Picardin found to be lethal to some amphibians

[James Marco]

In a new study, researchers have found that picardin is lethal in low doses when washed off your skin in a stream or pond. Here is a link for easy reading: https://www.adirondackalmanack.com/2018/11/study-widely-used-repellent-lethal-for-salamanders.html?utm_source=Adirondack+Almanack&utm_campaign=324912f3c4-Almanac_RSS_EMAIL&utm_medium=email&utm_term=0_b49eb0d11b-324912f3c4-24936693&mc_cid=324912f3c4&mc_eid=821e343f00

[Rex Sanders]

That newspaper article obviously was based entirely on a press release, which was based on a journal article. I’ve learned to dig deeper in such cases – start by skipping directly to the journal article.

Yep, there are problems.

• Pretty small sample sizes. At each of three doses they tested just 9 salamanders.
• Their own charts show no relationship between dose and death rates. Not a good sign.
• They didn’t test picaridin “when washed off your skin in a stream or pond.” They tested controlled doses in a lab.
• The press release demonizes “picaridin”, yet what they tested was a repellent with 80% other stuff. We’ve seen many times that “other stuff” can be more toxic than the active ingredient.

In fact, despite alarming language in the press release about how the situation could be worse in the real world, their first recommendation under further research states the opposite, and hints at the “other stuff” problem:

First, controlled outdoor mesocosm studies would inform whether the high mortality rates we observed in a laboratory setting are also observed under semi-natural conditions that may degrade, adsorb or neutralize lethal compounds present in formulations of commercially available picaridin repellents.

My conclusion: It’s pretty certain that Sawyer Premium Insect Repellent kills salamanders in a lab. Is it picaridin? Don’t know. Does that apply to the real world? Don’t know.

I do know the press release is full of hype.

— Rex

[James Marco]

Yup, preliminary studies are never definitive. just something that might be interesting…

[Arthur]

Rex. I like the way you think. I have subscribed to the New England Journal Medicine for almost 40 years. Get the journal on Wed. Read the wire service popular press reports on Thursday (New York Time, Washington Post, etc). Now I have the original information in one hand and the popular press tales in the other. Some weeks, the popular guys are so totally off base it is hard to tell which article they are even referring too. This lack of understanding has not gotten any better in 40 year. But now, the difference is that the twisted version is on the internet, so it is TRUE.

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