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Environmental fate & pathways

Adsorption / desorption

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Description of key information

Data have been obtained from secondary source.
Values of Koc, measured or estimated , from different types of soil are available.
Measured Koc for 2,4-dinitrophenol in alluvial sandy loam (7.8% clay, 30% silt, 62.2% sand, 1.1% organic matter, pH 8.1): 13.5
Measured Koc of 2,4-Dinitrophenol: 16.6
Soil Adsorption Coefficient estimated by KOCWIN v2.00 showed an Koc 460.8 L/kg (MCI method) and a Koc 284.3 L/kg (Kow method).
These Koc values suggest that 2,4-dinitrophenol is expected to have very high mobility in soil.

Key value for chemical safety assessment

Koc at 20 °C:
16.6

Additional information

WATER COMPARTMENT

The partitioning of dinitrophenols from water to suspended solids and sediment due to adsorption would transport these compounds from water to sediment.

The sorption and subsequent transport of dinitrophenols from water to suspended solids and sediment would be significant in natural waters that are acidic and/or have high organic matter and clay content. In a study of Kaufman (1976) and Callahan et al., (1979) it has been studied that the sorption of dinitrophenols by soil or sediment would depend on the organic carbon content, clay content, and pH of soil and sediment. An increase in clay and organic carbon content and a decrease in pH (thereby increasing the concentration of the un-ionized form) would increase the amount sorbed.

SOIL COMPARTMENT

The transport of dinitrophenols from soil to groundwater also may occur via leaching. The amount of DNP leached depends on the dinitrophenol adsorption capability of soils. Adsorption of phenols in soil increases with a decrease in pH and an increase in organic carbon, goethite (one of the most common iron oxides in soil), and clay content (Hudson-Baruth and Seitz 1986; Kaufman 1976; O’Connor et al. 1990; Shea et al. 1983; Stone et al. 1993).

The adsorption of 2,4-DNP in calcareous soils low in organic carbon, goethite and clay content, was low at a pH >7.

In soils containing goethite, 2,4-DNP adsorption is due to surface complex formation at protonated mineral surfaces. The adsorption of 2,4-DNP on goethite was shown to be maximum near pH 4.5 and negligible at neutral and alkaline pH (Hudson-Baruth and Seitz 1986; O’Connor et al. 1990).

The measured Koc for 2,4-dinitrophenol was 13.5 in alluvial sandy loam (7.8% clay, 30% silt, 62.2% sand, 1.1% organic matter, pH 8.1) (Martins JM, Mermoud A: J Contam Hydrol, 1998).

In a study of Chu W, Chen K-H 2000, Koc of 2,4-Dinitrophenol 16.6 was measured.

Koc values suggest that 2,4-dinitrophenol is expected to have very high mobility in soil (Martins JM, Mermoud A: J Contam Hydrol, 1998)

Soil Adsorption Coefficient estimated by KOCWIN v2.00 showed an Koc 460.8 L/kg (MCI method) and a Koc 284.3 L/kg (Kow method).