tailieunhanh - Heavy Metals Release in Soils - Chapter 7

Thuộc tính đất Kiểm soát phân vùng kim loại Thiết lập mức độ sàng lọc đất để đánh giá rủi ro cho cả hai khả dụng sinh học và bảo vệ nước ngầm dựa vào một sự hiểu biết của các lability hoá chất trong đất. Nó đã được ghi nhận rằng lability (di động và khả dụng sinh học) của các kim loại nặng khác nhau đáng kể với tính chất của đất đối với một nồng độ tổng số kim loại đất tương tự. Như vậy, xác định các thông số của đất chủ yếu ảnh hưởng đến. | CHAPTER 7 Soil Properties Controlling Metal Partitioning Christopher A. Impellitteri Herbert E. Allen Yujun Yin Sun-Jae You and Jennifer K. Saxe INTRODUCTION Establishment of soil screening levels for risk assessment for both bioavailability and the protection of groundwater relies on an understanding of the lability of chemicals in soils. It has been well documented that the lability mobility and bioavailability of heavy metals varies significantly with soil properties for a similar total soil metal concentration. Thus identification of the major soil parameters affecting metal lability in soils is requisite to predication of metal behavior and establishment of appropriate soil screening levels. The partitioning coefficient also known as the distribution coefficient in soils is a convenient and effective way of comparing the behavior of various contaminants in different soils. The partitioning coefficient Kd for a metal in a soil is the concentration of the metal associated with the soil solid divided by the concentration of the metal in soil solution. The availability of metals to organisms and therefore the toxicity of metals to organisms is more closely related to partitionable metal rather than total metal concentrations in soils. A soil with high total metal concentrations may be relatively harmless to soil organisms if conditions are such that the desorption dissolution of metals from soil solids is restricted. Conversely soils with lower total metal concentrations may affect soil organisms to a great extent if soil conditions are optimal for metal dissolution and desorption. In this chapter we will present a review of past and current research concerning metal partitioning in soils discussion on important parameters affecting partitioning of metals in soils and a case study on the natural and methodological factors that can affect results in metal partitioning studies. 149 2001 by CRC Press LLC 150 HEAVY METALS RELEASE IN SOILS THE PARTITIONING COEFFICIENT