Thread by @Nathan_Donley

I need to do something to stop stewing over the supreme court, so I'm just going to tell the story of how the endocrine disrupting pesticide #atrazine went from being on its last leg in the U.S. to being rubberstamped for the foreseeable future

biologicaldiversity.org/w/news/press-r…

No one is going to tell this story because there are a thousand other scandals happening right now and because it's super wonky.

Unlike a lot of the big environmental rollbacks that will hopefully be reversed after the election, this will likely fall under the radar

In 2016, under the Obama admin., EPA put out a devastating eco risk assessment of atrazine basically saying that its use has to be scaled back dramatically or there will be serious environmental consequences

In 50 years, this was the most hard-lined position EPA had taken

To be sure, the pesticide office would never ban atrazine - they are too captured by industry - but things looked different for the first time. And young children and vulnerable animals had hope

Then came the human health risk assessment in 2018. New admin., very different analysis.

EPA uses what are called "safety factors" to account for the inherent uncertainty in converting safety thresholds from mouse studies to what they would be for humans

These safety factors essentially lower the dose of atrazine that the EPA considers safe. The bigger the safety factor, the lower the safe dose. Super simple

For developmental toxins like atrazine, EPA typically applies a 1000-fold safety factor to take into account differences between mice and humans, chemical sensitivity differences between individuals, and the fact that young children are more vulnerable to effects than adults

In 2018, EPA decided to reduce the 1000-fold safety factor to 30-fold. It completely erased the 10-fold protection factor for small children and they used a model developed by Syngenta (the maker of atrazine) to justify reducing the interspecies safety factor by 3-fold

So instead of reducing the toxic dose in lab rats by 1000-fold to ensure the most vulnerable among us were protected - as it did in 2006 - it's now reduced only 30-fold

This was the first time in 50 years that protections had ever been erased for atrazine

This served an obvious purpose. A 1000-fold safety factor would have ensured that use of atrazine on grass and turf could no longer be approved. Agricultural applications would likewise have to be reduced considerably

But the new 30-fold SF lets things slide right through

And that great eco risk assessment done in 2016? Completely ignored and relegated to nothing more than an anomaly.

Despite recommending that allowable levels of atrazine in water be reduced 3-fold, the current approval allows it to increase by 50%

EPA didn't make a big, sweeping move. It was death by 1000-cuts in complex risk assessments that no one reads

These types of environmental rollbacks are a dime a dozen and in some ways are the most dangerous

They happen under the radar with no public scrutiny

Let's change that

Atrazine was one of the few pesticides that EPA had actually applied a mandated 10x safety factor for children after the Food Quality Protection Act was passed

And like that. Poof. It's gone

Retweet if you think children are more important than Big Corn
biologicaldiversity.org/w/news/press-r…