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.     

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.     

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.     

Characterization of polycyclic aromatic hydrocarbon bioavailability in estuarine sediments using thin-film extraction

It is well documented that the bioavailability of hydrophobic organic chemicals (HOCs) can vary substantially among sediments. This makes risk assessments based on total sediment concentrations problematic. The present study investigates the application of thin-film solid-phase extraction to measure bioavailable concentrations of phenanthrene in estuarine sediment by comparing concentrations of phenanthrene in the amphipod Corophium colo and in thin ethylene/vinyl acetate films at different concentrations in three geochemically different sediments. For all sediment types, concentrations of phenanthrene in sediments and thin films followed linear relationships, indicating first-order exchange kinetics. Organism/thin-film concentration ratios did not vary systematically among sediment types but dropped significantly with increasing phenanthrene concentration in the sediments. While at low phenanthrene concentrations in the sediment fugacities of phenanthrene in the amphipods approached the fugacities in the thin films, they were significantly lower than those in the sediments at higher concentrations. While phenanthrene concentrations in the three sediment types were identical, biota sediment accumulation factors and concentrations in amphipods and thin films were consistently lower in sediments enriched with black carbon than in sediments with sedimentary organic matter bearing a more diagenetic organic signature. It is concluded that, for the range of concentrations tested, thin-film solid-phase extraction can be a useful tool in the characterization of differences in bioavailability of HOCs among sediment types.     

Digestive bioavailability to a deposit feeder (Arenicola marina) of polycyclic aromatic hydrocarbons associated with anthropogenic particles

Marine sediments around urban areas serve as catch basins for anthropogenic particles containing polycyclic aromatic hydrocarbons (PAHs). Using incubations with gut fluids extracted from a deposit-feeding polychaete (Arenicola marina), we determined the digestive bioavailability of PAHs from fly ashes, coal dusts, diesel soots, tire tread materials, and urban particulates. We found that gut fluids solubilize significant concentrations of PAHs from two tire treads, two diesel soots, and the urban particulates. However, PAHs in fly ashes and coal dusts were not available to the digestive agents in gut fluid. Potential digestive exposure to PAHs is much greater than that predicted to be available from these materials using equilibrium partitioning theory (EqP). Amending an already-contaminated sediment with fly ash decreased phenanthrene solubilization by gut fluid. In contrast, addition of tire tread to the sediment resulted in increased solubilization of four PAHs by gut fluid. Therefore, addition of certain types of anthropogenic particles to sediments may result in an increase in bioavailable PAHs rather than a net decrease, as predicted by EqP. Difficulty in predicting the amount of change due to amendment may be due to interactions occurring among the mixture of compounds solubilized by gut fluid.     

A micelle inhibition model for the bioavailability of polycyclic aromatic hydrocarbons in aquatic systems

A mathematical model was developed to quantify micelle suppression on the bioavailability of hydrophobic organic compounds in aquatic systems. The model was based on a three-compartment dynamic system in which the hydrophobic compounds are taken up and eliminated by organisms with an equilibrium partitioning between water and micelle. The model was validated against data obtained from in vitro studies of the bioaccumulation of naphthalene, anthracene, and chrysene into the gills of the freshwater mussel (Ellipto complanata) in the presence of a surfactant (Tween 80). The model predictions agreed well with the experimental results for all three chemicals. Sensitivity analyses were performed to examine model responses to the surfactant parameters. From the model, we derive an equation for a bioconcentration factor in aquatic surfactant systems to predict the maximum concentration of polycyclic aromatic hydrocarbons (PAHs) in aquatic organisms. From these results, we also propose a micelle inhibition factor for bioconcentration that is a function of the surfactant concentration, critical micelle concentration, and partition coefficient of hydrophobic compounds between water and micelle. Knowledge of these parameters may improve understanding of the partitioning of PAHs into organisms in the presence of surfactants.     

Evaluating polycyclic aromatic hydrocarbons using a yeast bioassay

Sixteen polycyclic aromatic hydrocarbons (PAHs) were evaluated for the ability to activate aryl hydrocarbon (Ah) receptor signaling in a yeast-based bioassay. Individual PAHs were classified as inactive or as weakly, moderately, or strongly active based on induction of human Ah receptor signaling. Indeno[1,2,3-cd]pyrene, chrysene, benzo[a]anthracene, benzo[a]pyrene, benzo[j]fluoranthene, and benzo[k]fluoranthene were the most potent activators of human Ah receptor signaling. Various mixtures of PAHs had additive or synergistic effects in the bioassay. Environmental samples from the New Orleans (Louisiana, USA) and Detroit (Michigan, USA) areas that were previously analyzed for PAH composition and quantity were tested in this bioassay. Weak but statistically significant relationships were found when the analytically measured levels of PAHs were correlated with sample dilutions that gave 25% effective concentration signaling levels in the Ah receptor assay. We conclude that this Ah receptor signaling assay may be useful for preliminary biomonitoring of samples for PAHs and other Ah receptor ligands.     

Role of source matrix in the bioavailability of polycyclic aromatic hydrocarbons to deposit-feeding benthic invertebrates

The bioavailability of polycyclic aromatic hydrocarbons (PAHs) to benthic organisms is complicated by the variety of ways that they are introduced to coastal waters (dissolved, as nonaqueous phase liquids, and tightly bound to soot, coal, tire rubber, and eroded shale). In order to better understand the controlling variables that affect chemical and biological availability of PAHs, a study was conducted in which three deposit-feeding infaunal benthic invertebrate species (Cirriformia grandis, Clymenella torquata, and Macoma balthica) were exposed to sediments amended with PAH-rich materials (coal dust, tire rubber, diesel soot, creosote, crude oil, and fuel oil). Lipid and organic carbon normalized bioaccumulation factors (BAF(1oc)s) were calculated after 20 d of exposure and PAH bioavailability from the different treatments was assessed. Bioaccumulation of coal-derived PAHs usually was too low to be measured, though PAHs associated with soot and tire rubber showed significant accumulation in organism tissues. Polycyclic aromatic hydrocarbons from the fuel oil, creosote, and crude oil treatments were more bioavailable than PAHs bound in solid carbonaceous matrices (soot, coal, and tire rubber). Desorption of PAHs from the amended sediments into seawater also was measured using XAD resin. As was observed with bioaccumulation, PAHs in coal were desorbed the least; tire rubber and diesel soot were intermediate; and creosote, fuel oil, and crude oil desorbed to the greatest extent. In only one out of the three species evaluated was PAH bioaccumulation related to extent of desorption after 20 d. Decoupling between biological and chemical availability may be due to species-specific factors such as surfactant-mediated solubilization in the guts of some deposit-feeding organisms. A significant finding of this work was the demonstration that PAHs associated with soot and tire rubber in their native state (rather than experimentally added) are available to some benthic biota.     

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

Bulletin of Environmental Contamination and Toxicology -     

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。     

Origin and distribution of polycyclic aromatic hydrocarbons in surficial sediments from the savannah river

Surface sediments collected from the Savannah River, located in the southeastern state of Georgia, USA, in June–July 1994 were analyzed for individual polycyclic aromatic hydrocarbons (PAHs). Three subdivisions of the river were identified for the study: upstream from, adjacent to, and downstream from the city of Savannah. There was high spatial variability in the total PAH (ΣPAH) concentrations that ranged from 29 to 5,375 ng/g with an average concentration of 1,216 ± 1,161 (SD). Of the three subdivisions, the highest ΣPAH concentrations were in the middle segment, which was adjacent to urban and industrial areas. To elucidate sources, molecular indices based on indices among phenanthrene versus anthracene and fluoranthene versus pyrene were used to determine pyrogenic and petrogenic sources, respectively. These indices have been used by other authors to differentiate sources. In most cases, PAHs in sediments nearest the city of Savannah were of high temperature and pyrogenic origin. These pyrogenic PAHs were highly associated with toxicity to benthic organisms. The two-ringed naphthalene and substituted naphthalenes, which are petroleum-related PAHs, were significantly higher in the lower section of the river relative to the subdivisions. This river segment receives inputs primarily from shipping and boating traffic. Perylene, which is indicative of nonanthropogenic terrestrial inputs of carbon, had the highest concentration among the individual PAHs measured. High perylene concentrations were found at stations located upstream and adjacent to forested terrain and where salinity level was low. To discriminate pattern differences and similarities of individual PAHs among samples, principal component analysis (PCA) was performed on the more hydrophobic and persistent nonalkylated PAHs. These differences and similarities were used to infer perylene origin. PCA was performed on 14 nonalkylated PAHs that was normalized to the sum of nonalkylated PAHs, using a correlation matrix. Generally, the PAHs were separated into group patterns according to chemical and physical properties associated with log K _OW, except perylene. Perylene, a five-ringed PAH, was distinctly separated from the other five-ringed PAHs. The sources for perylene are likely from biogenic, terrestrial precursors. The collected data show that pyrogenic PAHs were highly associated with biological effects on benthic organisms, based on bioassay results. Perylene, a nonanthropogenic PAH, was found throughout the river and constituted a large percentage of total PAHs in the upper river. Received: 20 November 2001/Accepted: 3 May 2002     

多环芳烃的皮肤毒性及损伤机制研究进展

多环芳烃（polycyclic aromatic hydrocarbons，PAHs）是广泛存在于人类生存环境中的一种持久性有机物，结构稳定且难以降解，对生物体和周围环境造成极大的威胁，是国内外广泛关注的有机污染物之一。研究发现，PAHs在多种皮肤疾病的发生发展中发挥重要作用，如导致皮肤过早老化、色素沉着、痤疮、肿瘤以及特应性皮炎。研究表明，PAHs的慢性暴露干扰皮肤的正常屏障功能，进而导致皮肤病的发生；但确切机制目前尚不完全明确。本文拟就PAHs所致皮肤毒性及可能的损伤机制进行综述，以期为PAHs所致皮肤疾病的预防和诊疗提供一些研究思路。     

Desorption and bioavailability of polycyclic aromatic hydrocarbons in contaminated soil subjected to long-term in situ biostimulation

The distribution and potential bioavailability of polycyclic aromatic hydrocarbons (PAHs) in soil from a former manufactured-gas plant (MGP) site were examined before and after long-term biostimulation under simulated in situ conditions. Treated soil was collected from the oxygenated zones of two continuous-flow columns, one subjected to biostimulation and the other serving as a control, and separated into low- and high-density fractions. In the original soil, over 50% of the total PAH mass was associated with lower density particles, which made up <2% of the total soil mass. However, desorbable fractions of PAHs were much lower in the low-density material than in the high-density material. After more than 500 d of biostimulation, significant removal of total PAHs occurred in both the high- and low-density materials (77 and 53%, respectively), with three- and four-ring PAHs accounting for the majority of the observed mass loss. Total PAHs that desorbed over a 28-d period were substantially lower in treated soil from the biostimulated column than in the original soil for both the high-density material (23 vs. 63%) and the low-density material (5 vs. 20%). The fast-desorbing fractions quantified by a two-site desorption model ranged from 0.1 to 0.5 for most PAHs in the original soil but were essentially zero in the biostimulated soil. The fast-desorbing fractions in the original soil underestimated the extent of PAH biodegradation observed in the biostimulated column and thus was not a good predictor of PAH bioavailability after long-term, simulated in situ biostimulation.     

5种多环芳烃化学物的雌激素样作用研究

目的 评价5种多环芳烃化学物的雌激素样作用。方法 采用大鼠子宫增生实验和MCF—7细胞增殖实验。结果 苯并(a)芘、7，12—二甲基苯并蒽和2，3，6，7—二苯并蒽不仅引起大鼠子宫湿重明显增加(P＜0．01，P＜0．05)，而且能明显诱导MCF—7细胞增殖(P＜0．01)。苯并(a)蒽和1，2—苯并菲既不能导致大鼠子宫湿重明显增加(P＞0．05)，也不能诱导MCF—7细胞增殖(P＞0．05)。结论 苯并(a)此、7，12—二甲基苯并蒽和2，3，6，7—二苯并蒽具有明显的雌激素样作用，而苯并(a)蒽和1，2—苯并蒽没有检测到雌激素样作用。     

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.     

Studies on bioremediation of polycyclic aromatic hydrocarbon-contaminated sediments: bioavailability,biodegradability, and toxicity issues

The widespread contamination by polycyclic aromatic hydrocarbons (PAHs) has created a need for cost-effective bioremediation processes. This research studied a chronically PAH-contaminated estuarine sediment from the East River (ER; NY, USA) characterized by high concentrations of PAHs (approximately 4-190 ppm), sulfide, and metals and a marine sediment from New York/ New Jersey Harbor (NY/NJH; USA) with only trace quantities of PAHs (0.1-0.6 ppm). The focus was to examine the relationship between bioavailability of PAHs and their biological removal in a slurry system. Freshwater and marine sediment toxicity tests were conducted to measure baseline toxicity of both sediments to amphipods, aquatic worms, fathead and sheepshead minnow larvae, and a vascular plant; to determine the cause of toxicity; and to evaluate the effectiveness of the biotreatment strategies in reducing toxicity. Results showed the ER sediment was acutely toxic to all freshwater and marine organisms tested and that the toxicity was mainly caused by sulfide, PAHs, and metals present in the sediment. In spite of the high toxicity, most of the PAH compounds showed significant degradation in the aerobic sediment/water slurry system if the initial high oxygen demand due to the high sulfide content of the sediment was overcome. The removal of PAHs by biodegradation was closely related to their desorbed amount in 90% isopropanol solution during 24 h of contact, while the desorption of model PAH compounds from freshly spiked NY/NJH sediment did not describe the bioavailability of PAHs in the East River sediment well. The research improves our understanding of bioavailability as a controlling factor in bioremediation of PAHs and the potential of aerobic biodegradation for PAH removal and ecotoxicity reduction.