Perchlorate, an oxidant used in fireworks and road flares and as
an accelerant in rocket fuel, has been found hiding out in the town
of Rialto, a small town in Southern California. Where does it reside?
It seems this chemical has befouled nearly half the town's drinking
water supply.
But Rialto is just one of many communities faced with this problem;
officials in 36 states where the Environmental Protection Agency
(EPA) has detected perchlorate are trying to determine when to close
wells, whom to sue and how to not get sued.
For Rialto, the problem stems from a 2,800-acre tract of land north
of downtown that once housed World War II munitions, Cold War weapons-makers,
and now, fireworks warehouses and a dump. City fathers suspect each
occupant of the tract contributed to what's become a 7-mile stretch
of perchlorate 400 feet below the ground that's polluting the town's
aquifer as well as groundwater from neighboring areas.
Massive Repercussions
In all, six of the town's 13 water wells have tested positive for
perchlorate. The projected cleanup costs are more than double Rialto's
annual city budget of $40 million. As a result, the city has:
- Sued dozens of suspected contributors to the contamination,
including the Defense Department.
- Raised local water rates by 65 percent.
- Begged local residents to conserve water.
Meanwhile, both officials and townspeople want to know the degree
of harm perchlorate bestows: For starters, if exposed to high amounts,
the chemical can interrupt the production of thyroid hormones, which
are needed for pre- and postnatal development. The EPA set a safety
limit for perchlorate exposure level to 24.5 parts per billion (ppb)
(in drinking water), and with Rialto's detections ranging as high
as 88 ppb, Rialto's officials decided to shut down any well where
perchlorate was found.
And, because standard filtering doesn't work on perchlorate, the
town has invested hundreds of thousands of dollars in equipment
that uses a resin to get rid of it. However, town officials believe
the only long-term solution is forcing polluters to fund a cleanup.
Wired
News
April 23, 2005