Investigation of Organic Contamination of Ground Water in South Brunswick Township, New Jersey

Analyses of several hundred ground‐water samples from over 100 wells, and water table elevations measured in about 60 wells were used to determine the sources, distribution and movement of organohalide contaminants within two unconsolidated aquifers in South Brunswick Township, New Jersey. 1,1,1‐trichloroethane and other organic contaminants were found to have migrated more than 3,000 feet from one source to a public supply well. Lithologic logs from existing wells and monitor wells drilled for the investigation indicate that the Old Bridge aquifer, used for domestic supplies, is underlain by a clay aquitard (Woodbridge clay?) which in turn is underlain by the Farrington sand, a very productive and heavily pumped aquifer used for public supply. Well logs and water elevations were used to define the existence and location of a breach or window in the clay formation. This feature recharges the deeper aquifer and has allowed organic contaminants to reach the Farrington after contaminating wells screened in the upper unit. A large‐capacity well has been contaminated as a result. Water table altitudes were used to show the possible existence of a second breach in the clay layer that may allow organics to reach a second public supply well screened in the lower aquifer within the next few years.