The concentration of arsenic (and other trace elements) in watercress in Christchurch waterways

Abstract

This report investigates the concentration of arsenic (and other trace elements) in watercress (Rorippa nasturtium-aquaticum) growing in small, spring-fed lowland streams and drains of the Christchurch region. Watercress is an aquatic perennial herb that grows in drains and lowland streams and such aquatic plants can act as hyper-accumulators of arsenic. Sampling site location has been based on previous reports of elevated arsenic in local groundwater, and focussed on four sites; Woodend/Tuahiwi, Te Waihora/Lake Ellesmere, Lyttleton and the University of Canterbury Campus. Sediments and water samples were also collected at these sites.