Microbial transformation of synthetic estrogen 17α-ethinylestradiol

Natural estrogens such as estrone, 17β-estradiol, estriol, and the particularly recalcitrant synthetic estrogen 17α-ethinylestradiol used as oral contraceptive, accumulate in the environment and may give rise to health problems. The processes participating in their removal from soil, wastewater, water-sediments, groundwater-aquifer material, and wastewater or sewage treatment plant effluents may involve the action of bacterial and microbial consortia, and in some cases fungi and algae. This review discusses the different efficiencies of bacterial degradation of 17α-ethinylestradiol under aerobic and anaerobic conditions, the role of sulfate-, nitrate-, and iron-reducing conditions in anaerobic degradation, and the role of sorption. The participation of autotrophic ammonia oxidizing bacteria and heterotrophic bacteria in cometabolic degradation of estrogens, the estrogen-degrading action of ligninolytic fungi and their extracellular enzymes (lignin peroxidase, manganese-dependent peroxidase, versatile peroxidase, laccase), and of algae are discussed in detail.     

Acetochlor as a soil pollutant

Acetochlor is a widely used herbicide all over the world. Similarly to other organic pollutants, the environmental fate of the acetochlor is strongly related to its adsorption properties. Static adsorption equilibrium measurements were carried out at 25 degrees C on different types of Hungarian soils characterized by varying amounts of organic matter and pH values. Isotherms obtained under different conditions, as well as on various soils, exhibit a similar shape, thus indicating a two-step adsorption process. The plots cannot be interpreted according to the classes of isotherms suggested by Giles. The adsorption coefficients (K) were estimated from the initial slope of the curves. These values were determined not only by the type of the soil, but also by the composition of the aqueous media. The organic matter adsorption coefficients (Kom) were also calculated and they were approximately identical for soils of high organic matter. Due to the low value of the adsorption coefficients, the acetochlor is a rather mobile pollutant of the soil posing a potential danger to the aquatic environment. For soils with high organic content, the Kom values are similar to each other and, due to the significant coverage of the inorganic surfaces, the adsorption is controlled by the solute-organic substance interactions. The adsorption of weakly polar compounds, however, is remarkable even on those soils where the organic content is low. In this case, the binding is governed by the solute-inorganic surface interactions. This conclusion is nicely proved by the adsorption of the acetochlor on quartz. According to our hypothesis, the second part of the adsorption step is controlled by the solute-adsorbed solute interactions. The role of the organic matter in this region of the isotherm is probably negligible. As the organic matter content of the soils plays an important role in the acetochlor adsorption, humic substances must have a strong influence upon the transport of this compound. Experiments to obtain adsorption isotherms of further pesticides and the development of a quantitative model are in progress.     

Aromatic photonitration in homogeneous and heterogeneous aqueous systems

This work describes the nitration of aromatics upon near-UV photolysis of nitrate and nitrite in aqueous solution and upon photocatalytic oxidation of nitrite in TiO2 suspensions. Phenol is used in this work as a model aromatic molecule and as a probe for *NO2/N2O4. The photoinduced nitration of phenol in aqueous systems occurs upon the reaction between phenol and *NO2 or N2O4, and is enhanced by the photocatalytic oxidation of nitrite to *NO2 by TiO2. Aromatic photonitration in the liquid phase can play a relevant role in the formation of nitroaromatics in natural waters and atmospheric hydrometeors, thus being a potential pathway for the condensed-phase nitration of aromatics. Furthermore, the photoinduced oxidation of nitrite to nitrogen dioxide suggests a completely new role for nitrite in natural waters and atmospheric aerosols.     

Herausforderungen des Klimawandels

Ohne Zusammenfassung     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

Effect of arsenic and mercury speciation on inhibition of respiration rate in activated sludge systems

The inhibition effect of arsenite, As(III), arsenate, As(V), inorganic mercury, Hg(II) and methylmercury, MeHg, on the respiration rate of activated heterotrophic sludge microorganisms was evaluated. As(III) and MeHg were much more toxic to activated sludge than As(V) and Hg(II) respectively. The effect of various experimental parameters on the toxicity, such as sludge age, concentration of suspended solids and exposure time, was investigated. An increase of sludge age or the concentration of suspended solids reduces the observed inhibition. Longer exposure seems to dramatically increase the inhibition of As(III), MeHg and Hg(II) during the first hours of exposure, while the later inhibition increases at a slower rate. On the contrary, in the presence of As(V), 24 hours after exposure, the respiration rate was similar to that of the control biomass.     

International standardization of water analysis

The efficiency of a water treatment program or a water monitoring program can be checked only if it is accompanied by water analysis procedures allowing meaningful statements on water quality. Meaningful statements do not only include high accuracy, but high precision as well. With high precision values, good repeatability and reproducibility is aimed for. Repeatability and reproducibility may either be monitored by regular inter-laboratory trials, without prescribing a distinct analytical method, or by applying a standardized method which has undergone thorough checks concerning its reliability and efficiency. The article presents the structure of the ISO, CEN and DIN standardization work in water analysis.     

Surface ozone comparison conducted in two rural areas in central-southern Spain

Purpose  

The purpose of this work is to contribute to the understanding of the photochemical air pollution analysing the levels and temporal variations of surface ozone in two rural areas situated in central-southern Spain.     

Acute effect of benzo[a]anthracene on the biodegradation of peptone under aerobic conditions

Background

This study investigated the acute effect of benzo[a]anthracene, a significant compound among polycyclic aromatic hydrocarbons, on the biodegradation of a synthetic organic substrate??a peptone/meat extract mixture??under aerobic conditions.

Methods

A laboratory-scale sequencing batch reactor was sustained at steady state at a sludge age of 10?days with substrate feeding. Inhibition tests involved running a series of batch reactors initially seeded with the biomass obtained from the parent reactor. After the biomass seeding, the reactors were started with the peptone mixture and a range of initial benzo[a]anthracene concentrations between 0.5 and 88?mg/L. Experimental profiles of oxygen uptake rates and polyhydroxyalkanoates were evaluated by calibration of a selected model.

Results

Lower doses of benzo[a]anthracene had no effect on process kinetics. The noticeable acute impact was only observed with the addition of 88?mg/L of benzo[a]anthracene, but it was limited with the storage mechanism: the amount of organic substrate diverted to polyhydroxyalkanoates was significantly reduced with a corresponding decrease in the maximum storage rate, k _STO, from 2.7 down to 0.6?day^?1. Similarly, the maximum growth rate from internally stored polyhydroxyalkanoates was lowered from 2.3 to 1.0?day^?1.

Conclusion

Among the mechanisms for direct substrate utilization, only the hydrolysis rate was slightly reduced, but otherwise, the overall COD removal efficiency was not affected.