Trends Of Polycyclic Aromatic Hydrocarbons Research Articles

Polycyclic aromatic hydrocarbons (PAHs) in the water column and sediment core of Deep Bay, South China

The levels of 15 polycyclic aromatic hydrocarbons (PAHs) were determined in seawater, suspended particulate matter (SPM), surface sediment and core sediment samples of Deep Bay, South China. The average concentrations Σ 15PAHs were 69.4 ± 24.7 ng l −1 in seawater, 429.1 ± 231.8 ng g −1 in SPM, and 353.8 ± 128.1 ng g −1 dry weight in surface sediment, respectively. Higher PAH concentrations were observed in SPM than in surface sediment. Temporal trend of PAH concentrations in core sediment generally increased from 1948 to 2004, with higher concentrations in top than in sub-surface, implying a stronger recent input of PAHs owing to the rapid economic development in Shenzhen. Compared with historical data, the PAH levels in surface sediment has increased, and this was further confirmed by the increasing trend of PAHs in the core sediment. Phenanthrene, fluoranthene and pyrene dominated in the PAH composition pattern profiles in the Bay. Compositional pattern analysis suggested that PAHs in the Deep Bay were derived from both pyrogenic and petrogenic sources, and diesel oil leakage, river runoff and air deposition may serve as important pathways for PAHs input to the Bay. Significant positive correlations between partition coefficient in surface sediment to that in water ( K OC) of PAH and their octanol/water partition coefficients ( K OW) were observed, suggesting that K OC of PAHs in sediment/water of Deep Bay may be predicted by the corresponding K OW.

Spatial and Temporal Trends of Polycyclic Aromatic Hydrocarbons and Other Traffic-Related Airborne Pollutants in New York City

Traffic-related air pollutants have been associated with adverse health effects. We hypothesized that exposure to polycyclic aromatic hydrocarbons (PAHs), elemental carbon (EC, diesel indicator), particulate matter (PM2.5), and a suite of metals declined from 1998 to 2006 in NYC due to policy interventions. PAH levels from personal monitoring of pregnant mothers participating in the Columbia's Center for Children's Environmental Health birth cohort study, and EC, PM2.5, and metal data from five New York State Department of Environmental Conservation stationary monitors were compared across sites and over time (1998-2006). Univariate analysis showed a decrease in personal PAHs exposures from 1998 to 2006 (p < 0.0001). After controlling for environmental tobacco smoke, indoor heat, and cooking, year of personal monitoring remained a predictor of decline in sigmaPAHs (beta = -0.269, p < 0.001). Linear trend analysis also suggested that PM2.5 declined (p = 0.09). Concentrations of EC and most metals measured by stationary site monitors, as measured by ANOVA, did not decline. Across stationary sites, levels of airborne EC and metals varied considerably. By contrast PM2.5 levels were highly intercorrelated (values ranged from 0.725 to 0.922, p < 0.01). Further policy initiatives targeting traffic-related air pollutants may be needed for a greater impact on public health.

Spatial and temporal trends of polycyclic aromatic hydrocarbons in wild mussels from the Cantabrian coast (N Spain) after the Prestige oil spill

Polycyclic aromatic hydrocarbon (PAH) levels were determined in tissues of wild mussels (Mytilus galloprovincialis) collected at 17 stations along the Cantabrian coast (N Spain), from Navia (Asturias) to Fuenterrabía (Basque Country), in order to assess the extent of the environmental impact caused by the Prestige oil spill (November 13, 2002). Six sampling campaigns were carried out in April, June and November in 2003 and 2004. The comparison of PAH data with those obtained earlier in 2000 showed a widespread pyrolytic and petrogenic contamination and allowed an estimation, for the first time, of the background pollution in the region and identification of the chronic hotspots. The spatial distribution found in the first samples after the oil spill revealed the eastern area as the most affected due to the continuous arrival of fuel slicks since early summer 2003. Several stations in this area showed increased total PAH concentrations of up to 15 times the pre-spill levels, which did not recover until April 2004, more than one year after the accident. Molecular parameters within the aliphatic and aromatic fractions were determined to assess the presence of Prestige oil in these samples.

Resolving the Long-Term Trends of Polycyclic Aromatic Hydrocarbons in the Canadian Arctic Atmosphere

Polycyclic aromatic hydrocarbon (PAH) air concentrations measured over the period 1992-2000 at the Canadian High Arctic station of Alert were subject to time-series analysis using dynamic harmonic regression (DHR). For most of the PAHs, the DHR model fit to the observed data was good, with DHR capable of interpolating over missing data points during periods when air concentrations were below detection limits. As expected, DHR identified seasonal increases in PAH air concentrations. However, it has also identified additional, subtler "seasonal" patterns as a series of harmonics with varying periodicity. For example, a regular summer high in air concentrations was apparent for many PAHs, particularly the lower molecular weight (two- to three-ringed) compounds, which may be attributed to summertime regional combustion events such as forestfires and/or revolatilization from surfaces (e.g., soil and oceans, as well as arctic surfaces). Comparison of wintertime PAH concentrations (where sigmaPAH ranged from 260 to 516 pg m(-3)) with an earlier arctic study did not reveal a reduction in PAH levels. However, removal of the seasonal components by DHR revealed a declining trend in PAH concentrations over the 1992-2000 period. For many lighter PAHs, this was typified by a linear decrease over the whole time series, although, for the higher molecular weight PAHs, a marked reduction was apparent in the first few years of sampling followed by a leveling off in concentrations by the mid/late-1990s. This behavior is similar to reported trends of other air pollutants in the Arctic, may be attributed to the decline in Soviet industry during the early 1990s, and has implications regarding the major PAH sources affecting the Arctic.

中国北京市におけるエアロゾル中多環芳香族炭化水素類(PAHs)と微量金属及び水溶性イオン成分の長期的動向

中国北京市におけるエアロゾル中多環芳香族炭化水素類(PAHs)と微量金属及び水溶性イオン成分の長期的動向

Trends in Hydrophobic Organic Contaminants in Urban and Reference Lake Sediments across the United States, 1970−2001

A shift in national policy toward stronger environmental protection began in the United States in about 1970. Conversely, urban land use, population, energy consumption, and vehicle use have increased greatly since then. To assess the effects of these changes on water quality, the U.S. Geological Survey used sediment cores to reconstruct water-quality histories for 38 urban and reference lakes across the United States. Cores were age-dated, and concentration profiles of polycyclic aromatic hydrocarbons (PAHs) and chlorinated hydrocarbons were tested statistically. Significant trends in total DDT, p,p'-DDE, and total PCBs were all downward. Trends in chlordane were split evenly between upward and downward, and trends in PAHs were mostly upward. Significant trends did not occur in about one-half of cases tested. Concentrations of p,p'-DDE, p,p'-DDD, and PCBs were about one-half as likely to exceed the probable effect concentration (PEC), a sediment quality guideline, in sediments deposited in the 1990s as in 1965-1975, whereas PAHs were twice as likely to exceed the PEC in the more recently deposited sediments. Concentrations of all contaminants evaluated correlated strongly with urban land use. Upward trends in PAH concentrations, the strong association of PAH with urban settings, and rapid urbanization occurring in the United States suggest that PAHs could surpass chlorinated hydrocarbons in the threat they pose to aquatic biota in urban streams and lakes.

Historical trends of polycyclic aromatic hydrocarbons in the reservoir sediment core at Osaka

Abstract The historical trends of polycyclic aromatic hydrocarbons (PAHs) in the sediment core of the moat in Osaka Castle, located at the center of Osaka city, Japan, were studied. The moats in Osaka Castle were built in the 1620s, and the undisturbed sediment core, which consists of atmospheric deposits in Osaka city from 1671 to 1976, was withdrawn from the moat. PAHs in the sediment core were identified and quantified in the total concentration range of 0.053–26 mg kg−1 dry wt. The highest content of PAHs was found in the sample, which was dated to 1944 during World War II. Osaka Castle was exposed to intense bombing raids during World War II, and the spiked peak of the PAH concentration during the mid-1940s was due to the air attacks. The total PAH concentration in the sediment core sample during World War II was about two-fold greater than the average after the war. This study made it appear that the largest impact of PAHs on the atmospheric environment in Osaka city in almost 300 years was caused by modern warfare.

Origin of atmospheric polycyclic aromatic hydrocarbons (PAHs) in Chinese cities solved by compound-specific stable carbon isotopic analyses

We report measurement of molecular and carbon isotopic compositions of atmospheric polycyclic aromatic hydrocarbons (PAHs) in three Chinese cities, Beijing, Chongqing, and Hangzhou. Precision of δ13C measurement by GC/C/IRMS ranged from 0.4 to 0.7‰, and accuracy ranged from 0.0 to 0.4‰. δ13C of atmospheric PAHs ranged from −22.9 to −27.2‰ for Chongqing, from −24.2 to −26.8‰ for Hangzhou, from −21.1 to −26.1‰ for Beijing summer and from −22.5 to −25.7‰ for Beijing winter. Atmospheric PAHs of both Chongqing and Hangzhou become more depleted in 13C with increasing PAH molecular weight. On the other hand, atmospheric PAHs in Beijing become more enriched in 13C with increasing PAH molecular weight. The difference of isotopic signature between “Beijing” and “Chongqing + Hangzhou” is statistically significant (t-test, P<0.05). The isotopic trends of PAHs in Chongqing and Hangzhou are similar to that obtained from fluidized-bed coal combustion particles, whereas the isotopic trend of PAHs in Beijing air is similar to that obtained from automotive exhaust particles. According to this observation, it appears that automotive exhausts significantly affect PAH loading to Beijing air and that coal combustion is the main cause of PAH existence in Chongqing and Hangzhou air. While the isotopic signatures can classify the three Chinese cities into two groups, the molecular profiles do not show a clear trend among them. This can be explained by the following description: carbon isotopic signatures of PAHs are expected to have source- and/or combustion field-specific values and patterns mainly, whereas molecular compositions of PAHs depend on various factors such as source material, burning temperature, air/fuel ratio, and environmental alteration during transport.

Processes driving the short-term variability of polycyclic aromatic hydrocarbons in the Baltimore and northern Chesapeake Bay atmosphere, USA

Polycyclic aromatic hydrocarbons (PAHs) were measured in the Baltimore and adjacent Chesapeake Bay in July 1997. Time series of 4- and 12-h samples were taken at two sites 15 km apart in order to evaluate the influence of a number of processes on the short-term variability of PAH in the Baltimore and northern Chesapeake Bay atmospheres. PAH concentrations were 2–3-fold higher in the Baltimore atmosphere than in the adjacent Chesapeake Bay atmosphere. For example, gas-phase phenanthrene and pyrene concentrations were 12.5 and 2.14 ng m −3 in the Baltimore site and 5.57 and 0.548 ng m −3 in the Chesapeake Bay, respectively. The influence of wind direction, wind speed and temperature was evaluated by multiple linear regressions which indicated that atmospheric gas-phase PAH concentrations over the Chesapeake Bay were significantly higher when the air mass was from the urban/industrial Baltimore area. Furthermore, the increase of gas-phase low-MW PAH concentrations with temperature and wind speed suggests that volatilization from the bay is an important source of pollutants to the atmosphere, at least when air masses are not influenced by the Baltimore urban and industrial area. Indeed, while on the long-term, the Chesapeake Bay is a receptor of atmospherically deposited PAHs, on the short-term and during appropriate meteorological conditions, the bay acts as a source of pollutants to the atmosphere. Aerosol-phase PAH concentrations and temporal trends showed a strong dependence on aerosol soot content due to the high affinity of PAHs to the graphitic structure of soot. These results confirm the important influence of urban areas as a source of pollution to adjacent aquatic environments and as a driving factor of the short-term variability, either directly by transport of urban-generated pollutants or by volatilization of previously deposited pollutants. Conversely, the complex diurnal trends of gas-phase PAHs at the Baltimore site suggests that degradation processes dominate the diurnal trends of PAHs in urban atmospheres. This conclusion is supported by estimated rate constants for PAH reaction with OH radicals which show good agreement with reported values within a factor of two.

Temporal Trends of Polycyclic Aromatic Hydrocarbons in Precipitation of Poznań and Its Vicinity (Poland)

Samples of precipitation: rain, sleet and snow, were collected at the centre of the city of Poznań and in the Wielkopolski National Park. Samples were collected from 26 Nov. 1996 to 20 Nov. 1999. PAHs were isolated by extraction in the system liquid-solid state (columns for SPE and a Speedisk-adsorbent C18). Determination was performed on a liquid chromatograph HPLC. The breakdown curves for naphthalene (SPE, Empore and Speedisk) were given. The main PAHs occurring in the samples from the city and from the National Park area were naphthalene and anthracene. The other PAH compounds occurred at much lower concentrations. The content of benzo[a]pyrene did not exceed the permissible level. Significant differences were noted in the content of certain PAHs depending on the kind of precipitation. Differences in PAHs concentrations were also observed between the precipitation samples collected in winter and spring. The results of PAH determinations over the few years of observation, from 1996 to 1999, prove a decrease in the contents of the majority of PAHs in precipitation, which is directly related to intense modernisation of the system of central heating and the changeover from coal to gas heating.

TRENDS OF POLYCYCLIC AROMATIC HYDROCARBON LEVELS AND MUTAGENICITY IN SANTIAGO'S INHALABLE AIRBORNE PARTICLES IN THE PERIOD 1992?1996

Trends of polycyclic aromatic hydrocarbons (PAHs) for 1992–1996 (cold season) and their mutagenic activity were investigated in organic extracts from the Santiago, Chile, inhalable particles (PM10). The highest PAH concentrations were observed in 1992 and declined dramatically in the following years. During this period, total PAHs decreased 85%, carcinogenic PAHs 82%, and benzo[a]pyrene, the most potent carcinogen, 85%. In spite of this significant decrease, PAH levels in respirable particles were higher than those reported in recent studies in Australia, Europe, and the United States. PAH profiles were analyzed by principal component (PC) analysis and Pearson correlation analysis. PC1 represents 71% of the variance, suggesting that most PAHs might originate predominantly from one main generic source. Higher correlations were obtained for the major carcinogenic PAHs. Most of the samples assayed were highly mutagenic to Salmonella typhimurium both in the presence and in the absence of metabolic activation system (S9), especially in the coarse fraction, but direct mutagenicity did not decline significantly. Incubation of calf thymus DNA with organic extracts from particulate matter and xanthine oxidase allowed the detection of five nitro-PAH?DNA adducts. Thus, nitroarenes might play an important role in the mutagenic activity of inhalable particles in Santiago, representing a high risk for human health.

Polymeric Anionic Surfactant for Electrokinetic Chromatography: Separation of 16 Priority Polycyclic Aromatic Hydrocarbon Pollutants

Electrokinetic chromatography (EKC) with poly(sodium undecylenic sulfate) (poly-SUS) is utilized to separate environmental pollutants such as 2−6-ring polycyclic aromatic hydrocarbons (PAHs). Parameters such as pH, concentration of polymeric surfactants, and the use of organic modifiers were investigated to follow the retention trends of PAHs. A baseline separation of all 16 PAHs in about 30 min, using 0.50% (w/v) of poly-SUS/12.5 mM sodium phosphate−borate buffer (pH 9.2) with 40% (v/v) acetonitrile, was possible for the first time in EKC by a single-surfactant system.

The recent depositional trend of polycyclic aromatic hydrocarbons and elemental carbon to the Agassiz Ice Cap, Ellesmere Island, Canada

Polar ice caps can provide long-term records of atmospheric deposition. Owing to the prevalent conditions, the layers of accumulated snow are subject to little chemical or physical change and are temporally well defined. Sampling of the Agassiz Ice Cap on Ellesmere Island was undertaken in early 1993 to investigate the potential of polar ice caps for use in determining recent historical trends in the deposition of anthropogenic contaminants to the Arctic. Discrete annual snow and ice layers representing the last 30 years of accumulation were sampled from a deep pit to obtain large volume samples for the determination of polycyclic aromatic hydrocarbons (PAHs) and elemental carbon (EC). The flux of PAHs to the ice cap has remained relatively constant for the past 20 years, with a mean value of 11 (± 6) μg/m2/year. This equates to a total annual loading of PAH to the Arctic of 37 t/year for the same period. Prior to this period, a greater flux of 74 (± 20) μg/m2/year is observed. Mean values for EC concentration and flux were found to be 2.6 (± 2.8) μg/l and 310 (± 370) μg/m2/year, respectively. However, analytical complications were encountered with the analysis of EC, and these data should be considered as preliminary baseline values only.