Persistence of 1,2-dibromoethane in soils: entrapment in intraparticle micropores

Impact of mineral micropores on transport and fate of organic contaminants: A review

“…As a result, bulky organic molecules with low diffusivities may take very long time to adsorb into micropores. Sorption in mineral micropores has been widely observed for halogenated hydrocarbons (e.g., Farmer, 1993, 1995;Aochi et al, 1992Aochi et al, , 2003Ball and Roberts, 1991;Castilla et al, 2000;Cheng and Reinhard, 2006a,b, 2007, 2008Cornelissen et al, 1998;Farrell and Reinhard, 1994;Farrell et al, 1999aFarrell et al, ,b, 2002Grathwohl and Reinhard, 1993;Li and Werth, 2004;Qafoku et al, 2009;Riley et al, 2010;Steinberg et al, 1987;Werth and Reinhard, 1997a,b;Werth et al, 1997), while there have also been limited reports for aromatic hydrocarbons (Chang et al, 2003;Hatzinger and Alexander, 1997;Hundal et al, 2001) and pesticides (Ahmad et al, 2004;Wu and Laird, 2002).…”

“…Temperature-stepped desorption technique coupled with model calculations has also been used to elucidate the mechanism of slow desorption from silica gels and natural sediments, which revealed that the slow diffusion rates were controlled by sorptive forces at hydrophobic micropore constrictions Werth and Reinhard, 1997a,b;Werth et al, 2000). Experimental results indicate that the diffusion coefficients of chlorinated ethylenes sorbed in the micropores of porous geological media were in the range of 10 − 17 -10 − 8 cm 2 /s (Cheng and Reinhard, 2006a,b;Grathwohl and Reinhard, 1993;Li and Werth, 2004;Steinberg et al, 1987;Werth and Reinhard, 1997a), which are many Fig. 3.…”

“…For examples, 1,2-dibromoethane, a soil fumigant that is easily biodegradable with a hydrolysis (uncatalyzed) half-life ranging from 2 to 4 years at 22-25°C (Pignatello and Cohen, 1990), was observed to persist in agricultural topsoils for two decades and desorbed extremely slowly from the soils (Steinberg et al, 1987). High concentrations of pesticide carbaryl (1-naphthyl methylcarbamate), which is easily biodegradable with a hydrolysis half-life of~10 days at pH 7, remained in undisturbed soil more than 12 years after contamination, and only half of the residue pesticide was water-extractable (Ahmad et al, 2004).…”

Modeling desorption kinetics of a persistent organic pollutant from field aged sediment using a bi-disperse particle size distribution

“…For example, Freundlich sorption isotherms (Miller and Pedit 1992;Lin et al 1994;Rugner et al 1999;Braida et al 2001;Gamst et al 2004) or linear sorption isotherm (Wu and Gschwend 1986;Steinberg et al 1987;Rijnaarts et al 1990;Ball and Roberts 1991;Brusseau et al 1991;Pignatello et al 1993;Pedit and Miller 1994;Li and Werth 2004) were used to model desorption kinetics. In radial diffusion models, particle-size effects are generally lumped into a single-fit-parameter D a /R 2 , where D a is a diffusion coefficient and R the radius of the spheres.…”

Temporal change in the distribution patterns of hexachlorobenzene and dichlorodiphenyltrichloroethane among various soil organic matter fractions

“…Despite the extensive consensus on the residence time effect, the relevant mechanisms still remain a matter of debate. The possible mechanisms include intraorganic matter (Cornelissen et al, 2005) and intraparticle diffusion (Steinberg et al, 1987), and transformation of soil organic matter (SOM) (Chen and Xing, 2005). Accordingly, different mathematical models, such as one-and two-compartment first order, two-compartment polymer diffusion and porediffusion kinetics have been proposed (Carroll et al, 1994;Johnson et al, 2001).…”