Preliminary test of arsenic and mercury uptake by Poa annua

Arsenic (As) and mercury (Hg) are among the most dangerous heavy metals to humans and the environment because of their toxicity towards all living organisms and their related accumulation capability it is known that some plant species are able to detoxify water and soil from some pollutants. In this paper we strive to investigate how a common plant species is able to accumulate these metals. In this research we considered Poa annua, a plant species easily growing in Italy and deeply involved in the food chain, to understand problems related to its use as fodder for wild and farm animals (i.e. cattle) and suitability to be used for phytoremediation purposes. Hydroponic experiments were set up; P. annua was seeded in different substrates: gravel and zeolite, alone and mixed at different percentage. For each metal three different levels of contamination were chosen, for As 0.25, 0.5 and 5 mgL(-1), for Hg 0.1, 0.2 and 2 mgL(-1). No substantial difference in metal absorption among plant samples watered with different As and Hg concentrations, was observed during the testing phase. Nevertheless, results show that concentrations of As and Hg accumulated in P. annua increase with the increasing contamination exposure. (C) 2008 Elsevier B.V. All rights reserved.