CAS RN: 51-28-5

Exposure Summary

2,4-Dinitrophenol's production and use in the manufacture of dyes and diaminophenol or its use as an indicator may result in its release to the environment through various waste streams; its former use as a pesticide resulted in its direct release to the environment. If released to air, a vapor pressure of 3.9X10-4 mm Hg at 20 deg C indicates 2,4-dinitrophenol will exist solely as a vapor in the atmosphere. Vapor-phase 2,4-dinitrophenol will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 24 days. 2,4-Dinitrophenol may react with nitrate radicals in the atmosphere. 2,4-Dinitrophenol does absorb light at wavelengths >290 nm and therefore may be susceptible to direct photolysis by sunlight. If released to soil, 2,4-dinitrophenol is expected to have very high mobility based upon measured Koc values of 13.5 and 16.6. The pKa of 2,4-dinitrophenol is 4.09, indicating that this compound will exist almost entirely in anion form in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts, as is evident by the measured Koc values. Volatilization from moist soil is not expected because the acid exists as an anion and anions do not volatilize. Utilizing the Japanese MITI test, 0% of the theoretical BOD was reached in 4 weeks indicating that biodegradation is not an important environmental fate process. However, the biodegradation half-life of 2,4-dinitrophenol in an acidic soil was reported as 32.1 days and the biodegradation half-life in a basic soil was reported as 4.6 days. If released into water, 2,4-dinitrophenol is not expected to adsorb to suspended solids and sediment based upon the measured Koc values. The biodegradation half-life of 2,4-dinitrophenol was reported as 68 days and 2.8 days in aerobic and anaerobic waters, respectively. Volatilization from water surfaces is not expected to be an important fate process based upon its anionic state. BCFs of <0.4-0.7 and <3.7 were measured in carp (Cyprinus carpio) suggesting bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since 2,4-dinitrophenol lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to 2,4-dinitrophenol may occur through inhalation and dermal contact with this compound at workplaces where 2,4-dinitrophenol is produced or used. Monitoring data indicate that the general population may be exposed to 2,4-dinitrophenol via inhalation of ambient air, ingestion of drinking water, and dermal contact with products containing 2,4-dinitrophenol. (SRC)
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