June, 1997
For nearly two years, the city of Cupertino debated whether to fluoridate their water supply. Then, in September, 1974, the water commission learned that the concentration of fluorides in Cupertino waste water was already nearly four times the amount recommended for fluoridation. The average fluoride concentration at the sewer outflow metering station was 3.8 ppm. The waste water from a residential area of Cupertino had 1.75 ppm. (One ppm is one part per million which is equivalent to 1 mg/liter.) A well that supplied water to that area only had 0.2 ppm fluoride. The difference of about 1.5 ppm in residential waste water was thouhgt to come from food, toothpaste and detergents. (1)(2)(3)
The waste water from Cupertino goes to the treatment plant at Alviso which is owned by the City of San Jose. The high level of fluoride discharge was in violation of a San Jose waste water discharge ordinance that limited fluorides in waste water to 1.5 ppm. Further investigation revealed that all the dischargers that fed waste water to the San Jose waste water treatment plant were sending waste water with fluoride concentrations higher than the allowed 1.5 ppm. The San Jose ordinance was declared "archaic." (4) The San Jose City Council voted to change the allowable level to 5.0 ppm. (5)(6)
Hydrogen fluoride is used for etching computer chips. As the computer chip industry grew in Silicon Vally, fluoride became a major pollutant in waste water. By 1988, the total hydrogen fluoride being dumped into waste water by the top twelve fluoride polluters was 61,849 pounds per year. (7) By 1992, the legal limit of fluorides in waste water was raised to 10.0 ppm. (8) In 1994, the Cities of San Jose and Santa Clara were considering raising the fluoride in waste water limit to 32 ppm. This still was not high enough for National Semiconductor, a major source of hydrofluoric acid in waste water, which proposed raising the limit to 65.5 ppm. (9) Justification for this proposal was that the hydrofluoric acid is diluted by the total amount of waste water when it reaches the San Francisco Bay so that it does not make a significant difference. The concentration of fluoride going into the Bay in treated waste water was estimated to be 1.0 ppm. The additional fluoride from semiconductor manufacturers was estimated to be 0.25 ppm. Additionally, the pounds per day of hydrofluoric acid discharged by semiconductor factories into the sewer system is about the same as it had been, but the concentration of waste water going immediately from the factory to the sewer has been going up because the semiconductor factories have been redesigning their waste disposal process so that less water is needed. This is to conserve water in time of drought. (10) Reference was made to a scientific report showing that fluoride concentrations must be quite high before they cause death of selected species of aquatic life, but the tests were only measures of acute intoxication lasting not more than 96 hours. They did not measure the effects of chronic exposure. (11) National Semiconductor maintained that there is already fluoride in the environment and it does not seem to be doing any harm. (10)
| Fluoride in Silicon Valley may largely have come from many years of industrial air pollution. In 1971, the Bay Area Pollution Control District reported that fluoride air pollution from the ten largest sources of fluorides was 19.4 tons per day. The table on the right lists the ten largest sources. (12) |
| Source | Tons Per Day |
|---|---|
| Pacific Gas and Electric Co. (10 Plants) | 6.6 |
| Phillips Petroleum Co., Martinez | 3.7 |
| Standard Oil Co., Richmond | 3.6 |
| Kaiser Cement and Gypsum, Permanente | 1.7 |
| Shell Oil Co., Martinez | 1.7 |
| Industrial Chemical Division, Allied Chemical Co., Richmond | 0.5 |
| Union Oil Co., Rodeo | 0.4 |
| Hercules Corp., Hercules | 0.4 |
| FMC Corp, Newark | 0.4 |
| Fibreboard Corp., Antioch | 0.4 |
Apricot orchards in the Niles Canyon area of Fremont were reported to be damaged by fluoride air pollution in 1969. The apricot leaves contained 200 ppm fluoride and turned brown because of enzyme damage. (13) Raspberry crops grown in the Santa Clara Valley had accumulated 54 ppm fluoride. (14) Fluoride air pollution comes from a variety of industrial processes. Grinding lime to make cement contributes to airborne fluorides. The fluoride content of limestone and dolomite deposits ranges from around 100 ppm to more than 3500 ppm. (15) The Permanente cement factory in Cupertino had the largest lime grinding mill in the world when it was built in 1967. (16) It was emitting 1.7 tons of fluoride per day in 1971.
The City of San Jose no longer restricts the dumping of industrial waste hydrofluoric acid into the sewer system. The East Bay Municipal Utility District does not limit fluorides in waste water. The City of Palo Alto, as of 1995, set a limit of 65 mg/liter.
National Semiconductor would prefer to continue to dump hydrofluoric acid into the sewer system. One solution is to precipitate hydrofluoric acid with calcium hydroxide (lime) which yields calcium fuoride. National Semiconductor estimated that hydroxide precipitation could produce five tons per day of calcium fluoride sludge. (9) Calcium fluoride is much less toxic than hydrofluoric acid.
The the 91 signatories to the Convention on the Dumping of Wastes at Sea agreed on November 13, 1972 to prohibit the dumping of wastes and other matter that is likely to be hazardous to human health. Under this agreement, a permit is required to dump fluorides outside territorial waters. (17)
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comment by RICHARD G. FOULKES, B.A., M.D. BOX 278 ABBOTSFORD, B.C., CANADA TELEPHONE (604) 850 3171 U.S.A. TELEPHONE/FAX (360) 758 7133
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There are serious problems with "laboratory" experiments as opposed to
"field" studies. Those preparing the National Semiconductor brief were
very selective in what they presented to make their point. As you can
see, our review included the same major "laboratory" studies and, like
those responsible for environmental reports in British Columbia and Canada,
obtain quite different results. The low figure for fresh water effects
of levels of F above 0.2-0.3 mg/L are supported by a major field study
(Damkaer and Dey) where fish are lost not by immediate death but by delays
in the vital upstream migration.
What it boils down to is this - a TAO of fluoride, we might call it. Our ecosystem has developed in response to the following levels of fluoride: 1. for fresh water, 0.1-0.2 mg fluoride /L.; 2. for sea water, 0.4 - 0.7 mg /L of "ionic" (i.e., "unbound" ) fluoride plus an equal amount of fluoride that is "bound" (primarily to magnesium) or, better, a ratio of f luorine to chlorine of 10 to the minus 5th : 1); 3. there is a limit also to the amount of fluoride in sediment. When any of these natural, balances are distorted by fluoride pollution, the ecosystem is in peril! It is as simple as that! If the EPA really served the long-term interest of the public (and the ecosystem), they would permit zero discharges. The polluters should be forced to neutalize and dispose of their wastes or recycle regardless of their bottom line. San Jose, is currently fluoridated to 1 mgF/l, therefore, its taxpayers are already operating a disposal. mechanism for the phosphate fertilizer industry. Do they want to increase their contribution further? Is the Waterworks in the business of distributing safe drinking water or processing industrial waste? Ask them. |