Page 237 - Plant-Based Remediation Processes

11 Flax (Linum usitatissimum L.) and Hemp (Cannabis sativa L.)... 229

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Table 11.7 OEKO-TEX Limit values and fastness
II III IV
I In direct contact With no direct Decoration
Product Class Baby with skin contact with skin material
1
Extractable heavy-metals (mg kg )
Sb (Antimony) 30.0 30.0 30.0
As (Arsenic) 0.2 1.0 1.0 1.0
Pb (Lead) 0.2 1.0 a 1.0 a 1.0 a
Cd (Cadmium) 0.1 0.1 0.1 0.1
Cr (Chromium) 1.0 2.0 2.0 2.0 b
Cr (VI) Under detection limit c
Co (Cobalt) 1.0 4.0 4.0 4.0
Cu (Copper) 25.0 d 50.0 d 50.0 d 50.0 d
Ni (Nickel) e 1.0 4.0 4.0 4.0
Hg (Mercury) 0.02 0.02 0.02 0.02
1 f
Heavy metals in digested sample (mg kg )
Pb (Lead) 90.0 90.0 a 90.0 a 90.0 a
Cd (Cadmium) 50.0 100.0 a 100.0 a 100.0 a
a
No requirement for accessories made from glass
b 1
For leather articles 10.0 mg kg
c 1 1
Quantification limits: for Cr(VI) 0.5 mg kg , for arylamines 20 mg kg , for dyestuffs
50 mg kg 1
d
No requirement for accessories made from inorganic materials
e
Including the requirement by EC-Directive 94/27/EC
f
Applicable to all non textile accessories and components as well as for spun dyed fibres and
articles containing pigments
In fact, there is a limited knowledge on distribution of accumulated HMs in specific
tissues/cells of industrial (technological) importance (fibre cells or filaments, fibre
bundles). There are several studies dealing with HMs contamination of flax and hemp
fibre (the main raw material of fibre crops). Linger et al. (2002) concluded the fact that
hemp accumulates heavy metals (provided data for Cd, Pb and Ni content in fibres and
hurds) limits its use as a raw material in clothes. However, the high quality of the fibres
and hurds, which were not affected by the HMs contamination, allows them to be used
in special products like composite materials, where the fibres are embedded in
polymers and could not be set free. Fibre bundle fineness and strength were not
influenced by HMs contamination. Based on these facts authors considered hemp
ideal candidate as profit yielding crop when used for phytoremediation purposes.
Lo ¨ser et al. (2002) were more critical to use HMs contaminated raw material,
nevertheless, they used in their study heavily contaminated river sediment which
resulted in relatively high accumulation of Cd in fibres.
There are several industrial processing variants of HMs-contaminated biomass:

• Fibre and whole biomass contains excessive amounts of HMs: Energy use
(combustion, recyclation of ash HMs).