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Land Application of Sewage Sludge and Biosolids - Chapter 5

Hiệu lực của bùn nước thải và Chất rắn sinh học Sự xâm nhập của các nguyên tố vi lượng và phản ứng trong đất GIỚI THIỆU Các phản ứng của các nguyên tố vi lượng và vi chất dinh dưỡng thực vật trong đất và tích lũy sự hấp thu và các nhà máy ảnh hưởng đến sự sẵn có cho các loài động vật và con người. Nhà nước của các nguyên tố vi lượng trong đất thường rơi vào các loại sau:. | CHAPTER 5 The Effect of Sewage Sludge and Biosolids on Uptake of Trace Elements and Reactions in Soil INTRODUCTION The reactions of trace elements and plant micronutrients in soil and their uptake and accumulation by plants affect the availability to animals and humans. The state of trace elements in soils generally falls into the following categories Soluble Exchangeable Insoluble inorganic precipitates Chelated complexed on organic matter or its fractions Adsorbed on inorganic colloids As minerals The uptake of trace elements and plant micronutrients depends on the soluble equilibrium and exchangeability of an element and therefore its concentration in the soil solution. Adsorption mechanisms are important in determining the availability of the metal to plants. In addition to adsorption by soil organic matter metal adsorption by reactive soil surfaces is important. Corey et al. 1981 indicated that adsorption on mineral surfaces is probably the dominant process controlling metal solution activities. Activity is generally considered as effective concentration. When metals are added through the application of biosolids solution metal activities would be controlled by adsorption to biosolids and soil mineral surfaces as long as the amount of metal added did not exceed the capacity of specific surface adsorption sites in the soil. Some have suggested that the metal chemistry of a particular biosolid may be important in the availability of the metal to plants. Heavy metals can also revert with time to chemical forms less available to plants Epstein and Chaney 1978 . Sposito et al. 1983 found that Zn from biosolids reverted to the less available carbonate form over time. However metal reversion in 2003 CRC Press LLC soil is small and or slow and can be reversed by soil acidity Logan and Chaney 1983 . The form of the heavy metal in soil affects its solubility and therefore the potential for movement through the soil and uptake by plants. This section discusses the .