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Radiocesium and radiostrontium are among the most problematic soil contaminants following nuclear fallout dueto their long half-lives and high fission yields. Their chemical resemblance to potassium, ammonium and calciumfacilitates their plant uptake and thus enhances their chance to reach humans through the food-chain dramatically.The plant uptake of both radionuclides is affected by the type of soil, the amount of organic matter and theconcentration of competitive ions.In the present lysimeter scale experiment, soil-plant transfer of Cs-137 and Sr-90 was investigated in anagricultural silty soil amended with digestate, a residue from a biogas plant. The liquid fraction of the digestate,liquor, was used to have higher nutrient competition. Digestate application was done in accordance with thefield practice with an application rate of 34 Mg/ha and mixing it in top 5 cm soil, yielding a final concentrationof 38 g digestate/Kg soil. The top 5 cm soil of the non-amended reference soil was also submitted to the samemixing procedure to account for the physical disturbance of the top soil layer. Six months after the amendmentof the soil, the soil contamination was done with water-soluble chloride salts of both radionuclides, resulting in acontamination density of 66 MBq/m2 for Cs-137 and 18 MBq/m2 for Sr-90 in separate experiments.Our results show that digestate application led to a detectable difference in soil-plant transfer of the investigatedradionuclides, effect was more pronounced for Cs-137. A clear difference was observed in plant uptake ofdifferent plants. Pest plants displayed higher uptake of both radionuclides compared to wheat. Furthermore, loweractivity values were recorded in ears compared to stems for both radionuclides.

Biogas digestates and biochar are emerging soil amendments. Biochar is a byproduct of pyrolysis process which isthermal decomposition of biomass to produce syngas and bio-oil. The use of biochar for soil amendment is beingpromoted for higher crop yields and carbon sequestration. Currently, the numbers of biogas plants in Germany areincreasing to meet the new energy scenarios. The sustainability of biogas industry requires proper disposal optionsfor digestate. Biogas digestates being rich in nutrients are beneficial to enhance agricultural productions. Contraryto the agronomical benefits of these organic amendments, their use can influence the mobility and bioavailabilityof soil contaminants due to nutrients competition and high organic matter content. So far, the impact of suchamendments on highly problematic contaminants like radionuclides is not truly accounted for.In the present study, sorption-desorption behavior of cesium and strontium was investigated in three soilsof different origin and texture. Two agricultural soils, a loamy sand and a silty soil, were amended with biocharand digestate in separate experiments, with field application rates of 25 Mg/ha and 34 Mg/ha, respectively. Forcomparison a third soil, a forest soil, was incubated without any amendment. The amendments were mixed intothe top 20 cm of the field soils, resulting in final concentrations of 8-9 g biochar/Kg soil and 11-12 g digestate/Kgsoil. The soils were incubated for about six months at room temperature. Sorption-desorption experiments wereperformed with CsCl and SrCl2 after pre-equilibrating the soils with CaCl2 solutions.The amendments with field application rates did not have a significant effect on the relevant soil parametersresponsible for the sorption behavior of the two radionuclides. Comparatively, the soil type lead to distinctivedifferences in sorption-desorption dynamics of the two radionuclides. Cesium showed a higher affinity for siltysoil followed by forest soil and lowest for sandy soil. Comparatively, strontium displayed a lower adsorption forall three soils, with a slightly higher adsorption in silty soil and almost similar sorption for both forest and sandysoils.We conclude that the applied organic amendments with field application rates will not deplete the FES(Frayed Edge Sites) responsible for cesium sorption in mineral soils. Furthermore, with the present applicationrates the increase in amount of organic matter is not high enough to significantly affect the strontium sorption inmineral soils. The desorption experiments showed that about 1/3 of the adsorbed cesium was extractable in siltysoil and almost half was extractable in forest and sandy soils. In case of strontium, about half was extractable inthe three soils. Similar to sorption, the effect of amendments was negligible compared to the soil type.

To overcome the problem of on farm point sources of pollution stemming from improper handling, spillages,and leakages of pesticides during filling and cleaning of spraying equipment, environmental friendly and lowcost technology filter systems are currently under development. Based on a laboratory screening approach, wheredifferent biomixtures (soil, with biochar and/or digestate) are tested a full scale outdoor system will be developed.Therefore, different fundamental processes like pesticide mineralization, metabolization, sorption-desorption, andtransport behavior of three radiolabelled pesticides (Bentazone, Boscalid and Pyrimethanil) will be investigated.Biochar and digestate mixtures with two contrasting soils (sandy and silt loam) had been used as a novel biofiltermaterial for respiration study instead of conventional soil and straw mixtures. To analyze the pesticide degradationpotential and to gain information about the temporal evolution of the degradation process of the biochar anddigestate soil mixtures microbial respiration was measured over the course of three month. As expected, digestateacts as an easily available C-source leading to highest release of CO2 compared to other biomixtures used. Incontrast, the addition of even small amounts (1 %) of biochar caused a profound suppression in the CO2 releasefrom digestate based mixtures. The exact driving mechanism for this suppression can be manifold likes negativepriming or chemisorption of CO2 on biochar or NH3 toxicity induced by the large amount of digestate appliedin the experiment (30 %) or can be combination of all effects. Surprisingly, a repeated experiment with same butaged digestate did not show such negative priming.On the other hand, the fate of applied organic contaminants to biomixtures depends on several factors likesoil properties and climatic conditions as well as biological degradation. To analyze the degradation potentialof the different soil/amendment mixtures a degradation study was performed to determine the effects of biocharand digestate in different mixing rates on the metabolization behavior of the studied pesticides, and to identifyand quantify the metabolites derived during the degradation process. The results from the 14C Bentazone studyindicate that 5 % digestate and 5 % biochar mixture showed highest (nearly 15 %) and 1 % biochar lowest rateof mineralization (1 %), whereby highest microbial activity was measured in the soil/digestate mixture.

Made available in DSpace on 2020-12-10T16:34:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-05-01 The purpose of this study was to separate homogeneous regions and to estimate the numbers of years necessary to evaluate the variables: sunshine, global solar radiation and photossintetically active radiation in Sao Paulo State. Monthly data of sunshine, solar radiation and photossintetically active radiation for 18 places in Sao Paulo State were used in the analysis. The homogeneity of the variances among the months for the 18 places (seasonal variability) and the homogeneity of variances among places in each month (spatial variability) were tested by the test of homogeneity of Bartlett. In addition, the sample size for each place was calculated during the year. The results show the existence of seasonal and spatial variability in the estimates of sunshine, solar radiation and photossintetieally active radiation for the 18 cities evaluated in Sao Paulo State. Moreover, the variability of the sample size for sunshine, solar radiation and photossintetically active radiation depend on the site and season of the year in Sao Paulo State. UTFPR, BR-85660000 Dois Vizinhos, PR, Brazil Univ Sao Paulo, ESALQ, Escola Super Agr Luiz De Queiroz, Sao Paulo, Brazil Univ Fed Santa Maria, Santa Maria, RS, Brazil Forschungszentrum Julich, ICG 4, D-52425 Julich, Germany Univ Estadual Paulista, Escola Super Agr Luiz De Queiroz, Sao Paulo, Brazil Univ Estadual Paulista, Escola Super Agr Luiz De Queiroz, Sao Paulo, Brazil