Heavy metal release from plants into the atmosphere

Abstract

INDUSTRIAL activity has been assumed to be largely responsible for the heavy metal content of atmospheric particulates¹. We have obtained, however, laboratory evidence that higher plants may naturally contribute to the heavy metal composition of the atmosphere. Experiments with radioisotopes have shown that plants are capable of releasing from their foliage a small fraction of the total amount of several elements originally absorbed by their roots. The mechanism giving rise to the release process is as yet not fully understood but seems to be associated with submicron particles. In this way plants could generate local biogeociheimical provinces in the atmosphere and reflect underlying geochemical anomalies. Moreover, this process could also be responsible for the general enrichment of certain heavy metals in the atmosphere relative to the soil and may partly explain the surprising chemical uniformity of atmospheric particulates¹.