PLANT 42 TO DRILL WELLS TO MONITOR TOXICS.

Byline: Charles F. Bostwick Staff Writer

PALMDALE - The Air Force plans to drill more monitoring wells at Air Force Plant 42 to help estimate the size and spread of two underground plumes of a toxic industrial solvent.

One monitoring well will be drilled north of a building at the plant's Site 8, where a test found trichloroethylene, or TCE, more than 180 feet below the ground surface.

Three other wells are being drilled around Boeing's space shuttle modification plant at Site 1, where TCE has reached drinking water wells that serve the plant.

``It seems to be concentrated near the source area,'' consultant John Lovenburg said of the Site 1 contamination.

Lovenburg spoke at a briefing Wednesday night for the Plant 42 Environmental Restoration Advisory Board, which offers the Air Force advice on its clean-up efforts.

TCE is a solvent and degreaser used through the 1970s, said Lovenburg. At Site 1, the substance may have gotten into the ground by leaking out of floor drains in the northern part of the assembly building now used for space shuttle modification.

At Site 8, which is used by Lockheed Martin, it probably came from waste water from a jet engine overhaul operation, which included a parts cleaning section, that operated from 1967 to 1971, Lovenburg said.

Over those five years, nearly 56 million gallons of wastewater were allowed to run into an earthen ditch north of Building 870.

Another well will be drilled on Site 3, now used by Northrop Grumman, after soil-gas tests detected TCE.

The wells on Site 1 are being drilled between the shuttle modification building and Los Angeles County Waterworks District wells northwest of Plant 42, to help confirm if water - and contaminants - move in that direction.

TCE was detected at about 3 parts per billion - below the standard considered unsafe by regulatory agencies - in a Site 1 drinking water well, which is now shut down most of the time. Traces have turned up a well on neighboring Site 2, Lovenburg said.

At Site 8, officials were able to test for TCE down to 185 feet, but the auger drilling the hole could go no deeper, Lovenburg said. The monitoring well will be drilled deeper.

Water at that point lies about 430 feet below the ground surface, he said. A drinking water well near Plant 8, and between the contaminated area and Palmdale Water District wells south of Avenue P, shows no sign of TCE, he said.