engleski

Exposure to extractable metals from tanned leather

Despite the widespread use of synthetic fibers nowadays, leather is still the material of choice for many applications due to its properties unmatched by any synthetics. During the environmentally challenged process of leather making, the tanning step is of great importance in order to render stability against many factors, like microbial degradation, heat and sweat. Commonly chromium (III) is used due to the excellent properties that it renders to the leather and because of the simplicity of operation. Apart from chromium also other metals can be used for tanning or are involved in other steps of the leather making procedure. Furthermore certain elements are present in the natural skin matrix and can thus be found also in the final leather product. Nocuous effects to human skin by wearing leather textile products or from car seats have been observed, mainly related to the release of chromium. In the presented studies different tanned and dyed leather samples were studied for their total contents and the extractable amounts of certain metals, namely Al, As, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Ni, Pb, Sc, Se, Si, Sm, Sn, Sr, Tl, V, and Zn. Firstly, all samples were dried at 65°C overnight and then cut in small pieces using a ceramic knife. For quantification of the total metal contents, the samples were weighed and analyzed by inductively coupled plasma - optical emission spectrometry after microwave assisted digestion. Digestion was performed using approximately 0.2 g of each sample applying a mixture of concentrated nitric acid (HNO3) and concentrated hydrochloric acid (HCl). To determine the quantity of soluble amounts of the elements of interest, extraction experiments were carried out using artificial sweat solution. For each extraction 10, 0 mL of the sweat solution was added to about 0.5 g of each sample. The solutions were shaken at 37°C for different time periods ranging from 5 minutes to two weeks. For each element present in the extraction solution, the extraction yield was calculated and compared, if available, with maximum permitted values. The following elements were below the respective limit of detection in the extraction solutions: As, Be, Bi, Cd, Co, Fe, Hg, Mn, Mo, Pb, Sc, Se, Sm, Tl, V.

ICP-OES; trace elemental analysis; leather;

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