Low Polycyclic Aromatic Hydrocarbons Concentrations Research Articles

Biochars with low polycyclic aromatic hydrocarbon concentrations achievable by pyrolysis under high carrier gas flows irrespective of oxygen content or feedstock

The release of polycyclic aromatic hydrocarbons (PAHs) from biochar is a concern when applied in agriculture or other sectors. Therefore, the objective of this study was to produce “clean” biochars under pyrolysis conditions presumed to minimize their PAH content. Willow, Miscanthus, wheat straw and Sida hermaphrodita feedstocks were pyrolysed under controlled conditions in a laboratory pyrolyzer for 4h at temperatures of 500, 600 and 700°C under a continuous stream of nitrogen. Additionally, the oxygen content was varied from 0 up to 2.0% during the pyrolysis of Miscanthus. Elemental analyses confirmed that the biochars met the European Biochar Certificate (EBC) and International Biochar Initiative (IBI) guidelines. Their resulting PAH concentrations, quantified with an optimized analytical method, were consistently very low (<1.5mgkg−1dw), and qualified them as premium grade (EBC) or Class 1 (IBI). Neither the feedstock nor the oxygen content had a significant influence on the PAH content. Although at 600°C the PAH concentrations were significant lower than at the other temperatures, the temperature range of 500–700°C is considered suitable to obtain minimal PAH concentrations. This work confirms the hypothesis that complete removal of gas-phase pyrosynthesized PAHs leads to biochars with low PAH concentrations.

Miniscale Liquid-Liquid Extraction Coupled with Full Evaporation Dynamic Headspace Extraction for the Gas Chromatography/Mass Spectrometric Analysis of Polycyclic Aromatic Hydrocarbons with 4000-to-14 000-fold Enrichment.

A new sample preparation approach of combining a miniscale version of liquid-liquid extraction (LLE), termed miniscale-LLE (msLLE), with automated full evaporation dynamic headspace extraction (FEDHS) was developed. Its applicability was demonstrated in the extraction of several polycyclic aromatic hydrocarbons (PAHs) (acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, and pyrene) from aqueous samples. In the first step, msLLE was conducted with 1.75 mL of n-hexane, and all of the extract was vaporized through a Tenax TA sorbent tube via a nitrogen gas flow, in the FEDHS step. Due to the stronger π-π interaction between the Tenax TA polymer and PAHs, only the latter, and not n-hexane, was adsorbed by the sorbent. This selectivity by the Tenax TA polymer allowed an effective concentration of PAHs while eliminating n-hexane by the FEDHS process. After that, thermal desorption was applied to the PAHs to channel them into a gas chromatography/mass spectrometric (GC/MS) system for analysis. Experimental parameters affecting msLLE (solvent volume and mixing duration) and FEDHS (temperature and duration) were optimized. The obtained results achieved low limits of detection (1.85-3.63 ng/L) with good linearity (r(2) > 0.9989) and high enrichment factors ranging from 4200 to 14 100. The optimized settings were applied to the analysis of canal water sampled from an industrial area and tap water, and this methodology was compared to stir-bar sorptive extraction (SBSE). This innovative combined extraction-concentration approach proved to be fast, effective, and efficient in determining low concentrations of PAHs in aqueous samples.

Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in sediments from Khuzestan province, Iran

Khuzestan, Iran is heavily industrialised with petrochemical and refinery companies. Herein, sediment and soil samples were collected from Hendijan coast, Khore Mosa and Arvandroud River. The CHEMSIC (CHEmometric analysis of Selected Ion Chromatograms) method was used to assign the main sources of polycyclic aromatic hydrocarbon (PAH) pollution. A four-component principal component analysis (PCA) model was obtained. While principal component 1 (PC1) was related to the total concentration of PAHs, the remaining PCs described three distinct sources: PC2 and PC3 collectively differentiate between weathered petrogenic and pyrogenic, and PC4 is indicative for a diagenetic input. The sources of PAHs in the Arvandroud River were mainly relatively fresh oil with some samples corresponding to a weathered oil input. Further, perylene (indicator for diagenetic source) was identified. Samples from Khore Mosa revealed a mixture with high proportions of high-molecular-weight PAHs, indicating a pyrogenic/weathered petrogenic source. Samples from Hendijan coast contained low relative concentrations of PAHs, thus only little information on pollution sources.

Field evaluation and calibration of a small axial passive air sampler for gaseous and particle bound polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs

Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated analogues (OPAHs) are ubiquitous air pollutants known to cause adverse health effects. PAH air levels are commonly monitored by active sampling but passive sampling has become popular because of its lower cost and simplicity, which facilitate long-term sampling and increased spatial coverage. However, passive samplers are less suitable for short-term sampling and are in general less accurate than active samplers because they require reliable sampling rate (Rs) measurements for individual analytes under diverse environmental conditions. In this study a small passive sampler designed to sample both particle-bound and gaseous compounds was evaluated and calibrated for PAHs and OPAHs in a traffic environment by co-deployment with active samplers for two weeks. Despite the relatively low average air concentrations of PM10 (20 μg/m3), PM2.5 (5 μg/m3), total PAHs (4.2 ng/m3), and OPAHs (2.3 ng/m3) at the site, detectable quantities (on average 24 times above blank values) of the full range of PAHs and OPAHs were captured, with low variability (average RSD of 16%). This was accomplished by using a Tenax® TA-modified glass fiber substrate that is compatible with highly sensitive thermal desorption GC-MS analysis, which made it possible to achieve detection limits per sample in the pg range. Experiments with inverted samplers revealed that the relative contribution of gravitational settling to the sampling of particles carrying PAHs and OPAHs was around 3.5 times larger than other deposition mechanisms. Average Rs values for individual OPAHs and PAHs were 0.046 ± 0.03 m3/day and 0.12 ± 0.07 m3/day, respectively, with no appreciable difference between the values for particle-associated and gaseous compounds. Furthermore, the Rs values were competitive with other currently used passive samplers if normalized for substrate area. Overall, the new sampler’s performance, simplicity and ability to generate relatively time-resolved data make it a promising candidate for diverse SVOC monitoring studies.

Monitoring of polycyclic aromatic hydrocarbons in a produced water disposal area in the Potiguar Basin, Brazilian equatorial margin.

The Potiguar Basin has oil and gas production fields offshore and onshore. All treated produced water (PW) from these fields is discharged through submarine outfalls. Although polycyclic aromatic hydrocarbons (PAHs) are minor constituents of PW, their input into the marine ecosystem is environmentally critical due to potential ecological hazards. A 2-year monitoring program was conducted in the vicinity of the outfalls to evaluate PAH bioaccumulation in marine life from PW discharges. The study was performed using transplanted bivalves Crassostrea brasiliana and semipermeable membrane devices (SPMDs) to measure PAH concentrations via bioaccumulation and in seawater. The bioaccumulation of PAH in transplanted bivalves reached up to 1105ngg(-1) in the vicinity of the monitored outfall. Significantly lower PAH concentrations were found in the reference area in comparison to the studied area around the outfalls. Time-integrated PAH concentrations in seawater ranged from 38 to 0.3ngL(-1) near the outfalls and from 10ngL(-1) to not detected in the reference area. Both measurement techniques were found to be effective for determining a gradient of descending PAH concentrations from the outfalls. In addition, this study also evaluated the bioavailability of PAH for local marine biota and provided information about the influence of PW discharges on the water quality of marine ecosystems.

Oil Sorbents based on Methacrylic Acid - Grafted Polypropylene Fibers: Synthesis and Characterization

People are exposed to polycyclic aromatic hydrocarbons (PAHs) outdoors and indoors. Although there is a fair amount of literature review concerning exposure to settled dust, and in particular, to PAHs indoors, no attempts have been made to report contamination in household settled floor dust in Jordan. In this study we aimed at identifying the source origin of the PAHs as indoors or outdoors inside eight selected dwellings in Amman, Jordan. We also aimed at investigating the spatial variation of the analyzed PAHs concentrations within Amman. The floor dust samples were collected from the entrance and living room areas. The total PAHs concentrations at the living room area ranged from 65422 ng/g to about 641 ng/g. At the entrance area, the highest total PAHs concentration was about 9266 ng/g and the lowest was about 241 ng/g. The differences among dwellings for the total and individual PAHs concentrations confirms that each dwelling has its own environmental conditions and we cannot make a general conclusion with respect to the source origin as indoors or outdoors. The spatial variation of the PAHs concentrations showed that the north-eastern part of Amman had lower PAHs concentrations than that observed in the south-western part. This agrees well with a previous study about the spatial variation of fine aerosol particle number concentrations measured within the city during the same period by Hussein et al. who reported that fine particle number concentrations in the north eastern part of the city is lower than that in the south western part.

Evaluation of the boundary condition influence on PAH concentrations in the water column during the sediment dredging of a port

The mobilisation of sediments and related contaminants connected to dredging activities is one of the most critical issues to the environmental risk and exposure assessment of a dredging project. The aim of this paper was an investigation of the mobilisation of polycyclic aromatic hydrocarbons (PAHs) due to the dredging of the Port of Genoa (Italy) to identify the temporal and spatial extent of the contaminant transport, and the influence of the dredging and the boundary conditions on it. The results showed relatively low background PAH concentrations in the water column and confirmed the dredging as the primary rising factor of concentrations in the water column, but also showed a complex scenario in which the different environmental and dredging factors forced the concentrations at different levels and moments. The post dredging phase showed PAH values close to the background conditions and the concentrations remained relatively high only for a few PAHs.

Low concentrations of PAHs induce tolerance in nitrifying bacteria

The ability of marine microbes to develop tolerance to polycyclic aromatic hydrocarbons (PAHs) was examined in a 90-day experiment. PAH levels in sediment were increased 0.3 and 1.6 times compared to the control sediment. Day 30, 60 and 90 the microbes were re-exposed to PAHs in a short-term toxicity test to detect tolerance, where nitrification and denitrification were used as endpoints. In addition, molecular analysis of the microbial communities was performed to detect possible differences in proportions of nitrifying bacteria compared to total bacterial abundance (amoA/rpoB-ratio) between treatments and control. We here show PAH-induced tolerance in nitrifying microbial communities after 60 and 90 days of pre-exposure, as potential nitrification EC10-values were significantly higher in the low treatment (L) after 60 days and in both treatments after 90 days compared to control. Tolerance development in denitrification was not detected. Furthermore, the developed tolerance resulted in reduced nitrification efficiency, compared to control. It was also shown that the induced tolerance produced dissimilar amoA/rpoB-ratio between treatments and control, indicating that development of tolerance changed the community composition and that the development time depended on initial exposure. The results from this study have implications for future studies or environmental monitoring programs of long-term oil and PAH-contaminated sites. The possibility for development of tolerance needs to be taken into account and potential nitrification can be used for evaluation of marine microbial health. Furthermore, changed proportions of nitrifying microbes can alter the capacity of ammonium oxidizing in benthic marine sediments.

Polycyclic aromatic hydrocarbons in soils from urban to rural areas in Nanjing: Concentration, source, spatial distribution, and potential human health risk

Polycyclic aromatic hydrocarbons (PAHs) have become a major type of pollutant in urban areas and their degree of pollution and characteristics of spatial distribution differ between various regions. We conducted a comprehensive study about the concentration, source, spatial distribution, and health risk of 16 PAHs from urban to rural soils in Nanjing. The mean total concentrations of 16 PAHs (∑16PAHs) were 3330ngg−1 for urban soils, 1680ngg−1 for suburban soils, and 1060ngg−1 for rural soils. Five sources in urban, suburban, and rural areas of Nanjing were identified by positive matrix factorization. Their relative contributions of sources to the total soil PAH burden in descending order was coal combustion, vehicle emissions, biomass burning, coke tar, and oil in urban areas; in suburban areas the main sources of soil PAHs were gasoline engine and diesel engine, whereas in rural areas the main sources were creosote and biomass burning. The spatial distribution of soil PAH concentrations shows that old urban districts and commercial centers were the most contaminated of all areas in Nanjing. The distribution pattern of heavier PAHs was in accordance with ∑16PAHs, whereas lighter PAHs show some special characteristics. Health risk assessment based on toxic equivalency factors of benzo[a]pyrene indicated a low concentration of PAHs in most areas in Nanjing, but some sensitive sites should draw considerable attention. We conclude that urbanization has accelerated the accumulation of soil PAHs and increased the environmental risk for urban residents.

Combined chemical and toxicological evaluation of leachate from municipal solid waste landfill sites of Delhi, India.

In the present study, landfill leachate of three landfill sites of Delhi, India, was toxico-chemically analyzed for human risk assessment. Raw leachate samples were collected from the municipal solid waste (MSW) landfills of Delhi lacking liner systems. Samples were characterized with relatively low concentrations of heavy metals while the organic component exceeded the upper permissible limit by up to 158 times. Qualitative analysis showed the presence of numerous xenobiotics belonging to the group of halogenated aliphatic and aromatic compounds, polycyclic aromatic hydrocarbons (PAHs), phthalate esters, and other emerging contaminants. Quantitative analysis of PAHs showed that the benzo(a)pyrene-toxic equivalence quotient (BaP-TEQ) ranged from 41.22 to 285.557 ng L(-1). The human risk assessment methodology employed to evaluate the potential adverse effects of PAHs showed that the cancer risk level was lower than the designated acceptable risk of 10(-6). However, significant cytotoxic and genotoxic effects of leachates on HepG2 cell line was observed with MTT EC50 value ranging from 11.58 to 20.44 % and statistically significant DNA damage. Thus, although the leachates contained low concentrations of PAHs with proven carcinogenic potential, but the mixture of contaminants present in leachates are toxic enough to cause synergistic or additive cytotoxicity and genotoxicity and affect human health.

Foreword to ‘Fracking: Environmental Challenges and Solutions for Unconventional Oil and Gas Development' Research Front

The amalgamation of advanced horizontal drilling and multistage hydraulic fracturing has enabled the economic feasibility of oil and gas recovery from unconventional resources. Fossil energy from these unconventional resources is the fastest growing component of new supplies of oil and gas. In addition to extensive use of these technologies in the United States, there are many new unconventional oil and gas resources that are being exploited in Asia, Europe, Australia and Africa. These developments have generated public concern over the potential for adverse social, environmental and human health impacts. As the environmental challenges and solutions for oil and gas development are emerging and growing, accumulation of the initial scientific body of research addressing environmental issues is underway. This is an important time to highlight significant findings. In this Research Front, Gregory and Mohan provide an overview of issues associated with well casing and cementing, hydrological fracturing, and the chemistry and management of produced waters, for the general reader who may be unfamiliar with this topic. This is followed by three original research articles. Tang et al. report on a combined chemical and bioanalytical assessment of water associated with coal seam gas (CSG) in Australia. They found that, in addition to high concentrations of sodium, chloride and bicarbonate, the waters contained low concentrations of polycyclicaromatic hydrocarbons (PAHs). However, the observed concentrations of PAHs and other constituents explained only 5% of the observed effects on induction of several stress response genes in bioassays. Regardless, the observed responses were similar to those observed for treated wastewater effluent, storm water or surface water. Payne et al. describe the toxicity of CSG-associated water to human gastrointestinal cell lines. Although acute cytotoxicity was observed in this study, it was found that a 5-fold dilution of the water would reduce toxicity to below the threshold of the assay. The authors point out that there are many possible fracturing fluid mixtures that should be characterised; in some cases these mixtures can contain up to 80 chemical constituents posing a challenge for regulators. Their assay is offered as a potential screening tool, although they indicate that other cell types and endpoints should be evaluated. Finally, Monzon et al. report on the use of microbial fuel cells (MFCs) to treat hypersaline-produced water and to generate electricity. Based on pyrosequencing data, they identified a single genus (Halanaerobium) that constituted ,86% of the microbial community colonising the anode of theMFC. The study demonstrates the feasibility of this technology to treat produced waters and suggest avenues for future research. Together these articles clearly outline some of the challenges associated with understanding the chemistry and toxicity of produced waters, as well as some of the potential solutions to assessing and mitigating their risks.

Environmental quality assessment of a tropical wetland contaminated by weathered hydrocarbon wastes

In this work, was assessed the environmental quality of Santa Alejandrina wetland impacted by the Mexican oil industry. The assessment was achieved by conducting an analysis of variance between the content of total petroleum hydrocarbons (TPH) and that of polycyclic aromatic hydrocarbons (PAH), including the biological indexes for both flora and fauna. Significantly higher values (p <0.05) of richness and biodiversity were found in the control zone compared to contaminated zones. It was observed that the control zone had low concentrations of both TPH and PAH, which allows for the support of a greater number of species than in the rest of the contaminated zones. We conclude that biological indexes and concentrations of TPH and PAH are useful to determine the environmental degradation of a wetland associated to soil contaminated by weathered hydrocarbon wastes. We considered that the approach used in this study may be applied to other wetlands. [Received: March 27, 2014; Accepted: March 27, 2014].

High concentrations of polycyclic aromatic hydrocarbons (naphthalene, phenanthrene and pyrene) failed to explain biochar's capacity to reduce soil nitrous oxide emissions

The presence of polycyclic aromatic hydrocarbons (PAHs) has been postulated as a mechanism by which biochar might mitigate N2O emissions. We studied whether and to what extent N2O emissions were influenced by the three most abundant PAHs in biochar: naphthalene, phenanthrene and pyrene. We hypothesised that biochars contaminated with PAHs would show a larger N2O mitigation capacity and that increasing PAH concentrations in biochar would lead to higher mitigation potentials. Our results demonstrate that the high-temperature biochar (550 °C) had a higher capacity to mitigate soil N2O emissions than the low-temperature biochar (350 °C). At low PAH concentrations, PAHs do not significantly contribute to the reductions in soil N2O emissions; while biochar stimulated soil N2O emissions when it was spiked with high concentrations of PAHs. This study suggests that the impact of biochar on soil N2O emissions is due to other compositional and/or structural properties of biochar rather than to PAH concentration.

Molecular composition of fossil charcoal and relationship with incomplete combustion of wood

Upper Triassic charcoal extracts were studied using gas chromatography–mass spectrometry (GC–MS) to recognize their molecular composition. Extractable compounds were divided into: (i) biomarkers, i.e. diagenetically changed primary wood components and (ii) products of combustion. Major compounds in the first group were: 1,2,5-trimethylnaphthalene and 1,2,5,6-tetramethylnaphthalene, cadalene, dehydroabietane, simonellite and retene. All of these are derived from resins. Moreover, propyl phenols, butyl acetophenones and pentyl acetophenones, as products of lignin breakdown, as well as fatty acids with a predominance of palmitic acid, typical constituents of wood, were also detected. Polycyclic aromatic hydrocarbons (PAHs), as well as ketones and aryl phenols, considered as high temperature combustion products, occurred at relatively low concentration in the samples due to their enhanced solubility in gelified, non-charred wood fragments, and vaporization of the major part of the burn products. Despite the low PAH concentrations, their distribution, with a significant contribution from typical pyrolytic compounds such as anthracene, 4H-cyclopenta[def]phenanthrene, benz[a]anthracene and benzo[a]pyrene was typical for rapid combustion. We propose to estimate paleo-wildfire temperature based on the PAH concentrations in the paleo-charcoal samples. The presence of thermally less stable organic compounds and low PAH abundances indicates a temperature < 400°C. High PAH amounts seem to be characteristic for charring between 400 and 500°C. Above these temperatures PAH concentrations again decrease, but less stable compounds are absent.

Characterization and sources analysis of polycyclic aromatic hydrocarbons in surface sediments in the Yangtze River Estuary

Eighteen polycyclic aromatic hydrocarbons (PAHs), including 16 PAHs selected as priorities for control by the US Environmental Protection Agency, 1-methylnaphthalene and 2-methylnaphthalene, were determined in sediment samples from the Yangtze River Estuary, including the intertidal marshes and the river plume area. Results showed the PAH concentrations in marsh sediments (316–792 ng g−1) were higher than those in the river plume sediment (98–391 ng g−1). Further analysis suggested the PAH concentrations are correlated with total organic carbon (r = 0.71, p < 0.05), as well as water current and industrial activities. However, particle size less affects distribution of PAHs in Yangtze River Estuary. Results also showed a difference in PAHs’ compositions between marsh and river plume sediments: PAHs with two rings were more abundant than other PAHs’ compositions in river plume sediments, while PAHs with 3–4 rings were dominated in marsh sediments. This distribution pattern suggested different contamination sources between marsh and river plume sediments. The diagnostic ratios of PAH isomers and principal component analysis further demonstrated the PAHs in the marsh sediment came from burning biomass or coal, and those from river plume sediments derived from a mixture of petrogenic and pyrolytic source. The concentrations of total PAHs in the sediments from Yangtze River Estuary were relatively low in comparison with other estuaries around the world. And ecological risk assessment also suggested that the PAHs in the Yangtze River Estuary sediments present little ecotoxicological risk. However, a risk assessment for chronic exposure to low PAH concentrations should be performed in a further study.

The application of d-SPE in the QuEChERS method for the determination of PAHs in food of animal origin with GC–MS detection

This paper reports the evaluation of the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for the determination of polycyclic aromatic hydrocarbons (PAHs) in food of animal origin with GC–MS detection. Although in the available literature, there is a lot of information about sample preparation method for PAHs determination in food samples, but the QuEChERS method application for PAHs determination in food of animal origin has not been reported as yet. The results showed that the best recovery ratios 72.4–110.8 % with relative standard deviation lower than 10 % for all determined compounds were received for the method with ethyl acetate as an extraction solvent, primary–secondary amine and C18 sorbents and evaporation to dryness and dissolving the residues in the hexane. The limit of quantification ranged from 0.0003 to 0.0030 mg kg−1 for pyrene and benzo[a]anthracene, respectively. This method was also used for the determination of PAHs in 15 samples of pork ham. In 8 of 15 samples selected, PAHs were identified. It was observed that in 6 cooked ham and one smoked and cooked samples, any PAHs were found. In other samples, which were smoked and roasted, some low concentration of PAHs was detected. In one sample benzo[a]pyrene (0.0015 mg kg−1), in one sample benzo[b]fluoranthene (0.0015 mg kg−1) and in one sample chrysene (0.0024 mg kg−1) were detected. A number of other less harmful PAHs were also determined. There were no exceedances of maximum levels (according to Commission Regulation (EU) No 835/2011) for determined PAHs in any of the analysed samples.

Comparative DNA damage and oxidative effects of carcinogenic and non-carcinogenic sediment-bound PAHs in the gills of a bivalve

Polycyclic aromatic hydrocarbons (PAHs) regarded as carcinogenic and non-carcinogenic to humans are ubiquitous hydrophobic pollutants that tend to be trapped in aquatic sediments. As a consequence of their acknowledged toxicity and pro-mutagenic or even carcinogenic potential, PAHs are deemed prioritary in biomonitoring programmes. Still, the differences between the toxicity of carcinogenic and non-carcinogenic PAHs are poorly known especially, when aquatic organisms are exposed to ecologically-relevant concentrations of these compounds in sediments. Laboratory bioassays with sediments spiked with phenanthrene (Phe) and benzo[b]fluoranthene (B[b]F), non-carcinogenic and carcinogenic PAH, respectively, were conducted and the effects of exposure (related to DNA damage and oxidative stress) were analyzed in the gills of a burrowing clam, Ruditapes decussatus (Bivalvia, Veneridae). To ensure ecological relevance, two contaminant concentrations (termed “low” and “high”) were selected in accordance with available PAH sediment quality guidelines. The results showed that, even in “low” concentrations, both compounds caused a likely genotoxic effect in the gills, which is in accordance with the link between PAHs in water. Glutathione S-transferase activity and glutathione biosynthesis appear to be associated with limited lipid peroxidation even though they were insufficient to prevent higher and faster genotoxicity induced by exposure to the carcinogenic B[b]F, comparative to Phe. Overall the findings indicate that low concentrations of sediment-bound PAHs, carcinogenic or not, may be rendered significantly bioavailable to benthic filter-feeders as to induce genotoxicity, revealing that even PAHs considered non-carcinogenic to humans detain a latent, albeit significant, pro-mutagenic hazard to bivalve molluscs.

Water quality assessment of the Tubarão River through chemical analysis and biomarkers in the Neotropical fish Geophagus brasiliensis

The Tubarão River rises in Santa Catarina, Brazil, and has been historically affected by coal mining activities around its springhead. To evaluate its water conditions, an investigation regarding a possible decontamination gradient associated with the increased river flow toward the estuary, as well as the influence of seasonality over this gradient was performed through a series of biomarkers (vitellogenin, comet assay, lipid peroxidation, protein carbonylation, gluthatione, gluthatione S-transferase, acetylcholinesterase, light microscopy in liver, and scanning electron microscopy in gills) and chemical analysis (polycyclic aromatic hydrocarbons (PAHs) in bile and metal analysis in sediment) in the cichlid Geophagus brasiliensis. Two collections (summer and winter) were made in four distinct sites along the river, while sediments were sampled between those seasons. As expected, the contamination linked exclusively to mining activities was not observed, possibly due to punctual inputs of contaminants. The decontamination gradient was not observed, although seasonality seemed to have a critical role in the responses of biomarkers and availability of contaminants. In the summer, the fish presented higher histopathological damages and lower concentrations of PAHs, while in the winter they showed both higher genetic damage and accumulation of PAHs. The Tubarão suffers impacts from diverse activities, representing health risks for wild and human populations.

A comparative assessment of PM2.5exposures in light-rail, subway, freeway, and surface street environments in Los Angeles and estimated lung cancer risk

According to the U.S. Census Bureau, 570000+ commuters in Los Angeles travel for over 60 minutes to work. Studies have shown that a substantial portion of particulate matter (PM) exposure can occur during this commute. This study represents the integration of the results from five commute environments in Los Angeles. Personal PM exposures are discussed for the: (1) METRO gold line, a ground-level light-rail route, (2) METRO red line, a subway line, (3) the 110, a high volume freeway with low heavy-duty vehicle (HDV) fraction, (4) the 710, a major corridor for HDVs from the Port of Los Angeles, and (5) Wilshire/Sunset Boulevards, major surface streets. Chemical analysis including total and water-soluble metals and trace elements, elemental and organic carbon (EC/OC), and polycyclic aromatic hydrocarbons (PAHs) was performed. The focus of this study is to compare the composition and estimated lung cancer risk of PM2.5 (dp < 2.5 μm) for the five differential commute environments. Metals associated with stainless steel, notably Fe, Cr, and Mn, were elevated for the red line (subway), most likely from abrasion processes between the rail and brakes; elements associated with tire and brake wear and oil additives (Ca, Ti, Sn, Sb, and Pb) were elevated on roadways. Elemental concentrations on the gold line (light-rail) were the lowest. For water-solubility, metals observed on the red line (subway) were the least soluble. PAHs are primarily derived from vehicular emissions. Overall, the 710 exhibited high levels of PAHs (3.0 ng m−3), most likely due to its high volume of HDVs, while the red and gold lines exhibited low PAH concentrations (0.6 and 0.8 ng m−3 for red and gold lines, respectively). Lastly, lung cancer risk due to inhalation of PAHs was calculated based on a commuter lifetime (45 years for 2 hours per workday). Results showed that lung cancer risk for the 710 is 3.8 and 4.5 times higher than the light-rail (gold line) and subway (red line), respectively. With low levels of both metal and PAH pollutants, our results indicate that commuting on the light-rail (gold line) may have potential health benefits when compared to driving on freeways and busy roadways.

Polycyclic Aromatic Hydrocarbons in Birch Wood Slow Pyrolysis Products

The products from slow pyrolysis of birch hardwood are promising to be used for various purposes, in addition to conventional charcoal. To evaluate their utilization, knowledge about their polycyclic aromatic hydrocarbons (PAHs) is needed. The content and distribution of the PAHs in the different products were determined in a test run with a typical slow pyrolysis carbonization retort. The PAH compositions of gases, and distillates including aqueous phases and tars, were followed in terms of time and retort temperature. Also, other compounds in gases and aqueous phases through the test run were analyzed. PAHs were found in all the products, but were mostly concentrated in the tars. Because of the results, the PAH contents in the tars has to be considered. In contrast, very low PAH concentrations were found for the tar-free aqueous phases. Because of low PAH and also low benzene contents, the aqueous phases are promising to be utilized in various applications, for example as biodegradable pesticides. Due t...