| Arsenic as one of the major heavy metals pollution in soil, its environmental behaviorand eco-toxicological effect have been one of the research hotspots both here and abroad. Thispaper chose18typical farmland soil of our country which have different quality as theresearch material. The adsorption-desorption characteristics of arsenic has been systematicallyand comprehensively researched and provide the theoretical basis for the effectiveness andecological effect and contaminated in soils of arsenic in different types of soil. Analysis therelationship of its adsorption-desorption characteristics and the physical and chemicalproperties of soil. To analysis the toxic action of wheat by arsenic, pot experiment had beencarried out and got the following conclusions:(1) The influence of the physical and chemical properties of soil on the ability of adsorbthe exogenous arsenic of soil is very serious, in which the influence of the soil pH on theability of adsorb the exogenous arsenic of soil is particularly prominent. In addition to pH, therest of the physical and chemical properties, like the total phosphorus, available phosphorus,CEC and CaCO3has a negative contribution to the adsorption of exogenous arsenic by soilwhile the soil clay and organic matter contents have a positive contribution to this process andthe content of soil clay is higher. In the soil which pH <6.25, the content of the exogenousarsenic absorbed by soil is among0.26mg/g~1.64mg/g, the average amount of adsorption is0.97mg/g, the adsorbed rate is between0.74%and6.83%, the average amount of adsorbedrate is3.98%. In the soil which pH is between6.27and6.93, the content of the exogenousarsenic absorbed by soil is among0.19mg/g~0.36mg/g, the average amount of adsorption is0.26mg/g, the adsorbed rate is between0.64%and1.5%, the average amount of adsorbedrate is1.04%. In the soil which pH>7.9, the content of the exogenous arsenic absorbed bysoil is among0.16mg/g~0.19mg/g, the average amount of adsorption is0.17mg/g, theadsorbed rate is between0.29%and0.88%, the average amount of adsorbed rate is0.66%.(2) For the acid soil (brown earth of Liaoning, latosolic red soil of Yunnan, purple soilChongqing) which has more organic matter and clay content, the desorption effect of citricacid and oxalic are better. For the red soil with low content of organic matter, the desorptioneffect of the phosphate buffer is better. For the alkaline soil, because of the differences in soil properties, the effect of desorbing arsenic in different soil by strippant is different. Themoisture soil of Shandong and Tianjin, both the NaOH and phosphate buffer have the bettereffect but the effects of two sodium salts in moisture soil of Henan and Hebei are better thanothers. In the lou soil, the desorption effect of citric acid is the best. For other alkaline soil, thedesorption effects of the NaOH and phosphate buffer are similar. From the results of this study,after adsorbing the arsenic by soil.(3) In addition to the two yellow brown soil, red soil of Hunan and latosolic red soil ofYunnan of the two treatments on the concentration does not exceed the national grain theharvest food safety standards, the low concentrations of the black soil of Heilongjiang and thelou soil of Shanxi did not exceed the handling of national food safety standards, the harvestgrain from other soil is exceed the handling of national food safety standards. The BCF of thegrain from acid soil is lower than alkaline soil and the BCF of the grain from the soil withmore organic matter and clay content is lower than the soil with less organic matter and claycontent. |
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