Remediation of benzo[a]pyrene contaminated soils by moderate chemical oxidation coupled with microbial degradation.

Chemical oxidation is a promising technology for the remediation of organics-contaminated soils. However, residual oxidants and transformation products have adverse effects on microbial activities. This work aimed at moderate chemical oxidation coupled with microbial degradation (MOMD) for the removal of benzo[a]pyrene (BaP) by optimizing the type and dosage of oxidants. Potassium permanganate (KMnO4), Fe2+ + sodium persulfate (Fe2+ + PS), Fenton's reagent (Fe2+ + H2O2), and hydrogen peroxide (H2O2) were compared for BaP removal from loam clay and sandy soils. Overall, the removal efficiency of BaP by a moderate dose of oxidant coupled indigenous microorganism was slightly lower than that by a high dose of relevant oxidant. The contributions of microbial degradation to the total removal of BaP varied for different oxidants and soils. The removal efficiency of BaP from loam clay sandy soil by a moderate dose of KMnO4 (25 mmol/L) was 94.3 ± 1.1 % and 92.5 ± 1.8 %, respectively, which were both relatively higher than those under other conditions. The indirect carbon footprint yielded by the moderate dose of oxidants was 39.2-72.8 % less than that by the complete oxidation. A moderate dose of oxidants also reduced disturbances to soil pH and OC. The microbial communities after MOMD treatment were dominated by Burkholderiaceae, Enterobacteriaceae, Alicyclobacillaceae, and Oxalobacteraceae. These dominant microorganisms promoted the removal of BaP through the expression of polycyclic aromatic hydrocarbon-ring hydroxylated dioxygenase gene. Compared with complete chemical oxidation, MOMD is also a promising technique with the utilization of indigenous microorganism for remediating BaP-contaminated soils.

Effect of Shixiao San on inflammatory factors and pain in rats with endometriosis.

ETHNOPHARMACOLOGICAL RELEVANCE: In the practice of traditional Chinese medicine, endometriosis is believed to be caused by blood stasis and is characterised by dysmenorrhea, which is difficult to control. Shixiao San (SXS) has a long history of use in the treatment of gynaecological diseases. The prescriptions composed of SXS include Typhae Pollen and Faeces Trogopterori, both of which have anti-inflammatory activity. In addition, Typhae Pollen can be used to treat many kinds of blood stasis diseases. AIM OF THE STUDY: The purpose of the present study was to investigate the effect of SXS on pain relief in rats with endometriosis and to preliminarily explore its mechanism of action in alleviating pain. MATERIAL AND METHODS: Ten rats received sham operation as the Sham group, and 30 endometriosis model rats were randomly divided into three groups: the Model, Shixiao San-Low (SXS-L), and Shixiao San-High (SXS-H) groups. The rats were administered the appropriate treatment via intragastric gavage for 4 weeks. The thermal radiation pain and mechanical pain thresholds of the rats were measured every 7 days after treatment. Finally, the distribution density of nerve fibres in endometrial tissue, the inflammatory infiltration of the dorsal root ganglion (DRG), the expression of TRPV1 in the DRG, and the expression of IL-1ß, TNF-α, and IL-6 in ectopic tissue were measured. RESULTS: After SXS treatment, the growth of ectopic tissue in rats with endometriosis was significantly suppressed, their thermal radiation pain and mechanical pain thresholds increased, the density of nerve fibres and the expression of inflammatory factors in ectopic tissues reduced, and inflammatory cells infiltration in the DRG of the animals alleviated. Meanwhile, the expression of TRPV1 in the DRG was downregulated in rats with endometriosis. CONCLUSIONS: SXS could possibly inhibit the development of endometriosis and relieve pain in patients with endometriosis by reducing inflammatory responses in ectopic tissue and the DRG.

Occurrence, Formation, and Oxidative Stress of Emerging Disinfection Byproducts, Halobenzoquinones, in Tea.

Halobenzoquinones (HBQs) are frequently detected disinfection byproducts (DBPs) in drinking water with high toxicity and relevance to public health. In this study, we characterized the occurrence, formation, and oxidative stress of the HBQs in tea. 2,6-DCBQ and TetraC-1,2-BQ were identified in all prepared teas at total concentrations of 1.3-2.0 ng/L. 2,6-DCBQ originated from drinking water DBPs, while TetraC-1,2-BQ originated from tea leaves or were generated during tea polyphenol chlorination. HBQs in tea induced the formation of reactive oxygen species and semiquinone radicals, and the oxidative stress could be depleted by tea polyphenols, e.g., (-)-epigallocatechin gallate (EGCG). High-resolution mass spectrometry analysis indicated that the HBQs combined with EGCG and formed adducts at a ratio of 1:1 or 2:1 with the binding sites on the A ring and B ring of EGCG. The viability of HepG2 cells exposed to 50 µM 2,6-DCBQ was increased from 20.0% to 65.2% when 50 µM of EGCG was added. These results demonstrated that various HBQs can occur in tea due to the HBQ DBPs in drinking water, the leachate from tea leaves, and the chlorination of tea polyphenols; furthermore, the oxidative stress and cellular toxicity induced by HBQs in tea could be decreased by tea polyphenols. This is the first study to report HBQs in tea, elucidate the sources of HBQs, and assess relevant health risks.

Contamination characteristics and source apportionment of methylated PAHs in agricultural soils from Yangtze River Delta, China.

Alkylated PAHs (APAHs) have been shown to be more toxic and persistent than their non-alkylated parent compounds. However, little is known about the extent of soil contamination by these pollutants. To help understand agricultural soil pollution by these compounds at a regional scale, a total of 18 methylated PAHs (MPAHs, a major class of APAHs) in 243 soil samples were analyzed. These soil samples were collected from 11 sites in the Yangtze River Delta (YRD) region, a representative fast developing area in China. The total concentration of MPAHs (∑18MPAHs) ranged from 5.5 to 696.2 ng/g dry soil, with methylnaphthalenes (M-NAPs) and methylphenanthrenes (M-PHEs) accounting for more than 70% of the compositional profile. Relatively high concentrations of ∑18MPAHs were found in Jiaxing and Huzhou areas of Zhejiang province, as well as on the border between the cities of Wuxi and Suzhou. Different MPAH groups showed dissimilar spatial distribution patterns. The spatial distribution of lower molecular weight MPAHs was related to agricultural straw burning and emissions/depositions from industrial activities, whereas that of higher molecular weight MPAHs was much more a function of the total organic carbon (TOC) content of soil. Although coal, biomass (crop straw and wood), and petroleum combustion were identified to be the major emission sources for most of the sampling sites, the areas with relatively severe pollution with ∑18MPAHs resulted from the localized hotspots of petroleum leakage. Isomeric MPAHs with methyl group substituted at 2- (ß) position exhibited significantly higher concentrations than those substituted at 1- (α) position. Results of this work help to understand soil pollution by MPAHs, and are useful for designing effective strategies for pollution control so as to ensure food safety in areas with fast economic growth.

The toxicity of naphthalene to marine Chlorella vulgaris under different nutrient conditions.

The toxicity of naphthalene to Chlorella vulgaris was studied under nitrogen (N)-, phosphorus (P)-enriched and N,P-starved condition. Results showed that naphthalene was less toxic under N,P-starved condition. The inhibitory rates were less than 15.3% to C. vulgaris during 7 days exposure with the initial concentrations of naphthalene at 5, 10, 50, 100mg/L, respectively under N,P-starved condition, while they were 7.5-72.3% under N,P-enriched condition. The malondialdehyde (MDA) content indicated that there was no oxidative damage to algae when the initial concentration of naphthalene was less than 10mg/L, and oxidative damage exhibited to algae at 50-100mg/L of naphthalene under N,P-starved condition. Naphthalene induced oxidative damage to the algae at all tested concentrations (5-100mg/L) under N,P-enriched condition. The results indicated that there was a negative relationship between the special growth rate (SGR) and naphthalene concentration in the medium. Under N,P-enriched condition SGR of the control decreased slowly from 0.669 to 0.186. However, SGR of the naphthalene treated group decreased sharply during the first 2-3 days when the dissolved concentration of naphthalene was above 0.1mg/L, and then increased gradually with the evaporation of naphthalene.

Sorption of phenanthrene by nanosized alumina coated with sequentially extracted humic acids.

BACKGROUND, AIM, AND SCOPE: Sorption of hydrophobic organic compounds (HOCs) to natural organic matter (NOM) is an important process that affects the transport, transformation, bioavailability, and fate of HOCs in the environment. Manufactured nanoparticles (NPs) such as nano-oxides will inevitably enter the environment in the processes of their production, transfer, and use and could be coated by the ubiquitous NOM. Thus, sorption of HOCs to NOM in the environment could be affected by the NP interactions with NOM. Furthermore, the toxicity of nano-oxides could be increased due to the adsorbed HOCs. Therefore, sorption of phenanthrene by nano-Al(2)O(3) coated with humic acid (HA) was examined in this study to explore the possible effect of nanoparticles (NPs) on the environmental behavior of HOCs and the potential environmental and health risks of NPs. MATERIALS AND METHODS: Four HAs were sequentially extracted with 0.1 mol/L NaOH from a peat soil. HAs, nano-Al(2)O(3), and HA-coated nano-Al(2)O(3) were characterized by techniques such as elemental analysis, solid-state (13)C NMR, N(2) surface area analysis, and zeta potential measurement. Adsorption isotherms of HAs by nano-Al(2)O(3) and phenanthrene by HAs and HA-coated nano-Al(2)O(3) were obtained using a batch equilibration technique at 25 +/- 1 degrees C. HA concentrations were measured by total organic carbon analysis. Phenanthrene concentrations were measured by liquid scintillation counting. RESULTS: The adsorption maxima of HAs by nano-Al(2)O(3) was one order of magnitude higher than that by soil inorganic minerals. Phenanthrene isotherms of HA-coated nano-Al(2)O(3) were more nonlinear than that of their respective bulk HAs. Concentration-dependent organic carbon-normalized sorption coefficients (K' (oc)) of phenanthrene by HA-coated nano-Al(2)O(3) were lower than those for their respective bulk HAs, especially at relatively high concentrations. DISCUSSION: Isotherm nonlinearity of phenanthrene could be interpreted by a combination of partitioning accompanied by linear isotherm with adsorption accompanied by nonlinear isotherm. HA conformation changes during their adsorption on nano-Al(2)O(3) could play an important role in phenanthrene sorption and were responsible for higher nonlinearity of phenanthrene isotherms and lower phenanthrene K' (oc) on the adsorbed HAs than their respective bulk HAs. Adsorption of HA on nano-Al(2)O(3) would form a more condensed HA state with higher pi-polarity/polarizability and lower partitioning affinity than the respective bulk HA, leading to an increase of relative contribution of adsorption to the total sorption and more nonlinear phenanthrene isotherms in the adsorbed HA due to the increase in phenanthrene adsorption affinity and decrease in phenanthrene partitioning affinity. CONCLUSIONS: Adsorption of HA on nano-Al(2)O(3) was much higher than that on soil oxide minerals and could form a more condensed HA state with higher pi-polarity/polarizability and lower partitioning affinity than the bulk HA, causing the significant difference in phenanthrene sorption between the adsorbed HA and the respective bulk HA. Therefore, once released in the environment, NPs such as nano-Al(2)O(3) will strongly alter the environmental transport, fate, and bioavailability of HOCs and could be potentially more toxic due to the adsorbed toxic chemicals. RECOMMENDATIONS AND PERSPECTIVES: Due to the high adsorption of HA on nano-Al(2)O(3) and its significant effect on phenanthrene sorption, interactions of NOM with nano-oxides and their mechanistic relations with NOM conformation changes and HOC sorption merit further research. In addition, due to the higher sorption of phenanthrene on the HA-coated nano-Al(2)O(3) than the pure counterpart, the effect of NOM and HOCs on the ecotoxicity of NPs should be addressed in the future.

Characterization and phenanthrene sorption of tea leaf powders.

The sorption of hydrophobic organic compounds by natural organic matter is mainly regulated by its aromatic and aliphatic fractions, but it is not clear which fraction is more dominant. In this study, six types of Chinese tea leaves (three varieties of tender and three corresponding mature leaves) and their respective brewed ones were analyzed by elemental analysis, 13C NMR, and Fourier transform infrared attenuated total reflectance. Their sorption of phenanthrene was examined using a batch equilibration technique. The aromatic carbon content of tea leaves reduced while the aliphatic carbon content increased with increasing maturity and brewing. Sorption isotherms by all of the 12 tea sorbents were practically linear, showing a partition type sorption. The phenanthrene KOC (organic carbon-normalized sorption capacity) of the 12 sorbents ranged from 6960 to 32,900 mL/g, which increased with increasing aliphatic carbons and decreasing aromatic carbons in the tea leaves. The dissolved organic matter was released into solution from the sorbents during the sorption process, which could bind phenanthrene in the solution, and thereafter leading to underestimation of sorption capacity of the sorbents, but this did not change the correlation trends between KOC and functional carbon group content. Aliphatic fractions rather than aromatic moieties regulated the phenanthrene sorption of the tea leaf powders used in this study.

Factors affecting transfer of polycyclic aromatic hydrocarbons from made tea to tea infusion.

Factors affecting transfer percentages of 12 polycyclic aromatic hydrocarbons (PAHs) were investigated, including tea variety, tea/water ratio (TWR, g/mL), brewing times, washed tea or unwashed tea, and covered cup or uncovered cup. It was observed that %PAH transfer varied with tea variety and increased with the decrease of TWR. The mean %PAH transfer with TWR = 1/150 was 1.12 and 1.65 times higher than that with TWR = 1/100 and 1/50, respectively. %PAH transfer reduced greatly as the brewing times increased. The mean %PAH transfer in the first brewing time occupied 51.6% of the total three mean %PAH transfers in the three brewing times. The mean %PAH transfer decreased by 30.4% after the tea had been washed immediately before brewing. Brewing the tea within uncovered cup diminished %PAH transfer by a degree of 4.31-31.7% compared to brewing the tea within a covered cup.

Tea plant uptake and translocation of polycyclic aromatic hydrocarbons from water and around air.

This study, which aimed to investigate the capacity of tea plant uptake and translocation of polycyclic aromatic hydrocarbons (PAHs), was divided into two sections. One was to study tea plant root uptake of PAHs from water and translocation to leaves. The other was to research tea plant leaf uptake of PAHs from air. It was observed that tea plant roots and leaves could strongly accumulate PAHs from around the environment. The capacity of tea plant uptake and translocation of PAHs were found to be closely relative to the physical-chemical properties of PAHs. With the increase of IgK(ow) (octanol-water partition coefficient) of the PAHs, both root concentration factors and leaf concentration factors increased exponentially, while translocation factors from roots to leaves decreased exponentially.

PAHs in aquatic sediment in Hangzhou, China: analytical methods, pollution pattern, risk assessment and sources.

Eleven surface sediment samples, from Hangzhou section of Qiantang River and Jinghang Canal, west Lake the inland river were collected to investigate 17 polycyclic aromatic hydrocarbons (PAHs) pollution in aquatic sediments of Hangzhou. Accelerated solvent extraction(ASE) was used to extract PAHs from sediments with satisfactory recoveries. It was found that the total PAHs in the sediments ranged from 308.4 to 3037 ng/g dw, and PAHs pollution in sediments from Jinghang Canal were the heaviest. Lowest effect level (LEL) and severe effect level (SEL) sediment quality guidelines were introduced to perform risk assessment for PAHs pollution in aquatic sediments. Only one sample in Jinghang Canal had adverse impact on benthic organism. 2-3 ring PAHs had a noticeable contribution to total PAHs, especially NA, PHEN. A quantity method was used to determine the major source, the results showed petroleum origin was the chief source to PAHs pollution in all sediments with the exception of sediments from Jinghang Canal where combustion sources had a larger contribution.

A novel solubilization of phenanthrene using Winsor I microemulsion-based sodium castor oil sulfate.

Problems associated with polycyclic aromatic hydrocarbons (PAHs) contaminated site in environmental media have received increasing attention. Ex situ soil washing is commonly used for treating contaminated soils by separating the most contaminated fraction of the soil for disposal. Surfactant-enhanced soil washing is being considered with increasing frequency to actually achieve soil-contaminant separation. In this research, a novel solubilization of phenanthrene and extraction of phenanthrene from spiked soil by sodium castor oil sulfate (SCOS) microemulsion was presented and compared with the conventional surfactants, Triton X-100 (TX100), Tween 80 (TW80), Brij35, sodium dodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS). Unlike conventional surfactants, SCOS forms stable microemulsion in water and thus behaves much like a separate bulk phase in concentrating organic solutes. The extent of solubility enhancement is linearly proportional to the concentration of SCOS microemulsion, in contrast with the effect of a conventional surfactant in which a sharp inflection occurs in the vicinity of the measured critical micelle concentration. SCOS microemulsion exhibits the largest mass solubilization ratio among the selected surface active agents (SAAs) in both soil-free system and soil-water system. The partitioning coefficients of phenanthrene between the emulsified phase and the aqueous phase, Kem, is slightly larger than those between the micellar pseudo phase and the aqueous phase, Kmc. The extraction experiments demonstrate high and fast desorption of phenanthrene from spiked soil by SCOS microemulsion perhaps due to its high solubilization capacity compared with the conventional surfactant solutions. The results show that SCOS could be an attractive alternative to synthetic surfactants in ex situ washing for PAH-contaminated soils.

Concentrations and health risk of polycyclic aromatic hydrocarbons in tea.

Sixteen polycyclic aromatic hydrocarbons (PAHs) were simultaneously measured in 8 brands of tea and in infusions of one brand of black tea. It was observed that the total contents of the 16 PAHs (summation PAHs) in the tea samples ranged from 323 to 8800 microg/kg with the highest summation PAHs found in a black tea. PAHs (3-4 rings) were dominant in all tea samples, with a contribution of 77.7-98.7% of the summation PAHs. Infusion times from 10 to 120 min were studied during which 3.03-7.69% of the total PAHs contained in the black tea was released into the liquor. The percentages of PAHs released (RR) from the tea into the liquor were inversely proportional to the lgK(ow) of the PAHs with a mean formula of RR=261.7/lgK(ow)-41.32 and R=0.899. To analyze the potential health risk, sanitary standards of the 16 PAHs for tea leaves were calculated to be 0.1-110 mg/kg and the daily PAHs intake from the black tea was calculated to be 6.36 microg per person.

Polycyclic aromatic hydrocarbons: pollution and source analysis of a black tea.

Investigations into the manufacturing process of one kind of black tea revealed that it included five steps: withering, rolling, fermentation, drying, and drying and sorting. A total of 16 polycyclic aromatic hydrocarbons (PAHs) were simultaneously measured in fresh leaves, withered leaves, rolled leaves, fermented leaves, crude black tea, and black tea sampled after each manufacturing stage and in the indoor and outdoor air of the drying house. It was observed that the total contents of the 16 PAHs (SigmaPAHs) in the crude black tea and the black tea were obviously higher than those in the tea leaves sampled after each manufacturing step before the drying stage; the air SigmaPAHs in the drying house were about 100 times higher than those outside the drying house. It can be concluded that quantities of PAHs were released into the drying house from the combustion of pine firewood during the drying stage, and then were absorbed by the tea leaves, thus resulting in the high PAH contents in the black tea.

Water solubility enhancements of PAHs by sodium castor oil sulfonate microemulsions.

Water solubility enhancements of naphthalene(Naph), phenantherene(Phen) and pyrene(Py) in sodium castor oil sulfonate(SCOS) microemulsions were evaluated. The apparent solubilities of PAHs are linearly proportional to the concentrations of SCOS microemulsion, and the enhancement extent by SCOS solutions is greater than that by ordinary surfactants on the basis of weight solubilization ratio(WSR). The logK(em) values of Naph, Phen, and Py are 3.13, 4.44 and 5.01 respectively, which are about the same as the logK(ow) values. At 5000 mg/L of SCOS concentration, the apparent solubilities are 8.80, 121, and 674 times as the intrinsic solubilities for Naph, Phen, and Py. The effects of inorganic ions and temperature on the solubilization of solutes are also investigated. The solubilization is improved with a moderate addition of Ca2+, Na+, NH4+ and the mixture of Na+, K+, Ca2+, Mg2+ and NH4+. WSR values are enhanced by 22.0% for Naph, 23.4% for Phen, and 24.6% for Py with temperature increasing by 5 degrees C. The results indicated that SCOS microemulsions improve the performance of the surfactant-enhanced remediation (SER) of soil, by increasing solubilities of organic pollutants and reducing the level of surfactant pollution and remediation expenses.