Ground Water Flow Velocity Derived from Tritium Measurements at the Gloucester Landfill Site, Gloucester, Ontario

Abstract

Ground water contaminated by organic compounds from a special waste disposal area at the Gloucester Landfill site is migrating through a confined glaciofluvial aquifer toward water supply wells. The distribution of tritium in ground water samples, collected in October 1982, indicates that tritium has originated from two distinct sources: atmospheric nuclear weapons testing in the 1950's and 60's and on-site waste disposal. By comparing the tritium concentration pattern in ground waters to the 1953 to 1982 record for tritium in precipitation at Ottawa, broad zones of the aquifer corresponding to different recharge periods may be defined. Based on the distribution of these zones, an average groundwater velocity of 5.5 cm/day is estimated. A zone of high tritium concentration immediately below the waste disposal compound is attributed to the disposal of tritiated wastes.