In vivo and in vitro metabolism of tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), by the freshwater planarian, Dugesia japonica

Cigarette smoke is a risk factor for human health, and many studies were conducted to investigate its adverse effects on humans and other mammals. However, since large amounts of cigarette products are produced and consumed, it is possible that tobacco chemicals can end up in aquatic environments through several routes, thus influencing aquatic organisms. In this study, the presence of tobacco-specific nitrosamine (TSNA), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), in aquatic environment was demonstrated. Since toxic effects on and distribution patterns of tobacco chemicals in aquatic organisms were rarely studied, after results of an acute toxicity pretest were obtained, experiment was conducted to investigate the bioaccumulation pattern of NNK and distribution patterns of its metabolites, mainly 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), in NNK-treated freshwater planarians, Dugesia japonica. Results from in vivo and in vitro studies showed that NNK was readily converted to NNAL through the carbonyl reduction in bodies of NNK-treated planarians. Tissue concentrations of both chemicals increased in time- and dose-dependent manners. Furthermore, we examined the end products of NNK/NNAL α-hydroxylation in NNK-treated planarians, but only 1-(3-pyridyl)-1,4-butanediol was detected, suggesting that NNK metabolism in planarians partially differs from that in mammalian systems. This is the first report on NNK metabolism in an aquatic organism and can be used as a foundation for developing freshwater planarians as a new in vivo model for the study of NNK toxicology in the future.     

Photolysis of 2-(2-furyl)benzimidazole (Fuberidazole)

The photooxidatior. of 2-(4-thiazolyl)-1H-benzimidazole (Thia=bendazole (1) in methanol in presence and absence of a photo=sensitizer (methylene blue), is investigated. Dimethyl oxalate, thiazole-4-(N-carbomethoxy)-carboxamide (6), methyl benzimida=zole-2-carboxylate (7), benzimidazole-2-carboxamide (8), and benzimidazole (9), were the main products of the photolysis. Some reaction mechanisms are discussed.     

Synthesis and pesticidal activity of new N-alkyl-N-[1-(2-hydroxyphenyl) ethyl]amines

A series of novel N-alkyl-N-[1-(2-hydroxyphenyl) ethyl]amines were synthesized as potential new agents to control pests. Their structures were confirmed on the basis of IR, NMR and elemental analyses. Six new N-alkyl-N-[1-(2-hydroxyphenyl) ethyl]amines were prepared by reduction of corresponding Schiff bases using sodium borohydride in 80–87 % yields. These compounds were tested for their antifungal activity against two pathogenic fungi viz., Rhizoctonia bataticola ITCC 0482 and Sclerotium rolfsii ITCC 5226 and for insecticidal activity against insects of stored grain pest Callosobruchus analis. Fungicidal bioassay revealed that compound N-Decyl-N-[1-(2-hydroxyphenyl)ethyl]amine, was highly effective against R. bataticola (ED₅₀ 6.86 mg L^?1) which was comparable with that of commercial fungicide hexaconazole (ED₅₀ 6.35 mg L^?1). Also compounds N-Heptyl-N-[1-(2-hydroxyphenyl)ethyl]amine, N-Octyl-N-[1-(2-hydroxyphenyl)ethyl]amine and N-Nonyl-N-[1-(2-hydroxyphenyl)ethyl]amine displayed promising fungitoxicity against same pathogen. However, compound N-Heptyl-N-[1-(2-hydroxyphenyl)ethyl]amine was also found to be effective against S. rolfsii (ED₅₀ 4.92 mg L^?1 as against 1.27 mg L^?1 for hexaconazole). Compound N-Hexyl-N-[1-(2-hydroxyphenyl)ethyl]amine was most effective as insecticide followed by compound N-Octyl-N-[1-(2-hydroxyphenyl)ethyl]amine. LC₅₀ values for these compounds were 155.0 and 275.0 mg L^?1 respectively as against 36.70 mg L^?1 for commercial insecticide dichlorovos. The results obtained from bioassays indicate that this class of compounds can be utilized for the design of new substances endowed with pesticidal activities.     

Acceleration of the Fe(III)EDTA(-) reduction rate in BioDeNO(x) reactors by dosing electron mediating compounds

BioDeNO(x), a novel technique to remove NO(x) from industrial flue gases, is based on absorption of gaseous nitric oxide into an aqueous Fe(II)EDTA(2-) solution, followed by the biological reduction of Fe(II)EDTA(2-) complexed NO to N(2). Besides NO reduction, high rate biological Fe(III)EDTA(-) reduction is a crucial factor for a succesful application of the BioDeNO(x) technology, as it determines the Fe(II)EDTA(2-) concentration in the scrubber liquor and thus the efficiency of NO removal from the gas phase. This paper investigates the mechanism and kinetics of biological Fe(III)EDTA(-) reduction by unadapted anaerobic methanogenic sludge and BioDeNO(x) reactor mixed liquor. The influence of different electron donors, electron mediating compounds and CaSO(3) on the Fe(III)EDTA(-) reduction rate was determined in batch experiments (21mM Fe(III)EDTA(-), 55 degrees C, pH 7.2+/-0.2). The Fe(III)EDTA(-) reduction rate depended on the type of electron donor, the highest rate (13.9mMh(-1)) was observed with glucose, followed by ethanol, acetate and hydrogen. Fe(III)EDTA(-) reduction occurred at a relatively slow (4.1mMh(-1)) rate with methanol as the electron donor. Small amounts (0.5mM) of sulfide, cysteine or elemental sulfur accelerated the Fe(III)EDTA(-) reduction. The amount of iron reduced significantly exceeded the amount that can be formed by the chemical reaction of sulfide with Fe(III)EDTA(-), suggesting that the Fe(III)EDTA(-) reduction was accelerated via an auto-catalytic process with an unidentified electron mediating compound, presumably polysulfides, formed out of the sulfur additives. Using ethanol as electron donor, the specific Fe(III)EDTA(-) reduction rate was linearly related to the amount of sulfide supplied. CaSO(3) (0.5-100mM) inhibited Fe(III)EDTA(-) reduction, probably because SO(3)(2-) scavenged the electron mediating compound.     

Atmospheric volatilization and distribution of (Z)- and (E)-1,3-dichloropropene in field beds with and without plastic covers

The fumigant 1,3-dichloropropene (1,3-D) is considered to be a potential replacement for methyl bromide when methyl bromide is phased out in 2005. This study on surface emissions and subsurface diffusion of 1,3-D in a Florida sandy soil was conducted in field beds with or without plastic covers. After injection of the commercial fumigant Telone II by conventional chisels to field beds at 30cm depth which were covered with polyethylene film (PE), virtually impermeable film, or no cover (bare), (Z)- and (E)-1,3-D rapidly diffused upward. Twenty hours after injection, majority of (Z)- and (E)-1,3-D had moved upward from 30 cm depth to the layer of 5-20 cm depth. Downward movement of the two isomers in the beds with or without a plastic cover was not significant. (Z)-1,3-D diffused more rapidly than (E)-1,3-D. Virtually impermeable films (VIF) had a good capacity to retain (Z)- and (E)-1,3-D in soil pore air space. Vapor concentrations of the two isomers in the shallow subsurface of the field bed covered with VIF were greater than that in the two beds covered with polyethylene film (PE) or no cover (bare). In addition, VIF cover provided more uniform distribution of (Z)- and (E)-1,3-D in shallow subsurface than PE cover or no cover. Virtually impermeable film also had a better capability to retard surface emissions of the two isomers from soil in field beds than PE cover or no cover.     

The relationship between real-time and time-integrated coarse (2.5-10 micrm), intermodal (1-2.5 microm), and fine (<2.5 microm) particulate matter in the Los Angeles basin

A periodic review of the National Ambient Air Quality Standards for Particulate Matter by the U.S. Environmental Protection Agency (EPA) will assess the standards with respect to levels, particle size, and averaging times. Some members of the scientific community in the United States and Europe have suggested the use of PM1 instead of PM2.5 as the fine particle measurement standard. This proposed standard is intended to reduce the influence of coarse particle sources on PM2.5, because some evidence suggests that PM1-2.5 is dominated by coarse particulate matter (PM) sources. In this study, coarse (PM2.5-10), intermodal (PM1-2.5), and fine (PM2.5) mass concentrations at four different sites are measured with continuous and time-integrated sampling devices. The main objective is to compare variations in these three size ranges while considering the effects of location, sources, weather, wind speed, and wind direction. Results show strong correlations between PM1 and intermodal PM in receptor sites. The contribution of PM1-2.5 to PM2.5 is highest in the summer months, most likely due to enhanced long-range transport. Coarse PM is poorly correlated with intermodal PM. Continuous data suggest that PM1 is growing into PM1-2.5 via complex processes involving stagnation of the aerosol during high relative humidity conditions, followed by advection during daytime hours.     

Biodegradation of nonionic surfactants. I. Biotransformation of 4-(1-nonyl)phenol by a Candida maltosa isolate

Results are reported concerning biodegradation of 4-(1-nonyl)phenol by cultures of a Candida maltosa strain isolated from aerobic sludge samples collected at a depuration plant treating wastewaters from a textile industry. The yeast was able to utilize 4-(1-nonyl)phenol as a sole carbon and energy source. Preliminary attempts to draw the actual metabolic pathway evidenced microbial attack on the alkyl chain with the production of 4-acetylphenol. To the best of our knowledge this is the first report describing a microorganism capable of attacking nonylphenol in axenic culture and at the same time allowing for the identification of its degradation products.     

Synthesis of the DDT metabolite 2,4-dichloro-1-[2-chloro-1-(4-chlorophenyl)ethenyl]benzene (o-Cl-DDMU) and its detection in abiotic and biotic samples

Environmental Science and Pollution Research - Technical dichlorodiphenyltrichloroethane (DDT) has been used worldwide as a pesticide since the beginning of the 1940s. Due to its persistence, DDT...     

Degradation of RPA 202248 [U-14C-phenyl]-α(-(cyclopropylcarbonyl)-2-(methylsulfonyl)-β-oxo-4-(trifluromethyl)benzenepropanenitrile), the Primary Degradation Product of Isoxaflutole,in an Outdoor Aquatic Microcosm System

Abstract

Isoxaflutole, the active ingredient in BALANCE® WDG and BALANCE® PRO corn herbicides and a co-formulant with the herbicide flufenacet in the product EPIC?, is readily degraded in soil and water to RPA 202248 α(-(cyclopropylcarbonyl)-2-(methylsulfonyl)-β-oxo-4-(trifluromethyl)benzenepropanenitrile). Because RPA 202248 is responsible at the molecular level for isoxaflutole's herbicidal activity it is important to understand the environmental behavior of the degradation product. Laboratory studies suggest that RPA 202248 is stable to hydrolysis and photolysis in aqueous systems and hence poses a possible environmental concern. As part of a program of work towards understanding the actual field situation, an outdoor microcosm study was carried out. Over the course of the 29-day study, residues remained predominantly in the aqueous phase. A slow but steady degradation of RPA 202248 was observed leading to the formation of RPA 203328 (2-methylsulfonyl-4-trifluoromethylbenzoic acid), which has no herbicidal activity. The half-life of RPA 202248 was calculated to be 103 days. These findings indicate that aqueous degradation should be considered as a potential route of dissipation when assessing the fate of RPA 202248 in large scale impounded water bodies, such as ponds, lakes, or reservoirs in the Mid-West Corn Belt.     

Kinetics of hydrolysis and cyclization of ethyl 2-(aminosulfonyl)benzoate to saccharin

The cyclization of ethyl 2-(aminosulfonyl)benzoate (ASB) to give saccharin was investigated in aqueous solutions at pH between 5.2 and 9.5 and in the temperature range of 296.2-334.2 K. The initial concentration of the reactant was varied between 1.45 x 10(-5) and 3.86 x 10(-4) M. Ultraviolet spectroscopy was used to obtain the kinetic data. The reaction is acid catalyzed and follows pseudo-first-order kinetics. The experimental rate constant, k(obs), increases with temperature and pH. Its dependence on the temperature and pH is well described by: k(obs) = k1 [OH-] = [(2.52 +/- 0.9) x 10(16) exp(-20.2 +/- 1 kcalmol(-1)/RT) s(-1)][OH-] A mechanism is proposed and the half-life of ethyl ASB is calculated.     

Crystal structure analysis of enantiomerically pure (+) and (-) beta-hexabromocyclododecanes

The molecular structures of individual HBCD stereoisomers are not elucidated yet. Recently, we isolated 8 of the 16 possible stereoisomers from a technical HBCD mixture and tentatively assigned their relative configurations. Herein we report on the isolation of enantiomerically pure (+) and (-) beta-HBCDs, both obtained from preparative chiral-phase liquid chromatography, and we present their absolute configurations determined from X-ray diffraction analysis. The absolute configuration of (+) beta-HBCD was found to be (1S,2S,5S,6R,9S,10R), while the one of (-) beta-HBCD was assigned to (1R,2R,5R,6S,9R,10S). The given structural information allows, for the first time, the unambiguous identification of these two important HBCD stereoisomers, which are typically found in technical products at proportions of about 3-5% for each enantiomer.     

Analysis of difference in vivo effects of TCDD between c-src +/+ mice, c-src deficient, -/+ and -/- B6, 129-Src(tm 1 sor) mice and their wild-type littermates

Toxicities of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were tested on two strains of c-src deficient B6, 129-Src(tm 1 sor) mice, c-src -/+ and c-src -/- and their matched wild-type littermates c-src +/+ mice along with another c-src +/+ mice, from the same genetic lineage, B6, 129-Fos(tm 1 Pa) mice. The most conspicuous effect of c-src deficiency on the toxicity of TCDD appears to be the reduced hepatotoxicity. TCDD-treated c-src deficient mice show only modest degrees of hepatomegaly and triglycerides accumulation as compared to treated wild-type mice.     

Toxicity and biodegradation of the LAS surfactant 1-(p-sulfophenyl)nonane in presence of the ascidian Styela plicata

The main objective of this study, within development of engineering solutions for coastal areas depuration, was to establish the role of the benthic macro-organisms in the biodegradation of the detergents in marine environment and to estimate the toxicity of these substances for a particular marine species: the ascidian Styela plicata. The experimental studies undertaken in aquarium with seawater enriched in a pure lynear alkylbenzene sulfonate (LAS), the 1-(p-sulfophenyl)nonane (1C9-LAS), showed that the degradation was two times more fast in presence of the S. plicata, than of the only marine bacteria. The toxicity of this pollutant was also determined. This study demonstrates that the ascidia S. plicata can be a potential biomediator for the surfactant 1C9-LAS, and it can be used to design a pilot project, to bioremediate harbours and the coastal areas interested from the urban pollution.     

Gas-phase ozonolysis of the monoterpenoids (S)-(+)-carvone, (R)-(−)-carvone, (−)-carveol, geraniol and citral

Biogenic emissions of volatile organic compounds (VOCs) play a fundamental role in atmospheric chemistry. Vegetation is the most abundant natural source of VOCs, while terpenoids, as limonene, α and β pinene and mircene, top the plants emission list. Much interest has been demonstrated in oxidation and photooxidation reactions of VOCs, particularly of monoterpenoids, owing to their diversity and to uncertainties regarding their mechanism of reaction. Quantification of primary carbonylic compounds, as well as of biradical reaction components, is highly relevant to the understanding of the major reactions. In this context, taking into account both structural factors and the fact that these compounds are found in the essential oils of plants typically found in Brazil and that they may be present in the atmosphere from emission by the plants, the monoterpenoids (S)-(+)-carvone, (R)-(−)-carvone, (−)-carveol, geraniol and citral (a mixture of the isomers geranial and neral) were selected for this study.The ozonolysis reactions of the monoterpenoids were carried out under dark conditions for all experiments, due to their photochemical reactivity. The analysis of the results lets us propose a mechanism by which these reactions occur. The observed results of the ozonolysis of S and R carvone suggest that the stereochemistry of asymmetric carbon does not affect either in the yields of both formaldehyde and of OH radicals produced in the reaction, or in the reactivity of these compounds, for which the rate constants were in the scale of 10⁻⁶ s⁻¹.We found that, in the (−)-carveol's cis and trans mixture, even though the hydroxyl in the axial position—in the case of trans-(C) and cis-(D′) isomers—favors the attack by the ozone molecule on the external double bond, thus increasing the mixture's reactivity , it affects the average production of formaldehyde. The presence of geraniol and citral led to the production of formaldehyde, propanone, glyoxal, methyl–glyoxal and cyclohexanone (OH radicals) as reaction products. The influence of an electron attractor group bonded to the carbon of the double bond, on the reactivity of the double bond, could not be observed in the case of citral, due to strong interference occurring in the instrument in all experiments with this monoterpenoid. For this reason, only the kinetics of geraniol was monitored .     

Surface properties and catalytic performance of La(1-x)Sr(x)FeO(3) perovskite-type oxides for methane combustion

La(1-x)Sr(x)FeO(3) (x=0.0-1.0) perovskites were prepared and tested for the combustion of methane. X-ray diffraction (XRD) patterns revealed the presence of a single perovskite structure for substitutions 0x0.3, however Fe(2)O(3), SrCO(3) and SrFeO(3) phases were observed for substitutions x>0.3. The results of activity test indicate that with La(1-x)Sr(x)FeO(3) as the catalyst, the combustion of methane can take place at low temperatures around 400 degrees C. Partial substitution of La with Sr increases the activity and an optimal substitution fraction (x=0.5) exists in the La(1-x)Sr(x)FeO(3) catalysts. Catalyst activity can be well correlated to the product of the specific surface area and atomic ratio of Fe to La+Sr on the catalyst surface. Experimental results of O(2)-TPD and CH(4)-TPD in the range of 350-500 degrees C indicate that the amount of oxygen desorbed from the La(1-x)Sr(x)FeO(3) catalysts is far larger than that of methane. Therefore, it can be proposed that the catalytic oxidation of CH(4) over these catalysts proceeds with the surface reaction between CH(4) in the gas phase and the adsorbed O(2). Addition of water vapor or CO(2) to the feed inhibited catalyst activity, but the inhibition was reversible and became negligible at high reaction temperature.     

Atmospheric Volatilization and Distribution of (Z)- and (E)-1,3-Dichloropropene in Field Beds with and without Plastic Covers

Abstract

The fumigant 1,3-dichloropropene (1,3-D) is considered to be a potential replacement for methyl bromide when methyl bromide is phased out in 2005. This study on surface emissions and subsurface diffusion of 1,3-D in a Florida sandy soil was conducted in field beds with or without plastic covers. After injection of the commercial fumigant Telone II by conventional chisels to field beds at 30 cm depth which were covered with polyethylene film (PE), virtually impermeable film, or no cover (bare), (Z)- and (E)-1,3-D rapidly diffused upward. Twenty hours after injection, majority of (Z)- and (E)-1,3-D had moved upward from 30 cm depth to the layer of 5–20 cm depth. Downward movement of the two isomers in the beds with or without a plastic cover was not significant. (Z)-1,3-D diffused more rapidly than (E)-1,3-D. Virtually impermeable films (VIF) had a good capacity to retain (Z)- and (E)-1,3-D in soil pore air space. Vapor concentrations of the two isomers in the shallow subsurface of the field bed covered with VIF were greater than that in the two beds covered with polyethylene film (PE) or no cover (bare). In addition, VIF cover provided more uniform distribution of (Z)- and (E)-1,3-D in shallow subsurface than PE cover or no cover. Virtually impermeable film also had a better capability to retard surface emissions of the two isomers from soil in field beds than PE cover or no cover.     

Degradation of RPA 202248 [U-14C-phenyl]alpha(-(cyclopropylcarbonyl)-2-(methylsulfonyl)-beta-oxo-4-(trifluromethyl)benzenepropanenitrile), the primary degradation product of isoxaflutole, in an outdoor aquatic microcosm system

Isoxaflutole, the active ingredient in BALANCE WDG and BALANCE PRO corn herbicides and a co-formulant with the herbicide flufenacet in the product EPIC, is readily degraded in soil and water to RPA 202248 alpha(-(cyclopropylcarbonyl)-2-(methyvlsulfonyl)-beta-oxo-4-(trifluromethyl)benzenepropanenitrile). Because RPA 202248 is responsible at the molecular level for isoxaflutole's herbicidal activity it is important to understand the environmental behavior of the degradation product. Laboratory studies suggest that RPA 202248 is stable to hydrolysis and photolysis in aqueous systems and hence poses a possible environmental concern. As part of a program of work towards understanding the actual field situation, an outdoor microcosm study was carried out. Over the course of the 29-day study, residues remained predominantly in the aqueous phase. A slow but steady degradation of RPA 202248 was observed leading to the formation of RPA 203328 (2-methylsulfonyl-4-trifluoromethylbenzoic acid), which has no herbicidal activity. The half-life of RPA 202248 was calculated to be 103 days. These findings indicate that aqueous degradation should be considered as a potential route of dissipation when assessing the fate of RPA 202248 in large scale impounded water bodies, such as ponds, lakes, or reservoirs in the Mid-West Corn Belt.     

The evolution of the pH in Europe (1986-1997) using panel data

The temporal evolution of pH values in precipitation over Europe during the period 1986-1997 is examined using panel data. The use of panel data techniques allows us to determine the temporal evolution of groups of stations rather than analyzing the temporal behavior of each of them. The analysis reveals three different temporal patterns: Peripheral, Central and French. We find a significant increasing trend (P < 0.00001) in both Peripheral and Central patterns. The annual increases are +0.057 pH-units yr(-1) and +0.022 pH-units yr(-1) respectively. However the French pattern is characterized by a significant decreasing trend (P < 0.004) and the annual decrease is -0.022 pH-units yr(-1). The standard errors of panel data estimates are around 47% smaller than those of classical pooling and 32% smaller than aggregate time-series regression. The use of panel data produces higher R2 values than classical pooling and aggregate data. This technique takes into account the individual heterogeneity, allows a larger number of data points and improves the efficiency of the estimates. In general, the policies of governments to reduce pollutant emissions seem to be effective.     

Emissions of OTNE (Iso-E-super) - mass flows in sewage treatment plants

The fate and mass flows of OTNE ([1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethylnaphthalen-2yl]ethan-1-one) which is commercialized as Iso-E-Super were studied in three large scale sewage treatment plants (STPs) in detail. The results are compared to 14 smaller ones located in Germany and Switzerland. OTNE inflow concentrations ranged from 4000 to 13,000 ngl(-1) while the effluent concentrations ranged from 500 to 6,900 ngl(-1). It is eliminated from the waste water with 56-64% during waste water treatment. High OTNE concentrations in sewage sludge showed that the elimination was mainly driven by sorption to sludge. This complies with major elimination in the first settling basins (primary settling tanks) while it was removed to a lesser extent in the aeration basin of the activated sludge treatment or in successive biofilters. The mass flows of OTNE in the influent of the German STPs were between 0.9 and 1.9 g per inhabitant and year. In the annual effluents mass flows of OTNE ranged between 0.2 and 0.8 g per inhabitant which complies with data measured in 13 smaller STPs from Switzerland. The similarity of data suggests that the observed mass flow data might be extrapolated to other European regions.     

Comparison of Fe(VI) (FeO4(2-)) and ozone in inactivating Bacillus subtilis spores

The protozoan parasites such as Cryptosporidiumparvum and Giardialamblia have been recognized as a frequent cause of recent waterborne disease outbreaks because of their strong resistance against chlorine disinfection. In this study, ozone and Fe(VI) (i.e., FeO(4)(2-)) were compared in terms of inactivation efficiency for Bacillus subtilis spores which are commonly utilized as an indicator of protozoan pathogens. Both oxidants highly depended on water pH and temperature in the spore inactivation. Since redox potential of Fe(VI) is almost the same as that of ozone, spore inactivation efficiency of Fe(VI) was expected to be similar with that of ozone. However, it was found that ozone was definitely superior over Fe(VI): at pH 7 and 20°C, ozone with the product of concentration×contact time (CˉT) of 10mgL(-1)min inactivate the spores more than 99.9% within 10min, while Fe(VI) with CˉT of 30mgL(-1) min could inactivate 90% spores. The large difference between ozone and Fe(VI) in spore inactivation was attributed mainly to Fe(III) produced from Fe(VI) decomposition at the spore coat layer which might coagulate spores and make it difficult for free Fe(VI) to attack live spores.