engleski

Exposure to extractable chromium from tanned leather

Although synthetic fibers are nowadays widely used for a variety of textile products, leather is still a material unmatched in properties by synthetics. Leather making is an environmentally challenged process. A tanning process is indispensable in order to render to the skin matrix stability against many factors, such as microbial degradation, heat and sweat. A common way of tanning is using chromium(III) not only due to the excellent properties that it renders to the leather, but also because of the simplicity of operation. Apart from the environmental pollution caused by chromium containing wastewater allergic reactions are reported for persons working wearing leather gloves. Indeed poor uptake of chromium during tanning process has been stated, but nevertheless nocuous effects to human skin have been observed. Therefore the chromium contents of raw leather as well as of chromium tanned leather samples were determined. First all samples were dried at 65 °C overnight and then cut in small pieces using a ceramic knife. In order to receive the total chromium amount the samples were weighed and analyzed after microwave assisted digestion of the entire sample. Digestion was performed using about 0.2 g of each sample applying a mixture of concentrated nitric acid and concentrated hydrochloric acid (5:1, v/v). To determine the quantity of soluble chromium extraction experiments were carried out using four different kinds of solvent, e.g. distilled water, artificial sweat solutions (pH 5.5 and 8.0), and artificial saliva. For each experiment 10 mL of the extraction solution were added to about 0.5 g of sample, which were then shaked at 37 °C for one or three hours, respectively. The quantification measurements of chromium were performed using inductively coupled plasma-optical emission spectrometry (ICP-OES, Perkin-Elmer Optima 3000 XL, concentric nebulizer). The limits of detection (LODs ; 3σ ) calculated for chromium in all media were in the range from 1 ppb up to 6 ppb. The total chromium amounts found were 100 μ g/g, 1 μ g/g and 30 mg/g for untreated cow skin, washed skin after primary treatment with sodium hydroxide and final chromium tanned leather, respectively. The results of the extraction experiments reflect these findings. Whereas only small amounts of chromium were extracted from the raw skin and the primary treated skin, up to 2 mg/g were leached from the tanned leather sample.

chromium; tanned leather; ICP-OES

Toxicology Letters 164 (2006) (S1) S1-S324