Gilbert + Sutherland

How big a risk to human health are soils containing Arsenic? A garden variety radish may help provide an answer. Assessing the phytotoxicity of an Arsenic-contaminated Ferosol soil using radish was the topic of an August 4, 2010 presentation by Gilbert & Sutherland Environmental Scientist Michelle Foster to the 19th World Congress of Soil Science in Brisbane.

Co-authored by Principal Agricultural & Environmental Scientist Neil Sutherland and Principal Agricultural Scientist Dr Phil Matthew, Foster’s paper reported the findings of a direct assessment of As phytotoxicity and soil availability in a Ferosol using a quick growing, common residential garden vegetable.

The results of this study may be used to inform a review of the adequacy of the current phytotoxicity investigation level (PIL) of 20mg Total As/kg soil. The phytotoxicity trial growing long scarlet radish (Raphanus sativus) revealed no significant difference in root elongation in soils contaminated with 10, 86, 169, 244, 315 and 656mg As/kg. The current PIL of 20mg/kg is excessive in this Ferrosol and remediation to the health investigation level (HIL) of 100mg kg-1 would be sufficient. The PIL should be specific to the remediation site and based on plant availability of As.

Click here to view soil paper