MOVEMENT OF DDT AND NITRATES DURING GROUND-WATER RECHARGE

The Robert S. Kerr Water Research Center, U.S. Department of the Interior, and Southwestern Great Plains Research Center, U.S. Department of Agriculture, recently cooperated in a field investigation of the fate of DDT and nitrates when artificially recharged into the Ogallala aquifer. The USDA provided recharge and observation wells and hydraulic equipment for injecting 350 gallons per minute of water with known concentrations of radio‐active tracer, DDT, and nitrates. Following 10 days of recharge, the recharge well was pumped for 12 days at 500 gallons per minute. During recharge the nitrates moved to the observation wells e:ssentially at the same rate as the recharge water, and the DDT was adsorbed to the aquifer material very near the recharge well. During the pumping phase, 94% of both the recharge water and the nitrates was recovered. The concentration of DDT in the pumped water was about 16 times the recharge concentration at initiation of pumping but dropped below recharge concentration within one hour. Apparently a major portion of the DDT introduced during recharge was not recovered during pumping but remained in the aquifier. Copyright 1969 by the American Geophysical Union.