Bioaccumulation of As and heavy metals by Pteris vittata from soil contaminated by glass industry wastes: a small-scale field study

This study was aimed at evaluating the phytoextraction efficiency of the fern Pteris vittata, recently identified as an arsenic hyperaccumulator and thus proposed as a suitable species for phytoremediation of As contaminated sites. The experimental activity was carried out directly in the field, in a site located in the Murano island (Venice, Italy), where the Venetian glass manufacturing industry is operating since ancient times. The soil of the study area is contaminated not only by arsenic, but also by other metals and metalloids, such as Cd, Se, Cu and Pb. Adult plants of P. vittata (one and two-years old) were transplanted in the study area in June 2009. Some of the ferns were also previously inoculated with arbuscular mycorrhizae, in order to investigate the effects of mycorrhizal symbioses on plant growth in the presence of contaminants and on arsenic phytoextraction efficiency. Bioaccumulation in ferns was assessed by collecting monthly frond samples from each plant, and carrying out analyses for metal and metalloid content. Soil samples were collected at the beginning of the experiment and analyzed to determine both the total amounts and the bioavailable fractions of these contaminants. In the winter period ferns were left on the field, in order to evaluate survival and growth after exposure to cold weather conditions, and the possibility of a second experimental cycle with the same plants