Arizona environmental officials are worried that a plume of polluted water under a Pacific Gas & Electric Co. facility near Needles may be threatening drinking water wells on their side of the Colorado River.
Arizona's concerns, repeated as recently as last week in a letter to the California Department of Toxic Substances Control, are complicating what is already a thorny problem for the utility and its parent, San Francisco-based PG&E Corp.
Pollution from PG&E's Topock natural gas compressor station in the Mojave Desert has created alarm at the Metropolitan Water District of Southern California, which serves Los Angeles and 25 other cities and local water agencies. And five Indian tribes that live along the Colorado River fear that a sacred tribal site will be despoiled by the utility's planned cleanup effort.
The Topock plant, which pushes natural gas through a pipeline from West Texas to markets in California, sits atop a pocket of at least 108 million gallons of water tainted with hexavalent chromium, a chemical compound that can cause cancer if inhaled as dust or steam.
The chromium 6 threat was at the center of the 2000 movie "Erin Brockovich," which focused on a sister PG&E plant in the desert community of Hinkley, near Barstow. Chromium 6 was used at both plants and at a third station at Kettleman City in Kings County to control corrosion and mold in cooling towers. At Topock, PG&E dumped untreated wastewater in the ground between 1951 and 1969.
"The plume of hexavalent chromium may have already moved beneath the Colorado River and may now be contaminating Arizona's groundwater," Environmental Quality Director Steve Owens wrote to California officials on March 14.
Owens said Friday that he had no evidence of PG&E-generated pollutants migrating to Arizona. PG&E has offered to pay more than $350,000 for a study of possible groundwater contamination in several communities on the Arizona side of the river, which marks the border between the two states.
Owens' latest letter was a response to a Feb. 22 announcement by California regulators that they detected high levels of chromium 6 in a monitoring well just 60 feet from the Colorado River, a source of drinking water for more than 18 million Southern Californians and 4 million Arizonans. The sample found concentrations of 354 parts per billion for total chromium, seven times greater than California's safety standard.
California officials said that they had no indication that the chromium 6 plume had reached the river. But as a cautionary move, they ordered PG&E to increase pumping from extraction wells to try to draw the plume back from the river. Also, Toxic Substances Control Director B.B. Blevins told PG&E to increase its monitoring for contaminants.
Owens, however, contended in his letter that the discovery of heavy levels of chromium 6 at a depth of 90 to 100 feet below the surface, so close to the river's edge, signaled that "the potential threat to Arizona's groundwater and surface water resources from the plume has increased significantly."
He urged California to begin sampling Colorado River at a variety of depths and to test river sediment for possible chromium 6 contamination.
In an interview Friday, Owens said Arizona's worries were "not taken seriously" by PG&E and California officials a year ago when the danger posed by chromium 6 to the river first became public. He said he couldn't understand why officials in California "would be so dismissive of the concerns of a fellow agency whose interest is protecting the health and safety of its people" on the other side of the river.
"This isn't some fantasy that our technical people have conjured up," Owens said.
California's Department of Toxic Substances Control complained in January that Arizona officials hadn't contacted them directly with concerns about the possibility that the toxic plume might be moving under the Colorado River. At the time, Karen Baker, chief of the department's geology, permitting and corrective action division, said that "at present, there are no data indicating any contamination has migrated to Arizona."
Baker later suggested that any chromium 6 that might turn up in Arizona wells could be caused by the presence of naturally occurring background readings, or could be linked to alleged pollution from a nearby El Paso Corp. natural gas compressor plant on the Arizona side of the state line.
California regulators and PG&E executives contend that studies of local geology and hydrology seem to indicate that it's unlikely that an underground plume of liquids would travel under the Colorado River's bed. "It's got to go uphill," Baker said.
Local Indian tribes also accuse PG&E and the toxic substances department of rushing to build a treatment plant that is blocking access to the entrance of the adjacent Topock Maze. Members of the nearby Fort Mojave tribe believe that the ancient site marks the portal for spirits of the recently dead to enter heaven. The tribe is mounting a fight in the state Legislature and the courts to force PG&E to move the treatment site away from the maze, said tribal attorney Courtney Coyle.
"The tribe is going to aggressively pursue every option it has to protect its sacred place and try to reverse some of the destruction that's been caused by PG&E," Coyle said.
Dan Richard, a PG&E senior vice president who met with the tribal leaders last week, said the utility "wants to step up and do whatever it has to do to keep hexavalent chromium out of the Colorado River" without impinging "on a great cultural resource for the people who live right in that area."