CAS RN: 299-42-3

Exposure Summary

(L)-Ephedrine's production and use as medicine may result in its release to the environment through various waste streams. It is found in plants of the genus Ephedra (Ephedraceae) and known in traditional medicine as Ma Huang. (L)-Ephedrine also occurs in the Ephedraceae, Ranunculaceae, Celastraceae, Taxaceae, Malvaceae and Papaveraceae families of plants. If released to air, an estimated vapor pressure of 1.2X10-3 mm Hg at 25 deg C indicates (L)-ephedrine will exist solely as a vapor in the atmosphere. Vapor-phase (L)-ephedrine 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 4 hours. (L)-Ephedrine is reported to decompose gradually on exposure to light; therefore, (L)-ephedrine may be susceptible to direct photolysis by sunlight in air or on soil surfaces or natural waters exposed to sunlight. If released to soil, (L)-ephedrine is expected to have high mobility based upon an estimated Koc of 72. The pKa of (L)-ephedrine is 9.65, indicating that this compound will exist primarily in cation form in the environment and cations generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 8.7X10-11 atm-cu m/mole. (L)-Ephedrine is not expected to volatilize from dry soil surfaces based upon its vapor pressure. (L)-Ephedrine has been classified as readily biodegradable by sewage sludge following acclimation. If released into water, (L)-ephedrine is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. An estimated BCF of 1.4 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions (pH 5 to 9). Occupational exposure to (L)-ephedrine may occur through dermal contact with this compound at workplaces where (L)-ephedrine is produced or used. The general population may be exposed to (L)-ephedrine through ingestion of medicines containing the compound that are used as bronchodilators. (SRC)
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