## 3 Results and Discussion
### M. sylvestris Biomass Valorization Options
#### 3.5.1 The Textile Dyeing Valorization Chain
The TE concentrations in the natural dye extract solution respected the threshold set by the Eco passport by OEKO-Tex (Table 5) [56]; therefore, it might be assumed that they are safe to be used in the textile sector. Indeed, this European standard aims to reinforce processes and product safety at every stage of the chemical value chain by certification. The Cu and Zn concentrations were higher compared to Cd and Pb. The results on the raw fabrics showed lower TE concentrations in the cotton compared to in the silk (Table 6). In general, the order of the TE concentrations was as follows: Zn >> Cu >> Pb > Cd. The iron and alum pretreatment conducted before dyeing seemed to have increased the Cu and Zn concentrations in the two fabrics, with the lowest concentrations being found in cotton. After dyeing, the highest TE concentrations were measured in silk fabrics, especially Zn and Cu. The highest Cu and Zn concentrations in dyed silks could be related to a better affinity of the dye with this fabric, as observed by the stronger color obtained in silk after dyeing with the mallow extract. Other studies [55; 57] have shown that the textile's fabric origin and the dye used could change the TE concentrations that were measured; our results were in accordance with these. The TE concentrations in all fabric materials (Table 6), notably for Cd and Pb, were significantly inferior to the total limit (ug g\({}^{-1}\)) or the sweat extractable (ug g\({}^{-1}\)) limit set in the OEKO-Tex standard 100 (Cd: 40, Cu: 50, Pb: 90, Zn: 750; Supplementary Materials Table S3) [58]. This indicates that, according to the OEKO-Tex label, the cotton and silk fabrics dyed with natural dye of TE-contaminated origins in this study could be considered as sanitary and safe for textiles that are in direct contact with the skin. The results of the TE concentrations in the different steps of the dyeing process (dye extract and textile fabrics) suggested that the dyeing valorization chain with natural dye could become a phytomanagement option after a preliminary assessment of the TE concentration in the dye and the textile fabrics. Nevertheless, to confirm this, a sweat extraction should be performed, and the dyed fabrics should respect the threshold set for other chemicals by OEKO-Tex standard 100 (Supplementary Materials Table S3) [58]. In order to further assess the use of _Malva sylvestris_ flower extract as a textile dye, additional investigations should be performed concerning the dyeing process, such as testing alternative biomordants, dyeing other fabrics, modifying the chemical composition of the dye extract, and testing the dyeing resistance to light, time, and washing [59]. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & & **Dye** & **Dye** & **Dye** & **Dye** & **Usual** & **Eco** \\  & & **Extract** & **Extract** & **Extract** & **Extract** & **Extract** & **Concentration** & **Passport** \\  & & **Area 1** & **Area 2** & **Area 3** & **RT * & **10 \({}^{\circ}\)C** & **in Dye ** ** & **Threshold** \\ \hline Cd & ug L\({}^{-1}\) & 0.96 & 0.87 & 0.88 & 1.08 & 0.66 & - & - \\  & ug g\({}^{-1}\) & 0.0001 & 0.0009 & 0.0009 & 0.001 & 0.0007 & 1 & 20 \\ Cu & ug L\({}^{-1}\) & 105.3 & 69.8 & 74.7 & 45.1 & 47.3 & - & - \\  & ug g\({}^{-1}\) & 0.105 & 0.07 & 0.075 & 0.045 & 0.047 & 33–110 & 250 \\ Pb & ug L\({}^{-1}\) & 3.99 & 4.86 & 6.36 & 3.02 & 2.81 & - & - \\  & ug g\({}^{-1}\) & 0.004 & 0.005 & 0.006 & 0.003 & 0.003 & 6–52 & 90 \\ Zn & ug L\({}^{-1}\) & 1108 & 1960 & 1945 & 584 & 683 & & \\  & ug g\({}^{-1}\) & 1.1 & 1.96 & 1.95 & 0.58 & 0.68 & 3–32 & 1500 \\ \hline \hline \end{tabular}  
* RT: room temperature, reported ** in [55], ** Eco passport by OEKO-Tex [56].  
\end{table} 
Table 5: TE concentration in the dye extract solution (ug L\({}^{-1}\) and ug g\({}^{-1}\) of dye extract solution; \(n=1\)).