Distribution of polycyclic aromatic hydrocarbons in thirty typical soil profiles in the Yangtze River Delta region, east China

Polycyclic aromatic hydrocarbons (PAHs) were quantified in 30 soil profiles from the Yangtze River Delta Region, in east China. Relative concentrations of PAH compounds with different benzene rings and ratios of fluoranthene to fluoranthene plus pyrene and benz(a)anthracene to benz(a)anthracene plus chrysene were used to identify the possible sources of soil PAHs. Total concentrations of 15 PAHs in topsoils ranged from 8.6 to 3881 microg kg(-1) with an average of 397 microg kg(-1). Half of the soil samples were considered to be contaminated with PAHs (>200 microg kg(-1)) and two sampling sites were heavily polluted by PAHs with concentrations >1000 microg kg(-1). Phenanthrene was found in soils below a depth of 100 cm in half of the sampling sites, but the detectable ratio of benzo(a)pyrene decreased sharply from 100% in topsoil to 0 in the 4th horizon.     

Leaves of Quercus ilex L. as biomonitors of PAHs in the air of Naples (Italy)

Polycyclic aromatic hydrocarbons (PAHs) were determined by the GC-MS chromatography in the leaves of Quercus ilex L., an evergreen Mediterranean oak, to monitor the degree of pollution in the urban area of Naples compared to remote areas. Leaf samples were collected in July 1998 from four urban parks, six roadsides and two sites in remote areas. The total PAH contents in Q. ilex leaves ranged from 106.6 in a control site to 4607.5 ng/g d.w. along a road with a high traffic flow. The mean concentration factors (urban/control) were 3.8 for the parks and 15 for the roads. The contribution of carcinogenic PAHs (benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, indeno[1,2,3-c,d]pyrene) was higher in urban area and differed according to the site, ranging from 6.7% to 21.3%. The total PAH burden in control sites was dominated by the low molecular weight PAHs, whilst along the urban roads fluoranthene, pyrene and benz[a]anthracene among the measured PAHs showed the highest values. PAHs were positively correlated (P<0.01) to trace metals measured in a previous study.     

Embryotoxicity of polycyclic aromatic hydrocarbons (PAHs) in three domestic avian species, and of PAHs and coplanar polychlorinated biphenyls (PCBs) in the common eider

The embryotoxicity of an artificial mixture of 18 polycyclic aromatic hydrocarbons (PAHs) was tested by injection into the yolk sacs of eggs of four avian species: chicken Gallus domesticus, turkey Meleagris gallopavo, domestic duck Anas platyrhynchos and common eider Somateria mollissima. A dose of 2.0 mg kg egg(-1) of the PAH mixture increased the mortality among the embryos of all four species. In the domestic duck, but not in the three other species, there was a significantly increased embryonic mortality at a dose of 0.2 mg kg(-1) of this mixture. All 18 individual compounds in the mixture were tested for embryotoxicity in the chicken. The compound most toxic to chick embryos was benzo[k]fluoranthene. This substance also proved to be highly embryotoxic in the three other species. Previous studies have shown coplanar polychlorinated biphenyls (PCBs) to be much more embryotoxic in the chicken than in other avian species studied. In accordance with this, eider duck embryos proved to be considerably less sensitive to 3,3',4,4'-tetrachlorobiphenyl and 3,3',4,4',5-pentachlorobiphenyl than was previously found for chick embryos. For PAHs, however, chick embryos did not have a higher sensitivity than the other species tested.     

Polycyclic aromatic hydrocarbons in marine organisms from the Adriatic Sea, Italy

Polycyclic aromatic hydrocarbons (PAHs) were analyzed in bivalves (Mitylus galloprovincialis), cephalopods (Todarodes sagittatus), crustaceans (Nephrops norvegicus) and fish (Mullus barbatus, Scomber scombrus, Micromesistius poutassou, Merluccius merluccius) in several pools coming from the Central Adriatic Sea. These marine organisms were selected because of their multitude, wide distribution and common use in the Italian diet, they were sampled and analyzed during the year 2004. Acenaphthene, benzo(a)pyrene, dibenz(a,h)anthracene, benzo(ghi)perylene and indeno(1,2,3-cd)pyrene showed levels below the instrumental detection limit in all samples. Fluorene, phenanthrene, anthracene, fluoranthene, benz(a)anthracene, benzo(b)fluoranthene and benzo(k)fluoranthene were detected at different concentrations in analyzed samples. Chrysene was detected only in mussels with very low values (average 0.74ngg(-1) wet weight). PAHs composition pattern was dominated by the presence of PAHs with 3-rings (62%) followed from those with 4-rings (37%) and 5-rings (1%). Atlantic mackerel, European hake and blue whiting showed the highest PAH concentrations, ranging from 44.1 to 63.3ngg(-1) wet weight, the group of invertebrate organisms showed a level of contamination about three times lower than those of the vertebrate groups. Mediterranean mussels that did not present very high levels of contamination expressed as sum of PAHs showed one of the highest values of benzo(a)pyrene equivalents (BaPEs). Conversely the latter value was very low in Atlantic mackerel even if this species reported the highest total PAH concentrations. No significant correlation was observed between weight, length and trophic levels and total PAHs.     

GC/MS analysis of polynuclear aromatic hydrocarbons in sediment samples from the Niger Delta region

Thirteen sediment samples from different locations in the Niger Delta region of Nigeria were analyzed for the presence of 16 polynuclear aromatic hydrocarbons (PAHs) via gas chromatography/mass spectrometry. The specific target compounds for this study included naphthalene, acenaphthylene, acenaphthene, flourene, phenanthrene, anthracene, flouranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]flouranthene, benzo[a]pyrene, benzo[ghi]perylene, dibenz[a,h]anthracene, and indeno[1,2,3-cd]pyrene. Four isotopically labeled polynuclear aromatic hydrocarbons (acanaphthene-d10, phenanthrene-d10, chrysene-d12 and perylene-d12) were used for internal standardization. All 16 PAHs were found in most of the thirteen samples with concentration ranging from 0.1 microg/kg to 28 microg/kg. It was also found that the 5 and 6-ring PAHs were present in higher concentrations than all the other compounds, indicating their high resistance to microbial degradation.     

The differential removal of aged polycyclic aromatic hydrocarbons from soil during bioremediation

Composting for the removal of polycyclic aromatic hydrocarbons (PAH) from soil was assessed as a treatment option at a former tar contaminated site, alongside conventional land treatment. The key objective of the study was to illustrate differences in the extent of removal of the different PAH compounds undergoing biological treatment. Soil composting led to more extensive PAH removal than did 2 variations on the land treatment process. Soil composting was substantially more effective in removing benzo(a)anthracene, chrysene, benzo(b+k)fluoranthene, benzo(a)pyrene, dibenz(ah)anthracene, indenopyrene and benz (gih)perylene, than the land treatment processes. The extents of removal of these higher molecular weight PAH were at least 50% over the 7 month treatment period where composting was used, whereas degradation did not exceed 5% for each of these PAH compounds in the land treatments over the same period. Implications from the study for the practical and effective composting of PAH compounds in soil, are (1) moisture in the soil-compost mix should be kept constant, (2) fresh organic matter should be used and (3) efforts need to be made to ensure soil is properly homogenized, both prior to and during soil mixing.     

Interaction of polycyclic aromatic hydrocarbons and heavy metals on soil enzyme

Actions and interactions of heavy metals (cadmium, zinc and plumbum) and polycyclic aromatic hydrocarbons (PAHs) [phenanthrene, fluoranthene, benzo(a)pyrene] on the soil urease and dehydrogenase activity were studied after 49 days exposure. The experimental approach was based on the uniform design which can cut the experiment time and improve the efficiency of experiments. Data treatment was essentially based on the multiple regression technique. The results showed that the action and interaction between heavy metals and PAHs were strongly dependent on the time of pollution. The dehydrogenase exhibits more sensitive to the combined pollution than urease. The negative interaction between Zn and Cd to hydrogenase activity and the combined stimulatory activity of Phenanthrene and Benzo(a)pyrene (or fluoranthene) to soil enzyme were observed. The interactions between Zn (Cd) and phenanthrene towards urease (dehydrogenase) were positive, and the interaction between Zn and benzo(a)pyrene to urease activity was negative. This study corresponds to exploratory phase in order to reveal interaction effects of heavy metals and PAHs on the soil enzyme and then to set up more in-depth analysis to increase progressively the understanding of the ecotoxicological mechanisms involved.     

Interactions between a polycyclic aromatic hydrocarbon mixture and the microbial communities in a natural freshwater sediment

The toxicity of a polycyclic aromatic hydrocarbon (PAH) mixture was assessed on the indigenous microbial communities of a natural freshwater sediment. The fate and effects of the PAH mixture (phenanthrene, fluoranthene and benzo(k)fluoranthene) were studied over 28 days. Bacterial communities were described by bacterial counts (total bacteria and viable bacteria), and by some hydrolytic enzyme activities (beta-glucosidase and leucine-aminopeptidase), PAH concentrations were measured in the overlying waters and in the sediments. No effect of PAH was detected at 30 mg/kg for all bacterial parameters. At 300 mg/kg, the quantity of total bacteria and the proportion of viable bacteria markedly decreased, compared to the control (0 mg PAH/kg). At 300 mg/kg, an increase of the beta-glucosidase activity and a decrease of the leucine-aminopeptidase activity were observed. For all treatments, the benzo(k)fluoranthene concentration in the sediment was stable over 28 days whereas, in the same time, only 3-6% of the initial concentrations of phenanthrene and fluoranthene remained. This study shows that (1) PAH induce perturbations of sediment microbial communities in terms of density and metabolism (but not always as an inhibition), (2) indigenous bacteria of sediments might be used for toxicity assessment of specific organic pollutants, (3) native microorganisms of sediment seem to have a high capacity for PAH degradation, depending on the physico-chemical properties and the bioavailability of the substance encountered.     

Removal of PAHs from water using an immature coal (leonardite)

It has been studied an immature coal (leonardite) as an adsorbent for removing PAHs [fluorene, pyrene, benzo(k)fluoranthene, benzo(a)pyrene and benzo(g,h,i)perylene] from water. To determine the efficiency of leonardite as an adsorbent of PAHs, factors such as pH, contact time and equilibrium sorption were evaluated in a series of batch experiments. There were no significant differences in the removal percentages for the various pH values studied, except for fluorene. The adsorption of fluorene was higher at lower pH values. The equilibrium time was reached at 24h. At this time, more than 82% of the pyrene, benzo(k)fluoranthene, benzo(a)pyrene and benzo(g,h,i)perylene had been removed. During the first 2h, the adsorption rate increased rapidly. After that time, however, there was a minor decrease. Equilibrium data were fitted to Freundlich models to determine the water-leonardite partitioning coefficient. Physical adsorption caused by the aromatic nature of the compounds was the main mechanism that governed the removal process. The polarity of the humic substances in leonardite may also have influenced the adsorption capacity.     

Toxicity testing of heavy metals with theRhizobium-legume symbiosis: High sensitivity to cadmium and arsenic compounds

Legume root nodules are the site of biological nitrogen fixation in theRhizobium-legame symbiosis. Nodules are structures unique to this symbiosis and they are morphologically as well as physiologically distinct from other plant organs. Organic substances affecting the macro- or microsymbionts vitality, such as PAHs (Wetzel et al., 1991), reduce nodulation even before visible damage to the plant can be detected. We present data that the formation of nodules (nodulation) may also serve for ecotoxicological evaluation of heavy metals in different binding states. Tests were performed in petri dishes with alfalfa (lucerne) seedlings inoculated withRhizobium meliloti. Cultivation took place in growth cabinets with carefully standardized and documented growth conditions. Data from stressed plants was recorded after 14 days of cultivation on contaminated substrate. A dose responsive decrease in nodulation was found after application of cadmium acetate, cadmium iodide, cadmium chloride, sodium salts of arsenate and arsenite, arsenic pentoxide, and lead nitrate, whereas lead acetate showed no effect up to a concentration of 3 μM. The dose response curves were used to calculate EC10, EC50 and EC90 values. EC50 values for cadmium compounds range from 1.5 to9.5 pM. Testing different arsenic compounds results in EC50 from 2.6 to 20.1 μM. EC50 of lead nitrate is 2.2 μM. The sensitivity, reproducibility and reliability of this test system is discussed compared to established biotests.     

Effects of chronic exposure to lead,copper, zinc,and cadmium on biomarkers of the European eel,Anguilla anguilla

Exposure to specific metallic compounds can cause severe deleterious modifications in organisms. Fishes are particularly prone to toxic effects from exposure to metallic compounds via their environment. Species that inhabit estuaries or freshwater environments can be chronically affected by persistent exposure to a large number of metallic compounds, particularly those released by industrial activities. In this study, we exposed yellow eels (European eel, Anguilla anguilla) for 28 days to environmentally relevant concentrations of four specific metals; lead (300, 600, and 1,200 μg/l), copper (40, 120, and 360 μg/l), zinc (30, 60, and 120 μg/l) and cadmium (50, 150, and 450 μg/l). The selected endpoints to assess the toxicological effects were neurotransmission (cholinesterasic activity in nervous tissue), antioxidant defense, and phase II metabolism (glutathione-S-transferase [GST] activity, in both gills and liver tissues), and peroxidative damage. The results showed an overall lack of effects on acetylcholinesterase for all tested metals. Lead, copper, and cadmium exposure caused a significant, dose-dependent, increase in GST activity in gill tissue. However, liver GST only significantly increased following zinc exposure. No statistically significant effects were observed for the thiobarbituric acid reactive substances assay, indicating the absence of peroxidative damage. These findings suggest that, despite the occurrence of an oxidative-based response after exposure to lead, copper, and cadmium, this had no consequence in terms of peroxidative membrane damage; furthermore, cholinergic neurotoxicity caused by lead, copper, and cadmium did not occur. The implications of these results are further discussed.     

Some Improvements in the Determination of Benzo [α] Pyrene in Air Samples

The earliest measurements of benz[α]pyrene (BαP) in air samples were almost exclusively based on chroma-tography on alumina columns followed by ultraviolet absorption, in spite of the fact that the original discovery and isolation of BαP in coal tar was based on its fluorescence properties. With the increasing use of fluorescence techniques, the vastly increased sensitivity over ultraviolet measurements has become generally apparent. In air sample extracts containing the four polycyclics, benzo[a]pyrene (BαP) benzo[k]-fluoranthene (BkF), benzo[g,h,i]perylene, (BghiP), and BαP, ultraviolet measurements for BαP are particularly, inaccurate. Fluorescence measurements of BαP are much more accurate, but some improvement in accuracy seems desirable. The present work deals with improvement of the fluorescence measurement of BαP. It now is possible to measure BαP in the presence of BkF with greatly increased accuracy. Interferences resulting from the presence of benzo[k]fluoranthene are now much lower.     

Seasonal variations of hydrophobic organic contaminant concentrations in the water-column of the Seine Estuary and their transfer to a planktonic species Eurytemora affinis (Calanoïda, copepoda). Part 1: PCBs and PAHs

Hydrophobic organic contaminants (HOC) (i.e. PAHs and PCBs) were measured in the water column and in Eurytemora affinis samples from the Seine Estuary collected from November 2002 to February 2005. Results showed seasonal variations of both total PCB and PAH levels in the suspended particulate matter (SPM) and in the copepods with maximum levels during winter times. PAH and PCB concentrations in the SPM ranged from 499 to 5819ngg(-1) and from 58 to 463ngg(-1), respectively. Phenanthrene, pyrene and benzo[b+j+k]fluoranthene (B[b+j+k]F) were the predominant PAH compounds in the water column, while CB 101, 118, 153 and 138 were the most abundant PCB congeners. PCBs and PAHs bioaccumulated by E. affinis (EA) varied between 383 and 1785ngg(-1) and 165-3866ngg(-1). CB101, 153, 138 and B[b+j+k] were, respectively, the major compounds of PCB and PAH fingerprints in EA. Thereby, the copepods could reach high accumulation factor (ACF) (91000 for PCBs and 17000 for PAHs). The principal component analyses of contaminant concentrations and environmental parameter datasets distinguished two groups of copepods. The winter time cluster, with high percentage of adult copepods, which bioaccumulated the highest PCB and PAH body-burdens, and the second cluster with juveniles showing the lowest HOC concentrations. Thus, PAH and PCB concentrations in EA exhibited significant correlations with the percentage of adults making up the samples.     

Comparison of the adsorption of lead,cadmium, copper,zinc and barium to freshwater surface coatings

Measurements were made regarding the adsorption of lead, cadmium, copper, zinc and barium to freshwater surface coatings (biofilms and associated minerals), which were collected in Nanhu Lake in Jilin Province, PR China, in order to investigate the variability of adsorption capacities of these heavy metals mentioned in the above surface coatings. The adsorption of lead and other heavy metals to the biofilms was observed to decrease in the following order: copper, lead, zinc, cadmium, and barium. Generally, the values of Gamma(max) (the maximum adsorption, micromol/m(2)) increased with the standard electrode potential of metal elements used and were recorded as 166.7, 40.0, 29.4, 10.8, and 1.8 for copper, lead, zinc, cadmium and barium, respectively. The values of 1/Gamma(max) increased linearly with the decrease in values of the standard electrode potential of metal elements with a significant correlation (n=5, p=0.01) and increased linearly with the increase in values of covalent radius of metal elements with a significant correlation (n=5, p=0.05). This indicates that standard electrode potential and covalent radius were two of the principal characteristics of metals employed, causing the variation of lead and other heavy metal adsorption to the surface coatings.     

Removal of PAHs from laboratory columns simulating the humus upper layer of vertical flow constructed wetlands

Removal of three polycyclic aromatic hydrocarbons or PAHs (fluoranthene, pyrene and benzo(k)fluoranthene) from two types of PAH-contaminated effluents was investigated using four laboratory columns filled with two different organic media: a green compost and a layer coming from the first stage of vertical flow constructed wetlands. Synthetic runoff polluted by polycyclic aromatic hydrocarbons were fed through the columns during a period of two months. After a period of hydrodynamic stabilisation, the results showed a great adsorption of PAHs (>95%) on the solid media due to their large adsorption capacities. Leaching of these compounds by water was monitored. The concentrations of PAHs in leaching samples indicated that PAHs were strongly adsorbed on organic substrates and that lixiviation was limited. Fluoranthene metabolites were also investigated. Accumulation of metabolites was transitory and located in the first few cm of the media, as was observed for PAH concentrations. A toxicity test of leachates based on the inhibition of the bioluminescence of luminescent bacteria Vibrio fischeri indicated a low inhibition which can be enhanced by metal traces.     

Responses of antioxidant systems and LPO level to benzo(a)pyrene and benzo(k)fluoranthene in the haemolymph of the scallop Chlamys ferrari

The effects of benzo(a)pyrene (BaP), benzo(k)fluoranthene (BkF) and their mixture on antioxidant enzyme activities and lipid peroxidation (LPO) levels of haemolymph of scallop (Chlamys ferrari) were studied. The superoxide dismutase (SOD) activities of 0.5 microg/L and 1.0 microg/L were significantly higher than controls (P<0.05), while it increased at beginning and then dropped (lower than controls) in the end at 10.0 microg/L and 50.0 microg/L PAHs groups. The catalase (CAT) activities were very little during the whole experimental time. The glutathione peroxidase (GPx) activities in each PAHs group all increased significantly (P<0.05). LPO levels all increased significantly (P<0.05) with time at each PAHs group except for the 0.5 microg/L group of less than hour 12. The toxicity of PAHs in a descending order was BaP>BkF>mixture of BaP and BkF. The changes in antioxidant enzyme activities and LPO level in haemolymph could reflect the detoxification functions and damage levels of whole organism.     

Effect of chronic exposure to cadmium on hepatic drug metabolism

In an attempt to examine the chronic effect of low levels of cadmium on hepatic drug-metabolizing enzyme system, an experiment was carried out in which growing male rats were given 0, 5, 10, and 20 ppm of cadmium in drinking water for a period of 8 weeks. An ip administration of a hypnotic dose of pentobarbital to the cadmium-treated and the control rats 24 hr following the termination of the experiment exhibited that there was no significant difference in the drug metabolism in control and any of the treated groups. Next, liver microsomes were isolated from animals in all groups to study their ability to metabolize drugs in vitro. The results indicated that the activity of benzphetamine N-demethylase and aniline hydroxylase, and the concentration of microsomal cytochrome P-450 were almost identical in the control and treated groups. On the other hand, a single ip dose of cadmium (2 mg/kg) caused significant decrease in the vivo and in vitro microsomal drug metabolism. These results suggest that although a single ip dose of cadmium (2 mg/kg) causes significant inhibition of drug metabolism, chronic exposure to cadmium up to 20 ppm in drinking water over a period of 8 weeks is unlikely to affect hepatic drug metabolism.     

Occurrence and assessment of polycyclic aromatic hydrocarbons in soils from vegetable fields of the Pearl River Delta, South China

Surface soil (0-20 cm) samples from nine representative vegetable fields located in Guangzhou, Shenzhen, Zengcheng and Huadu within the Pearl River Delta, South China were collected and analyzed for 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) using gas chromatography coupled to mass spectrometry (GC-MS). Total concentrations of 16 PAHs (Sigma(PAHs)) ranged from 160 to 3700 microg kg(-1). Large variations were observed also between concentrations of individual PAHs from different vegetable fields and within the site as well. Acenapthylene, benzo[b]fluoranthene, fluoranthene, benzo[a]pyrene and benzo[k]fluoranthene were consistently the most prevalent individual PAHs. The values of PAH isomer ratios [anthracene/(anthracene+phenanthrene) and fluoranthene/(fluoranthene+pyrene)] indicate that combustion processes are the major sources of PAHs. Concentrations of PAHs were poorly correlated with organic carbon concentrations of soils, suggesting different sources and also indicating that the PAH pollution of this area is recent. The same outcome is confirmed by the predominance of PAHs with fewer rings (相似文献   

Effect of chronic exposure to cadmium on hepatic drug metabolism

Abstract

In an attempt to examine the chronic effect of low levels of cadmium on hepatic drug‐metabolizing enzyme system, an experiment was carried out in which growing male rats were given 0, 5, 10, and 2 0 ppm of cadmium in drinking water for a period of 8 weeks. An ip administration of a hypnotic dose of pentobarbital to the cadmium‐treated and the control rats 2 4 hr following the termination of the experiment exhibited that there was no significant difference in the drug metabolism in control and any of the treated groups. Next, liver microsomes were isolated from animals in all groups to study their ability to metabolize drugs in vitro. The results indicated that the activity of benzphetamine N‐demethylase and aniline hydroxylase, and the concentration of microsomal cytochrome P‐450 were almost identical in the control and treated groups. On the other hand, a single ip dose of cadmium (2 mg/kg) caused significant decrease in the in vivo and in vitro microsomal drug metabolism. These results suggest that although a single ip dose of cadmium (2 mg/kg) causes significant inhibition of drug metabolism, chronic exposure to cadmium up to 2 0 ppm in drinking water over a period of 8 weeks is unlikely to affect hepatic drug metabolism.