A test well at the boundary of Hercules Bacchus Works has a level of organic solvents that is much above federal safe-water standards, and the company has started a survey of private property nearby to determine if any wells there are also contaminated.
John R. Gale, director of Hercules' production, planning and control, told a press conference Friday that the company is looking for private wells in an area at the boundary of 41st South. The area searched continues north to 35th South and is bounded on the west by 80th West and on the east by 64th West.Only two private wells have been discovered so far, one of them used for drinking water and the other for irrigation. Hercules is testing the culinary well and expects to have its results by March 15.
Gale said the test well, located just south of the boundary, was sampled last summer, turning up concentrations of solvents that are above EPA drinking-water standards. The solvent, called DCE (technically, 1,1-dichloroethene), showed a concentration of 20 parts per billion, when the safety standard for drinking water is 5. The solvent TCE (trichloroethene) has an allowable level of 7 parts per billion and they discovered 22. Finally, TCA (1,1,1-trichloroethene) has a safe drinking water standard of 200 parts per billion, but the level detected was only 160.
"That is the solvent that's in use now," Gale said of TCA.
The private property north of the boundary is "down gradient" from the test well. That means underground aquifers flow in that direction. According to Hercules, the Salt Lake City-County Health Department was informed of the test-well results and the department found that few residential wells in the area are being used. But Hercules would like anyone within the area who knows of an operating well to contact the company.
Gale said area residents, including those who do have wells, have been cooperative.
The solvents, which can be toxic or cancer-causing at higher doses, were used for many purposes at Hercules. Gale said these included diluents for paints and adhesives, "engine de-gummers," and in spray paints. In the past, Hercules disposed of the solvents in ways that are now illegal and known to be dangerous.
"The practices we used then were such that they would allow it to get into the ground," Gale said. Hercules signed an agreement with the state that required the drilling of test wells and the cleanup of known sumps or other disposal sites where hazardous material remained. So far, 76 sites have been cleaned up. Hercules officials are not certain of the source of the solvent plume now detected.
It may have been sites already cleaned up or it may be a site not yet discovered, he said.