Precaution: much better than postcaution

The precautionary principle states that, when there’s scientific uncertainty about whether something could cause serious or irreversible damage to the environment, you should err on the side of caution.

Think of substances like asbestos and DDT, and how things could have turned out differently if we’d responded cautiously to early indications of danger.

Or consider more current threats like climate change and introduced species, or future issues like genetically modified organisms and nanotechnology, as discussed in the recent review of the Australian Environment Protection and Biodiversity Conservation Act 1999 by Dr Allan Hawke (see the Hawke review final report, especially Chapter 6: Current and emerging threats).

Nanotechnology is an interesting one, with both exciting potential and uncertainty about the possible dangers, as pointed out by no less august bodies than the United Kingdom’s Royal Society and Royal Academy of Engineering.

A commonly-used example of the possible problems is that of socks. Specifically, socks treated with silver nanoparticles to kill bacteria and prevent foot odour.

 Nano-silver socks with foot support and half cushion, from the Beijing Kuailu Knitting Co., Ltd.
Nano-silver socks from the Beijing Kuailu Knitting Co., Ltd.

This is not to deny that smelly socks aren’t themselves a major threat to our well-being, and possibly world peace as well. But although killing bacteria might sound like a good idea, there are also plenty of good bacteria in the world, such as those in our intestines and in sewage treatment plants. What happens when we wash our socks and the silver nanoparticles escape into waste water and the environment?

Recently, investigators from the United States Environment Protection Agency discovered that silver nanoparticles could indeed be found in sewage treatment plants (Potera C 2010, “Transformation of silver nanoparticles in sewage sludge”, Environmental Health Perspectives, 118:a526-a527). It’s not known how toxic were the silver sulfides they found, but the precautionary principle tells us it’s better to be safe than sorry.

So far this all sounds like common sense, but as the Hawke review found, there isn’t actually anyone looking out for new threats to the environment, and there isn’t much in the way of a mechanism to regulate threats if they’re discovered.

As a result, they recommended a change in the Act to create periodic reports to identify emerging threats and provide policy options, and the formation of a Unit or Taskforce “devoted to foresighting to identify and guide management responses to emerging threats.” Which you’d have to agree is pretty much essential if you want to rely on anything other than hindsight.

For more on the precautionary principle, particularly in the context of nanotechnology, see the Friends of the Earth (


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s