This report summarizes a portion of the results of a large-scale tracer test conducted at the U.S. Geological Survey research site on Cape Cod, Massachusetts. The site is located on a large sand and gravel glacial outwash plain in an unconfined aquifer. In April 1993, about 10,000 liters of groundwater from the site were injected into the shallow aquifer with bromide (BR), chromate (Cr(VI)), and four metals (Lead Pb), copper (Cu), nickel (Ni), zinc (Zn) complexed with ethylenediaminetetraacetic acid (EDTA) added as tracers. At the time of the tracer test, shallow groundwater at the site was contaminated by secondary sewage effluent that was discharged since 1936 onto infiltration beds located about 240 m (meters) upgradient of the injection wells. Vertical concentration gradients in dissolved oxygen, pH, dissolved Zn, and other water quality parameters are caused by the mixing of the sewage effluent with ambient groundwater. The experiment was carried out such that the water with tracers would be injected across these vertical gradients in water quality. Thus, the mobility of the tracers under variable chemical conditions could be compared and the fate of the tracers in response to different chemical processes could be contrasted.

"March 2001." "Project Officer, Robert W. Puls, Subsurface Protection and Remediation Division." Includes bibliographical references (Part 1 p. 13-15, Part 2 p. 16-19)

Part 1. Experimental design and transport of broide and nickel-EDTA tracers -- Part 2. Transport of chromium(IV) and lead-, copper, and zinc-EDTA tracers.