Radiotracer estimates of benthic activity effects on trace metal diffusion into mangrove sediments.

Potential influences of the whole benthic organisms' activity (i.e., coupled faunal and microbial effects) on (58)Co, (51)Cr and (65)Zn diffusion into surface mangrove sediment layers (0-6 cm depth) were evaluated in 36 h experiments. Benthic activity indices (BAI) were proposed, calculated as the relative percent difference between untreated sediments and formaldehyde-treated sediments data in relation to untreated sediments data. Benthic activity was estimated as responsible for 32%-44% of total inventories within sediments, being the chromate anion spiked the less affected radiotracer, while (65)Zn was the most sensitive. Benthic activity was quantitatively evidenced as a control on trace metal diffusion into the sediments, contributing to determine the sediment role as a metal sink. This influence can also affect metal potential bioavailability, considering that recently diffused metals can be more readily available to biological uptake.

Technetium-99m -- new production and processing strategies to provide adequate levels for SPECT imaging.

The most important radioisotope for use in Nuclear Medicine is (99m)Tc, supplied in the form of a (99)Mo/(99m)Tc generator. After the supply crisis of (99)Mo starting in 2008 the availability of (99)Mo became a worldwide concern. The purpose of this work is to do a brief story of the availability of (99)Mo in the world followed by an overview of the production routes of (99)Mo and the generators technology.