Comparative assessment of soil microbial community in crude oil contaminated sites.

Petroleum refineries generate oily sludge that contains hazardous polycyclic aromatic hydrocarbons (PAH), and hence, its proper disposal is of foremost concern. Analysis of the physicochemical properties and functions of indigenous microbes of the contaminated sites are essential in deciding the strategy for bioremediation. This study analyses both parameters at two geographically distant sites, with different crude oil sources, and compares the metabolic capability of soil bacteria with reference to different contamination sources and the age of the contaminated site. The results indicate that organic carbon and total nitrogen derived from petroleum hydrocarbon negatively affect microbial diversity. Contamination levels vary widely on site, with levels of PAHs ranging from 5.04 to 1.66 × 103 µg kg-1 and 6.20 to 5.64 × 103 µg kg-1 in Assam and Gujarat sites respectively, covering a higher proportion of low molecular weight (LMW) PAHs (fluorene, phenanthrene, pyrene, and anthracene). Functional diversity values were observed to be positively correlated (p < 0.05) with acenaphthylene, fluorene, anthracene, and phenanthrene. Microbial diversity was the highest in fresh oily sludge which decreased upon storage, indicating that immediate bioremediation, soon after its generation, would be beneficial. Improvement in the bio-accessibility of hydrocarbon compounds by the treatment of biosurfactant produced by a (soil isolate/isolate) was demonstrated., with respect to substrate utilization.

Polycyclic aromatic hydrocarbons (PAHs) in dry tea leaves and tea infusions in Vietnam: contamination levels and dietary risk assessment.

The total mean ∑[Formula: see text] in samples were from 75.3 to 387.0 ng/g dry weight (d.w) and showed high value in black dry tea, followed by herbal, oolong, and green tea. The mean ∑[Formula: see text] (a combination of benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene) values were 54.3 ng/g, 16.4 ng/g, 14.2 ng/g, and 6.6 ng/g for black, herbal, green, and oolong teas, respectively. Concentration for benzo[a]pyrene (BaP) was from 0.4 to 35.8 ng/g, and the BaP equivalent concentration values ranged from 0.3 to 48.1 ng/g. There was only 1 black tea sample that BaP concentration exceeded the maximum level according to European Union (EU) standards. Tea samples marketed in Vietnam showed insignificant difference with the samples from other origins by same analytical method. Black teas showed high PAHs contents in dry tea samples but the released percentage of sum of PAHs from tea-to-tea infusion was lower than that in other tea type samples. The released percentages of PAH4 from tea-to-tea infusion were 40.7, 15.4, and 1.9 for green, herbal, and black tea. High temperature in black tea manufacturing processes might reduce essential oil content in tea that might effect on the PAHs partially release into the infusion. Indeed, based on EU regulations, we may conclude that tea consumers are safe in risk of exposure to PAHs obtained from teas.

Evaluation of New Diagnostic Ratios of Naphthalenes and Fluorenes by Identifying Severely Weathered Oils Collected in Laboratory Simulations and Coastal Weathering Experiments.

The composition and physical properties of spilled oil have great changes during the seriously weathering process. It brings great difficulties to the source identification of oil spill. So, the stable and trustworthy diagnostic ratios (DRs) for accurate identification of severely weathered spilled oils are very important. The explosion of Sinopec pipeline happened on November 22, 2013 at Qingdao, China. Local beaches at Jiaozhou Bay were polluted by spilled oils. We have collected original spilled oil samples from an area free from human interference near the oil leakage point after the accident. Synchronized with actual beach weathering, laboratory experiments were conducted to simulate oil weathering for 360 days by using the collected original spilled oil samples. Based on the t test and the repeatability limit method, 65 DRs of naphthalenes and fluorenes were screened. Fifteen DRs, namely, C2Nap/(C2Nap + C3Nap), C2Nap/(C2Nap + C4Nap), C2Nap/total Nap, C3Nap/(C3Nap + C4Nap), C3Nap/total Nap, C4Nap/total Nap, C2Flu/(C2Flu + C3Flu), C2Flu/total Flu, C2Nap/(C2Nap + Flu), C2Nap/(C2Nap + C1Flu), C2Nap/(C2Nap + C2Flu), C2Nap/(C2Nap + C3Flu), C3Nap/(C3Nap + Flu),C3Nap/(C3Nap + C1Flu), total Nap/(total Nap + total Flu), have maintained remarkable stability during the simulated weathering experiments and field weathering process. These stable ratios can retain the characteristics of oil source during weathering. They are very beneficial to improve the accuracy of identifying the source of severely weathered oil and can be used as an effective supplement to existing index system for source identification.

Polycyclic aromatic hydrocarbons in teas using QuEChERS and HPLC-FLD.

Polycyclic aromatic hydrocarbons (PAHs) are food-processing contaminants considered to be carcinogenic and genotoxic. Due to its drying process stage, teas may be contaminated with PAHs. The aim of the study was to validate an analytical method involving QuEChERS and HPLC-FLD for the determination of PAH4 in teas and evaluate the contamination levels in 10 different types of teas from Brazil. Recoveries varied from 54% to 99% and relative standard deviations from 1% to 21%. Limits of detection and quantification were from 0.03 to 0.3 µg/kg and 0.1 to 0.5 µg/kg, respectively. Mate tea presented the highest PAH levels, with PAH4 varying from 194 to 1795 µg/kg; followed by black (1.8-186 µg/kg), white (24-119 µg/kg), and green teas (3.1-92 µg/kg). Teas with lowest PAH4 were strawberry, lemongrass, peppermint, and boldo. Only trace levels of PAHs were detected in tea infusions, so apparently it would not affect PAH intake by Brazilian population.

Contamination of Tea and Tea Infusion with Polycyclic Aromatic Hydrocarbons.

The aim of this work was to validate the method of determination of polycyclic aromatic hydrocarbons (PAHs), i.e., benzo(a)pyrene and sum of benzo(a)pyrene, benz(a)anthracene, benzo(b)fluoranthene and chrysene in different types of tea, as well as to assess the transfer of these contaminants from tea to tea infusion. The research materials were popular types of black, green, red and white tea. Quantitative and qualitative determination of PAHs was performed by High Performance Liquid Chromatography with fluorimetric detection (HPLC-FLD). The samples were prepared by QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) technique followed by cleaning-up by dispersion solid-phase extraction (d-SPE). Values of limit of detection and limit of quantification obtained in the validation of the method were lower than the respective maximum values given in Commission Regulation (EU) No. 836/2011. The level of contamination of popular teas commercially available on the Polish market with PAHs is similar to that of teas available in other countries, with a very large variation in the concentration of each of the compounds. The highest benzo(a)pyrene and Σ4PAHs contents (209 ± 42 µg/kg and 756 ± 151 µg/kg, respectively) were found for black tea leaves. The transfer of Σ4PAHs from black tea to tea infusions was 0.48%, while it was 1.55-1.72% for red, white and green teas.

Chemical Analysis of Counterfeit Hepatitis C Drug Found in Japan.

In January 2017, counterfeits of the hepatitis C drug 'HARVONI® Combination Tablets' (HARVONI®) were found at a pharmacy chain through unlicensed suppliers in Japan. A total of five lots of counterfeit HARVONI® (samples 1-5) bottles were found, and the ingredients of the bottles were all in tablet form. Among them, two differently shaped tablets were present in two of the bottles (categorized as samples 2A, 2B, 4A, and 4B). We analyzed the total of seven samples by high-resolution LC-MS, GC-MS and NMR. In samples 2A, 3 and 4B, sofosbuvir, the active component of another hepatitis C drug, SOVALDI® Tablets 400 mg (SOVALDI®), was detected. In sample 4A, sofosbuvir and ledipasvir, the active components of HARVONI®, were found. A direct comparison of the four samples and genuine products showed that three samples (2A, 3, 4B) are apparently SOVALDI® and that sample 2A is HARVONI®. In samples 1 and 5, several vitamins but none of the active compounds usually found in HARVONI® (i.e., sofosbuvir and ledipasvir) were detected. Our additional investigation indicates that these two samples are likely to be a commercial vitamin supplement distributed in Japan. Sample 2B, looked entirely different from HARVONI® and contained several herbal constitutents (such as ephedrine and glycyrrhizin) that are used in Japanese Kampo formulations. A further analysis indicated that sample 2B is likely to be a Kampo extract tablet of Shoseiryuto which is distributed in Japan. Considering this case, it is important to be vigilant to prevent a recurrence of distribution of counterfeit drugs.

Comparative study on the occurrence of polycyclic aromatic hydrocarbons in breast milk and infant formula and risk assessment.

The study compared the polycyclic aromatic hydrocarbons (PAH) profile of human milk collected from Italian mothers and different brands of infant formula available on Italian market. Levels of 14 PAHs most frequently occurred in food, PAH markers listed by Commission Regulation (EC) No. 1881/2006, and carcinogenic PAHs classified by the International Agency for Research on Cancer, were determined by high-pressure liquid chromatography with fluorescence detector. The average concentrations of total PAHs were 114.93 in breast milk and 53.68 µg kg-1 in infant formula. Furthermore, Benzo(a)pyrene (BaP) and the sum of ∑PAH4 markers (BaP, Chrysene, Benzo(a,h)anthracene and Benzo(b)fluoranthene) were higher than the permissible limit of 1 µg kg-1 in 43% and 86% for breast milk and in 10% and 76% for infant formula samples, respectively. Breast milk showed higher levels (P < 0.05) of carcinogenic, and possible carcinogenic hydrocarbons than infant formula samples. Both in human and commercial milk, data showed the occurrence of low and high molecular weight PAHs, respectively from petrogenic and pyrolytic environmental sources, characterizing the infant and mother exposure. Particularly, waste incineration could have represented an important exposure source for infants during breastfeeding, through exposition of mothers resident in some areas of Southern Italy. High PAH levels detected in infant formula enriched with LC-PUFA might be related to the contamination of the vegetable oils added as ingredients. Results showed a high percentage of samples of both breast milk and infant formulas with margin of exposure (MOE) value indicating a potential concern for consumer health.

Optimization and validation of a method using UHPLC-fluorescence for the analysis of polycyclic aromatic hydrocarbons in cold-pressed vegetable oils.

Among the different food categories, the oils and fats are important sources of exposure to polycyclic aromatic hydrocarbons (PAHs), a group of organic chemical contaminants. The use of a validated method is essential to obtain reliable analytical results since the legislation establishes maximum limits in different foods. The objective of this study was to optimize and validate a method for the quantification of four PAHs [benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(a)pyrene] in vegetable oils. The samples were submitted to liquid-liquid extraction, followed by solid-phase extraction, and analyzed by ultra-high performance liquid chromatography. Under the optimized conditions, the validation parameters were evaluated according to the INMETRO Guidelines: linearity (r2 >0.99), selectivity (no matrix interference), limits of detection (0.08-0.30µgkg-1) and quantification (0.25-1.00µgkg-1), recovery (80.13-100.04%), repeatability and intermediate precision (<10% RSD). The method was found to be adequate for routine analysis of PAHs in the vegetable oils evaluated.

Degradation of some representative polycyclic aromatic hydrocarbons by the water-soluble protein extracts from Zea mays L. cv PR32-B10.

The ability of the water-soluble protein extracts from Zea mais L. cv. PR32-B10 to degrade some representative polycyclic aromatic hydrocarbons (PAHs), has been evaluated. Surface sterilized seeds of corn (Zea mais L. Pioneer cv. PR32-B10) were hydroponically cultivated in a growth chamber under no-stressful conditions. The water-soluble protein extracts isolated from maize tissues showed peroxidase, polyphenol oxidase and catalase activities. Incubation of the extracts with naphthalene, fluorene, phenanthrene and pyrene, led to formation of oxidized and/or degradation products. GC-MS and TLC monitoring of the processes showed that naphthalene, phenanthrene, fluorene and pyrene underwent 100%, 78%, 92% and 65% oxidative degradation, respectively, after 120 min. The chemical structure of the degradation products were determined by (1)H NMR and ESI-MS spectrometry.

Validation of analytical conditions for determination of polycyclic aromatic hydrocarbons in roasted coffee by gas chromatography-mass spectrometry.

Polycyclic aromatic hydrocarbons (PAHs) are of significant interest due to their genotoxicity in humans. PAHs quantification in coffee is complex since some of its compounds interfere in the chromatographic analysis, which hinders the reliable determination of the PAHs. Analytical conditions for the ultrasound extraction, purification and quantification of 16 PAHs in roasted coffee were studied. The better extraction efficiency of benzo[a]pyrene (68%) from ground-roasted coffee was achieved with a solvent ratio of Hex:MC (9:1 v/v) and three extraction periods of 20 min, followed by alkaline saponification and purification of the extracts. The detection limits were 0.85-39.32 ng mL(-1), and the quantification limits from 2.84 to 131.05 ng mL(-1), obtained for fluoranthene and chrysene, respectively. The extraction was effective for most of the analytes, with recoveries of 39.8% dibenzo[ah]anthracene and 69.0% benzo[b]fluoranthene. For coffee roasted in a spouted bed reactor, the summation of the 16 PAHs ranged from 3.5 to 16.4 µg kg(-1).

Determination of polycyclic aromatic hydrocarbons in dry tea.

Twenty-eight different tea samples sold in the United States were evaluated using high-performance liquid chromatography (HPLC) with fluorescence detection (FLD) for their contamination with polycyclic aromatic hydrocarbons (PAHs). Many PAHs exhibit carcinogenic, mutagenic, and teratogenic properties and have been related to several kinds of cancer in man and experimental animals. The presence of PAHs in environmental samples such as water, sediments, and particulate air has been extensively studied, but food samples have received little attention. Eighteen PAHs congeners were analyzed, with percentage recovery higher than 85%. Contamination expressed as the sum of the 18 analyzed PAHs was between 101 and 1337 µg/kg on dry mass and the average contents in all of the 28 examined samples was 300 µg/kg on dry mass. Seven of the congeners were found in all samples with wide ranges of concentrations as follows: fluorene (7-48 µg/kg), anthracene (1-31 µg/kg), pyrene (1-970 µg/kg), benzo(a)anthracene (1-18 µg/kg) chrysene (17-365 µg/kg), benzo(a)pyrene (1-29 µg/kg), and indeno(1,2,3-cd)pyrene (4-119 µg/kg). The two most toxic congeners benzo(a)pyrene and dibenzo(a,h)anthracene were found at high concentrations only in Earl Grey Twinnings, Earl Grey Harney& Sons Fine Teas, and Chai Ultra Spice Black Tea Twinnings. Six PAH congeners are considered as suspected carcinogens (U.S.EPA), formed the basis of the estimation of the toxic equivalent (TEQ), Chai Ultra-Spice Black Tea Twinnings had the highest TEQ (110.9) followed by two grey tea samples, Earl Grey Harney & Sons Fine Tea (57.7) and Earl Grey Twinnings (54.5). Decaffeinated grey teas had the lowest TEQs, decaffeinated Earl Grey Bigelow (9.4) and Green Tea Honey Lemon Decaffeinated Lipton (9.6).

Effect of contact time and the use of hydroxypropyl-ß-cyclodextrin in the removal of fluorene and fluoranthene from contaminated soils.

Sorption-desorption experiments of fluorene (FLU) and fluoranthene (FLT) in soils were carried out and correlated to their removal from aged contaminated soils using aqueous solutions in the absence and in the presence of hydroxypropyl-ß-cyclodextrin (HPBCD) as the extraction agent. FLU became more resistant to extraction in aged contaminated soils due to its initial adsorption onto the mineral and amorphous soil organic matter (SOM) domains, sites of lower binding energy from which, due to its small size, it could spread towards the condensed SOM as the contact time increased. Therefore, FLU will not be easily desorbed from aged contaminated soils due to physical entrapment mechanisms, even when using HPBCD as extractant, presenting FLU low risks to the environment. On the contrary, FLT was extracted from aged soils in the presence of HPBCD in solutions to a much greater extent than in its absence. Due to its more hydrophobic character FLT sorption in soils was relatively quicker, remaining more or less fixed on hydrophobic sites of the organic matter (OM) with different energies, and therefore the amount of FLT extracted was almost constant for different ageing times. During extraction experiments, the influence of the OM quality of the soils was also highlighted because an inverse proportionality between OM content of soil and extractability of sorbed FLT was observed. It was concluded that soils with lower OM content that had more diagenetically processed OM could block the extraction of FLT more effectively than soils with higher OM content that are less humified. This indicates the need to use not only adsorption-desorption data in contaminant fate and transport models, but also extraction studies in aged contaminated soils and other complementary analytical approaches when assessing soil contamination-related risks.

Polycyclic aromatic hydrocarbons (PAHs) in yerba mate (Ilex paraguariensis) from the Argentinean market.

Polycyclic aromatic hydrocarbons (PAHs) occurrence in 50 samples marketed in the main supermarkets from Argentina was surveyed. A high performance liquid chromatography (HPLC) method was applied with fluorescence detection (FLD) and UV-VIS diodes array detector (DAD) for the analysis of 16 PAHs in "yerba mate" (Ilex paraguariensis), with recoveries higher than 89% and limits of detection and quantification lower than that found by other methodologies in previous studies. Contamination expressed as the sum of 16 analysed PAHs ranged between 224.6 and 4449.5 µg kg(-1) on dry mass. The contamination expressed as PAH4 (sum of benzo(a)pyrene, chrysene, benzo(a)anthracene and benzo(b)fluoranthene) varied between 8.3 and 512.4 µg kg(-1). The correlation coefficient for PAH2 (sum of benzo(a)pyrene and chrysene) and PAH4 groups was 0.99, for PAH2 and PAH8 (sum of benzo(a)pyrene, chrysene, benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(g,h,i)perylene, dibenzo(a,h)anthracene and indeno(1,2,3cd) pyrene) 0.97 and for PAH4 and PAH8 0.98.

Determination of polycyclic aromatic hydrocarbons in smoked and non-smoked black teas and tea infusions.

This study describes the occurrence of polycyclic aromatic hydrocarbons (PAHs) in smoked tea and tea infusions, via the monitoring of benzo(a)anthracene, chrysene, benzo(b)fluoranthene and benzo(a)pyrene (PAH4) that have been chosen as indicators for the occurrence of PAHs in food by the European Food Safety Agency. The concentrations ranged from 1.2 µg/kg for benzo(b)fluoranthene to 125.0 µg/kg for benzo(a)anthracene in smoked tea leaves, and from 0.6 µg/L for benzo(a)anthracene to 1.2 µg/L for benzo(b)fluoranthene in smoked tea infusions. Benzo(a)pyrene was never detected in infusions. The concentrations in non-smoked tea leaves ranged from 0.6 µg/kg for benzo(a)anthracene to 10.8 µg/kg for benzo(b)fluoranthene. It was shown that the concentrations of benzo(a)anthracene and chrysene were higher in smoked tea than in non-smoked tea while no difference was observed for benzo(b)fluoranthene and benzo(a)pyrene. The concentrations of PAHs in tea infusions are low compared to other foodstuffs, but the migration rates from leaves into water are high (82-123%).

Isolation and characterization of a novel phenanthrene (PHE) degrading strain Psuedomonas sp. USTB-RU from petroleum contaminated soil.

The phenanthrene degrading novel bacterium strain USTB-RU was isolated from petroleum contaminated soil in Dagan oilfield, southeast of Tianjin, northeast China. The novel isolate was identified as Pseudomonas sp. USTB-RU on the basis of morphological, physicochemical characteristics and analysis of 16S rDNA gene sequence. The strain could degrade 86.65% of phenanthrene at an initial concentration of 100 mg L(-1) in 8 days and identified intermediate metabolite evident the biodegradation of phenanthrene through protocatechuate metabolic pathway. The strain showed the potential to produce surface-active compounds that may have caused for the resulted efficient biodegradation through enhancing the substrate bioavailability. The results highlighted that the adaptability of USTB-RU to grow in a range of temperature, pH and potential to utilize various commonly co-exist pollutants in contaminated site other than phenanthrene as sole carbon and energy source. Further, susceptibility of the strain for the tested antibiotics inferred the possibility to absence of risk of spreading drug resistant factor to other indigenous bacteria. Therefore, the isolated novel strain USTB-RU may have a high potential for application in in situ bioremediation of phenanthrene contaminated environment.

Evaluation of phase II toxicity identification evaluation methods for freshwater whole sediment and interstitial water.

Phase I whole sediment toxicity identification evaluation (TIE) methods have been developed to characterize the cause of toxicity as organic chemicals, metals, or ammonia. In Phase II identification treatments, resins added to whole sediment to reduce toxicity caused by metals and organics can be separated and eluted much like solid-phase extraction (SPE) columns are eluted for interstitial water. In this study, formulated reference sediments spiked with toxic concentrations of copper, fluoranthene, and nonylphenol were subjected to whole sediment and interstitial water TIE treatments to evaluate Phase I and II TIE procedures for identifying the cause of toxicity to Hyalella azteca. Phase I TIE treatments consisted of adding adsorbent resins to whole sediment, and using SPE columns to remove spiked chemicals from interstitial water. Phase II treatments consisted of eluting resins and SPE columns and the preparation and testing of eluates for toxicity and chemistry. Whole sediment resins and SPE columns significantly reduced toxicity, and the eluates from all treatments contained toxic concentrations of the spiked chemical except for interstitial water fluoranthene. Toxic unit analysis based on median lethal concentrations (LC50s) allowed for the comparison of chemical concentrations among treatments, and demonstrated that the bioavailability of some chemicals was reduced in some samples and treatments. The concentration of fluoranthene in the resin eluate closely approximated the original interstitial water concentration, but the resin eluate concentrations of copper and nonylphenol were much higher than the original interstitial water concentrations. Phase II whole sediment TIE treatments provided complementary lines of evidence to the interstitial water TIE results.

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.

Determination of glucosamine in raw materials and dietary supplements containing glucosamine sulfate and/or glucosamine hydrochloride by high-performance liquid chromatography with FMOC-Su derivatization: collaborative study.

A collaborative study was conducted for determination of glucosamine in raw materials and dietary supplements containing glucosamine sulfate and/or glucosamine hydrochloride by high-performance liquid chromatography (HPLC) with N-(9-fluorenyl-methoxycarbonyloxy) succinimide (FMOC-Su) derivatization. Thirteen blind materials, one pair of which were duplicates, were tested by 12 collaborating laboratories. The test samples consisted of various commercial products, including tablets, capsules, drink mix, and liquids as well as raw materials, blanks, and those for spike recovery analyses. The tests with blank products and products spiked with glucosamine showed good specificity of the method. The average recoveries at spike levels of 100 and 150% of the declared amount were 99.0% with a relative standard deviation (RSD) of 2.1%, and 101% with an RSD of 2.3%, respectively. The test results between laboratories on each commercial product were reproducible with RSD values of no more than 4.0%, and the results were repeatable in the same laboratory with an average RSD of 0.7%. HorRat values ranged from 0.5 to 1.7 on both tests of spike recovery and reproducibility between laboratories on commercial products. The average determination coefficient of the calibration curves from the laboratories was 0.9995 with an RSD of 0.03%. All of the 12 collaborating laboratories succeeded in the study and none of their reported test results were outliers, partly indicating the robustness of the method. It is recommended that the method be accepted by AOAC INTERNATIONAL as Official First Action.

Sample preparation improvement in polycyclic aromatic hydrocarbons determination in olive oils by gel permeation chromatography and liquid chromatography with fluorescence detection.

The determination of 15 polycyclic aromatic hydrocarbons (PAHs) in olive oil samples has been improved in order to obtain a fast methodology with a low limit of detection through the combination of liquid-liquid extraction with acetonitrile and preparative gel permeation chromatography (GPC) prior to the injection of purified extracts into a C18 column. Acetonitrile-water was used as the mobile phase with a gradient from 50 to 95%, w/w, acetonitrile in 30 min. The oven temperature was maintained at 15 degrees C, and fluorometric detection was made at a fixed excitation wavelength of 264 nm and variable, optimal emission wavelength for each analyte ranging from 352 nm for 11-H-benzo(b)fluorene to 500 nm for indeno(1,2,3-cd)pyrene. Recovery for all the compounds studied varied from 75 to 111%, and limit of detection values from 0.05 ng/g for benzo(k)fluoranthene to 0.48 ng/g for indeno(1,2,3-cd)pyrene, corresponding to 0.09 ng/g benzo(a)pyrene. Results were compared with those obtained by liquid-liquid extraction followed by a cleanup on silica and a direct GPC treatment of oil samples diluted in dichloromethane, 2 other methodologies that are appropriate for quantifying PAHs in olive oils. However, the proposed method improves the determination limits, reduces the time of analysis, and provides a highly stable baseline for sample chromatograms.

Long-term fate of polychlorinated biphenyls and polycyclic aromatic hydrocarbons in an agricultural soil.

Laboratory studies are useful for understanding the behavior of persistent organic pollutants (POPs) in soil, although such investigations do not always relate directly to field conditions. Outdoor lysimeter studies may be used to overcome this problem. This work aimed to investigate the behavior of two polycyclic aromatic hydrocarbons (PAHs) (fluoranthene and benzo[a]pyrene) and two polychlorinated biphenyls (PCBs; congeners 28 and 52) in soil, using lysimeters established in 1990 atthe Agrosphere Institute (Forschungszentrum Julich GmbH, Germany). The two PAHs were in one lysimeter, and the PCBs were in a second lysimeter. Afurther aim of the study was to determine soil half-lives for each of the contaminants. The overall decline in PAH concentrations was considerably greater than forthe PCBs over the 152 month study. The PCBs exhibited greater chemical extractability than the PAHs and were demonstrated to have migrated through the soil column to a greater extent than the PAHs. Loss of PCBs from surface soil was not considered to have been congener specific for the two PCB congeners in this study. The two PAHs varied in their extents of total loss and movement through the soil column. Soil half-lives were determined as 10.9 y for [12C]PCB 28, 11.2 yr for [12C]PCB 52, 2.7 yr for benzoqpyrene, and 32 d (phase 1) to 38 yr (phase 2) for fluoranthene. These are shown to disagree with some previous estimates of POP half-lives in soil, suggesting that previous studies underestimated persistence by 10-fold or more.