Capability of Selected Crop Plants for Shoot Mercury Accumulation from Polluted Soils: Phytoremediation Perspectives

Abstract

High-biomass crops can be considered as an alternative to hyperaccumulator plants to phytoremediate soils contaminated by heavy metals. In order to assess their practical capability for the absorption and accumulation of Hg in shoots, barley, white lupine, lentil, and chickpea were tested in pot experiments using several growth substrates. In the first experimental series, plants were grown in a mixture of vermiculite and perlite spiked with 8.35 microg g(-1) d.w. of soluble Hg. The mercury concentration of the plants' aerial tissues ranged from 1.51 to 5.13 microg g(-1) d.w. with lentil and lupine showing the highest values. In a second experiment carried out using a Hg-polluted soil (32.16 microg g(-1) d.w.) collected from a historical mining area (Almadén, Spain), the crop plants tested only reached shoot Hg concentration up to 1.13 microg g(-1) d.w. In the third experimental series, the Almadén soil was spiked with 1 microg g(-1) d.w. of soluble Hg; as a result, mercury concentrations in the plant shoots increased approximately 6 times for lupine, 5 times for chickpea, and 3.5 times for barley and lentil, with respect to those obtained with the original soil without Hg added. This marked difference was attributed to the low availability of Hg in the original Almadin soil and its subsequent increase in the Hg-spiked soil. The low mercury accumulation yields obtained for all plants do not make a successful decontamination of the Almadén soils possible byphytoremediation using crop plants. However, since the crops tested can effectively decrease the plant-available Hg level in this soil, their use could, to some extent, reduce the environmental risk of Hg pollution in the area.

Mercury fluxes and pools in three subtropical forested catchments, southwest China

“…Application RA-915þ analyzer with a multi-path analytical cell attached the RP-91 (cold vapor) and PYRO-91 (pyrolysis) accessories allow to analyze Hg in liquid and solid samples, and some authors have successfully used these methods for measuring Hg concentrations in water (Esbrí and Higueras, 2005;Higuerasa et al, 2006;Won et al, 2007) and solid (Chen et al, 2001;Oyarzun et al, 2007;Rodriguez et al, 2007;Shuvaeva et al, 2008) samples. In this study, the precision, obtained from eight replicate determinations of certificated reference material, was 3.0% for diluted (10 ng L À1 )…”

Spatial distribution of mercury deposition fluxes in Wanshan Hg mining area, Guizhou province, China

“…The Lumex instrument is portable atomic absorption spectrometer operating on the Zeeman principle to monitor Hg 0 in air, with a detection limit of 0.3 ng m −3 at a sampling flow rate of 18 l min −1 (Sholupov et al, 2004;Rodriguez et al, 2007). The instrument was installed in a car and air was brought to RA-915 + through a reinforced tube with inlet positioned well outside the vehicle perimeter.…”

High-precision measurement of mercury isotope ratios of atmospheric deposition over the past 150 years recorded in a peat core taken from Hongyuan, Sichuan Province, China

“…Mercury concentrations were determined for the dried samples using LUMEX 915 and PYRO 915 instruments; the processes were detailed by Rodriguez et al [36]. The accuracy (<10%) was checked using duplicate samples and the precision was found to be better than 10%.…”