostly unnoticed. While many studies documented improvements in air quality index, very few have explored the reduction in black carbon (BC) aerosols and polycyclic aromatic hydrocarbons (PAHs) concentrations due to lockdown. In this study, we evaluated the changes in concentrations of BC, PAHs, and PM_2.5 before and during the lockdown period. Our results show that lockdown resulted in a significant reduction in concentrations of these pollutants. The average mass concentration of BC, PAHs, and PM_2.5 before the lockdown was 11.71 ± 3.33 μgm^-3, 108.71 ± 27.77 ngm^-3, and 147.65 ± 41.77 μgm^-3, respectively. During the lockdown period, the concentration of BC, PAHs, and PM_2.5 was 2.46 ± 0.95 μgm^-3, 23.19 ± 11.21 ngm^-3, and 50.31 ± 11.95 μgm^-3, respectively. The diagnostic ratio analysis for source apportionment showed changes in the emission sources before and during the lockdown. The primary sources of PAHs emissions before the lockdown were biomass, coal combustion, and vehicular traffic, while during the lockdown, PAHs emissions were primarily from the combustion of biomass and coal. Similarly, before the lockdown, the BC mass concentrations came from fossil-fuel and wood-burning, while during the lockdown period, most of the BC mass concentration came from wood-burning. Human health risk assessment demonstrated a significant reduction in risk due to inhalation of PAHs and BC-contaminated air.

Polycyclic aromatic hydrocarbon concentrations in soils of greenhouses located in Aksu Antalya, Turkey

Polycyclic aromatic hydrocarbons (PAHs) are hydrophobic organic compounds that are generally absorbed on organic fraction of soils. It is known that some PAHs, which can pass to air, soil, water and food as a result of natural or anthropogenic processes, have carcinogenic, toxic and mutagenic effects on humans and animals. One of the important steps that is identified in the transition takes place during agricultural production. Greenhouses are commonly used as a type of agricultural production especially during the winter season in mid and temperate climates. Greenhouse cultivation is abundant in Antalya Aksu Region in Turkey. Two sampling campaigns (autumn and winter) were carried out to sample the soils in 53 glass and polyethylene covered greenhouses. The samples were analysed with gas chromatography-mass spectrometry (GC/MS) for 16 PAHs. The result showed that four ring PAHs were dominant in the region. In the winter season, PAHs concentrations increase because of low volatility of motor vehicle exhaust related PAHs in the atmosphere and of coal and wood combustion emissions used in the heating of greenhouses and surrounding village houses. The cross plots of diagnostic ratios also confirmed coal and wood combustion and traffic emissions in the region.

Genotoxicity and DNA damage signaling in response to complex mixtures of PAHs in biomass burning particulate matter from cashew nut roasting

Approximately 3 billion people world-wide are exposed to air pollution from biomass burning. Herein, particulate matter (PM) emitted from artisanal cashew nut roasting, an important economic activity worldwide, was investigated. This study focused on: i) chemical characterization of polycyclic aromatic hydrocarbons (PAHs) and oxygenated (oxy-) PAHs; ii) intracellular levels of reactive oxygen species (ROS); iii) genotoxic effects and time- and dose-dependent activation of DNA damage signaling, and iv) differential expression of genes involved in xenobiotic metabolism, inflammation, cell cycle arrest and DNA repair, using A549 lung cells. Among the PAHs, chrysene, benzo[a]pyrene (B[a]P), benzo[b]fluoranthene, and benz[a]anthracene showed the highest concentrations (7.8-10 ng/m³), while benzanthrone and 9,10-anthraquinone were the most abundant oxy-PAHs. Testing of PM extracts was based on B[a]P equivalent doses (B[a]P_eq). IC₅₀ values for viability were 5.7 and 3.0 nM B[a]P_eq at 24 h and 48 h, respectively. At these low doses, we observed a time- and dose-dependent increase in intracellular levels of ROS, genotoxicity (DNA strand breaks) and DNA damage signaling (phosphorylation of the protein checkpoint kinase 1 - Chk1). In comparison, effects of B[a]P alone was observed at micromolar range. To our knowledge, no previous study has demonstrated an activation of pChk1, a biomarker used to estimate the carcinogenic potency of PAHs in vitro, in lung cells exposed to cashew nut roasting extracts. Sustained induction of expression of several important stress response mediators of xenobiotic metabolism (CYP1A1, CYP1B1), ROS and pro-inflammatory response (IL-8, TNF-α, IL-2, COX2), and DNA damage response (CDKN1A and DDB2) was also identified. In conclusion, our data show high potency of cashew nut roasting PM to induce cellular stress including genotoxicity, and more potently when compared to B[a]P alone. Our study provides new data that will help elucidate the toxic effects of low-levels of PAH mixtures from air PM generated by cashew nut roasting.

Inhalation cancer risk estimation of source-specific personal exposure for particulate matter-bound polycyclic aromatic hydrocarbons based on positive matrix factorization

In previous studies, inhalation cancer risk was estimated using conventional risk assessment method, which was normally based on compound-specific analysis, and cannot provide substantial data for source-specific particulate matter concentrations and pollution control. In the present study, we applied an integrated risk analysis method, which was a synthetic combination of source apportionment receptor model and risk assessment method, to estimate cancer risks associated to individual PAHs coming from specific sources. Personal exposure particulate matter samples referring to an elderly panel were collected in a community of Tianjin, Northern China, in 2009, and 12 PAH compounds were measured using GC-MS. Positive matrix factorization (PMF) was used to extract the potential sources and quantify the source contributions to the PAH mixture. Then, the lung cancer risk of each modeled source was estimated by summing up the cancer risks of all measured PAH species according to the extracted source profile. The final results indicated that the overall cancer risk was 1.12 × 10^-5, with the largest contribution from gasoline vehicle emission (44.1%). Unlike other risk estimation studies, this study was successful in combining risk analysis and source apportionment approaches, which allow estimating the potential risk of all source types and provided suitable information to select prior control strategies and mitigate the main air pollution sources that contributing to health risks.

Environmental pollution of soil with PAHs in energy producing plants zone

Polycyclic aromatic hydrocarbons (PAHs) are widely distributed environmental toxicants primarily formed during the incomplete combustion of organic materials (for example, coal, oil, gasoline and wood). Power energy plants are the main sources of organic contaminants including PAHs. The purpose of the present research was to study the Novocherkassk Electric Power Station (NEPS) emission effects of PAHs accumulation in soils. The regional levels, types (groups) and spatial distribution of 16 priority PAHs were investigated. The monitoring sites were located on fallow lands of the 20 km around NEPS. PAHs extraction from collected soil samples was performed using the ecologically clean express-method of subcritical water extraction. The total PAHs content gradually increased in soil of the studied territories during 2016-2017 due to an increase in contaminants emission. Accordingly 16 priority PAHs were determined in the soil samples collected from the sites located to the northwest from NEPS in direction of predominant winds. The 5-km zone situated in direction of predominant winds was highly subjected to PAHs contamination, with maximal accumulation at a distance of 1.6 km from the source. The ratio of high- and low-molecular weight PAHs content in soils of monitoring sites was taken as an index of environmental soil contamination. The high-molecular weight PAHs concentration prevailed in monitoring sites soils situated in direction of predominant winds from NEPS, while the concentration of low-molecular weight PAHs prevailed in the monitoring sites soils situated around NEPS. Soil properties also influenced PAHs accumulation. Polyarenes content in Haplic Chernozems and Haplic Chernozems (Stagnic) was higher versus Fluvisols. This study provides the understanding and model the fate of PAHs in regional technogenic landscape.

Seasonal occurrence and cancer risk assessment of polycyclic aromatic hydrocarbons in street dust from the Novi Sad city, Serbia

This is the first investigation that identified seasonal occurrence, distribution and sources of 16 polycyclic aromatic hydrocarbons (PAHs) in 60 street dust samples collected within urban zone of Novi Sad, the second largest city in Serbia. The obtained results were further used for comprehensive assessment of carcinogenic risk of Serbian inhabitants exposed to PAHs present in street dust by the incremental lifetime cancer risk method. The total level of 16 PAHs ranged between 35 μg kg^-1 and 2422 μg kg^-1 in samples taken in summer and between 35 μg kg^-1 and 587 μg kg^-1 in samples taken in winter. In both seasons, 4-ring PAHs were the most dominant compounds and high molecular weight (HMW) PAHs had similar contribution (55% in summer and 65% in winter). The highest content was determined for fluoranthene (Fly) in both seasons (597 μg kg^-1 in winter, 301 μg kg^-1 in summer). The PAHs source apportionment was analyzed by principal component analysis (PCA) and diagnostic ratios, and combustion of petroleum seemed to be the main sources of the PAHs in street dust. The cancer risk level for children and adult were comparable for dermal contact and by ingestion, and ranged from 10^-6 to 10^-4 indicating a potential risk. Additionally, the total incremental life time cancer risk (ILCR) was assessed for children and adult population taking into account three possible exposure routs and the median total cancer risk was ˃10^-5, with 7% of the samples having the risk ˃10^-4 that should be considered of high concern with potential health problem. These results are the first of this kind for the whole Serbia and the Western Balkan region and can be considered as the base line for future research.

A Low-Cost Approach Using Diatomaceous Earth Biosorbent as Alternative SPME Coating for the Determination of PAHs in Water Samples by GC-MS

In this study, the use of recycled diatomaceous earth as the extraction phase in solid phase microextraction (SPME) technique for the determination of polycyclic aromatic hydrocarbons (PAHs) in river water samples, with separation/detection performed by gas chromatography-mass spectrometry (GC-MS), is proposed. The optimized extraction conditions are extraction time 70 min at 80 °C with no addition of salt. The limits of quantification were close to 0.5 μg L−1 with RSD values lower than 25% (n = 3). The linear working range was 0.5 μg L−1 to 25 μg L−1 for all analytes. The method was applied to samples collected from the Itajaí River (Santa Catarina, Brazil) and the RSD values for repeatability and reproducibility were lower than 15% and 17%, respectively. The efficiency of the recycled diatomaceous earth fiber was compared with that of commercial fibers and good results were obtained, confirming that this is a promising option to use as the extraction phase in SPME.

Spatio-temporal variability, distribution and sources of n-alkanes and polycyclic aromatic hydrocarbons in reef surface sediments of Kharg and Lark coral reefs, Persian Gulf, Iran

Environmental pollution, particularly oil pollution, has been a long-standing problem in marine areas. With the aim to assess the pollution status in the Persian Gulf, Iran, herein surface sediments were collected from Kharg and Lark coral reefs, in summer (dry season) and winter (wet season), to evaluate the spatio-temporal variations of n-alkanes and PAHs. The mean total organic carbon (TOC⁾ contents of sediments showed a significantly dramatic variation (p < 0.05) in both seasons at both Islands, with high values recorded at sites located near pollutant inputs. The total mean percent of clay grain-sized sediments at Kharg were 26.57% and 28.86% in dry and wet seasons, respectively, while in Lark were 26.73% in summer and 24.57% in winter. Additionally, at Kharg the mean ∑25n-alkanes and ∑30PAHs ranged from 81.35 to 573 µg g^-1 dw and 60.25-491 ng g^-1 dw in dry season, and 171-754 µg g^-1 dw and 41.61-693 ng g^-1 dw in winter, respectively. At Lark, the average ∑25n-alkanes and ∑30PAHs varied from 31.18 to 272 µg g^-1 dw and 41.25-196 ng g^-1 dw in summer, whilst oscillated from 57.99 to 332 µg g^-1 dw and 16.56-487 ng g^-1 dw in wet season, respectively. The lowest mean level of the examined pollutants were spanned in offshore sites, while the highest average concentrations indicated that contaminated sediments were at onshore stations at both Islands in both seasons. Significant seasonal variations (p < 0.05) were observed at most sampling sites for all pollutants. Molecular Diagnostic Ratio (MDR) and Principal Component Analysis (PCA) indicated that n-alkanes and PAHs had mostly a petrogenic source. The compositional profile of PAHs showed that 2 and 3-ring PAHs were abundant at both sampling sites. Significant positive correlation (r > 0.76) was observed between ∑25n-alkanes and ∑30PAHs at Kharg and Lark sediments with TOC content, especially for the sites with high total pollutant concentrations. Based on the potential impact and ecological risk of n-alkanes and PAHs in surface sediments, it is, therefore, necessary in future studies to focus on their effects on corals and other marine organisms within this ecosystem.

Quantitative evaluation of variation in defoliation traits among sugarcane genotypes

Development of easily defoliating sugarcane varieties is urgently needed to facilitate efficient mechanical harvesting, reduce production costs, and increase sugar yield in China. In order to quantify the defoliation characteristics of sugarcane, we investigated eight traits in two field experiments with a range of sugarcane varieties at maturity. The length (LSR) and angle (ASR) of the sheath ruptured from the stalk, defoliation force (DF), and self-defoliation (SD) were the traits with the greatest contribution to the quantitative assessment of sugarcane defoliation based on a principal component analysis, which accounted for more than 75% of the cumulative variability. A small set of traits, namely SD, ASR, and DF measured at the 10^th leaf were selected as predictors. Using these predictors, 37 out of 38 sugarcane cultivars were correctly classified into three groups (easy, difficult and intermediate in terms of ease of defoliation) that had been clustered based on six traits. These simplified measurements will be applied to screen new lines in the sugarcane breeding program in China.

Elucidating the urban levels, sources and health risks of polycyclic aromatic hydrocarbons (PAHs) in Pakistan: Implications for changing energy demand

Due to the severe fuel crisis in terms of natural gas, a paradigm shift in fuel combustion (diesel, gasoline, and biomass) may increase the atmospheric emissions and associated health risks in Pakistan. Present study was aimed to investigate the concentration of fugitive PAHs in the environment (outdoor and indoor settings), associated probabilistic health risk assessment in the exposed population, and possible linkage between fuel consumption patterns and PAHs emissions in twin cities (Rawalpindi and Islamabad) of Pakistan. Results showed that the mean PAHs concentrations (air: 2390pgm^-3; dust: 167ngg^-1) in the indoor environment were higher than that of the outdoor environment (air: 2132pgm^-3; dust: 90.0ngg^-1). Further, the source apportionment PCA-MLR receptor model identified diesel and gasoline combustion as the primary PAHs sources in the urban and sub-urban settings. Estimated life cancer risk (LCR) potential via inhalation to indoor PAHs was higher with a probability of 2.0 cases per 10,000 inhabitants as compared to outdoor exposure. Incremental lifetime cancer risk (ILCR) model from exposure to dust bound PAHs showed risk in the order of ingestion>dermal>inhalation for various exposure pathways. Likewise, estimated daily intake (EDI) model reflects that PAHs in surface dust enter into the human body mainly through the respiratory system because EDI for breathing was reported higher than that of oral intake. Therefore, adoption of sustainable fuels is recommended to meet the energy requirements and to reduce PAHs emissions and related health risks in the twin cities of Pakistan.

Review on characteristics of PAHs in atmosphere, anthropogenic sources and control technologies

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds composed of multiple aromatic rings. PAHs are ubiquitous atmospheric pollutants which are well-recognized as carcinogenic, teratogenic and genotoxic compounds. PAHs are released from incomplete combustion or pyrolysis of materials containing carbon and hydrogen, such as coal, oil, wood and petroleum products. Understanding the characteristics of PAHs in atmosphere, source profiles and technologies available for controlling PAHs emission is essential to reduce the impacts of PAHs. This paper offers an overview on concentration and distribution of atmospheric PAHs, emission factors and distribution of PAHs in different sources, and available control technologies. Characteristics of atmospheric PAHs vary with meteorological conditions and emission sources, while characteristics of PAHs emission depend on burned material and combustion condition. Combination of some technologies may be necessary for effective removal of both low-ring and high-ring PAHs.

Spatial distribution and composition of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and hopanes in superficial sediments of the coral reefs of the Persian Gulf, Iran

This study is the first quantitative report on petroleum biomarkers from the coral reefs systems of the Persian Gulf. 120 reef surface sediment samples from ten fragile coral reef ecosystems were collected and analyzed for grain size, biogenic elements, elemental ratios, and petroleum biomarkers (n-alkanes, PAHs¹ and Hopanes) to assess the sources and early diagenesis of sedimentary organic matter. The mean grain size of the reef sediments ranged from 13.56 to 37.11% (Clay), 26.92 to 51.73% (Sand) and 35.97 to 43.85% (Silt). TOC² (3.35-9.72 mg.g^-1) and TON³ (0.4-1.10 mg.g^-1) were identified as influencing factors on the accumulation of petroleum hydrocarbons, whilst BC⁴ (1.08-3.28 mg.g^-1) and TIN⁵ (0.13-0.86) did not exhibit any determining effect. Although BC and TIN demonstrated heterogeneous spatial distribution, TOC and TON indicated homogenous distribution with continually upward trend in concentration from the east to west ward of the Gulf. The mean calculated TOC/TN ratios vacillated according to the stations (p < 0.05) from 2.96 at Shidvar Island to 8.64 at Hengam Island. The high TOC/TN ratios were observed in the Hengam (8.64), Kharg (8.04) and Siri (6.29), respectively, suggesting a predominant marine origin. The mean concentrations of ∑C_11-35n-alkanes, ∑30 PAHs and ∑9Hopanes were found in the ranges of 385-937 μg.g^-1dw, (overall mean:590 μg.g^-1dw), 326-793 ng.g^-1dw (499 ng.g^-1dw), 88 to 568 ng.g^-1 d (258 ng.g^-1dw), respectively. Higher concentrations of detected petroleum biomarkers in reef sediments were chiefly distributed near main industrial areas, Kharg, Lavan and Siri, whilst the lower concentrations were in Hormoz and Qeshm. In addition, one-way ANOVA⁶ analysis demonstrated considerably significant differences (p < 0.05) among concentration of detected total petroleum hydrocarbons between most sampling locations. Some sampling sites especially Kharg, Lavan, Siri and Lark indicated higher concentration of n-alkanes due to the higher maintenance of organic matter by high clay content in the sediments. Furthermore, most sediment samples, except for Hormoz, Qeshm and Hengam showed an even carbon preference for n-alkanes which could be correlated to bacterial input. NPMDS⁷ analysis also demonstrated that among the congeners of petroleum biomarkers, n-C₁₂,n-C₁₄, n-C₁₆,n-C₁₈ and n-C₂₀ for n-alkanes, Phe⁸ and Naph⁹ along with their Alkyl homologues for PAHs (2-3 rings accounted for 60%) and C₃₀αβ and C₂₉αβ for Hopanes were discriminated from their other congeners in the whole study area. Our results based on the PCA¹⁰ analysis and diagnostic indices of AHs¹¹ and PAHs along with ring classification of PAHs, in addition, the ubiquitous presence of UCM,¹² and Hopanes revealed that the main sources of the pollution were petroleum and petroleum combustion mainly from offshore oil exploration and extraction, discharge of pollutants from shipping activities.

Diverse toxicological risks of PAHs in surface water with an impounding level of 175m in the Three Gorges Reservoir Area, China

The impounding level of 175m for the Three Gorges Reservoir (TGR) is of vital importance for efficient flood control, power generation and convenient navigation in China. However, little is known about the spatial distribution and toxicological risks of major pollutants in the Three Gorges Reservoir Area (TGRA) at that stage. The aim of this study is to probe the ubiquitous polycyclic aromatic hydrocarbons (PAHs) contamination and toxicological impacts in the surface water of the TGRA at the highest water impoundment level of 175m. Our results showed that the ƩPAHs levels ranged from 83 to 1631ng/L in the upper reaches, 354 to 1159ng/L in the middle reaches, and 23 to 747ng/L in the lower reaches of the TGRA. Source apportionment of PAHs indicated that coal combustion, industrial emissions, heavy traffic, agriculture and shipping activities were the primary sources. Compositional pattern highlighted >85% dominancy of low molecular weight (LMW) PAHs in the reservoir. Risk assessment based on risk quotients (RQs) implied moderate to high ecological risks: the upper reaches>the middle reaches>the lower reaches. However, gene expression profiles portrayed contrary scenario because of the presence of relatively higher footprints of high molecular weight (HMW) PAHs in the middle and the lower reaches, which was confirmed by Cox hazard proportional model. Moreover, the transgenic zebrafish Tg(cyp1a:gfp) induced by PAHs also expressed stronger fluorescent signals in the middle and lower reaches. Taken together, different approaches were employed to firstly reveal the real status of ecological toxicity of PAHs and explore the underlying mechanisms at the highest impounding level of 175m in the TGRA.

Characteristics, identification, and potential risk of polycyclic aromatic hydrocarbons in road dusts and agricultural soils from industrial sites in Shanghai, China

Road dusts and agricultural soil samples were collected from eight sites close to steel mills, chemical plants, and municipal solid waste incinerator in suburban Shanghai. Sixteen polycyclic aromatic hydrocarbons (PAHs) in the United States Environmental Protection Agency (US EPA) priority controlled list were analyzed quantitatively using GC-MS. The total PAH concentrations ranged from 0.79 to 6.2 μg g^-1 in road dust samples with a mean value of 2.38 μg g^-1 and 0.26 to 0.54 μg g^-1 in agricultural soils with an average of 0.36 μg g^-1. The most abundant individual PAHs were phenanthrene, fluoranthene, pyrene, chrysene, and benzo(b)fluoranthene in dust samples and phenanthrene, fluoranthene, chrysene, and benzo(b)fluoranthene, benzo (k) fluoranthene in soil samples. Dominant compounds were four-ring and five- to six-ring PAHs, which accounted for 41.5 and 31.5 % in dusts and 33.9 and 41.1 % in soils. The spatial distribution of PAHs in dusts and soils was consistent. The wind direction could affect the spatial distribution of PAHs. Organic matter contents were found to be significantly positively correlated with PAH concentrations in both dusts and soils while grain size of particles had no correlation with PAH concentrations and could not significantly influence the distribution of PAH concentrations. PAH isomer ratios showed that combustion of grass, wood, and coal was important sources of PAHs in road dusts and agricultural soils. Toxic equivalent concentrations indicated seven kinds of carcinogenetic PAHs were major toxic equivalent concentration (TEQ) contributors, accounting for 98 % of TEQ, in the road dusts and agricultural soils. Incremental lifetime cancer risk (ILCR) estimation results showed that the PAHs in the dusts and soils had potential cancer risk for both children and adults only by direct ingestion exposure. The TEQ and ILCR values of PAHs in road dusts were much higher than those in soils, which suggested that PAHs in road dusts could be an important source of PAHs in soils.

Polycyclic aromatic hydrocarbons in biomass-burning emissions and their contribution to light absorption and aerosol toxicity

In recent years, brown carbon (BrC) has been shown to be an important contributor to light absorption by biomass-burning atmospheric aerosols in the blue and near-ultraviolet (UV) part of the solar spectrum. Emission factors and optical properties of 113 polycyclic aromatic hydrocarbons (PAHs) were determined for combustion of five globally important fuels: Alaskan, Siberian, and Florida swamp peat, cheatgrass (Bromus tectorum), and ponderosa pine (Pinus ponderosa) needles. The emission factors of total analyzed PAHs were between 1.9±0.43.0±0.6 and 9.6±1.2-42.2±5.4mgPAHkg(-1)fuel for particle- and gas phase, respectively. Spectrophotometric analysis of the identified PAHs showed that perinaphthenone, methylpyrenes, and pyrene contributed the most to the total PAH light absorption with 17.2%, 3.3 to 10.5%, and 7.6% of the total particle-phase PAH absorptivity averaged over analyzed emissions from the fuels. In the gas phase, the top three PAH contributors to BrC were acenaphthylene (32.6%), anthracene (8.2%), and 2,4,5-trimethylnaphthalene (8.0%). Overall, the identified PAHs were responsible for 0.087-0.16% (0.13% on average) and 0.033-0.15% (0.11% on average) of the total light absorption by dichloromethane-acetone extracts of particle and gas emissions, respectively. Toxic equivalency factor (TEF) analysis of 16 PAHs prioritized by the United States Environmental Protection Agency (EPA) showed that benzo(a)pyrene contributed the most to the PAH carcinogenic potency of particle phase emissions (61.8-67.4% to the total carcinogenic potency of Σ16EPA PAHs), while naphthalene played the major role in carcinogenicity of the gas phase PAHs in the biomass-burning emission analyzed here (35.4-46.0% to the total carcinogenic potency of Σ16EPA PAHs). The 16 EPA-prioritized PAHs contributed only 22.1±6.2% to total particle and 23.4±11% to total gas phase PAH mass, thus toxic properties of biomass-burning PAH emissions are most likely underestimated.

Polycyclic aromatic hydrocarbons (PAHs) in water from three estuaries of China: Distribution, seasonal variations and ecological risk assessment

The distribution, seasonal variations and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in water from three estuaries in Hai River Basin of China, which has been suffering from different anthropogenic pressures, were investigated. In three estuaries, the average concentration of ΣPAHs was the lowest in Luan River estuary, followed by Hai River estuary, and the highest in Zhangweixin River estuary. There were significant seasonal variations in ΣPAHs, the concentrations of ΣPAHs were higher in November than in May and August. The composition profiles of PAHs in different sites were significantly different, and illustrated seasonal variations. Generally, 2-ring (Nap) and 3-ring PAHs (Acp, Fl and Phe) were the most abundant components at most sampling sites in three estuaries. The PAHs in three estuaries were mainly originated from pyrogenic sources. A method based on toxic equivalency factors (TEFs) and risk quotient (RQ) was proposed to assess the ecological risk of ΣPAHs, with the ecological risk of individual PAHs being considered separately. The results showed that the ecological risks caused by ΣPAHs were high in Hai River estuary and Zhangweixin River estuary, and moderate in Luan River estuary. The mean values of ecological risk in August were lower than those in November. The contributions of individual PAHs to ecological risk were different in May, August and November. 3-ring and 4-ring PAHs accounted for much more ecological risk than 2-ring, 5-ring and 6-ring, although the contributions of 5-ring and 6-ring to ecological risk were higher than these to PAHs concentrations.

Selection of oxidant doses for in situ chemical oxidation of soils contaminated by polycyclic aromatic hydrocarbons (PAHs): A review

In situ chemical oxidation (ISCO) is a promising alternative to thermal desorption for the remediation of soils contaminated with organic compounds such as polycyclic aromatic hydrocarbons (PAHs). For field application, one major issue is the selection of the optimal doses of the oxidizing solution, i.e. the oxidant and appropriate catalysts and/or additives. Despite an extensive scientific literature on ISCO, this choice is very difficult because many parameters differ from one study to another. The present review identifies the critical factors that must be taken into account to enable comparison of these various contributions. For example, spiked soils and aged, polluted soils cannot be compared; PAHs freshly spiked into a soil are fully available for degradation unlike a complex mixture of pollutants trapped in a soil for many years. Another notable example is the high diversity of oxidation conditions employed during batch experiments, although these affect the representativeness of the system. Finally, in this review a methodology is also proposed based on a combination of the stoichiometric oxidant demand of the organic pollutants and the design of experiments (DOE) in order to allow a better comparison of the various studies so far reported.

Mutagenicity profile of atmospheric particulate matter in a small urban center subjected to airborne emission from vehicle traffic and sugar cane burning

Atmospheric particulate matter (PM) is genotoxic and recently was classified as carcinogenic to humans by the International Agency for Research on Cancer. PM chemical composition varies depending on source and atmospheric conditions. The Salmonella/microsome assay is the most used mutagenicity test and can identify the major chemical classes responsible for observed mutagenicity. The objective of this work was to characterize the mutagenicity of PM samples from a countryside city, Limeira, Brazil, which is influenced by heavy traffic and sugar cane biomass burning. Six samples of total PM were collected. Air mass backward trajectories were calculated. Organic extracts were assayed using the Salmonella/microsome microsuspension mutagenicity assay using TA98, YG1041, and TA1538, with and without metabolic activation (S9). YG1041 was the most sensitive strain and mutagenicity reached 9,700 revertants per m(3) without metabolic activation. Potency for TA1538 was higher than TA98, indicating that this strain should be considered in air mutagenicity studies. The increased response to YG1041 relative to TA98, and the decreased response with S9, suggests that nitroaromatics are the major contributors. Limeira is among the most mutagenic cities in the world. High mutagenicity in Limeira seems to occur when the air mass from the area of sugarcane production is mixed with air from the region impacted by anthropogenic activities such as traffic. An increase in the formation of nitro-polycyclic aromatic hydrocarbons may result from longer contact time between the aromatic compounds and the atmosphere with high NOx and ozone concentration, although more studies are required to confirm this hypothesis.

Presence of PAHs in water and sediments of the Colombian Cauca River during heavy rain episodes, and implications for risk assessment

In Colombia little attention has been paid to river pollution with Polycyclic Aromatic Hydrocarbons (PAHs). Low environmental control and legislation in such emerging region could significantly contribute to high PAHs releases. In this study, we report the presence of PAHs in water and sediments of the Cauca River (Colombia). Three sampling campaigns were carried out between May 2010 and June 2011, and the samples were collected at eight relevant sites. The sampling time included measuring before, during, and after a season of heavy rains, which were influenced by the global coupled ocean-atmospheric phenomenon, which affected tropical countries with huge flooding, commonly called "La Niña", and/or "El Niño" Southern Oscillation (ENSO). The highest mean ∑PAH concentrations were 4476.5 ng/l and 1582.7 ng/g in water and sediments, respectively. The PAHs most detected were Benzo[b]fluoranthene, Benzo[k]fluoranthene, and Pyrene in sediments; and Fluorene, Acenaphtylene, and Anthracene in water. After the season of rains statistically significant higher PAH concentrations were detected. The results of the study were compared to other rivers worldwide at both environmental compartments, and did not show concentrations of special concern. In some sites, concentrations detected of PAHs were higher than screening benchmarks for ecological protection. Estimation of human health risks was carried out, and the results suggested some likely carcinogenic effects due to PAHs especially in children exposed during current recreational swimming and adults working in low technology sand extraction.

Emissions of PAHs derived from sugarcane burning and processing in Chiapas and Morelos México

Sugarcane burning is an agricultural practice implemented to ease farm worker duties; nevertheless, as a consequence, tons of particles are emitted to the atmosphere. Additionally, during harvesting the sugar-mills operate the whole day emitting hundreds of tons of pollutants. Therefore, health risks to neighboring population should be a major governmental concern, leading first to identification and quantification of toxic compounds, such as polycyclic aromatic hydrocarbons (PAHs). In order to establish the magnitude of the problem, four sampling campaigns of PM10 and PM2.5 were carried out in this study, during harvesting and no-harvesting seasons in two municipalities of México, with different climatic and social conditions. Concentrations of PM10, PM2.5, and organic compounds were determined daily, followed by extraction, identification and quantification of the 17 EPA-established PAHs from all samples. The results showed that during harvest, the PM10 mass increased lightly in Chiapas, but approximately twice in Morelos, whereas total PAH concentrations increased twice and six times, respectively. The most abundant PAHs, namely: indene [1,2,3cd] pyrene, benzo[b]fluoranthene, benzo[a]pyrene and dibenzo [a,h] anthracene are composed of 5 or more aromatic rings. Of the total PAHs quantified, 44% to 52% corresponded to carcinogenic compounds, consequently, the overall carcinogenic potential increased twice or three times. Principal component analysis with varimax rotation was applied to source apportionment at each site, suggesting three different sources during harvesting: the combustion process in the sugar mill, sugarcane burning and vehicular emissions. The combustion markers for sugar mill are, BAA, BBF, BKF, BAP, IND and BGP, whereas for sugarcane burning were ANT, PHE, FLT and PYR. The results obtained indicate that processing and burning sugarcane are the main sources of the PAH levels measured, proving that the health risks are boosted during harvesting due to increases of PM and PAHs.

Cytogenetic biomonitoring of occupationally exposed workers to ashes from burning of sugar cane in Ahome, Sinaloa, México

Burning the sugar cane field before harvesting has a negative impact on both air and human health, however this issue had not been explored in Mexico. The objective of this work was to determine the chromosomal damage in workers from sugar cane burning fields in Sinaloa, México. To this purpose, we analyzed 1000 cells of buccal exfoliated epithelia from 60 exposed workers and 60 non-exposed controls to determine micronucleus frequencies and other nuclear abnormalities. The results indicated significant higher values of micronucleus and nuclear abnormalities such as binucleate cells, pyknosis, karyolysis, chromatin condensation and nuclear buds frequencies in the exposed subjects compared to those that were not exposed. Our data indicates that sugar cane burning, that generates polycyclic aromatic hydrocarbons, represents a genotoxic risk for workers in this important sugar cane producing area in Mexico.

Ecological and human health hazards of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in road dust of Isfahan metropolis, Iran

This study investigates trace elements and PAHs content in road dust of Isfahan metropolis, central Iran. The mean concentrations of As, Cd, Cu, Ni, Pb, Sb and Zn are 22.15, 2.14, 182.26, 66.63, 393.33, 6.95 and 707.19 mg kg(-1), respectively. When compared with upper continental crust, the samples generally display elevated trace element concentrations, except for Co and Cr. The decreasing trend of calculated enrichment factors (EFs) is Cd>Pb>Sb>Zn>Cu>As>Ni>Cr>Co. Calculated potential ecological risk reveals that among the analyzed metals, Cd and Pb, have a higher potential ecological risk. Statistically, two identified main sources of trace elements include road traffic emissions and resuspension of soil particles. As, Cd, Cu, Pb, Sb and Zn in Isfahan road dust are strongly influenced by anthropogenic activity, mainly traffic emissions, while Co, Cr and Ni originate from resuspension of soil natural parent particles. The sum of 13 major PAHs (∑13PAHs) mass concentration ranges from 184.64 to 3221.72 μg kg(-1) with the mean being 1074.58 μg kg(-1). PAHs sources are identified using PCA analysis. It is demonstrated that the PAHs in Isfahan road dust are mainly derived from traffic emission, coal combustion and petroleum. Toxic equivalent concentrations (TEQs) of PAHs in the road dust ranges between 25.021 μg kg(-1) and 230.893 μg kg(-1). High correlation coefficients (r(2)=0.909 and 0.822, p<0.01) between Benzo[a]pyrene, Benzo[b+k]fluoranthene and toxicity equivalent concentrations of road dust indicate that Benzo[a]pyrene and Benzo[b+k]fluoranthenes are major TEQ contributors. The total incremental life time cancer risk (ILCR) of exposure to PAHs from Isfahan metropolis urban dust is 4.85 × 10(-4) for adult and 5.02 × 10(-4) for children. Estimated results of ILCR indicate that Isfahan residents are potentially exposed to high cancer risk via both dust ingestion and dermal contact.

A spatial multicriteria model for determining air pollution at sample locations

Atmospheric pollution in urban centers has been one of the main causes of human illness related to the respiratory and circulatory system. Efficient monitoring of air quality is a source of information for environmental management and public health. This study investigates the spatial patterns of atmospheric pollution using a spatial multicriteria model that helps target locations for air pollution monitoring sites. The main objective was to identify high-priority areas for measuring human exposures to air pollutants as they relate to emission sources. The method proved to be viable and flexible in its application to various areas.

Particle-bound PAHs quantification using a 3-stages cascade impactor in French indoor environments

Cascade Impactor is a powerful sampling method to collect airborne particles as a function of their size. The 3-stages Cascade Impactor used in this study allowed to sample simultaneously particles with aerodynamic diameter Dae>10 μm, 2.5 μm<Dae<10 μm, 1 μm<Dae<2.5 μm and Dae<1 μm. Once collected individual concentrations of the 16 US-EPA priority Polycyclic Aromatic Hydrocarbons (PAHs) bound to particles were quantified for 8 different indoor environments located in Strasbourg area in France. All the heavy PAHs owning between 4 and 6 aromatic rings were detected in all of the 8 sampling sites. The total PAHs concentration varied from 0.44 to 2.09 ng m(-3) for a low-energy building school and a smoking apartment, respectively. Results revealed also that high molecular weight PAHs were mainly associated to the finest particles. Our data are consistent with those measured elsewhere in European indoor environments.

Effect of water current on the distribution of polycyclic aromatic hydrocarbons, heavy metals and benthic diatom community in sediments of Haihe estuary, China

The pollution loads continuously increased in Haihe estuary, of Tianjin, China, due to intensive human activities, especially the construction of the Haihe Gate and Lingang Industrial Area. In 2011, hydrological variability in Haihe estuary was investigated and sediments were collected. Total organic carbon (TOC), particle size, total polycyclic aromatic hydrocarbons (ΣPAHs), heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn), and benthic diatom community were analyzed. The highest concentrations of ΣPAHs and heavy metals were found near the Haihe Gate. The Shannon diversity index and the relative abundance of Coscinodiscus perforatus (RC) indicated a decreasing trend seaward. Results of Pearson correlation analysis illustrated significant relations between water current velocity and ΣPAHs (p < 0.01), Cr (p < 0.05), and RC (p < 0.05). Path analysis further indicated that water current played an important role in the distribution of PAH, Cr, and RC.

Effects of Siberian wildfires on the chemical composition and acidity of atmospheric aerosols of remote urban, rural and background territories

Extensive forest fires occurred during the summer of 2012 in Siberia. This work presents the influence of long-range atmospheric smoke on the aerosol properties at urban, suburban and background sites, which are located 400-800 km from the fire source. The higher levels of submicron particles (PM1), organic (OC), secondary organic (SOC) and elemental (EC) carbon were observed at all sampling sites, whereas an increase in ionic species HCOO(-), K(+), NO3(-), and Cl(-) and a decrease in pH was higher at the background and suburban sites in comparison with the urban site. Other natural and anthropogenic factors appear to be more significant for ions Ca(2+) + Mg(2+), HCO3(-), NH4(+), SO4(2-) and Na(+). The present study indicates that the impact of remote fires on the aerosol characteristics depends on their background (without fires) levels at the sampling sites.

Model-based evaluation of the use of polycyclic aromatic hydrocarbons molecular diagnostic ratios as a source identification tool

Polycyclic Aromatic Hydrocarbons (PAHs) molecular diagnostic ratios (MDRs) are unitless concentration ratios of pair-PAHs with the same molecular weight (MW); MDRs have long been used as a tool for PAHs source identification purposes. In the present paper, the efficiency of the MDR methodology is evaluated through the use of a multimedia fate model, the calculation of characteristic travel distances (CTD) and the estimation of air concentrations for individual PAHs as a function of distance from an initial point source. The results show that PAHs with the same MW are sometimes characterized by substantially different CTDs and therefore their air concentrations and hence MDRs are predicted to change as the distance from the original source increases. From the assessed pair-PAHs, the biggest CTD difference is seen for Fluoranthene (107 km) vs. Pyrene (26 km). This study provides a strong indication that MDRs are of limited use as a source identification tool.

Nature and sources of particle associated polycyclic aromatic hydrocarbons (PAH) in the atmospheric environment of an urban area

The total PAH associated to the airborne particulate matter (PM10) was apportioned by one receptor model based on positive matrix factorization (PMF) in an urban environment (Zaragoza city, Spain) during February 2010-January 2011. Four sources associated with coal combustion, gasoline, vehicular and stationary emissions were identified, allowing a good modelling of the total PAH (R(2) = 0.99). A seasonal behaviour of the four factors was obtained with higher concentrations in the cold season. The NE direction was one of the predominant directions showing the negative impact of industrial parks, a paper factory and a highway located in that direction. Samples were classified according to hierarchical cluster analysis obtaining that, episodes with the most negative impact on human health (the highest lifetime cancer risk concentrations), were produced by a higher contribution of stationary and vehicular emissions in winter season favoured by high relative humidity, low temperature and low wind speed.

Rationing health protection: a proposal to exempt nuisance dust from US Clean Air Act regulations

The US House of Representative has passed a bill called the "Farm Dust Regulation Prevention Act" (Dust Act) that would exempt most types of particulate matter (PM) in rural areas from the air quality controls of the US Clean Air Act. The Dust Act would markedly change the country's air quality standards. An examination of the proposed provisions shows that they would exempt non-combustion PM pollutants from mining, smelting, petroleum production, and power generation from existing air quality standards. Persons downwind from pollutants generated in rural areas could be exposed to concentrations of carcinogenic heavy metals, asbestos, and benzene known to adversely affect their health and ecological resources. Existing federal air quality standards based on science would be replaced by a flexible standard that rations health protection.