Assertion: canna | /r/ObjectUse | used for phytoremdiation
Facets:
value: in order to remove toxic heavy metals
type: PURPOSE
Source sentences:
text: Canna have been used for phytoremdiation (the use of plants to absorb toxins from soils), in order to remove toxic heavy metals such as copper and zinc from pig waste, and to remove excess fertilizer and insecticides from greenhouse runoff.