Availability of arsenic, copper, lead, thallium, and zinc to various vegetables grown in slag-contaminated soils

To anticipate a possible hazard resulting from the plant uptake of metals f rom slag-contaminated soils, it is useful to study whether vegetables exist that are able-to mobilize a given metal in the slag to a larger proportion than in an uncontaminated control soil. For this purpose, we studied the s oil to plant transfer of arsenic, copper, lead, thallium, and zinc by the v egetables bean (Phaseolus vulgaris L. 'dwarf bean Modus'), kohlrabi (Brassi ca oleracea var. gongylodes L.), mangold (Beta vulgaris var. macrorhiza),le ttuce (Lactuca sativa L. 'American gathering brown'), carrot (Daucus carota L. 'Rotin', 'Sperlings's'), and celery [Apium graveiolus var. dulce (Mill. ) Pers.] from a control soil (Ap horizon of a Entisol) and from a contamina ted soil (1:1 soil-slag mixtures). Two types of slags were used: an iron-ri ch residue from pyrite (FeS2) roasting and a residue from coal firing. The metal concentrations in the slags, soils, and plants mere used to calculate for each metal and soil-slag mixture the plant-soil fractional concentrati on ratio (CRfractional,slag), that is, the concentration ratio of the metal that results only from the slag in the soil. With the exception of Tl, the resulting values obtained for this quantity for As, Cu, Pb, and Zn and for all vegetables were significantly smaller than the corresponding plant-soi l concentration ratios (CRcontrol soil) for the uncontaminated soil. The re sults demonstrate quantitatively that the ability of a plant to accumulate a given metal as observed for a control soil might not exist for a soil-sla g mixture, and vice verse.