Distribution of polycyclic aromatic hydrocarbons in the surficial sediments of Casco Bay,Maine

Bulletin of Environmental Contamination and Toxicology -     

Ecological risk assessment of parent and halogenated polycyclic aromatic hydrocarbons in surface sediments from an urban river in south China

In the present study, 16 priority polycyclic aromatic hydrocarbons (Σ(16) PAHs), including seven carcinogenic PAHs (Σ(7) PAHs) designated by the U.S. Environmental Protection Agency, in surface sediment from an urban river (Shenzhen, south China) were measured. The concentrations of Σ(16) PAHs and Σ(7) PAHs ranged from 27.92 to 7409 ng/g and 0.53 to 2326 ng/g, respectively. Source appointments indicated that the PAHs in surface sediments were mainly derived from coal combustion (36.6%), oil spills (22.2%), vehicle emission (19.5%), and waste incineration (12.1%). The ecological risks posed by PAHs and several halogenated PAHs in these sediment samples were assessed using two redefined guidelines incorporating the toxic equivalency quotients (TEQs) of individual PAH congeners: (1) TEQs effect range-low, and (2) TEQs effect range-median. The authors' results suggested that the PAHs they measured in most of the sediments in this urban river would not cause acute biological effects. On the contrary, the ecological risk posed by some halogenated PAHs was much higher than that of their corresponding parent PAHs. Finally, the relationships between PAH levels and catchment urbanization processes were examined. The results indicated that rapid urbanization has led to an obvious increase in PAH contamination in surface sediments.     

Importance of black carbon in distribution and bioaccumulation models of polycyclic aromatic hydrocarbons in contaminated marine sediments

The roles and relative importance of nonpyrogenic organic carbon (NPOC) and black carbon (BC) as binding phases of polycyclic aromatic hydrocarbons (PAHs) were assessed by their ability to estimate pore water concentrations and biological uptake in various marine sediments. Sediment bioaccumulation tests were performed with the marine polychaete Nereis virens, using a polyethylene device to estimate pore water concentrations of PAHs. Using existing partitioning data for pyrene and phenanthrene, it was found that the traditional Equilibrium Partitioning model, which assumes all organic carbon is NPOC (EqP(OC)), overestimated the measured pore water concentrations in the test sediments by one to three orders of magnitude. Instead, the measured pore water concentrations were better predicted from a distribution scenario that uses both BC and NPOC (EqP(NPOc,BC)) When comparing actual worm body burdens of pyrene and phenanthrene with the two model estimates of worm tissue concentrations, the EqP(OC) model tended to overestimate actual body burdens by three orders of magnitude, while the EqP(NPOC,BC) model came much closer to the true body burden values. The observed distribution of PAHs in the test sediments was used to calculate BC partition coefficients for five PAHs, which were one to two orders of magnitude higher than their corresponding organic carbon-normalized distribution coefficients, or K(OC)s. Together, these results suggest that, in certain situations, adding black carbon to distribution models may be necessary to predict accurately the bioavailability of PAHs.     

Determination of polycyclic aromatic hydrocarbons in industrial harbor sediments by GC-MS

Analysis of the 16 polycyclic aromatic hydrocarbons (PAHs) of the US Environmental Protection Agency priority pollutant list was carried out in sediment samples of an industrial port in the southern Kaohsiung Harbor of Taiwan which is supposed to be extensively polluted by industrial wastewater discharges. The determination and quantification of PAHs in sediment samples were performed using gas chromatography coupled to mass spectrometry (GC-MS) with the aid of deuterated PAH internal standards and surrogate standards. The total concentrations of the 16 PAHs varied from 4,425 to 51,261 ng/g dw, with a mean concentration of 13,196 ng/g dw. The PAHs concentration is relatively high in the river mouth region, and gradually diminishes toward the harbor region. Diagnostic ratios showed that the possible source of PAHs in the industrial port area could be coal combustion. As compared with the US Sediment Quality Guidelines (SQGs), the various observed levels of PAHs exceeded the effects range median (ERM), and could thus cause acute biological damages. The results can be used for regular monitoring, and future pollution prevention and management should target the various industries in this region for reducing pollution.     

Sources, distribution, and toxicity of polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants released from the incomplete combustion of fossil fuels and are always found as a mixture of individual compounds. Due to economic growth and a sharp increase in energy consumption in recent years, large quantities of PAHs have been released into the environment worldwide. Because many PAHs and their derivatives are strongly potent carcinogens, or mutagens, PAHs have been extensively studied recently. The authors reviewed the origin and distribution of PAHs in atmosphere, soil, and sediment in natural environments. PAHs represent a class of toxicological compounds that can create a variety of hazardous effects in vivo/in vitro, including genotoxicity, immunotoxicity, developmental toxicity, and carcinogenesis, which the authors also describe.     

Evaluation of the role of black carbon in attenuating bioaccumulation of polycyclic aromatic hydrocarbons from field-contaminated sediments

The significance of black carbon (BC) for the bioavailability of polycyclic aromatic hydrocarbons (PAHs) was examined by using historically contaminated intact sediment cores in laboratory exposure experiments with the deposit-feeding amphipod Monoporeia affinis. Log values of amphipod biota-sediment accumulation factors (BSAFs) were significantly related to log BC, whereas log BSAFs were related to log octanol-water partition coefficients only in background sediments containing less BC. In the background sediments, the BSAF for polycyclic aromatic hydrocarbons (PAHs) was 1 to 2 for phenanthrene, with lower values for more hydrophobic PAHs, indicating an increase in nonequilibrium conditions with increasing PAH molecular size. For the near-equilibrated phenanthrene and fluoranthene, higher BSAFs were measured during exposure to background sediments, with BSAF decreasing to <0.1 in contaminated sediments in the Stockholm waterways. In situ caged mussels (Dreissena polymorpha) exhibited field BSAF values (relative to sediment-trap-collected suspended matter) for polychlorinated biphenyls (PCBs) of 0.1 to 0.4, but for PAHs of similar hydrophobicity and molecular size, the field BSAFs were much lower and in the range 0.002 to 0.05. This PAH-PCB dichotomy is consistent with recently reported much stronger binding to diesel soot (a form of BC) for PAHs than for PCBs of equal hydrophobicities. Lower BSAFs for the near-equilibrated PAHs (phenanthrene and fluoranthene) in the urban sediments relative to the background sediments were consistent with the larger presence of BC in the urban sediments. This study provides the first linked BSAF-BC field data that supports a causal relationship between strong soot sorption and reduced bioavailability for PAHs.     

Weathering and toxicity of marine sediments contaminated with oils and polycyclic aromatic hydrocarbons

Many sediments are contaminated with mixtures of oil residues and polycyclic aromatic hydrocarbons (PAHs), but little is known about the toxicity of such mixtures to sediment-dwelling organisms and the change in toxicity on weathering. In the present study, we investigated the effects of a seminatural, two-year weathering period on PAH/oil chemistry and toxicity in a marine sediment that had been spiked with three different oils (a gas oil, a lubricating oil, and a crude oil; all tested at five concentrations). Toxicity of bioavailable, pore water-accommodated oil/PAH fractions was quantified using a bacterial (Vibrio fischeri) assay and the in vitro chemical-activated luciferase expression assay (DR-CALUX; using conditions to detect PAHs). Results of chemical analyses pointed to (microbial) degradation of all three oils: Sediment oxygen demand during weathering increased with increasing oil concentration, total oil concentrations decreased to between 17 and 29% of initial levels, and resolved n-alkanes were depleted in weathered oil fractions. Furthermore, a shift in the relative importance of different boiling-point fraction ranges of the oils was observed on weathering. Generally, the lowest fraction range (C10-C16) disappeared, whereas the relative proportion of the highest (C28-C40) fraction range increased considerably. Remarkably, for the gas oil, this fraction shift was dependent on the oil concentration in sediment. Similarly, degradation of PAHs was strongly affected by the sedimentary oil content, indicating that the presence of oil stimulated PAH degradation. This phenomenon applied to both low- and high-molecular-weight PAHs, although the first group (3- and 4-ring PAHs) was degraded most. Results from the V. fischeri and DR-CALUX assay showed that in most cases, pore-water toxicity decreased on weathering. Combining the assay responses with chemical data indicated that the observed toxicity probably was not caused by the analyzed PAHs but, rather, by specific oil constituents instead.     

重庆市某区小学女生多环芳烃内暴露水平及其与青春发动时相的关系

目的建立同时测定尿中4种多环芳烃(PAHs)代谢物的检测方法,研究重庆市某区女童青春发动时相提前与体内多环芳烃暴露水平的关系。方法研究对象采用目的性抽样,对重庆市某区4所小学1~4年级女生进行一般情况的问卷调查、生长发育的体格检查、并收集尿液,采用高效液相色谱-质谱联用法(HPLC-MS)对样品中4种PAHs代谢物进行定性和定量检测。结果 4种PAHs代谢物标准曲线相关性高,方法检出限为0.1 ng/mL。研究共调查女童737名,青春发动时相提前组209人,正常组528人。尿液检测结果显示4种PAHs代谢物检出率为100%,4种代谢物的检出浓度范围分别为1-羟基芘0.01~4.77 ng/mL,2-羟基萘0.15~50.00ng/mL,2-羟基芴0.06~12.59 ng/mL及9-羟基菲0.29~23.17 ng/mL。青春发动时相提前组和正常组在2-羟基芴(Z=-1.996)和9-羟基菲(Z=-3.161)暴露水平上差异具有统计学意义(P<0.05),控制了肥胖因素后,青春发动时相提前组9-羟基菲(Z=-3.012)暴露水平仍高于正常组(P<0.05)。结论该方法适用于4种PAHs代谢物的同时检测,研究地区女童青春发育早期均有PAHs暴露,且PAHs暴露可能是女童青春发动时相提前的因素之一。     

Amendment of sediments with a carbonaceous resin reduces bioavailability of polycyclic aromatic hydrocarbons

We evaluated the effectiveness of Ambersorb, a carbonaceous resin, in reducing bioavailability of polycyclic aromatic hydrocarbons (PAHs) in contaminated sediments collected from the field. In laboratory studies, sediment pore-water concentrations of eight unsubstituted PAHs were significantly decreased after resin addition. Reduced PAH concentrations in oligochaete tissues from a laboratory bioaccumulation test, along with increased survival/reproduction and reduced photo-enhanced toxicity and sediment avoidance, also resulted from sediment treatment with Ambersorb. Resin amendment also decreased pore-water PAH concentrations in field deployed sediments but did not improve benthic invertebrate colonization. Prediction of partitioning of PAHs between solid and aqueous phases in the test sediments was complicated by the presence of coal and soot. However, accurate predictions of bioavailability were achieved based on pore-water chemistry. Overall, these studies show that the addition of high affinity sorbents effectively reduces pore-water PAH concentrations and bioavailability and suggests that sorbent addition may serve as an option for in situ remediation of some contaminated sediments.     

Biochemical ripening of dredged sediments. Part 2. Degradation of polycyclic aromatic hydrocarbons and total petroleum hydrocarbons in slurried and consolidated sediments

Ripening of polycyclic aromatic hydrocarbons (PAH) and total petroleum hydrocarbons (TPH) polluted dredged sediment can be considered as a bioremediation technique. Aerobic biodegradation of PAH and TPH was studied in five previously anaerobic-slurried sediments during a 350-d laboratory incubation experiment. In addition, oxygen penetration and degradation of PAH and TPH were studied in three consolidated (physically ripened) sediments. All experiments were conducted in the laboratory at 30 degrees C. A double exponential decay model could adequately describe PAH and TPH degradation kinetics in the slurried sediments. First-order degradation rate constants for the rapidly degradable fractions (12-58%) were approximately 0.13 and 0.058 d(-1) for PAH and TPH, respectively, whereas the rate constants for the slowly degradable fractions were approximately 0.36 x 10(-3) (PAH) and 0.66 x 10(-3) d(-1) (TPH). Rate constants for the rapidly and slowly degrading fractions have the same order of magnitude as the mineralization rate constants of the rapidly and slowly mineralizing organic matter (OM) fractions in the sediments. Oxygen uptake by degradation of PAH and TPH was negligible compared to the oxygen uptake by sulfur oxidation and OM mineralization. In consolidated sediments, PAH and TPH degradation was limited to the oxygenated part. Amounts of PAH and TPH that degraded in the oxygenated parts of the consolidated sediments during 21 d of incubation were similar to the amounts that degraded during 21 d in the slurried sediments.     

Greatly reduced bioavailability and toxicity of polycyclic aromatic hydrocarbons to Hyalella azteca in sediments from manufactured-gas plant sites

The toxicity of polycyclic aromatic hydrocarbons (PAHs) to Hyalella azteca, was measured in 34 sediment samples collected from four manufactured-gas plant (MGP) sites ranging in total PAH16 (sum of 16 U.S. Environmental Protection Agency priority pollutant PAHs) concentrations from 4 to 5700 mg/kg, total organic carbon content from 0.6 to 11%, and soot carbon from 0.2 to 5.1%. The survival and growth of H. azteca in 28-d bioassays were unrelated to total PAH concentration, with 100% survival in one sediment having 1,730 mg/kg total PAH16, whereas no survival was observed in sediment samples with concentrations as low as 54 mg/kg total PAH16. Twenty-five of the 34 sediment samples exceeded the probable effects concentration screening value of 22.8 mg/kg total PAH13 (sum of 13 PAHs) and equilibrium partitioning sediment benchmarks for PAH mixtures (on the basis of the measurement of 18 parent PAHs and 16 groups of alkylated PAHs, [PAH34]); yet, 19 (76%) of the 25 samples predicted to be toxic were not toxic to H. azteca. However, the toxicity of PAHs to H. azteca was accurately predicted when either the rapidly released concentrations as determined by mild supercritical fluid extraction (SFE) or the pore-water concentrations were used to establish the bioavailability of PAHs. These results demonstrate that the PAHs present in many sediments collected from MGP sites have low bioavailability and that both the measurement of the rapidly released PAH concentrations with mild SFE and the dissolved pore-water concentrations of PAHs are useful tools for estimating chronic toxicity to H. azteca.     

Determination of polycyclic aromatic hydrocarbons in the lung

Polycyclie aromatic hydrocarbons (PAHs) accumulated in human lung samples from men (n = 236) and women (n = 128) were determined by high-performance liquid chromatography (HPLC) to examine their association with lung cancer. The mean values for benzo[a]pyrene (BaP), benzo[k]fluoranthene (BkF), and benzo[g,h,i]perylene (BghiP) in lungs (ng/g dry lung) of Japanese autopsied patients were 0.54, 0.44, and 0.87, respectively. The modal values were 0.3, 0.3 and 0.5, respectively. Each of the PAH concentrations was highly correlated with the others (r > 0.83). PAH concentrations in the lungs showed age-related increases with low correlation-coefficient values. BaP, BkF and BghiP concentrations in lungs of various subgroups were in the following order: male > female; and lung cancer > all cancers > non-cancer among male not female group. Only BghiP concentration in the lungs of the male smoker group is significantly higher (P < 0.10) than that of the male non-smoker group. Even among non-smoker groups, PAH concentrations in the lungs of male group were significantly higher than those of female group. In the male population, excess exposure to PAHs together with fine carbon particles, such as tobacco smoke or diesel exhaust, correlated with increased prevalence of lung cancer.     

Monitoring of polycyclic aromatic hydrocarbons in seafoods from Lake Timsah

Concentrations of polycyclic aromatic hydrpcarvons (PAHs) in some seafoods caught from Lake Timsah were determined. The tested samples were tilapia fish (Oreochromis aureus), crabs (Portuns pelagicus), bivalves (Venerupis decussata), clams (Strombus tricornis) and gastropods (Munes Sp.). Where these seafoods are locally and favorite consumed foods in the area around the lake (Ismailia governorate). Results showed that crabs contained significantly higher concentrations of both total and carcinogenic PAHs ranging from 1318.6 to 3767.4 and 1230.3 to 3442.2 microg kg(-1), respectively. Meanwhile, clams contained significantly lower levels with mean value of 28.4 microg kg(-1) for total and 24.4 microg kg(-1) for carcinogenic PAHs. The most frequently detected PAHs in the tested samples were indeno(1,2,3-cd)pyrene followed by benzo(a)pyrene, dibenzo(a,h)anthracene, and benzo(b)fluoranthene which are characterized as carcinogenic compounds.     

Impact of sediment manipulation on the bioaccumulation of polycyclic aromatic hydrocarbons from field-contaminated and laboratory-dosed sediments by an oligochaete

The accumulation kinetics of polycyclic aromatic hydrocarbons (PAHs) by the freshwater oligochaete Lumbriculus variegatus were measured for field-contaminated and laboratory-dosed sediment. In addition, sediment manipulations typically used for homogenization and dosing in bioaccumulation assays were compared. Rather than an asymptotic approach to steady state, both resident and dosed PAH accumulation exhibited a peak during the 14-d assays, with steeper declines being noted for the lower-molecular-weight compounds. Lack of evidence of a peak for higher-molecular-weight PAHs may be due to slower kinetics and the short length of the assay. Relative to minimally mixed sediment, slurried sediment enhanced the accumulation of less-soluble resident PAHs, did not affect moderately soluble PAHs, and reduced the uptake of the more-soluble PAHs, fluorene and phenanthrene. Aging sediment after mixing reduced the availability of highly to moderately soluble resident PAHs but had no effect on less-soluble PAHs. A similar effect was noted for dosed PAHs, though a larger reduction in bioavailability was observed. Dosed PAH uptake clearance coefficients (ks) exceeded those of minimally mixed resident PAHs by factors of 3 to 4 for pyrene and 26 for benzo[a]pyrene. These results demonstrate that sediment manipulations and contamination history need to be considered when measuring PAH bioaccumulation.     

Accumulation of metals,polychlorinated biphenyls,and polycyclic aromatic hydrocarbons in sediments from the lower Passaic River,New Jersey

Thirteen sediment cores of 1.5–6 m depth were collected from the lower Passaic River in Newark, New Jersey and assayed for metals, total petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), and Aroclor^® and coplanar polychlorinated biphenyls (PCBs). Chronological profiles of chemical concentrations at specified depths and sediment accumulation rates in each core were determined by ¹³⁷Cs and ²¹⁰Pb radioisotope measurements. Temporal concentrations of these chemicals were compared to available benchmark sediment toxicity values to assess historic and current toxic hazards to aquatic organisms. Elevated concentrations of several metals, including copper, lead, mercury, nickel, and zinc, were found in surface and buried sediments at concentrations that greatly exceeded Long and Morgan (1991) Effects Range-Low (ER-L) and Effects Range-Median (ER-M) values. Aroclors^® 1242, 1248, and 1254 and several PAHs were also found at concentrations exceeding Long and Morgan (1991) benchmark toxicity values. In general, the highest metal and PAH concentrations were found in sediment deposited prior to the 1960s. Elevated PCB concentrations were found in sediment deposited between 1950 and 1980. The results indicate that the lower Passaic River is heavily contaminated due to recent and historical municipal and industrial discharges from local and up-stream sources. The primary sources of PCBs, PAHs, and metals appear to be discharges of industrial effluents either directly into the waterway or through combined sewer overflows. Additional inputs are probably from urban runoff entering through combined sewer overflows and storm drains.     

Spatial and temporal distribution of polycyclic aromatic hydrocarbons and elemental carbon in Bakersfield,California

Despite increasing evidence that airborne polycyclic aromatic hydrocarbon (PAH) exposures contribute to adverse health outcomes for sensitive populations, limited data are available on short-term intraurban spatial distributions for use in epidemiologic research. Exposure assessments for airborne PAHs are uncommon because air sampling for PAHs is a labor-, equipment-, and time-intensive task. To address this gap, we measured wintertime PAH concentrations during 2010–2011 in Bakersfield, California, USA, a major city in the Southern San Joaquin Valley. Specifically, 58 96-hour integrated PAH samples were collected during four time periods at 14 locations from November 2010 to January 2011; duplicates were collected at two sites. We also collected elemental carbon (EC) at the same 14 sites and analyzed the two time periods with the highest ambient PAH pollution. We used linear regression models to quantify the relationship between potential spatial and temporal predictors of PAH concentrations. We found that wintertime PAH concentrations in Bakersfield, CA, are best predicted by meteorological variables and traffic proximity. Our model explains a moderate amount of the variability in the data (R ²?=?0.58), likely reflecting the major sources of PAHs in Bakersfield. We also observed that PAH concentrations were more spatially variable than EC concentrations. Comparing our data to historical monitoring data at one location in Bakersfield showed that the relatively low PAH concentrations during the 2010–2011 winter in Bakersfield is part of a long-term trend in decreasing PAH concentrations.