A naturally circular fibre: Sheep wool as a tool for assessing human and environmental exposure

In the context of the Circular Economy, the enhancement of raw wool in new bioproducts represents an important challenge. Wool is the main by-product of sheep, although its production has decreased largely during the last decades. In addition, wools with coarse fiber diameter have little economic value since they are not adequate to be used in the textile sector and, when not transformed, wool needs to be treated as a special waste. Wool is by its nature a circular fiber. Due to its complex chemical composition, physical structure and mechanical properties, it represents a biodegradable renewable resource and can find various value-added applications beyond the textile industry. The technological characteristics make wool particularly suitable for different applications such as thermo-acoustic insulation, agricultural amendment, biomedical polymers, etc. Furthermore, it absorbs harmful pollutants, becoming a specific chemical indicator. In fact, it has been shown that wool fibers are good bio-indicators of the environmental status (soil, water and air pollution). The concentration of pollutants reflects either the feed and nutrition quality and the general health status of sheep as well as the climatic and environmental conditions. The sustainable and innovative alternative uses of this livestock waste could reduce and minimise keratinous waste disposal, reduce environmental impact and increase commercial process sustainability and circular economy. The aim of this research was to investigate the degree of contamination of Sarda sheep wool to understand if wool fiber can be a contamination source for both the environment and human health. Chemical analyses were carried out through Liquid chromatography Orbitrap mass spectrometry and Inductively coupled plasma mass spectrometry. Both analytical techniques were targeted for a wide range of micropollutants including pesticides, veterinary drugs and heavy metals. The results obtained in this study represent the first step for developing a new wool valorization chain. Wool analysis can be an important strategy for the biomonitoring of human exposure to pesticides and for evaluating the quality of wool-based products.