The purpose of the consultation is to identify any current groundwater use in the Motorola 52nd Street Superfund Site area that might result in human exposure to site contaminants. The Arizona Department of Health Services previously evaluated well use in Operable Units 1 and 2 in 1992. This report updates the well use inventory for Operable Units 1 and 2 and provides an evaluation of potential groundwater exposure pathways in Operable Unit 3.

The purpose of this health consultation is to determine whether contaminants in groundwater from the Motorola 56th Street facility represent a threat to public health. The facility was first occupied in the spring of 1950 as the Western Military Electronics Center. From 1950 to 1958, it was primarily used for bench type electronics, electronic assembly, and semiconductor production. The chemicals used in these processes included solvent degreasers such as trichloroethylene, acetone, and freon, and metals such as cadmium, chromium, and arsenic. From 1959 through 1961, the facility was used primarily for document storage. Beginning in 1962, manufacturing of electronics resumed to include assembly of circuit boards, plating, and degreasing. Chemicals used between 1962 and 1974 included trichloroethylene, tetrachloroethylene, and a number of acids and metals including arsenic. In 1975, the facility began manufacturing liquid crystal products. These activities continued until 1982, when it was converted to office use. The investigations that have been conducted to date have shown that there are residual levels of arsenic and fluoride in down-gradient private wells west of the facility. Solvent contaminants that were found in the 1980s are no longer present at detectable levels in down-gradient private wells.

Mounted black and white photograph with a typescript annotation, "July 17 1914. Making the trip down Bright Angel trail at the Grand Canyon of Arizona on mules. Left to right: George H. N. Luhrs, Jr., unknown, George H. N. Luhrs, Emma Luhrs, Ella Luhrs. Bright Angel Trail to the Colorado River, at bottom on canyon."

Black and white print with members of the Luhrs family. Typescript annotation, "July 17th, 1914. Going down Bright Angel Canyon of Arizona, Those on the mules, from bottom up: unknown, unknown, Ella Luhrs, Emma Luhrs, George H. N. Luhrs, unknown, Roger Hunt, George Luhrs Jr., Catherine Margarita 'Gretchen' (Mrs Geo H. N.) Luhrs standing beside George Luhrs Jr." Beside the trail, a sign displays, "Photo by Kolb Brothers."