Sunday, June 02, 2013

Stuff we need to know - Haber's Law and neonicotinoids

Get your head round time dependent cumulative toxicity of neonics with Dr Henk Tennekes.  It's stuff we need to know:

The simple story is that the pesticide industry, government regulators and most of the rest, judge the toxicity of an insecticide by how much is needed to kill an insect straight away.  The Median Lethal Dose (LD50) test is, simply put, a measure of how much of the chemical is needed to kill 50% of the creatures it is applied to.  

However, neonicotinoids are cumulative poisons, binding to receptors in nerve cells.  If the insect is exposed to tiny doses, far less than the LD50 dose, but continuously over a long period of time, the poisons will accumulate and eventually kill the creature.

This LD50 test of toxicity carried out by the agro-chemical industry and accepted by government regulators is just not the appropriate measure.  Once time dependent cumulative toxicity is taken into account it becomes obvious that there is no safe dose below which neonics can safely be allowed in the environment.

As an introduction to measures of toxicity one might do worse than reading the Wikipedia pages on Median Lethal Dose and, in this context of neonics, the very important Haber's Law.

Or you might just share my opinion that neonicotinoids are an unnecessary catastrophic disaster in the making and should not be used, at all, ever.  Not even a little bit.


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