Micromodification of element distribution in glass using femtosecond laser irradiation

We report micromodification of Eu element distribution in a silicate glass with femtosecond laser irradiation. Elemental analysis shows that the content of Eu decreased at the focal point and increased in a ring-shaped region around the focal point, which indicates migration of Eu ions has been induced by the femtosecond laser irradiation. Confocal fluorescence spectra demonstrate that the fluorescence intensity of Eu3+ ions increased by 20% in the laser-induced, Eu-enriched, ring-shaped region compared with that for nonirradiated glass. The mechanism for the laser induced change in fluorescence properties of Eu3+ has been investigated. (C) 2009 Optical Society of America

Spatial and temporal variations of trace element distribution in soils and street dust of an industrial town in NW Spain: 15 years of study

Extensive spatial and temporal surveys, over 15 years, have been conducted in soil in urban parks and street dusts in one of the most polluted cities in western Europe, Avilés (NW Spain). The first survey was carried out in 1996, and since then monitoring has been undertaken every five years. Whilst the sampling site is a relatively small town, industrial activities (mainly the steel industry and Zn and Al metallurgy) and other less significant urban sources, such as traffic, strongly affect the load of heavy metals in the urban aerosol. Elemental tracers have been used to characterise the influence of these sources on the composition of soil and dust. Although PM10 has decreased over these years as a result of environmental measures undertaken in the city, some of the “industrial” elements still remain in concentrations of concern for example, up to 4.6% and 0.5% of Zn in dust and soil, respectively. Spatial trends in metals such as Zn and Cd clearly reflect sources from the processing industries. The concentrations of these elements across Europe have reduced over time, however the most recent results from Avilés revealed an upward trend in concentration for Zn, Cd, Hg and As. A risk assessment of the soil highlighted As as an element of concern since its cancer risk in adults was more than double the value above which regulatory agencies deem it to be unacceptable. If children were considered to be the receptors, then the risk nearly doubles from this element.