Environmental interactions of Sulphlex pavement.

Sulphlex, a mixture of elemental sulfur and plasticizers, has been considered for use as an asphalt substitute in road construction. Because this material contains substantial quantities of elemental sulfur, it is a potential substrate for growth of sulfur-oxidising bacteria. Experiments, performed to determine the susceptibility of Sulphlex in Sulphlex-containing media to degradation by Thiobacillus thiooxidans, resulted in breakdown of the Sulphlex material and concomitant production of acid. In concurrent studies, plants were grown in Sulphlex-amended soils. These plants exhibited higher sulfur content and reduced productivity as compared with plants grown in unamended soils, indicating that Sulphlex was being broken down in the soil and that the breakdown products were apparently having a detrimental effect on plant productivity. These experiments indicate that naturally occurring sulfur-oxidising bacteria have the potential to break down Sulphlex paving material, resulting in adverse effects on both the structural integrity of the pavement and the local environment.

Determination of U in human tissues by delayed neutron activation analysis.

A rapid, sensitive and highly selective technique using Delayed Neutron Activation Analysis (DNAA) has been used to determine U concentrations in human tissues. Two different sample preparation techniques were compared: one involves total matrix destruction to a dry ash while the other is a nondestructive preparation of the wet sample. The data obtained from the analyses of the same sample by DNAA of wet tissues, DNAA of ashed tissues and from radiochemical analyses using alpha spectroscopy (a standard method of U determination) were statistically equivalent on the basis of variance analysis at the p = 0.05 level.

Atmospheric concentrations and sources of trace metals at the South pole.

The chemical composition of atmospheric particulate material collected at the geographic South Pole indicates that Al, Sc, Th, Sm, V, Mn, Eu, Fe, La, Ce, Co, Cr, Na, K, Mg, and Ca are derived from either crustal weathering or the ocean. The relatively volatile elements Zn, Cu, Sb, Se, Pb, and Br are apparently derived from other sources. Because of their volatility, vapor-phase condensation or a high-temperature dispersion source is suspected for these elements or their compounds.