Five intact cores (25 cm in depth, 10 cm in diameter) were taken per
sampling event, and the top 5 cm were excluded from all analyses. The
sediment samples from the root zone of G. maxima collected were
compared to soil samples from three other locations differing in their
toxicity profiles: Five samples were collected per location, and each
sample consisted of 32 cores (5 cm in depth, 2.5 cm in diameter).