Jim Steinberg, Staff Writer
Posted: 09/26/2011 07:47:46 PM PDT

RIALTO – One well serving residents more than a decade ago might have delivered concentrations of perchlorate high enough to affect the development of fetuses, infants and children, state officials say.

But a new study says that drinking water supplied to residents currently by the Rialto-based West Valley Water District, the city of Rialto, the city of Colton and the Colton-based Terrace Water Co. is safe to drink and doesn’t put people at risk for health problems.

The study, a draft report open for public comment, is called “Evaluation of Exposure to Contamination at the BF Goodrich Superfund Site” in Rialto. It will be discussed by California public health officials at a public hearing at 6:30 p.m. Wednesday in the Rialto Senior Center, 1411 S. Riverside Ave.

The BF Goodrich site is a one-quarter mile area north of Rialto, where from 1952 to the mid-1980s, several companies made fireworks and different explosive devices, using among other chemicals, perchlorate and trichloroethylene.

Over time, these chemicals leaked out of pits where they had been dumped and into the groundwater of the Rialto-Colton basin, which serves a portion of the water needs of five water agencies.

Monitoring water supplies for perchlorate began in 1997.

The draft of the state Public Health Department study said that some drinking water supplied by the West Valley Water District’s Well No. 22, when it was used in the years 1981, 1982, 1985, 1987 and 1988, may have had amounts of perchlorate that could have been high enough to modestly impair iodine absorption by the thyroid gland.

This could potentially have lowered the levels of thyroid hormones in fetuses, infants and children below the amounts necessary for healthy development.

But state officials no longer believe that is the case.

On learning of the report, Anthony Araiza, general manager of the West Valley Water District, wrote state health officials that Well No. 22 was blended with water from other sources, including Lytle Creek.

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