Wednesday, November 16, 2011

To fluoridate, someday

Previous post dilemmaized over whether and how to fluoridate at my next Water District Board meeting, which was yesterday. Here's the news:

Santa Clara Valley Water District OKs adding fluoride to its drinking water

Silicon Valley's largest drinking water provider took the first steps Tuesday toward adding fluoride to the drinking water in most of Santa Clara County, including San Jose, the largest city in the nation without the cavity-battling additive.
After a lively 90-minute debate at a packed meeting, the board of the Santa Clara Valley Water District voted 7-0 to put the district on record supporting fluoridation.

It could've been 6-1 because of a side issue where I disagreed with my colleagues about creating yet another Board committee to oversee this, but they were willing to split up the vote so I could agree with them on the main issue and then get shot down over the new committee.

If you're so inclined, you can listen to a couple minutes of my comments while looking at uninteresting shot of the board room below (source link here):

I made clear that I wanted public education on infant formula and on reverse osmosis for those who don't want fluoride, and that we keep checking in on the scientific consensus. I think I'll win that fight. When we'll do this and who will pay for it is less clear. I think it's a legitimate expenditure of public funds, but we're not a public health agency. If they want Water District money to fix people's teeth, my vote would be that they have to wait a while. We need to fix our seismic risks at our dams, restore the environment, and reduce flood damages.

Thursday, November 10, 2011

To fluoridate or not to fluoridate, that is the question. Next Tuesday at my Water District Board meeting

I'll reproduce below most of an old post about fluoridation. I had previously expected to see an identical situation with climate change in terms of the debate, but it's not. I think factors overall favor fluoridating, but not quite as overwhelmingly as I expected. On Tuesday, my fellow Directors and I get to figure out next steps.

Fluoridation opponents have made lots of mistakes in my opinion, but supporters have overstated the consensus. In particular, fluoride levels four to eight times the recommended level do have rare adverse effects, which isn't a huge safety margin in toxicity issues (UPDATE: I mean rare and severe effects - some cosmetic problems to teeth are common). Very slight adverse effects on larger groups would also be hard to rule out.

The Center for Disease Control recommends mixing non-fluoridated water in formula for babies that use formula exclusively. I can also attest to hearing from the significant number of people, if still a minority, who are just anguished that we're putting something they consider toxic in their water. Home-based reverse osmosis systems can remove their fluoride, I think.

And then there's the money cost - over $4m to construct and $800k to operate. We might get funding to construct but get stuck with operating, which people forget is the bigger cost.

So. The staff recommendation is to proceed if someone else pays for it. We'll see. If we do go forward, we may need to educate people about infant formula and let people know they can get reverse osmosis kits if they want.

Anyway, here's most of the old post, with the science:

Fluoridating water, or a funny thing happened on my way to backseat driving

I originally labelled this blog Backseat Driving back in 2004 because I anticipated it to be a blog where I would second-guess decisions made by politicians and other people. That worked out fine more or less until November 2010, when for some reason I was elected to the Santa Clara Valley Water District Board. Turns out that San Jose is the largest city in the US without fluoridated water supplies (in much of the city, anyway), and the seven of us directors have to decide whether we'll help or hinder the fluoridation process. So I'm pushed into the front seat for this one.

We've got some legal and economic issues to handle (it's not quite as cheap as everyone says, I want to know where the money's going to come from), but the relevant issue here is science. I read the guest post at climate blogger Coby Beck's place, The Case Against Fluoride, fairly closely a while back, especially the raucous debate in the comments. As a spectator with some, limited reading of the available information, I'd say the fluoridators seemed more persuasive than skeptics, but it wasn't the absolute demolishing that I expected.

The fluoride skeptics really hurt their cause when say fluoride doesn't prevent cavities - it's so obviously effective that people making this claim are damaging their own credibility. I'd consider it comparable to denying that the planet has warmed in the last 50 years.

The closer issue is adverse effects, and whether a substantial number of people are very slightly harmed by fluoridation, or if a small number of people are substantially harmed. The 2006 National of Sciences report doesn't condemn fluoridation, but it doesn't absolve it, either:
Bone Fractures

....Overall, there was consensus among the committee that there is scientific evidence that under certain conditions fluoride can weaken bone and increase the risk of fractures. The majority of the committee concluded that lifetime exposure to fluoride at drinking-water concentrations of 4 mg/L or higher is likely to increase fracture rates in the population, compared with exposure to 1 mg/L, particularly in some demographic subgroups that are prone to accumulate fluoride into their bones (e.g., people with renal disease)....There were few studies to assess fracture risk in populations exposed to fluoride at 2 mg/L in drinking water. The best available study, from Finland, suggested an increased rate of hip fracture in populations exposed to fluoride at concentrations above 1.5 mg/L. However, this study alone is not sufficient to judge fracture risk for people exposed to fluoride at 2 mg/L. Thus, no conclusions could be drawn about fracture risk or safety at 2 mg/L....

(In California, 2 mg/L was the limit, and 0.7 is the new proposed goal. -Ed)
Neurotoxicity and Neurobehavioral Effects

Animal and human studies of fluoride have been published reporting adverse cognitive and behavioral effects. A few epidemiologic studies of Chinese populations have reported IQ deficits in children exposed to fluoride at 2.5 to 4 mg/L in drinking water. Although the studies lacked sufficient detail for the committee to fully assess their quality and relevance to U.S. populations, the consistency of the results appears significant enough to warrant additional research on the effects of fluoride on intelligence....

Endocrine Effects

The chief endocrine effects of fluoride exposures in experimental animals and in humans include decreased thyroid function, increased calcitonin activity, increased parathyroid hormone activity, secondary hyperparathyroidism, impaired glucose tolerance, and possible effects on timing of sexual maturity. Some of these effects are associated with fluoride intake that is achievable at fluoride concentrations in drinking water of 4 mg/L or less, especially for young children or for individuals with high water intake. Many of the effects could be considered subclinical effects, meaning that they are not adverse health effects. However, recent work on borderline hormonal imbalances and endocrine-disrupting chemicals indicated that adverse health effects, or increased risks for developing adverse effects, might be associated with seemingly mild imbalances or perturbations in hormone concentrations. Further research is needed to explore these possibilities....
(Removed discussion of bone cancer as not very troubling given its rarity. Ed.)

These were the most troubling findings, mostly about what hasn't been proven, and mostly dealing with levels that are five times what's planned for drinking water. The report expressly ignored the benefits of fluoridation. It's important to balance out potential concerns over rare, severe complications related to fluoride with the certainty that rare, severe complications can result from cavities.

The bottom line as a policy maker in my little arena is that I shouldn't try and figure out the science myself, but I should try to figure out what the scientific consensus is, figure out where the consensus doesn't yet exist, and then plug that information into everything else we have to balance.

The science seems to favor fluoridation, but it's not a slam dunk. And we still have potential policy barriers, and the overall cost issues. Figuring this all out will be interesting.

Tuesday, November 8, 2011

Tidal wetland sediment accretion might keep up with sea level rise in one location. Maybe.

I attended our annual Santa Clara County Creeks Conference last Saturday, with an even better than usual program that included a panel on tidal wetlands restoration in South San Francisco Bay, where we're bringing back 16,000 acres of tidal wetlands from former saltponds (will post a video link when it's online).

The restoration has barely begun, but the land that sank after being separated from tidal flows has gained sediment rapidly, something that's necessary to create a complex environment of open water, partially submerged, and emergent tidal environments. While it's slowed more after the first few years that individual ponds have been opened to the the tides, they're still adding sediment, two inches annually, far more than the worst projections for sea level rise.

So, good for us. Except that California is a geologically young area with lots of gradients, erosion, and sediment flow. Our particular part of San Francisco Bay might also disproportionately benefit from the "backwash" of sediment from the rest of the Bay.

Our tidal wetlands can keep up where they are, for now, but whether that will work in other places is less clear.  Still, it's one small piece of good news that demonstrates the value of restoring tidal wetlands, which have been lost to a far greater extent in the US than even freshwater wetlands have.