Determination of free heavy metal ion concentrations in soils around a cadmium rich zinc deposit

Abstract

The study of heavy metal speciation is of interest for the evaluation of their ecotoxicological risk. Free heavy metal ion concentrations of Cu 2+ , Zn 2+ , Ni 2+ and Cd 2+ were studied at different soil to soil solution ratio (SSR) to discuss metal bioavailability and toxicity in circumstance. The samples were collected from two farmed soils, impacted by a cadmium rich zinc deposit, Guizhou, China. One is near a bridge (QBT for short), which is 15 km away from smelter and is regarded as polluted by fly ash from smelter, the other is located 300 m away from a smelting factory (BXT for short), and it is polluted badly by waste water from smelter. To determine the free heavy metal ion concentration, Donnan Membrane Technique (DMT) and ECOSAT program were used. The concentrations of free copper and zinc ions in QBT and all studied metal ions in BXT were nearly in direct ratio with the soil to soil solution ratio, and they increased with the increasing of SSR. The variational trends of the concentrations of free nickel and cadmium ions in QBT were contrary to those of copper and zinc ions. The measured and predicted results were compared and they agreed with each other. Individual sorbents contribution to metal binding was also predicted. The results suggest soil organic matter is the most important sorbents in the two soils, and hydrous ferric oxide takes the second place.

Predicted Speciation and Mineral Solid Phases of some Heavy Metals in Sludge - amended Soil

“…This make the method complicated (Fotovat and Naidu, 1997). Donnan membrane technique able to measure several free metal ion concentrations at the same time, moreover, all the metals did not interfere each other (Temminghoff et al, 2000 andLI YI , et al, 2007). They added that attaining equilibrium under procedure circumstances was difficult, beside over estimated due to dissociation of labile species.…”

Root avoidance of toxic metals requires the GeBP‐LIKE 4 transcription factor in Arabidopsis thaliana

“…The local concentration of Cd absorbable to plant roots varies widely in the soil, depending on the physical and biochemical properties of the soil, such as pH, humidity, the presence of other nutrients (e.g. Zn and Pi), and decomposing plant and animal matter, and the composition of the microbial community in the rhizosphere (Boekhold et al, 1991;Wang et al, 2006;Yi et al, 2007;Sharma & Raju, 2013). Plants can withstand heavy metals either by tolerance and/or avoidance mechanisms (Millaleo et al, 2010).…”

Effects of rice straw ash amendment on Cu solubility and distribution in flooded rice paddy soils

“…The bioavailability and mobility of heavy metals in soils are determined by soil physicochemical characteristics, such as pH, redox potential, temperature, cation exchange capacity, and the types and contents of organic matters and minerals [4][5][6][7][8][9]. Among these factors, soil pH and redox potential are the primary factors governing the mobilization of heavy metals in soils for plant uptake and leaching to groundwater [6,8,10].…”