Hector, in addition to being a good fiend to many in Oro Valley, is also extremely knowledgeable on many technical issues confronting us.
Please take the time to read Hector's message. He addresses his concerns about the toxic waste site just to our north, known as Page Trowbridge Ranch. Hector has firsthand information he is sharing with us.
We previously discussed this (scary) issue, most recently on June 23. An Oro Valley Resident Addresses Toxic Waste Issue.
Art
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In the 1940’s the University Of Arizona (UA) started using a piece of vacant land in Falcon Valley as a dump site for chemicals used in the laboratories. The procedure consisted of throwing the chemicals in a ditch in the desert and leaving. The location was called the Page Trowbridge Ranch (PTR). At one time, they burned the solvents and thus the fire department discovered the un-permitted dumpsite. An Oracle resident wrote a long report and started questioning the procedure. By then it was around the year 2000. There were many meetings with the UA staff and the Department of Environmental Quality, in which I participated. I worked 5 years in a nuclear physics research lab in the past, so I was curious. They used radioactive scintillators in an organic solvent, for diagnostic purposes.
After a few years, due to rare circumstances, I became a member of a UA science committee on the PTR dumpsite. At the last meeting, a report came out related to the presence of volatile organic compounds (VOC) in amounts that far exceeded the permissible and at depths that nobody expected. The report of March 2003 was prepared by consultant Weston Solutions of Phoenix. Some experts at the meeting attributed the location and the unexpected shallow depth of the VOC’s to their travel speed --faster than the water in the aquifer -- and at depth of their own (100 to 200 feet). The committee never met again since.
At the time my wife fell ill and I could not devote any more time to the project which included traveling. My wife passed away last year, but I am reluctant to work on the project, and I'd rather like to have somebody take over, because of my age. What has to be done is to find out why they are building on top of VOC contaminated ground. It may be that some ground treatment is taking place, as is done with some other sites in Tucson, but I don’t know. The answer is in Phoenix. All this VOC information I have is 5 years old.
There are about 36 miles or 190,000 feet from Oracle and Tangerine to the dumpsite. Groundwater velocities vary from 100 to 10,000 feet per year in the aquifer and the direction of travel from Falcon Valley is N-S and then in Oro Valley it is E-W. The travel time could be 2,000 or 19 years. This is according to a study by W. Osterkamp in 1974. This applies to water, which carries most of the dissolved solids and has a well defined path underground. VOC’s may differ in its travel and needs to be detected by drilling (which was the next promised step in 2003) It will probably follow some easy geological path. The area between Falcon Valley and Oro Valley is a corridor 5 miles wide surrounded by mountains, so the path for VOC’s will follow the same route, going south. Since the terrain is about 400 feet higher in Falcon Valley, the VOC and water direction is the same. VOC’s close to the surface evaporate. Given the difference in altitude and the distance, drawdown has a negligible effect. The big effect is water use in Falcon Valley, which will reduce the underground water flowing to Oro Valley, about 8000 acre feet per year. I have calculated that at build-out of all the permitted development, there will not be any water flowing.
At this time the aquifer continues to be contaminated. We should get test results of commercial wells in Oracle Junction, for the chemicals that we know are dissolved in the aquifer. The dumpsite is covered with plastic today, but only on top, which is a halfway measure. The optimum would be to remove all the contaminants, an expensive undertaking. The time for contaminants to travel from PTR to the water company wells is many years, but the dumpsite is old, since this has started years ago.
Hector Conde
