Increase In Polycyclic Aromatic Hydrocarbons Concentrations Research Articles

Occurrence and Sources of Polycyclic Aromatic Hydrocarbons and Factors Influencing Their Accumulation in Surface Sediment of a Deep-Sea Depression, Namely, the Tatar Trough (Tatar Strait, the Sea of Japan)

The concentrations of 14 polycyclic aromatic hydrocarbons (PAHs) in the sediment of the Tatar Trough were studied. Despite the increase in PAH concentrations over recent decades, which is likely the result of the handling and transportation of fossil fuels, PAH levels and ecological risk were found to be low. The spatial pattern revealed that higher PAH concentrations were mainly in the deeper water sites, suggesting that trough slope failure transported the PAHs to the deeper part of the basin. There was no correlation between the PAHs and grain size or the PAHs and organic carbon that is related to the PAH input from a variety of sources and the heterogeneity of organic matter. The PAH composition, isomer ratio, and PCA identified two areas with different PAH sources. The most northern part of the Tatar Trough received petrogenic PAHs that are probably transported downslope from the northern Tatar Strait where fossil fuels are handled in some ports. Another trough part was polluted by the PAHs from the combustion of coal and biomass and the exhaust of marine vehicles. The minor presence of genes responsible for aerobic PAH destruction can be explained by the anaerobic degradation of PAHs or the spontaneous creation of favorable conditions that promote bacterial PAH oxidation.

Urbanization-related changes over the last 20 years in occurrence, sources, and human health risks of soil PAHs in rural Tianjin, China

Polycyclic aromatic hydrocarbons (PAHs) are major pollutants in urban areas, and thus present a high risk to the resident health. However, studies on local PAH emissions and associated health risks related to urbanization are scarce. Here, the concentrations of PAHs were determined in 57 surface soil samples obtained from two rural districts in 2018 in Tianjin, China. The sources, risks, and the linkage between urbanization and PAH contamination of soils in 2018 were compared with PAH data in 2001 from a previous study to investigate the changes induced by urbanization. Results show an increase in PAH concentrations from 2001 to 2018, with in particular the predominance of anthracene and dibenz[a,h]anthracene. The major sources of soil PAHs changed from coal combustion 32.9%, petroleum sources 32.1%, and traffic sources 22.1% in 2001, to traffic sources 63.7%, and petroleum and biomass combustion 18.7% in 2018. The carcinogenic risk of soil PAHs to residents also increased from safe level to low level, and dermal contact was the prevailing pathway of PAH exposure. The increase in cancer risk is mainly due to the changes in PAH sources.

Assessment of Polycyclic Aromatic Hydrocarbons Pollution in Lake and Reservoir Sediments in Korea

Polycyclic aromatic hydrocarbons (PAHs) are pollutants that require management as they are continuously formed by natural and anthropogenic processes. We assessed PAH pollution in freshwater sediment in major lakes and reservoirs of Korea. We collected samples of surface sediment in spring 2018; these were sieved to obtain sand, silt and clay (<2 mm). We extracted dry sediment using Hexane:Acetone(1:1) and analyzed the concentration of 16 PAHs by GC-MS. Measured concentration of PAHs was compared with threshold effect concentration(TEC) and probable effect concentration (PEC), and concentration ratio of chemical species was analyzed to track source. PAH concentrations ranged from 13 ng/g-dw to 1 337 ng/g-dw, (median 123 ± 204 ng/g-dw),which are below TEC and are similar or slightly lower than those reported by previous studies. At most sites, the dominant PAH source was natural combustion such as forest fires rather than anthropogenic such as petroleum. In contrast, the site with the highest PAH concentration (1 337 ng/g-dw) in Dae-am reservoir indicated natural and anthropogenic sources. Pollution levels of PAHs in reservoirs and lakes in Korea is not of concern in general. However, some sites with PAHs from anthropogenic sources need to be monitored to investigate possible increase in PAH concentrations in future. Key Words: PAHs, Sediment, Pollution assessment, Pollution evaluation guideline, Composition ratio of 16 PAHs

Uptake pathway and accumulation of polycyclic aromatic hydrocarbons in spinach affected by warming in enclosed soil/water-air-plant microcosms.

The partition of polycyclic aromatic hydrocarbons (PAHs) among water-soil-air is temperature-dependent. Thus, we hypothesized that climate warming will affect the accumulation and uptake pathway of PAHs in plants. To test this hypothesis, enclosed soil/water-air-plant microcosm experiments were conducted to investigate the impact of warming on the uptake and accumulation of four PAHs in spinach (Spinacia oleracea L.). The results showed that root uptake was the predominant pathway and its contribution increased with temperature due to the promoted acropetal translocation. Owing to the increase in freely dissolved concentrations of PAHs in soil pore water, the four PAH concentrations in roots increased by 60.8-111.5% when temperature elevated from 15/10 to 21/16 °C. A model was established to describe the relationship between bioconcentration factor of PAHs in root and temperature. Compared with 15/10 °C, the PAH concentrations in leaves at both 18/13 and 21/16 °C elevated due to the increase in PAH concentrations in air, while slightly decreased when temperature elevated from 18/13 to 21/16 °C because the PAH concentrations in air decreased, resulting from accelerated biodegradation of PAHs in topsoil. This study suggests that warming will generally enhance the PAH accumulation in plant, but the effect will differ among different plant tissues.

Historical trends and spatial distributions of polycyclic aromatic hydrocarbons in the upper reach of the Huai River, China: Evidence from the sedimentary record

The historical trends and spatial distributions of 15 polycyclic aromatic hydrocarbons (PAHs) in sediments from the upper reach of the Huai River were investigated. The concentrations of total PAHs (ΣPAHs) in the surface sediments varied from 3.96 to 379 ng/g (average: 65.3 ng/g). PAHs in the surface sediments of the studied area were at a low level compared with some other rivers around the world. The component characteristics showed that four-ring PAHs were predominant. The principal component analysis-multiple linear regression (PCA/MLR) showed that PAHs in the surface sediments primarily originated from coal combustion and vehicular emissions, which accounted for 62.7% and 37.3% of ΣPAHs, respectively. The concentration of ΣPAHs in the sediment core ranged from 2.31 to 21.9 ng/g with deposition flux ranging from 1.91 to 33.3 ng/cm2/year. The historical pattern of PAHs correlated with the Chinese socioeconomic conditions during 1912–2014, confirming that PAHs are a sensitive tracer for anthropogenic activity. Since the 1980s, there was a sharp increase in PAHs concentrations in the studied core. PCA/MLR showed that PAHs in the sediment core were mainly from the burning of fossil fuels. The concentration of PAHs in the surface sediment and sediment core was affected by the content of total organic carbon and black carbon. The result revealed in this study could serve as a reference for the development of relevant remedial strategies for the management of the Huai River.

Relationship between metabolic enzyme activities and bioaccumulation kinetics of PAHs in zebrafish (Danio rerio)

Many studies have investigated bioaccumulation and metabolism of polycyclic aromatic hydrocarbons (PAHs) in aquatic organisms. However, lack of studies investigated both processes simultaneously, and the interaction between these two processes is less understood so far. This study investigated the bioaccumulation kinetics of PAHs and metabolic enzyme activities, including total cytochrome P450 (CYPs) and total superoxide dismutase (T-SOD), in zebrafish. Mature zebrafish were exposed to the mixture of phenanthrene and anthracene under constant concentration maintained by passive dosing systems for 16days. The results showed that PAH concentrations in zebrafish experienced a peak value after exposure for 1.5days, and then decreased gradually. The bioaccumulation equilibrium was achieved after exposure for 12days. Both of the uptake rate constants (ku) and the elimination rate constants (ke) decreased after the peak value. The variation of PAH concentrations and metabolic enzyme activities in zebrafish had an interactive relationship. The activities of CYPs and T-SOD increased initially with the increase of PAH concentrations, but decreased to the lowest state when PAH concentrations reached the peak value. When the bioaccumulation equilibrium of PAHs was achieved, CYPs and T-SOD activities also reached the steady state. In general, CYPs and T-SOD activities were activated after exposure to PAHs. The decrease of PAH concentrations in zebrafish after the peak value may be attributed to the great drop of ku and the variation of CYPs activities. This study suggests that an interactive relationship exists between bioaccumulation kinetics of PAHs and metabolic enzyme activities in aquatic organisms.

Analysis of polycyclic aromatic hydrocarbons in cigarette samples using gel permeation chromatography clean-up by gas chromatography–tandem mass spectrometry

A new method using gel permeation chromatography (GPC) as clean-up by gas chromatography coupled to a triple quadrupole tandem mass spectrometry (GC–MS/MS) was established to measure the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in cigarette samples. GPC clean-up was employed to purify cigarette mainstream smoke samples collected from cigarettes in China, giving cleaner final extracts than traditional solid phase extraction (SPE). GC–MS/MS with a “pseudo” multiple reactive monitoring mode (PMRM) proved superior to the classic single quadrupole technique, with enhanced sensitivity and more accurate. Trace level PAHs could be readily confirmed by their retention times and characteristic ions. The concentrations of PAHs in these cigarette samples ranged from 455.9ng/cig to 1201.3ng/cig in the range of cigarette tar between 5mg and 12mg, with the main components being two-, three, and four-ring PAHs. When tar is over 10mg, there is 14.4% increase in PAH concentrations on average than that tar is between 8 and 10mg, while there is 28.6% decrease when tar is below 6mg. These results indicate that relative low-tar cigarettes provide relative low emission levels of PAHs.

Polycyclic aromatic hydrocarbons in blood related to lower body mass in common loons

We captured 93 wintering adult and subadult Common Loons (Gavia immer) in coastal Louisiana from 2011 to 2015 following the Deepwater Horizon oil spill. We tested blood samples for exposure to polycyclic aromatic hydrocarbons (PAHs) and measured physiological variables including hematocrit, hemoglobin and total blood protein. PAH concentrations in loon blood differed from year to year and by age class. High PAH concentrations were significantly related to lower body masses in both adult and subadult birds and higher serum protein levels in adults only. PAH concentrations had marginal relations with both hematocrit and hemoglobin levels. The types of PAHs detected also underwent a major shift over time. The PAHs detected in 2011, 2012, and 2015 were primarily low molecular weight (three carbon rings); however, in 2013, most detected PAHs were high molecular weight (four carbon rings). It is unclear what events led to the increase in PAH concentrations and the shift in type of PAHs over time.

Increased concentrations of polycyclic aromatic hydrocarbons in Alpine streams during annual snowmelt: investigating effects of sampling method, site characteristics, and meteorology.

Silicone passive samplers and macroinvertebrates were used to measure time-integrated concentrations of polycyclic aromatic hydrocarbons (PAHs) in alpine streams during annual snowmelt. The three sampling sites were located near a main highway in Arthur's Pass National Park in the Southern Alps of New Zealand. A similar set of PAH congeners, composed of 2-4 rings, were found in silicone passive samplers and macroinvertebrates. The background PAH concentrations were similar at all sites, implying that proximity to the highway did not affect concentrations. In passive samplers, an increase of PAH concentrations by up to seven times was observed during snowmelt. In macroinvertebrates, the concentration changes were moderate; however, macroinvertebrate sampling did not occur during the main pulse observed in the passive samplers. The extent of vegetation in the catchment appeared to affect the concentration patterns seen at the different stream sites. A strong correlation was found between PAH concentrations in passive samplers and the amount of rainfall in the study area, indicating that the washout of contaminants from snowpack by rainfall was an important process.

Localized enrichment of polycyclic aromatic hydrocarbons in soil, spruce needles, and lake sediments linked to in-situ bitumen extraction near Cold Lake, Alberta

The extraction of bitumen from the Alberta oil sands using in-situ technologies is expanding at a rapid rate; however, investigations into the environmental impacts of oil sands development have focused on surface mining in the Athabasca region. We measured polycyclic aromatic hydrocarbons (PAH) in soils, spruce needles, and lake sediment cores in the Cold Lake oil sands region to provide a historical and spatial perspective on PAH contamination related to in-situ extraction activities. A pronounced increase in PAH concentrations was recorded in one of two study lakes (Hilda Lake) corresponding to the onset of commercial bitumen production in ∼1985. Distance from extraction rigs was not an important predictor of PAH concentrations in soils, although two samples located near installations were elevated in alkyl PAHs. Evidence of localized PAH contamination in Hilda Lake and two soil samples suggests that continued environmental monitoring is justified to assess PAH contamination as development intensifies.

Gas–particle concentrations of atmospheric polycyclic aromatic hydrocarbons at an urban and a residential site in Osaka, Japan: Effect of the formation of atmospherically stable layer on their temporal change

A comparative study on atmospheric polycyclic aromatic hydrocarbons (PAHs) in particulate matter and the gaseous phase was performed at an urban and a residential site in Osaka, Japan, during 2005–2006. PAH concentrations at the urban site were found to be approximately twice higher than those at the residential site. At both sites, particulate PAH concentrations increased mainly in winter while the trends of temporal change in gaseous PAH concentrations were not clearly observed. The main sources of PAHs were estimated to be local traffic, e.g., diesel engines with catalytic converter. PAH concentrations did not significantly negatively correlate with ozone concentrations and meteorological parameters. Gas–particle partitioning coefficients of representative PAHs with low molecular weight (LMW) significantly negatively correlated with ambient temperature, showing that temporal change in the LMW PAH concentrations in PM could be attributable to the shift of their gas–particle distribution caused by the change in ambient temperature. For the first time, we studied the effect of the formation of atmospherically stable layer following an increase in PAH concentrations in Japan. At the urban site, PAHs showed a significant positive correlation with potential temperature gradients, indicating that temporal variability in PAH concentrations would be dominantly controlled by the formation of atmospherically stable layer in Osaka area.

Historical record and source apportionment of polycyclic aromatic hydrocarbons in the Lianhuan Lake sediments

Polycyclic aromatic hydrocarbons (PAHs) in a sediment core from the north Lianhuan Lake were collected to investigate its historical changes in the last one hundred years and its possible influence on ecological system in the lake. GC-MS was used to determine the concentrations of PAHs, and sediment chronological age was examined by (137)Cs dating approach. The concentrations of 16 different kinds of PAHs in the sediment samples ranged from 297 to 1,327 ng g(-1), and the low molecular weight (LMW) were predominant. The intensification of industrial and anthropogenic activities in the Daqing oil field may play the key role in the increase of PAHs concentrations in the late 1950s. To the early 1980s, the PAHs concentrations significantly decreased due to the grain size coarsening in the sediment samples, which was confirmed by the precipitation information. The 5-6 rings PAHs concentrations increased in the early 1980s may be attributed to the consumption of petroleum, coal and wood. The results showed that both the PAHs historical record and current concentrations may cause some influence on the Lianhuan Lake ecological system. The toxicology research on this ecological system should be done in the further investigations for determining the PAHs damage on human and ecological system health.

Sources, distribution and variability of hydrocarbons in total atmospheric suspended particulates of two Brazilian areas influenced by sugarcane burning

Polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons (AHs), such as n-alkanes, hopanes and steranes, were studied in relation to total atmospheric suspended particulates (TSP). Two representative Brazilian cities affected by sugarcane monoculture practices, with their rural surroundings, were chosen for the study. The cities chosen were Maceio (state of Alagoas, NE-Brazil) and Campos dos Goytacazes (state of Rio de Janeiro, SE-Brazil). Samples were collected during the harvesting period, when sugarcane burning occurs, and during the non-harvesting period. The aliphatic hydrocarbon fingerprints suggest a marked contribution of biogenic inputs and a slight contamination by aliphatics in areas far from the urban regions. In the urban areas, some petroleum contributions were observed, marked by the presence of hopanes (m/z 191) and steranes (m/z 217) in the mass chromatographic profiles. A marked increase in PAH concentrations was detected during the sugarcane burning periods, mainly at Campos dos Goytacazes. In a similar approach, n-alkane concentrations and BaP/nC24 ratios were higher during the sugarcane burning periods. These increases were mainly associated with PAH production by the pyrogenic process in relation to aliphatic hydrocarbons with the same carbon numbers. The PAH isomeric ratios and the mixture of petrogenic and pyrogenic compounds of the TSP suggest atmospheric contamination for all regions as a whole, but the more elevated pyrogenic contribution during the sugarcane burning period implies that the impact of this activity is relevant.

Temporal Change in Atmospheric Polycyclic Aromatic Hydrocarbons in Particulate Matter from an Urban Location of Osaka, Japan: Estimation of Causes of a Significant Increase in their Concentrations in the Winter Season

Forty-five compounds of ambient polycyclic aromatic hydrocarbons (PAHs) in particulate matter were examined at an urban location of Osaka, Japan, over the period of one year from April 2001 to March 2002. A comparative survey was performed at a roadside location of Shijonawate, located in eastern Osaka. PAH concentrations at the two locations decreased from spring to summer, and increased in winter. The maximum total PAH concentrations of >100ng m-3 were observed on 15∼16 January at the both locations. However, the use of automobile with diesel engine, estimated to be main emission sources of PAHs, was almost constant at the roadside location during the measuring period. Total PAH concentrations show negative correlations between ambient temperature, sunshine quantity and wind speed. Therefore, possible causes of the increase in PAH concentrations in the winter season is the enhancement of condensation of low-molecular-weight PAHs onto the surface of PM, the depression of the photolytic degradation and the appearance of atmospherically stable layer. In particular, from an estimation of potential temperature gradient, an abnormally strong stablelayer would form on 15∼16 January, resulting in the significantly high PAH concentrations on that day.

Historical changes in the concentrations of polycyclic aromatic hydrocarbons (PAHs) in Lake Peipsi sediments

The distribution of 11 individual polycyclic aromatic hydrocarbons (PAHs) was analysed in a (210)Pb dated sediment core from the deepest area of Lake Peipsi and in four surface sediment samples taken from littoral areas. According to the concentrations in the core three groups of PAHs may be distinguished: (1) relatively stable concentrations of PAHs within the whole studied time interval; (2) very low concentrations in sediments accumulated before intensive anthropogenic impact (from 19th century up to the 1920s) following a slight increase and (3) an overall increase in PAH concentrations since the 1920s up to the present. Comprehensive analysis of PAHs in the core and monitoring data obtained in the 1980s together with the lithology of sediments show that an increase of anthropogenically induced PAHs correlates well with the history of fuel consumption in Estonia and speaks about atmospheric long-distance transport of PAHs. The continuous increase of PAH concentrations since the 1920s do not support the earlier hypothesis about the dominating impact of the oil shale fired power plants near the lake, because their emissions decreased significantly in the 1990s. The concentration of PAHs in the deep lake core sample correlates well with the content of organic matter, indicating absorption and co-precipitation with plankton in the sediment.

Polycyclic aromatic hydrocarbons in soil and surface marine sediment near Jubany Station (Antarctica). Role of permafrost as a low-permeability barrier

Although Antarctica is still considered as one of the most pristine areas of the world, the growing tourist and fisheries activities as well as scientific operations and their related logistic support are responsible for an increasing level of pollutants in this fragile environment. Soils and coastal sediments are significantly affected near scientific stations particularly by polycyclic aromatic hydrocarbons (PAHs). In this work sediment and soil were sampled in two consecutive summer Antarctic expeditions at Potter Cove and peninsula, in the vicinity of Jubany Station (South Shetland Islands). Two- and 3-ring PAHs (methylnaphthalene, fluorene, phenanthrene and anthracene) were the main compounds found in most sites, although total PAH concentrations showed relatively low levels compared with other human-impacted areas in Antarctica. Pattern distribution of PAHs observed in samples suggested that low-temperature combustion processes such as diesel motor combustion and open-field garbage burning are the main sources of these compounds. An increase in PAH concentrations was observed from surface to depth into the active soil layer except for a unique sampling site where a fuel spill had been recently reported and where an inverted PAH concentration gradient was observed. The highest level was detected in the upper layer of permafrost followed by a sharp decrease in depth, showing this layer is acting as a barrier for downward PAH migration. When PAH levels in soil from both sampling programs were compared a significant decrease (p<0.01) was observed in summer 2005 (range at 75-cm depth: 12+/-1-153+/-22 ng/g) compared to summer 2004 (range at 75-cm depth: 162+/-15-1182+/-113 ng/g) whereas concentrations in surface sediment collected nearby the station PAHs increased drastically in 2005 (range: 36+/-3-1908+/-114 ng/g) compared to 2004 (range: 28+/-3-312+/-24 ng/g). Precipitation regime and water run off suggest that an important wash out of soil-PAHs occurred during the interval time between samplings. Results showed that the present PAH contamination level of Jubany Station is relatively low compared to other reported cases in Antarctica but also suggests that an increase in rain and in thawing processes caused by the global warming could result in an important soil-associated PAH mobilization with unpredictable consequences for the biota of Potter Cove.

The mobilisation of polycyclic aromatic hydrocarbons (PAHs) from the coal-tar lining of water pipes

The use of coal-tar as an internal lining for corrosion protection of water pipes was a common procedure from the 19th century up to the mid-1970s. It is reported that these coatings can lead to elevated concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) in the distributed drinking water. The aim of the project was to investigate the processes and mechanisms responsible for the occurrence of these substances in drinking water distribution systems. The results achieved in that research project showed that the occurrence of PAHs in a drinking water distribution system was linked to the presence of chlorine and chlorine dioxide used for common disinfection practice. In laboratory experiments it could be shown that the coal-tar surface represents a substrate for the growth of biofilms which exhibits protective effects. Generally, hostile environmental conditions for microbiological activity of the biofilm such as disinfection, stagnation periods and anaerobic conditions could be identified as important factors which favour the occurrence of PAHs in drinking water. Immediately after stagnation periods an increase of PAH concentrations was observed. Moreover, it was clearly shown that disturbances in the hydraulic regime such as water hammers, operation of valves and rapid increases in flow velocity can result in enhanced PAH concentrations by the destabilisation of the biofilm matrix or high shear forces affecting the pipe walls resulting in the release of particles highly contaminated with PAHs which may be responsible for the contamination of the drinking water.

Increases in polycyclic aromatic hydrocarbon content and mutagenicity in a cutting fluid as a consequence of its use.

The aim of this study was to evaluate the relationships between the length of time a cutting fluid was used, its content in polycyclic aromatic hydrocarbons (PAHs) and its mutagenic potential. The PAH concentrations were determined by means of a high-resolution gas chromatograph-mass spectrometer in samples of new cutting fluid and in samples used for 3, 6 and 9 months. The following PAHs were measured: phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene+triphenylene, benzo[e]pyrene, benzo[a]pyrene and perylene. Mutagenicity assays were carried out on the aforementioned samples using the Ames test. Salmonella typhimurium TA98 was used as an indicator to show up mutagens capable of inducing frame-shift genetic changes, and Escherichia coli WP2 uvrA was used as an indicator to detect mutagens capable of inducing base pair genetic changes. The mutagenic tests were carried out with and without microsomal activation, using 1:1, 1:10, 1:20 and 1:50 dilutions of cutting fluid samples. An increase in the concentrations of total PAHs over time was observed in the samples of cutting fluid used for 3, 6 and 9 months. The highest percentage increase in PAH concentrations was observed in the 6-month-old sample (10 times the initial concentration, from 45 to 411.8 micrograms of oil). None of the samples were mutagenic to S. typhimurium without metabolic activation or to E. coli with and without metabolic activation. All samples except for the 1:1 diluted sample showed moderate but significant mutagenic activity in the S. typhimurium test with metabolic activation.(ABSTRACT TRUNCATED AT 250 WORDS)

Trends and factors governing polycyclic aromatic hydrocarbon levels in Tokyo Bay sediments

Polycyclic aromatic hydrocarbons (PAHs) in a dated sediment core from Tokyo Bay were determined by gas chromatography and GC/MS. These PAHs increase in concentration from the 1950's to the beginning of the 1970's and decrease after then. These changes, especially the decreasing trend, are discussed with respect to changes in the atmospheric paniculate concentration and fossil fuel consumption in Tokyo and districts. The results suggest that the increase in PAH concentrations was due to the increase in the fossil fuel consumption, and the decreasing trend was caused by the following factors: 1. 1) less fuel oil consumption; 2. 2) legal curbs on industrial and vehicular emissions of particulates and hydrocarbons; and 3. 3) other factors such as a gradual decrease in consumption of heavy oil and a temporary drop in the use of asphalt.