t The effect of sesquioxidic i i ic gravels (>2 mm size fraction) on phosphorus sorption by two gravelly lateritic soils was investigated by phosphorus sorption experiments, X-ray diffraction, ti , autoradiography and electron microscopy. In one soil the abundance and size of gravels l decreased downslope. As the gravel content of both soils increased (13-61%), ), the proportion of large (>8 mm...

Phosphorus transport from agricultural soils contributes to eutrophication of fresh waters. Computer modeling can help identify agricultural areas with high potential P transport. Most models use a constant extraction coefficient (i.e., the slope of the linear regression between filterable reactive phosphorus [FRP] in runoff and soil P) to predict dissolved P release from soil to runoff, yet it...

The most toxic dioxin is 2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TCDD), and obtaining comprehensive experimental data for this compound is challenging. However, several nontoxic isomers of 2378-TCDD exist, and can provide significant experimental evidence about this highly toxic dioxin. The goal of this study was to obtain experimental evidence for the fate and transport of 2378-TCDD in natur...

The effect of management practices on soil potential for regulating the residual concentration of pesticides was examined in samples from a Calcic Haploxeralf in Toledo (central Spain). Sorption-desorption of alachlor and linuron was found to depend on inputs of lignocelullosic wastes or cattle manure for the past 16 years. For a given herbicide, the soil sorption capacity (K(f)) follows the or...

The effect of aging (residence time in soil) on dicamba (3,6-dichloro-2-methoxybenzoic acid) and a major metabolite, 3,6-dichlorosalicylic acid (3,6-DCSA) sorption was determined in an unamended and a carbon-amended sandy loam and in a silt loam soil. During the incubation, sequential solvent extraction with 0.01 M calcium chloride solution and aqueous acetonitrile + hydrochloric acid was used ...

Nitroaromatic compounds are produced and used in large quantities worldwide and are frequently detected contaminants in the environment. Sorption is one of the fundamental processes controlling the transport and availability of nitroaromatics, but previous studies have focused mainly on sorption to model clay minerals, whereas little attention has been paid to the sorptive interactions with nat...

Based on descriptors of n-octanol/water partition coefficients (logKow), molecular connectivity indices, and quantum chemical parameters, several QSAR models were built to estimate the soil sorption coefficients (logKoc) of substituted anilines and phenols. Results showed that descriptor logKow plus molecular quantum chemical parameters gave poor regression models. Further study was performed t...

Several studies emphasize the importance of soil organic matter characteristics in hydrophobic contaminant sorption and outline the strong dependence of sorption on organic matter aromaticity. In this study, the role of organic matter aromaticity in phenanthrene sorption was investigated using humic acids (HAs) from compost, peat, and soil that were structurally modified by bleaching, hydrolysi...

Batch sorption experiments were conducted with heavy metal solutions in 0.01 M CaCl2 at low equilibrium concentrations of Cu, Pb, Cd, and Cr in 10 different intact soil samples. Metal solid/liquid distribution coefficients Kd were determined from the adsorption isotherms obtained. Their values varied over a range from 57 to 53 000 mL/g. The soils used in the experiment were chosen according to ...

Polycyclic aromatic hydrocarbons (PAHs), abundant in mixed contaminant sites, often coexist with heavy metals. The fate and remediation of PAHs depend heavily on the sorption and desorption behavior of these contaminants. The sorption behavior can in turn be highly affected by certain soil components and properties, such as soil organic matter (SOM) and the presence of heavy metals. Through rev...