Wednesday, April 16, 2008

Polycarbonate redux

I am listening to NPR’s All Things Considered – it’s a story about bisphenol A, a common chemical that many of us have heard about by now. You know the estrogenic chemical that’s in those colorful polycarbonate clear plastic bottles that we all bought when we didn’t want to use bottled water, as well as in the linings of food tins and clear plastic baby bottles – that yes, I’m sure I used with my kids. And I’m thinking maybe we all ought to drink a little bisphenol A if it’s true that a little estrogen is good for improving memory.

Here’s why.

There is no question that exposure to estrogenic contaminants is problematic – particularly when exposure occurs during fetal development and in young children. There are reams of data that demonstrate adverse impacts on the development of reproductive organs, timing of puberty, and other effects on both male and female offspring of test animals exposed in utero and during lactation. Then there is the unfortunate example of diethylstilbesterol or DES, the synthetic estrogen prescribed to women back in the twentieth century to stem complications during pregnancy. It was found to be ineffective in the 1950’s but prescribed until the ‘70s (go figure) when the consequences of exposure to extraneous estrogenic chemicals during development first reared its ugly head in the form of clear cell adenocarcinoma in the daughters exposed in utero.

But did you know that at one time, back in the 1930’s scientists seeking synthetic estrogens like DES found that bisphenol A also behaved as a weak estrogen? That’s right. Back in the 30s this was known. Then some genius discovered that it could be linked together to make plastic. And voila – perimenopausal women like me just have to drink from our polycarbonate bottles to replenish our estrogen. Apparently back then no one figured anyone would be drinking from the plastic, or storing food in it, or sealing children’s teeth – and then when they did discover these uses of the plastic they must have forgotten that it was a known estrogen.

Seriously, we could all use a memory boost. Here’s a Science News article from back in 1999 by Janet Raloff which, besides being so last century, is so similar to recent reports about leaching of bisphenol A from polycarbonate that I did a double take when I came across it on the web (actually I probably read it back then, being a fan of Ms. Raloff, but have since forgotten.) It’s uncanny. Right down to reports that bisphenol A is more likely to leach from well-used polycarbonate and when liquids are heated in polycarbonate.

If that was then, why has it taken us ten years to toss our bottles? Maybe it’s because as Raloff pointed out, the jury was out. Well, almost ten years later it has returned in the form of a report by the National Toxicology Program’s Expert Panel evaluation of bisphenol A, here’s what they conclude (their emphasis):

“The NTP concurs with the conclusion of the CERHR Expert Panel on Bisphenol A that there is some concern for neural and behavioral effects in fetuses, infants and children, at current human exposures. The NTP also has some concern for bisphenol A exposure in these populations based on effects in the prostate gland, mammary gland and an earlier age for puberty in females.”

“The NTP has negligible concern that exposure of pregnant women to bisphenol A will result in fetal or neonatal mortality, birth defects, or reduced birth weight and growth in their offspring.”

Although I’ve confiscated my kids bottles I might keep them around for a few years in case I’m needing a little extra estrogen – if I can remember where I’ve stashed them!

Saturday, April 12, 2008

It’s TOXICANTS stupid

Whenever I have the opportunity to teach, I quickly learn how little I know. Maybe that’s what draws me towards the classroom. Besides the opportunity for human contact – especially contact with students who are so eager to learn about how we’ve managed to muck things up and what we can do about it.

A few months ago, I took on two challenges 1) introducing students at Mount Holyoke College to the fascinating world of toxicants, which, as they all now know– it’s toxi-c-a-n-t-s – unless of course it's a biologically produced toxin (and each time I reminded them of this, I was reminded of my graduate school advisor, the one we called “the pedant,” and shudder,) and 2) asking them to write about toxicants (and in one case, a toxin) for publication in the very public Encyclopedia of Earth or EOE ( (And write they did - articles ranging from PBDEs to Atrazine to Synthetic musks - something I hadn't know even existed!)

For some it was a slog. As one student wrote, and I’m sure more than a few students thought, “I never realized writing for the EOE would be so tedious.” For others it seemed a breeze. For me it was nerve-wracking. Particularly after I had the brilliant idea that each student should send her article out for review to whatever expert on her topic she felt most appropriate.
When they sent their work out for expert review, writing letters of introduction, attaching their articles and sending a small part of themselves out into the unknown – I warned them,

“Don’t be surprised if you don’t hear back.”

But then something amazing happened. Scientists wrote back. Scientists - many who are respected in their field, who are pressed for time, who let reviews for prestigious journals sit on their desk until pinged for the tenth time by the journal editor - these scientists took the time to review articles written by undergraduates struggling to comprehend and communicate their research.

It was frightening.

“I didn’t open the response for a day,” said one student about her “expert review.” Another found a sea of red marks – comments, corrections, and No! Wrong! Wrong again – followed by helpful suggestions and further reading.
I wondered if I’d thrown my students to the wolves. Though I’d commented, edited and corrected as best I could before review, the fact is – I could never claim expertise on the breadth of topics covered by this group of young women. This was the lesson I'd learned. I hadn't planned for that level of expert review - but when the drafts came rolling in, I knew I was over my head. Without reading each and every reference - there was no way I could truly comment on the accuracy of what they'd written.

So was it worth the ego-bruising effort? (And I'm not referring just to the students here.) I had asked my students to write not only for the highest level of review, but also in the end, to put themselves out there in a way that many scientists haven’t dared, communicating a highly technical topic - one which they'd just learned about virtually on their own, to the public and in plain language. 

It’s something that I never felt comfortable with until I was out of the lab. Until I felt I had nothing to lose. But these days it is often necessary for scientists to communicate not just with each other but with the public, and it is my hope that that’s the lesson that sticks.

Maybe the difference between “toxicant” and “toxin” is pedantic. But sometimes you’ve just got to get it right. I think they did.
Check out their articles on the Encyclopedia of Earth:

Tuesday, April 01, 2008

Toxicant Inspired Poetry: Happy April Fools!

I’d like to share a poem written by a student who is no April’s Fool.

Last week I'd asked my students to respond to an Earth Forum posting by Sidney Draggan about the detection of a range of chemicals from personal care products to pharmaceuticals to detergents (all considered indicators of municipal waste) measured in earth worms by scientists from U.S. Geological Survey’s Toxic Substances Hydrology Program and reported in Environmental Science and Technology.

Sidney asked if anyone was surprised.

This was one student's response:

When you have a disgruntling ache,
Ibuprofen’s the thing to take.
If you’re feeling a little blue,
Pop an antidepressant or two.
Your kid’s attention span is shorter than that of a fly?
Stimulant medication is the thing to try.
You see, we’ll cook up a cure for whatever ails you,
And maybe a smattering of things you never knew
We're problems with chemical solutions;
We assure you all your kinks have easy resolutions.
Pharmaceuticals are the way to go
When you get an infection in your big toe
If plaque has clogged your blood’s flow
If your hair refuses to grow
If your insulin has fallen a little low.
And a bazillion other things, you know.

With this present in your mind,
It may not be such a surprising find
That even our worms are taking drugs!
Yes these naughty little bugs
Load up all day long!
But before you begin to think them wrong,
And go about accusing,
You might consider it is not their choosing
To ingest this vile mix of stuff.
You see, oddly enough
We are the ones to blame.

We may nobly aim
With pills to eliminate our daily pain
But it all ends up going down the drain.
Everything we get down with a drink,
Everything we throw down the sink-
Be it detergent or anti-bacterial soap
(It would take ages to enumerate the scope)-
Goes right on to a waste treatment facility.
I hope it does not affect your mind’s tranquility
To hear this is not where they stay,
Some into our drinking water stray!
Others catch a ride on our own waste-
Or “biosolids” if you want to show some taste-
And are applied freely to agricultural fields
So they will have record-breaking yields.
Their life sentence may sound tragic,
But worms are the ones that work the magic-
Turning dung into beautiful soil,
And what do they get for all their toil?
A mouthful of our chemical excess.
I think this is something we should address.
There is simply no good to gain,
When these things enter the food chain.
Against our wishes,
Some find their way into our dishes.
You can imagine this creates
Some concern over the toxicity of what’s in our plates
Maybe the effects of these chemicals are not so bad,

Or maybe we’ll be driven raving mad.
But the truth is it’ll take years to unveil
The effects these multiple low-level exposures entail.
If we one day find
That deeply entwined
Are the causes of our health woes
And our daily chemical dose

I can assure you of this:
There is guaranteed eternal bliss
For the one who finds an antidote
Clarity Guerra

If you'd like to pass this around, please remember to credit Clarity!