Phytoremediation: Processing pollution through plants
By now most of us are aware of the fast fashion industry’s dependence on extensive chemical use. Synthetic chemicals are potentially applied during every phase of the fashion industry – from fibre farming to consumer use and you don’t need us to tell you the problems these practices can have on society and the natural world. Huge investments have been made in response to changing regulations for chemical processing. However, in the global South, far away from the eyes of the world and where the vast majority of fast fashion garments are produced, regulations can be lax and effluents are not always treated sufficiently before being released back into the environment. Water sources are often polluted with synthetic dyes or chemicals and this can disrupt ecological equilibrium, cause eutrophication and/or eventual harm to residents who consume the water. The effluent filtering systems that are beginning to be demanded by brands in the global North are expensive and it is spectacularly unrealistic to suggest that all small to medium enterprises (SMEs) can afford to install them.
Phytoremediation (ancient Greek – phyto ‘plant’ and Latin remedium meaning ‘restore balance’) is typically a natural process that uses the properties of various plants as a means of cleaning water and soil. It is regaining popularity in large industrial practices as a cheap, renewable and natural means of cleaning effluent and affected water bodies and soil. In fact, phytoremediation using the water hyacinth has shown to be an effective method of removing heavy metals and other pollutants from textile production effluent. Different plants have different abilities but the general process is similar to the way that trees sequester CO2 during their growth. A multitude of chemicals and heavy metals can be treated through phytoremediation or rhizofiltration (through the roots).
Take Cadmium for example, this metal is routinely used in textile dyes and pigments, but because of its high toxicity and its ability to bioaccumulate in living tissue, its use has been strictly regulated in the EU and other parts of the world. In other parts of the world, however, its use is still common and unregulated – generally at the detriment of local residents, wildlife and water bodies. Californian research into the filtering abilities of the sunflower reported very interesting findings that potentially offer a natural and cost-effective solution to the very serious problem of pollution. According to the report, the sunflower stems rapidly reduced heavy metal presence in sample solutions – with the absorption of 60-80% of Cd within the first 60 minutes of the experiment. Very promising indeed!