A new study has found that the water hyacinth plant is successful in removing toxic heavy metals from the River Tawes, south of Wales. The invasive tropical plant removes pollutants using a process known as phytoremediation. Using living plants to clean contaminated water is cheaper and more environmentally friendly than other conventional methods. The water hyacinth plant is native to Brazil, among other countries in South America. Researchers transplanted the plant (which is actually classified as an invasive species) to the highly polluted British river Nant-Y-Fendrod, a tributary of the River Tawe. Global copper productions in the 19th and 20th centuries resulted in millions of tons of copper and zinc smelting waste, contaminating soil and affecting waterways in the area. Three weeks after introducing the non-native plant to the river, researchers found that up to 100 % of the toxic metals (including cadmium, zinc, arsenic, lead, chromium, aluminum, copper, manganese and nickel) were removed.