Determination of toxic metals in leather by wavelength dispersive X-ray fluorescence (WDXRF) and inductively coupled plasma optical emission spectrometry (ICP OES) with emphasis on chromium

The tanning industry is one of the largest environmental polluters due to high generation waste in all production processes, but the tanning is particularly worrisome due to the use of significant amounts of chromium. Cr is an element potentially toxic to both health and the environment, depending on the concentration and the oxidation state. Cr(VI) can come in contact with human skin when using leather goods, which can cause allergies and dermatitis, besides being carcinogenic. Considering that approximately 90% of the world production of leather is performed with Cr salts, the determination of this element in leather is necessary to avoid exposure to the risks that the element can provide. The main goal of this study was the development of an alternative analytical method for the determination of Cr in leathers (ovine and bovine leather tanned with Cr and vegetable tannin) using wavelength dispersive X-ray fluorescence (WDXRF) for direct solid analysis. Besides performing analysis of the chemical composition and determination of Al, As, Ba, Ca, Cd, Cr, Cu, Fe, Mg, Ni, Pb, Sb, Sr, Ti, and Zn in leather by inductively coupled plasma optical emission spectrometry (ICP OES). Principal component analysis (PCA) was also used in the evaluation of the WDXRF and ICP OES data sets. WDXRF calibration models for Cr presented satisfactory figures of merit and the analysis of the leathers revealed an alarming concentration of total Cr in the samples reaching 21,353 mg kg^?1.     

Potential toxic elements in stream sediments,soils and waters in an abandoned radium mine (central Portugal)

Environmental Geochemistry and Health - The Alto da Várzea radium mine (AV) exploited ore and U-bearing minerals, such as autunite and torbernite. The mine was exploited underground from 1911...     

Production of biodiesel from waste frying oils

Waste frying oils transesterification was studied with the purpose of achieving the best conditions for biodiesel production. Transesterification reactions were carried out for 1 h using waste frying oils (WFOs), methanol, and sodium hydroxide as catalyst. In order to determine the best conditions for biodiesel production, a series of experiments were carried out, using methanol/WFO molar ratios between 3.6 and 5.4 and catalyst/WFO weight ratios between 0.2% and 1.0%. For oils with an acid value of 0.42 mg KOH/g, results show that a methanol/WFO ratio of 4.8 and a catalyst/WFO ratio of 0.6% gives the highest yield of methyl esters. Furthermore, an increase in the amount of methanol or catalyst quantity seems to simplify the separation/purification of the methyl esters phase, as showed by a viscosity reduction and an increasing purity to values higher than 98% for methyl esters phase.     

An integrated approach towards transforming an industrial park into an eco-industrial park: the case of Salaise-Sablons

This paper describes an integrated approach to transform an industrial park into an eco-industrial park by combining three interconnected goals, namely, the consolidation of industrial symbiosis, the promotion of sustainable accessibility and the development of multi-functionalities. The result is an interdependent approach where industrial and territorial ecosystems are jointly planned, seeking a more sustainable level of development that considers industrial activity, the transportation of people and goods and the spatial articulation with the neighbouring environment and urban areas. The critical points and challenges for improving the territorial integration of the French industrial park of Salaise-Sablons are discussed, providing lessons for the future. Regardless of the specificities of the case study, this approach has the potential to be adopted in similar industrial parks.