Taco Belle Times: "Tails" of a Baby Boomer Veterinarian: LEAD POISONING

I traveled earlier this month to Philadelphia for the flower show where this year’s theme was the national parks.

Listening to the local news, there was a lot of concern voiced about the safety of the aging, municipal water supplies in response to the recent headlines out of Flint, Michigan.

WHAT ARE SOME POSSIBLE SOURCES OF LEAD?

Lead based paint in older homes, older linoleum floors, and contaminated soil (then licking paws and fur) are major sources. Lead can also be obtained via other sources: toys, fishing tackle, drapery weights, and improperly glazed ceramic food or water bowls (imported from Mexico or China) http://www.cfsan.fda.gov/~lrd/fdaact.html#lead.

Water contamination via lead pipes has rarely made headlines until recently.

WHY WERE LEAD PIPES & SOLDER (to connect copper pipes) USED PRIOR TO THE 1980’S?

Going back thousands of years, lead pipes resisted pinhole leaks AND WERE soft enough to form shapes to deliver water efficiently.

AS CONCERN IS VOICED FOR CHILDREN, WHY ARE PUPPIES AT HIGHER RISK?

They are more likely to show signs due to chewing on foreign objects, greater intestinal absorption rates, and increased toxicity to the brain.

DEFINE “TENNESSEE LEAD POISONING.” IS BUCKSHOT A RISK TO CAUSE LEAD TOXICITY?

Pictured below are lead pellets found on the radiograph of a dog from a pellet gun and shotgun. NO, buckshot does not elevate blood lead levels. Lead is only absorbed out of an acid environment (GI tract, joints) leading to poisoning.

WHY THE SUDDEN NOISE ABOUT LEAD POISONING IN MUNICIPLE WATER SUPPLIES?

As a cost cutting measure, the city of Flint, Michigan cut off Detroit as their water supplier and switched to the Flint River as a source. THE INAPPROPRIATE CHEMICALS UTILIZED IN THE FLINT WATER WORKS’ FILTRATION LEACHED LEAD OUT OF THE PIPE LINING AT AN ALARMING RATE. Unfortunately, there are probably hundreds of cities, in the USA that have a silent risk.

HOW HIGH IS THE LEAD LEVEL IN FLINT, MICHIGAN?

From what I can gather about the Flint issue, the levels are still in the part per billion (ppb) range (5 to 1000 ppb depending on the reference). THE EPA SAYS ANYTHING OVER 15 ppb is unacceptable.Two Flint dogs recently tested positive for lead toxicity. It’s the state’s first lead toxicity cases involving dogs in five years.

SO WHAT IS CONSIDERED TOXIC ENOUGH TO CAUSE LONG TERM PROBLEMS?

This is where it gets confusing, as long standing thoughts are that no ill effects occur until levels rise to parts per million. So, to put it in prospective, I will use the data for pets as they are important household sentinels

<10 mcg/dl (0.1 ppm) baseline "normal"

15-20 mcg/dl (0.15-0.2 ppm) --suggest exposure to environmental lead

but not toxicosis

20 mcg/dl (0.2 ppm) --supportive of toxicosis in birds if accompanied by appropriate clinical signs

30-35 mcg/dl (0.3-0.35 ppm) --supportive of toxicosis in mammals if accompanied by appropriate clinical signs

50 mcg/dl (0.5 ppm) in birds--diagnostic for toxicosis

60 mcg/dl (0.6 ppm) --diagnostic for toxicosis in mammals (dogs, cats, people, etc.)

ppm = parts per million

So when I read of outrage in the news when a child’s level is 6.5 mcg/dl or 0.1 ppb, I am confused if the chart above is inaccurate or if this is a crisis blown out of proportion. I believe that story needs to be investigated from a scientific, not political, standpoint.

It is now accepted that there is NO safe level of lead for humans, and I would presume that's also true for mammals and birds .

EXPLAIN WHY THAT CAN BE CONFUSING TO ASSUME ALL IS GOOD!

Blood levels are not that reliable, especially for longer-term exposure, since lead will ACCUMULATE outside the bloodstream in bone, nervous system, and other organs (replacing Ca++ in bones and other organs, including the nervous system). Unfortunately, I think there's no good alternate testing, although hair samples are being investigated.

ARE THERE COMMON SIGNS OF LEAD POISONING IN PETS?

Gastro-intestinal signs, behavioral changes, and neurological signs with slow onset in chronic exposure.

My SOAPBOX ON THIS ISSUE!

There seems to be a strong economic and political motivation rather than pure science to explain the risk levels of lead. Blame is shared among many agencies to reach solutions.

DISCUSS OPTIONS FOR TREATMENT IN PETS SHOWING SIGNS.

The two chelators (BINDERS) of choice are calcium EDTA injections and oral succimer.

PREVENTION TIPS FOR PETS

Use stainless steel bowls for pets made in the USA. In at risk situations, consider filtered water for your pets; if not an option then run faucet 3 to 5 minutes before using the water in systems at risk.

HOW CAN YOU TEST WATER IN WAKE CO, NC? Goals?

Lead levels below 15 ppb

Well water testing: http://www.wakegov.com/water/wells/pages/watersampling.aspx

Municipal water supplies: www.epa/gov/ccr