【土壤有机碳不可交换H稳定同位素比测量】Marc Ruppenthal  Yvonne Oelmann and Wolfgang Wilcke. Optimized Demineralization Technique for the Measurement of Stable Isotope Ratios of Nonexchangeable H in Soil Organic Matter. Environ. Sci. Technol. 2013 47(2): 949–957

To make use of the isotope ratio of nonexchangeable hydrogen (δ²H_{n (nonexchangeable)}) of bulk soil organic matter (SOM) the mineral matrix (containing structural water of clay minerals) must be separated from SOM and samples need to be analyzed after H isotope equilibration. We present a novel technique for demineralization of soil samples with HF and dilute HCl and recovery of the SOM fraction solubilized in the HF demineralization solution via solid-phase extraction. Compared with existing techniques organic C (C_org) and organic N (N_org) recovery of demineralized SOM concentrates was significantly increased (C_org recovery using existing techniques vs new demineralization method: 58% vs 78%; N_org recovery: 60% vs 78%). Chemicals used for the demineralization treatment did not affect δ²H_n values as revealed by spiking with deuterated water. The new demineralization method minimized organic matter losses and thus artificial H isotope fractionation opening up the opportunity to use δ²H_n analyses of SOM as a new tool in paleoclimatology or geospatial forensics.

【预测农药挥发】Cleo L. Davie-Martin Kimberly J. Hageman and Yu-Ping Chin. An Improved Screening Tool for Predicting Volatilization of Pesticides Applied to Soils. Environ. Sci. Technol. 2013 47(2): 868–876

Pesticide volatilization and vapor drift can have adverse effects on nontarget sensitive ecosystems and human health. Four approaches for pesticide volatilization screening based on Fick’s Law were investigated. In each approach vapor pressures or environmentally relevant partition coefficients were used to describe pesticide behavior in an agricultural field system and to predict 24-h cumulative percentage volatilization (CPV_24h) losses. The multiphase partitioning approach based on soil–air (K_soil–air) and water–air (K_water–air) partition coefficients wa