CALIFORNIA, ARIZONA
Chromium 6, the toxic element made infamous by the movie
Erin Brockovich, is back in the news. In
Southern California and central Arizona, water officials fear that
the chemical might contaminate drinking water for some 20 million
people, as it creeps toward the Colorado River from a pump station
on a natural gas pipeline in the Mojave Desert.
Between
1951 and 1964, Pacific Gas and Electric dumped 6 million gallons
per year of chromium-tainted water into a wash near Needles, Calif.
The chromium was used to prevent corrosion at the Topock pump
station, but the contaminated water leached into groundwater. Then
it started seeping toward the Colorado River about 40 miles
upstream of intakes for the Metropolitan Water District, which
supplies Los Angeles and San Diego, and the Central Arizona
Project, which supplies Phoenix and Tucson.
When inhaled,
chromium 6 is known to cause cancer, but scientists disagree about
whether the chemical is a carcinogen in drinking water.
Nonetheless, the U.S. Environmental Protection Agency allows no
more than 100 parts per billion of chromium in drinking water,
while California’s standard calls for less than 50 parts per
billion. In December, tests revealed that water with chromium 6
concentrations of 111 parts per billion was only 125 feet from the
Colorado River. About 600 feet from the river, concentrations
reached 11,000 to 12,000 parts per billion.
Pacific Gas
and Electric is still determining how to clean up the pollution
permanently. In the meantime, in early March, the company began
pumping 26,000 gallons of contaminated water per day from the
Topock site. The Metropolitan Water District has also asked Pacific
Gas and Electric to protect the Colorado River with an underground
barrier 1,600 feet long and 100 foot deep, a project that could
take a year to complete.” Our focus is to prevent anything on-site
from getting to the river,” says Bob Muir, spokesman for the
Metropolitan Water District. “It’s an imminent danger.”
This article appeared in the print edition of the magazine with the headline Toxic chemical creeping toward Colorado River.
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