선택한 단어 수는 입니다.
최소 단어 이상 선택하여야 합니다.
최소 단어 이상 선택하여야 합니다.
선택한 단어 수는 30입니다.
최대 10 단어까지만 선택 가능합니다.
최대 10 단어까지만 선택 가능합니다.
제안 방법
- A series of metalspiked soils was generated by adding 100 mL of the each stock solution to 250 g of air-dried soil, which produced metal loadings of Cu and Zn of 50, 100, 200, and 400 mg kg−1, and Cd of 2.5, 5, 10, and 20 mg kg−1.
- Four levels of Cd were tested in the Hudson, Carlisle (organic) and Arkport soils, but the waterextractable Cd concentration was often below the detection of limit of ICP (0.003 µM) in the lowest Cd treatment (2.5 mg kg−1) of the Hudson and Carlisle soils, which allowed us to quantify Kd values only for the 5, 10 and 20 mg kg−1 Cd treatments in these soils.
- In the case of the Oxisol and Egmont soils, however, there was not enough soil to create four different levels of metal loading, and therefore, only two metal loadings, the highest level (Cd 20 mg kg−1 and Cu and Zn 400 mg kg−1) and the medium level (Cd 5 mg kg−1 and Cu and Zn 100 mg kg−1) were prepared.
- One-week and one-month of equilibration were required to stabilize the Kd values for the 100 mg kg−1 and the 400 mg kg−1 Cu treatment, respectively.
- During the metalequilibration period, appropriate amounts of de-ionized water were added to the samples to maintain constant soil moisture over time. Soil solution was collected repeatedly from the same soils by vacuum extraction at equilibrium times of 1 day, 3 days, 1 week, 1 month, 3 months, 6 months, and 1 year. To measure total metal concentrations in the soils after 1 year, a microwaveassisted HF digestion technique (EPA 3052) was used.
- ) were characterized for pH, electrical conductivity (EC), and dissolved organic carbon (DOC) contents (Table 2). The EC measurement was carried out with an OAKTON conductivity meter at 25℃, and the DOC levels in the soil solutions were determined using persulfate oxidation/CO2 analysis (OI Analytical model 1010 TOC/DOC autoanalyzer, College Station, TX).
- values on total Zn loadings. The Kd values for Zn in the Carlisle were significantly higher than those for the other soils, presumably due to higher levels of OM and extractable Fe oxides in this soil, yet lower than that of the Hudson which had the highest pH of the soils tested in this study. The difference in pH probably accounts for the ability of the Hudson mineral soil to sorb Zn more effectively than the organic soil at the same loadings, indicating the importance of pH in determining the degree of Zn sorption in soils over time.
- To measure total metal concentrations in the soils after 1 year, a microwaveassisted HF digestion technique (EPA 3052) was used. The amount of Cd, Cu, and Zn in the soil digests as well as in the solution extracts was analyzed by inductively coupled plasma (ICP) emission spectrometry (SPECTRO CIROS CCD-ICP Spectrophotometer).
- Soil solution extracts collected at times ranging from 1 day to 1 year were analyzed for dissolved Cd, Cu, and Zn concentrations, and for chemical properties including pH, dissolved organic carbon (DOC) content, and electrical conductivity (EC). To facilitate comparison among the soils and the metals tested, and for the practical interest of predicting metal behavior in the soil environment, the results of this study were presented in terms of metal partitioning coefficients (Kd) estimated over the 1-year period of equilibration.
대상 데이터
- Five soils, including two Alfisols with different textures (an Arkport fine sandy loam and a Hudson silt loam, collected in Tompkins County, NY), an Andisol (Egmont series, New Zealand), a Histosol (Carlisle, Orange County, NY), and an Oxisol (Ap horizon of an Acrohumox, Brazil), were tested for the present study. The surface soils were collected, air-dried, mixed thoroughly, passed through a 2-mm stainless steel screen, and then stored in sealed plastic bins prior to use.
이론/모형
- Soil pH was determined in deionized water (1 : 2 w/v), and the organic matter (OM) levels of the soils were measured using the WalkleyBlack method (Allison, 1965). Cation exchange capacity (CEC) of the soils was determined by an unbuffered BaCl2 extraction method (Gillman, 1979), and the concentration of extractable Fe oxides was estimated by the Coffin method (Coffin, 1961). All the measurements are reported on a soil dry weight basis.
- Characteristics of the soils were measured using the bulk control subsamples. Soil pH was determined in deionized water (1 : 2 w/v), and the organic matter (OM) levels of the soils were measured using the WalkleyBlack method (Allison, 1965). Cation exchange capacity (CEC) of the soils was determined by an unbuffered BaCl2 extraction method (Gillman, 1979), and the concentration of extractable Fe oxides was estimated by the Coffin method (Coffin, 1961).
※ AI-Helper는 부적절한 답변을 할 수 있습니다.