Methods for radioactivity measurements in drinking water using gamma spectrometry.

In this study, three methods to measure activity concentrations of radionuclides through high resolution gamma spectrometry are developed, optimized, and tested on drinking water samples. Two pre-concentration methods (partial evaporation and ion-exchange resins) were optimized for accuracy, precision, detection limits, costs, preparation, and measurements times. A new sampling method for 222Rn was designed and optimized to directly sample water from the tap, reducing and minimizing losses of radon during the sampling. A total number of 85 water samples were collected between 2017 and 2019 in collaboration with two drinking water suppliers in a wide area (~2000 km2) of the Veneto region, northeast Italy. These are the first results of radionuclides activity concentration in drinking water concerning a large extension in the foothill Veneto region. Finally, this study provides a first attempt of determining the spatial distribution and seasonal variations of radon activity concentration in drinking water in the study area.

Anthranilamides: new antimicroalgal active substances from a marine Streptomyces sp.

2-[Methyl-(3-phenylpropionyl)amino]-benzoic acid (1e) was isolated from a culture of marine Streptomyces sp. strain B7747. Analogous compounds have potential importance as phytotoxic substances, hence compound 1e and the analogues 1a approximately 1d and 1f approximately 3a were synthesised. Antimicroalgal activity of the anthranilamide analogues showed that esters 1b, 1f and 2b were more active than the free acids. The minimum inhibitory concentration (MIC) against Chlorella vulgaris, Chlorella sorokiniana, Chlorella salina and Scenedesmus subspicatus ranged from 20 to 107 micrograms/ml. All anthranilamides were inactive against Staphylococcus aureus, Escherichia coli, and Mucor miehei.