ORGANIC-COMPOUNDS IN-CLOUD WATER AND THEIR DEPOSITION AT A REMOTE CONTINENTAL SITE

Some organic compounds (alkylbenzene, chlorinated hydrocarbons and polycyclic aromatic hydrocarbons) in clouds have been determined from samples collected above the canopy of a coniferous forest. The cloud samples were collected during 1987 and 1988 at Mt. Mitchell State Park, North Carolina, a remote high elevation (approximately 2006 m MSL) continental site. Concentrations of the organic chemicals in clouds were in the range of 0.2 to approximately 200 ng mL-1; and their estimated deposition rates via clouds were found to range from 1.58 * 10(4) to 4.67 * 10(6) ng m-2 yr-1. Great variations in concentrations were found which can best be explained, based on 72 hour back trajectory analysis, by different source locales and moving air masses. The concentration of these chemicals exceeded their water solubility as predicted by Henry's Law, suggesting that clouds are an excellent scavenger of organic chemicals in the ambient environment.