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Knowledge about translocation of plant protection products (PPP's) in plants is important to understand the uptake via the root system. Here we report the combination of analysis of tissue extracts by LC-HRMSn, autoradiography of 14C-labeled compounds and MALDI-MSI, which combine qualitative and quantitative information of chemical composition and the spatial distribution of PPP's and their metabolites in situ. Therefore, the uptake of the phenylamide fungicide metalaxyl was studied in tomato plants (Solanum lycopersicum) using a hydroponic system. The plants have been cultivated in perlite until the two-leaf stage and were transferred into the hydroponic test system afterwards. The radioactive labeled fungicide was readily taken up by the roots during the normal water consumption and radioactivity was translocated uniformly to the aboveground part of the tomato plants, while only small proportion of the applied radioactivity were observed in the roots. The distribution of metalaxyl after the plant uptake experiment in the primary roots where analyzed by a transversal tissue section in the zone of maturation. Metalaxyl is mainly localized in root xylem and in cortex located at the epidermis. With LC-HRMSn and radiochemical analyses of stem and leaf, no parent compound was detectable. Four polar metabolites were the main identified components of the residue and could be visualized by MALDI-imaging mass spectrometry. With these results we could show, that the fungicide metalaxyl is taken up by the plant via the roots during the regular water consumption and transported to xylem.

During production of active pharmaceutical ingredients, process waste water is generated at several stages of manufacturing. Whenever possible, the resulting waste water will be processed by conventional waste water treatment plants. Currently, incineration of the process waste water is the method to eliminate compounds with high biological activity. Thus, ozone treatment followed by biological waste water treatment was tested as an alternative method. Two prominent representatives of the large group of fluoroquinolone antibiotics (ciprofloxacin and moxifloxacin) were investigated, focussing on waste water of the bulk production. Elimination of the target compounds and generation of their main transformation products were determined by liquid chromatography - high resolution mass spectrometry (LC-HRMS). The obtained results demonstrated, that the concentration of moxifloxacin and its metabolites can be effectively reduced (>99.7%) prior entering the receiving water. On the contrary, the concentration of ciprofloxacin and its metabolites remained too high for safe discharge, necessitating application of prolonged ozonation for its further degradation. The required ozonation time can be estimated based on the determined kinetics. To assure a low biological activity the ecotoxicity of the ozonated waste water was investigated using three trophic levels. By means of multiple-stage mass spectrometry (MSn) experiments several new transformation products of the fluoroquinolones were identified. Thus, previously published proposed structures could be corrected or confirmed.

The photodegradation kinetics and the break down pathway of fenhexamid were studied in aqueous systems using [phenyl-UL- 14 C]- and [carbonyl- 14 C]-labelled compounds. The photolysis of fenhexamid followed first-order kinetics. The degradation rate of fenhexamid was significantly influenced by the solution pH with rate constants ( k ) of 2.11 × 10 −2 , 4.47 × 10 −2 , 6.11 × 10 −1 and 1.69 h −1 at pH 5.0, 6.6, 7.3 and 9.0, respectively. Fenhexamid exhibited no significant change in degradation rate in the presence of acetone and hydrogen peroxide, while humic and fulvic acids retarded the degradation rate, because they shielded the active molecules from light. However, in phosphate medium, the photolysis rate was significantly enhanced as a function of concentration. About 3–8% and 10–25% photo mineralization were observed, using [carbonyl- 14 C]- and [phenyl-UL- 14 C]-labelled fenhexamid in aqueous solutions at different pH, respectively. In addition to four known metabolites, one major and five minor photoproducts out of which one is reported for the first time, were identified using high resolution LC–MS/MS and NMR. The toxicity of the new metabolite was tested against the fish Oncorhynchus mykiss with no lethal effect at 100 mg L −1 .

The photodegradation of two fluoroquinolone veterinary antibiotics, difloxacin (DIF) and sarafloxacin (SARA) has been explored for the first time in aqueous systems. The study was performed to evaluate the influence of pH, inorganics, humic substances, and other additives. The drugs followed first-order degradation kinetics in matrix free aqueous medium with a rate constant ‘ k ’ value of 0.82 and 0.26 h −1 for DIF and SARA, respectively. Studies performed at various pH revealed that the photolysis rates dropped sharply at pH >7 for DIF, while SARA dissipated faster with increasing pH. Humic substances acted as light barriers by attenuating the light intensity, to retard the drug degradation process. However, rapid drug dissipation was observed in the presence of additives like acetone, hydrogen peroxide, and phosphates, while inorganics such as fluoride, nitrate, and sulfate did not influence the drug photodegradation. Studies on the photolysis of DIF and SARA in river water revealed that both the drugs degraded rapidly under conditions that were relevant to natural systems, following direct photolysis mechanism. It was observed that SARA was the primary photoproduct of DIF and showed relatively a higher persistence than DIF. The findings were also substantiated by the quantum yield ( Ф c ) calculations. The analytical measurements were carried out with LC–MS/MS.

The elimination has been studied of racemic and enantioenriched metalaxyl applied as an emulsifiable concentrate and wettable powder combined with copper in a Cameroonian field site. The kinetics of the degradation/dissipation of metalaxyl and its acid metabolite were investigated using reversed phase HPLC-MS/MS, while the enantiomeric ratios were measured by HPLC-MS/MS using a Chiralcel OD-H HPLC column. Some soil enzymes activities were determined concurrently for 120 d. The elimination of racemic metalaxyl was shown to be enantioselective, with the R-enantiomer being degraded more slowly than the S-enantiomer. Dissipation followed approximate square root first-order kinetics (R > 0.98) without lag phases. The enantiomers of metalaxyl have different elimination rates, with half-lives ranging from only 0.8 to 1.5 days. After application to soil, the elimination of metalaxyl in the copper containing formulation was slower. The activities of acid phosphatase, alkaline phosphatase, and alkaline glucosidase were monitored throughout the experiments. No significant influence of metalaxyl and copper could be observed on these parameters. The significantly shorter half-life values of all forms of metalaxyl under field conditions, compared to the previously reported laboratory derived ones, may have implications for the plant disease control with these fungicides in tropical rainforest areas.

It has recently become clear that an isomer specific view of technical 4-nonylphenol (NP) is absolutely necessary for the evaluation of the biological behavior of NP, raising additional questions concerning enantiomer specific effects. For the first time, in this study enantioselective HPLC was applied to enantiomeric separation of chiral NP isomers. A semipreparative separation of two NP isomers could be achieved. A GC-MS method has been developed for the simultaneous detection of three chiral NP isomers in water samples. Investigation of influent and effluent samples from a wastewater treatment plant in Germany indicated that enantioselective degradation could occur in the environment. In one examined influent, an enantiomer ratio of 1.7 for two different isomers was determined.

Under laboratory condition, dissipation of metalaxyl in sterile and non-sterile soils, its sorption behaviour and fate in presence of light have been studied. The half-life value of metalaxyl was found in the range of 36-73 d in non-sterile soil. 5.3-14.7% dissipation was observed due to abiotic factors other than light. Metalaxyl was found photostable in soil showing half-life of 188- 502 h under simulated sunlight. In adsorption study, a non-linear relationship between concentration of metalaxyl and its adsorption into soils was observed. Estimated koc value increased as organic carbon content decreased. Adsorption and desorption kD values ranged between 53.5 and 151.1.

The photochemical degradation of quinolones in aqueous solution proceeds in two main steps. The first step is the degradation of the piperazine substitution forming 7-amino compounds which are more stable against photolysis than the corresponding parent compound. Further photochemical degradation down to CO2 formed intermediate polar substances. By liquid/liquid partition with chloroform/water, ion exchange chromatography and semipreparative HPLC the polar compounds could be isolated. The structures of the photolytically formed pyridone tri- and dicarboxylic acids were elucidated on the basis of HPLC/MS/MS measurement. Additionally the half-life of the main polar compound, 1-cyclopropyl-pyridone-2,3,5-tricarboxylic acid was analysed by HPLC.

In this study the environmental fate of amitrole in terrestrial and aquatic model ecosystems was investigated. Under aerobic conditions mineralization of amitrole is the main degradation pathway. The experiments revealed that the leaching behaviour is low in the presence or the absence of dissolved organic matter (DOM) despite the high water solubility due to a strong binding of amitrole to soil constituents. Under anaerobic conditions the addition of DOM increases the transport of amitrole in soil columns. The tests with water/sediment model ecosystems showed that the mineralization of amitrole is lower in comparison to aerobic soil experiments. Up to 80.6% of the applied 14C-labelled amitrole transfer into the sediment and about 1/3 of this amount formed bound residues, which are not extractable.

The adsorption and degradation behaviour of triphenyl phosphate (TPP) in soil was investigated using radiolabelled test substance. TPP was found to be absorbed strongly to three soil types. Triphenyl phosphate was degraded rapidly and mineralized to a great extent in soil in laboratory experiments. Under aerobic conditions the amount of TPP in soil decreased steadily and accounted for 46.6% of the applied compound after an incubation time of 32 days. Under the same conditions using heat-sterilized soil, mainly unchanged test compound was recovered after 101 days of incubation. According to these results the degradation of TPP in soil is mostly of microbial nature. Under anaerobic conditions the dissipation was equally as rapid and extensive as under aerobic conditions. The half-life of TPP under anaerobic conditions was 32 days in the same loamy sand soil. Several known and unknown degradates were detected, carbon dioxide being the main metabolite under aerobic and anaerobic conditions.

Sulfadiazine is a widely used veterinary medicine that has high potential to enter the environment, especially the soil compartment by the application of manure on agricultural land and grass land or by the deposition of dung pats on pasture. Once it reaches the soil environments, it may enter into surface and ground water. Therefore, sorption-desorption behavior of sulfadiazine was studied under laboratory conditions in five different soils varying in their physicochemical properties. A batch equilibration technique was used with initial aqueous solution concentration of sulfadiazine at 5, 0.5, 0.05, and 0.005 microg mL(-1). Sorption-desorption data in soils with and without manure were well fitted with Freundlich model in log form (r(2), 0.99). A sorption-desorption hysteresis effect was apparent in all soils. A significant amount of sulfadiazine was found tightly bound to the soil particles and did not desorb after the desorption process. Moreover, presence of manure enhanced hysteresis effect. Hysteresis coefficient (H) value from soils in absence of manure (0.9-1.0) increased to the soils in presence of manure (0.9-1.8). Soils in the absence of manure showed low level of K(D Sorp.) values ranging from 0.1 to 24.3, suggesting low level sorption of sulfadiazine with appreciable risk of run-off and leaching, and in turn, surface and ground water contamination. However, presence of manure increased the sorption tendency of sulfadiazine significantly (K(D Sorp.), 6.9-40.2). K(D) values pertaining to desorption cycle increased from 1.2-90.4 to 10.4-167.3 in absence and presence of manure, respectively.

Photolysis of 14C-sulfadiazine in aqueous solution under simulated sunlight followed first-order kinetics. The impact of H2O2, humic acid, fulvic acid and acetone to enhance the photodegradation of sulfadiazine (SDZ) was studied. Six photoproducts, 4-OH-SDZ, 5-OH-SDZ, N-formyl-SDZ, 4-[2-iminopyrimidine-1(2H)-yl] aniline, 2-aminopyrimidine, and aniline were identified. Extrusion of SO2 was found to be the main degradation process during irradiation. These photoproducts can occur in water and soil upon sunlight exposure, when soil is treated with SDZ contained in manure. Due to photodegradation the experimental half-life of the SDZ in water was 32 h and in the presence of photosensitizers the half-life values were 19.3–31.4 h, 17.2–31.4 h, 12.6–29.8 h, and 3.8–30.7 h for H2O2, humic acid, fulvic acid, and acetone, respectively depending on the concentration of the photosensitizers. The presence of photosensitizers markedly reduced SDZ persistence, indicating that indirect photolytic processes are important factors governing the photodegradation of SDZ in aqueous environments. Investigation revealed further persistence behavior of SDZ in manure. The half-life value of SDZ in manure was 158 h.

Laboratory soil sorption experiments were conducted on mefenoxam, formulated metalaxyl (F-metalaxyl), pure metalaxyl (P-metalaxyl) and metalaxyl acid metabolite to elucidate differences in their sorptive behaviour on typical Cameroonian forest soil (sand clay loam, pH 4.8 and 3.01% OC) and German soil (sandy loam, pH 7.2, 1.69% OC) using a batch equilibrium method. The data obtained on all test chemicals conformed to linear and Freundlich adsorption isotherms. The Langmuir equation failed to describe the sorption of the substances tested. All substances were adsorbed to a greater extent by the Cameroonian soil. The average percentage adsorptions for mefenoxam, F-metalaxyl, P-metalaxyl and the acid metabolite on the Cameroonian soil were 27.8%, 28.3%, 31.8% and 46.8% respectively while for the German soil they were 21.7%, 21.5%, 24.7% and 9.8% respectively. The KD and KF parameters and the Freundlich exponential term (1/n) were low, indicating that the interactions between soil particles and the fungicides were weak. The sorption parameters were lower in the German soil. P-metalaxyl exhibited a higher adsorption capacity than F-metalaxyl in both soils. Mefenoxam and F-metalaxyl exhibited similar sorption parameters in soils, whereas those of P-metalaxyl and acid metabolite differed. Differences observed in the adsorption between the two soils could be attributed to their properties. Desorption studies revealed that the adsorbed fungicides were not firmly retained by soil particles and their adsorption was reversible. Desorption of adsorbed mefenoxam, P-metalaxyl and of the acid metabolite from German soil was almost completely reversible with percentage desorption rates of more than 91.0%, whereas the rate for F-metalaxyl was 74.1%. All compounds exhibited some resistance to desorption from the Cameroonian soil, with percentage desorption rates less than 77.0%. Therefore if degradation in the soil is slow the fungicides described have a potential to leach to lower soil horizons.