article_snippet: Many samples also contained traces of cancer-causing heavy metals, which come from the plants growing in contaminated soil.
article_snippet: Others had high levels of pesticides.
article_snippet: The solvents used like alcohol and heptane to make the concentrates also contribute startling levels of contaminants, LaFrate warned.
highlights_snippet: Also found high levels of fungus, bacteria, heavy metals, pesticides and other contaminants in much of the pot .