RE: OEHHA’s Scientific Rationale for a New Perchlorate Public Health Goal

The PSG’s comprehensive comments focused on key concerns in the scientific evidence OEHHA did and did not consider, noting specific long-standing scientific studies that were ignored or excluded from consideration while other studies with less scientific rigor were given undue attention. The group strongly advised OEHHA that its proposal and supporting documents will likely be unable to withstand scientific scrutiny and may be indefensible in the face of the preponderance of scientific evidence.

The PSG stressed that the current document falls far short of OEHHA’s directive to use the best science in setting public health goals.

The PSG’s 94-page comment document exposed numerous areas where OEHHA’s assumptions and conclusions were not scientifically based and therefore in supportable. Some of the key flaws in OEHHA’s rationale proposing a new PHG include:

  • OEHHA’s calculations are based in part on the assumption that infants consume 130 percent of their blood volume in drinking water every day. This is the equivalent of an average adult drinking almost two gallons of water daily.
  • Nowhere in OEHHA’s document does it show that California’s current perchlorate standard is not health protective or that lowering the public health goal from 6 parts per billion (ppb) in water to 1 ppb will offer any additional health benefit.
  • It’s well understood that be low 245 ppb in drinking water, perchlorate has no effect. This was confirmed by the National Academy of Sciences (NAS) in 2005 and no new research, including the studies OEHHA cites, challenges this fundamental fact.
  • It is also a fundamental scientific fact that the only effect of perchlorate demonstrated at high doses is Iodine Uptake Inhibition (IUI). OEHHA treats IUI as if it is an adverse effect when in fact the NAS emphasizes it is not. IUI is actually something that happens naturally in the body every day as a results of naturally occurring compounds in the foods we eat specifically nitrate and thiocyanate) which have the exact same non-adverse effect on the body as high doses of perchlorate.
  • OEHHA’s position on sensitive populations is in direct conflict with the US. EPA’s Office of Inspector General, the Centers for Disease Control, Agency for Toxic Substances and Disease Registry, and the National Academy of Sciences National Research Council.
  • Although there are more than 60 years of scientific literature on perchlorate, OEHHA bases its proposal about sensitive populations on just three studies (two based on the exact same data set) which have been repeatedly criticized for flaws in their methodology. Highlighting the flaws in just one of these studies required 12 pages in the PSG comments.

Public health goals developed by OEHHA are based on adverse effects. The PSG maintains that OEHHA has based a proposed goal for perchlorate on a “no effect” level for a nonadverse effect and that this is scientifically indefensible given the numerous studies cited by the NAS which contradict OEHHA’s position.

Research on perchlorate spans six decades, dating back to its use as a medicine, making it one of the most understood compounds regulators are examining today. In addition to determining the “no effect” level, the research on perchlorate has also definitively concluded perchlorate does not cause cancer or birth defects, and neither mimics a hormone nor directly stimulates a hormonal
response (it is not an endocrine disruptor).

Learn More

The Perchlorate Study Group (PSG)’s final comments on the California OEHHA’s public health goals for perchlorate in drinking water are posted on the Perchlorate Information Bureau site.

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