Phytoremediation of groundwater contaminated with pesticides using short-rotation willow crops: A case study of an apple orchard

ABSTRACT

The occurrence of pesticides in groundwater represents an important health issue, notably for population whose drinking water supply source is located in agricultural areas. However, few solutions have been considered with regard to this issue. We tested the efficacy of a vegetal filtering system made of shrub willows planted at a high density (16,000 plants ha⁻¹) to filter or degrade pesticides found in the groundwater flowing out of an apple orchard. Ethylene urea (EU), ethylene thiourea (ETU), tetrahydrophthalimide (THPI), atrazine, and desethylatrazine were monitored in the soil solution in willow and control plots over one growing season. ETU and atrazine concentrations were lower in the willow plots relative to the control plots, whereas desethylatrazine concentration was higher in the willow plots. No significant difference was detected for EU and THPI. Furthermore, pesticide concentrations displayed complex temporal patterns. These results suggest that willow filter systems can filter or degrade pesticides, notably ETU and atrazine, and could be used for phytoremediation purposes. Yet, this potential remains to be quantified with further studies using experimental settings allowing more estimation in time and space.

KEYWORDS:

• atrazine
• desethylatrazine
• ethylene urea
• ethylene thiourea
• Salix spp
• tetrahydrophthalimide

Acknowledgments

The authors would like to thank Adela Voicu and Simon Louis Lajeunesse for their assistance with sample collection and field surveys, and Marc Beaudry for access to his apple orchard.

Funding

This study was funded by the Programme de soutien à l'innovation en agroalimentaire (PSIA) program of Québec Department of Agriculture, Fisheries and Food (MAPAQ) and Agriculture and Agri-Food Canada.