Pilot project of mechanical-biological treatment of waste in Brazil.

By mechanical-biological treatment (MBT) of residual municipal solid waste the behaviour of landfills can be significantly improved. After MBT the organic content (COD and BOD5), total organic carbon, and total nitrogen in the leachate, as well as the gas production rate, are reduced to values lower than 90% of the fresh untreated waste. The volume of the stabilized material to be disposed on landfills decreases enormously, by up to 70%. The monitoring effort for a landfill constructed under these conditions is reduced to a minimum and the stabilized material can be used in other ways, as material for reforestation, for cover material or for thermal utilization to produce energy. Environmental conditions are important in MBT, as well as waste characteristics. This paper describes the results of a pilot project of MBT performed in Rio de Janeiro, Brazil. The results have shown that this technology can be used successfully in developing countries, with economy for the society and important results for the environment.

[The problem of mammography in patients with breast cancer following organ-preserving surgery and irradiation]. / Zur Problematik der Mammographie bei Patienten mit Mammakarzinom nach organerhaltender Operation und Bestrahlung.

In our study therapy induced early and late effects on the breast were investigated with mammography. All patients with breast carcinoma were treated with conserving surgery and then irradiated. Criterium for the evaluation of the changes was a postoperative mammogram for comparison with the found changes. Severe limitations for the diagnosis of tumour recurrence did not result for this form of therapy.

Environmental distribution and long-term dispersion of reactor 14CO2 around two German nuclear power plants.

Carbon-14 data on atmospheric CO2 as well as on plant material (tree leaves and wheat) from the vicinity of two German boiling water reactors (Philippsburg and Isar/Ohu) are reported. Atmospheric CO2 samples taken routinely with an integration time of one or two weeks 1.75 km downwind of the Philippsburg reactor (900 MW electrical power) show a maximum 14C excess concentration of delta 14C (excess) = 300 +/- 7%, corresponding to 12.7 mBq m-3 (STP air). The long-term average excess amounts to delta 14C (excess) = 47 +/- 3%, corresponding to 2.0 mBq m-3 (STP air). The concentrations observed with plant material at the same sampling site range between delta 14C (excess) = 0% and 120%, corresponding to 0 and 27 mBq (g carbon)-1. With the meteorological dispersion parameters actually measured at the nuclear power plants, the dispersion factors for the various sampling sites and for the individual periods of sampling were calculated on the basis of a one-dimensional Gaussian plume model. With the observed 14C excess concentrations and the dispersion factor, a "theoretical" (i.e. calculated) reactor 14C source strength is then determined. For the Philippsburg reactor, which is situated in the flat Rhine valley, the "theoretical" and the observed yearly mean 14C emissions compare rather well (within a factor of 2). A significant systematical deviation from the model was found in the concentration decrease with source distance: the decrease predicted between the 1.75-km and 3.25-km distances is steeper than actually observed. The 14C excess concentrations found in tree leaves around the Isar/Ohu reactor (907 MW electrical power) at 1-2 km distance fall into the same range as observed at Philippsburg. In the hilly terrain at this reactor site, the model calculations agree well with the observed values up to a distance of 1 km if the relative elevation of the sampling site is taken into account by introducing a "reduced stack height" in the model calculations. This method fails in predicting the concentrations at distances greater than 1 km from the source.

Early holocene ooids in modern littoral sands reworked from a coastal terrace, southern Tunisia.

Locally, Early Holocene (Atlanticum) oöids, dated with carbon-14, form the major compound in the Recent near-shore sediments of the Gulf of Gabes (southern Tunisia, Mediterranean Sea). They are reworked from coastal oölites and are not forming today. The Holocene oölites crop out at the seaward side of a coastal terrace, while the oölitic rocks from the inland side give a straightforward carbon-14 age of 20,000 to 30,000 years before the present. The entire terrace was formerly dated as Tyrrhenian III (= last interglacial time).

Tracers determine movement of soil moisture and evapotranspiration.

The downward movement of water in soil is a layered one. Marking a certain layer with hydrogen-isotope tracer, and watching its displacement, makes possible a water balance and gives information on evaporation and groundwater recharge.