Arsenic And Oz

It appears that Dr. Oz has gotten a few facts about apple juice wrong (or at least incomplete).

Arsenic in apple juice! Fed to babies! And it probably came from China! Television's Dr. Mehmet Oz is under fire from the FDA and others for sounding what they say is a false alarm about the dangers of apple juice.

Oz, one of TV's most popular medical experts, said on his Fox show Wednesday that testing by a New Jersey lab had found what he suggested were troubling levels of arsenic in many brands of juice.

The Food and Drug Administration said its own tests show no such thing, even on one of the same juice batches Oz cited.

"There is no evidence of any public health risk from drinking these juices. And FDA has been testing them for years," the agency said in a statement.

The flap escalated Thursday, when Oz's former medical school classmate Dr. Richard Besser lambasted him on ABC's "Good Morning America" show for what Besser called an "extremely irresponsible" report that was akin to "yelling 'Fire!' in a movie theater."

Besser was acting head of the Centers for Disease Control and Prevention before joining ABC news as health and medical editor several years ago.

Arsenic is naturally present in water, air, food and soil in two forms -- organic and inorganic. According to the FDA, organic arsenic passes through the body quickly and is essentially harmless. Inorganic arsenic -- the type found in pesticides -- can be toxic and may pose a cancer risk if consumed at high levels or over a long period.

"The Dr. Oz Show" did not break down the type when it tested several dozen juice samples for total arsenic. As a result, the FDA said the results are misleading.

Fear sells a lot better than good news. And what kind of levels were found by Oz? Tens of parts per billion. What did the FDA find? Two to six parts per billion.

What are the current US legal limits for arsenic in water?

Arsenic levels in public drinking water are regulated in the United States by the Environmental Protection Agency (EPA). As of January 2006, the maximum contaminant level for inorganic arsenic permitted in US drinking water is 10 μg/L (micrograms per liter), or 10 ppb (parts per billion)

Even if Dr. Oz is correct you would have to be drinking almost nothing but apple juice for your whole life before this became a concern.

What foods are high in arsenic? Seafoods other than fish (I'm going to have to cut back on lobster - fortunately I don't care for it much and besides I can't afford it) and fish are the biggies. So what should you eat? Vegetables, beef, chicken, and dairy products. Got another half gallon of ice cream dear? I need to lower my arsenic intake.

And no mention of chocolate. Eat a pound with every meal. If you are not diabetic. And if you are diabetic? Smoke pot.

Cross Posted at Classical Values

Nuke Plant Data Storm

Instapundit links to a story about a Nuke Plant going offline due to a data storm.

The device responsible for flooding the network with data appears to be a programmable logic controller (PLC) connected to the plant's Ethernet network, according to an NRC information notice on the incident. The PLC controlled Unit 3's condensate demineralizer -- essentially a water softener for nuclear plants. The flood of data spewed out by the malfunctioning controller caused the variable frequency drive (VFD) controllers for the recirculation pumps to hang.

It is what you get when you use a non-deterministic (crash) protocol like Ethernet instead of a time division protocol like MilStd 1553 or an arbitrated protocol like CAN Bus. The fundamental problem is Einstenian. What is simultaneous when signals only travel at the speed of light? Unless you provide each unit on the bus with its own time slot (1553) or arbitrate addresses as they go down the bus (CAN) you will have problems when two transmitters try to start at the same time (which assumes absolute time at a certain level - a problem that need ony concern engineers)

Crash buses are not allowed in critical systems in aircraft design.

In a nuke plant all systems are critical. Three Mile Island started with a valve malfunction and a burnt out lightbulb in a relatively non-critical part of the plant.

So why don't people stick with the more deterministic buses? There is a lot of design and documentation overhead with such an approach. Every time a new element is added to the bus the bus control software must be at minimum inspected and at most totally reconfigured. In addition the peak data handling capacity of such busses is not as good as Ethernet especially over longer distances. The alternative of course is to continue on with the plug and pray approach. I might note that all wireless busses are essentially crash busses. They will not help much.

BTW I have nuke plant operational experience (US Navy) and aircraft electrical systems design experience (Sundstrand Aerospace).