Exchangeable Cation Hydration Properties Strongly Influence Soil Sorption of Nitroaromatic Compounds

Nitroaromatic compounds (NACs) are commonly found as soil contaminants in military training sites and manufacturing facilities, and may adversely affect human and ecosystem health. Exchangeable cation effects on p-nitrocyanobenzene (p-NCB) and 1,4-dinitrobenzene (1,4-DNB) sorption by the Webster (fine loamy, mixed, mesic Typic Haplaquoll) soil series A (WA) and B (WB) horizons were determined from batch sorption experiments. Smectite is the most abundant mineral in the horizons of this soil. Soil organic matter (SOM) removal increased p-NCB sorption to the WA and WB horizons by approximately 1.5 times, and increased 1,4-DNB sorption to the A and B horizons by approximately 1.2 to 2.2 times, respectively. Greater sorption of NACs by whole soils after SOM removal suggests that SOM suppresses p-NCB and 1,4-DNB sorption by soil mineral components. Clay (