R6 AM Plant Uptake of Organic Pollutants - Processes and Modeling
Thursday, 17 November 2005: 8:00 AM - 11:40 AM in 324-326

(SCH-1117-579851) Accumulation of PAHs in Plant Tissue During Phytoremediation of Contaminated Soils.

Schwab, A¹, Banks, M¹, Cofield, N¹, ¹ Purdue University, West Lafayette, IN, USA

ABSTRACT- A recurring concern in the phytoremediation of contaminated soil is whether the pollutants will be introduced in the food chain through plant uptake and subsequent consumption by grazers. For hyperaccumulators of metals, uptake of the target metal into plant tissues is part of the phytoremediation process. This is also the case for the use of plants to remove nitrate and atrazine from water with rapidly respiring trees. In these cases, the concentrations of contaminants in plant tissues must be monitored carefully, and exclusion of grazers may be necessary. Plant accumulation of hydrophobic contaminants such as PAHs is not a part of the remediation process, and the chemistry of PAHs in soils and roots is highly unfavorable for plant accumulation. Nevertheless, the question of PAH uptake is always asked, and our research group has investigated this issue on several occasions. We have found that accumulation of PAHs in contaminated soils seldom exceeds concentrations found in plants growing in unimpacted areas. Plants will accumulate or transpire the ¹⁴C from radiolabeled PAHs, but only after the parent compound has been altered in the rhizosphere. In agreement with predictive models, PAH assimilation from soils by higher plants is negligible.

Key words: plant uptake, PAHs, phytoremediation