Friday, June 20, 2008

Will Nanoregulators avoid the Woulda, Coulda, Shoulda syndrome?

Before heading into nanotoxicology over the next few weeks (the bit that there is), I wanted to add the following tidbits both of which I think reiterate the need for sincere action – in the spirit of avoiding the inevitable shoulda, coulda, woulda, or maybe worse inertia:

1) The U.K. Council for Science and Technology, cautions that unlike in the past government “must cease to rely primarily on responsive mode of funding to fill the knowledge gaps.”

2) In their history of nanotoxicology, Oberdorster, Stone and Donaldson (2007) referring to abundance of national and international meetings producing and associated reports, “…these reports are not followed by appropriate action, thus creating the impression that there may be just too many of these meetings without serious follow-up.”

So as development and production of NP steams ahead of health effects research, for what it’s worth, national and international governments and regulators are wary and eager to track progress related to analysis and evaluation of the health impacts of nanoparticles (NP).

The result is an international consensus on some key issues that should guide future research and regulatory efforts:

1) There are potential differences of NP behavior in both the environment and in biological systems compared with their larger (or smaller) counterparts, and the potential inadequacy of traditional toxicity exposure and testing currently employed to evaluate NP toxicity. (And if you really read this – you note the overuse of potential. Of course there are plenty of synonyms, possible, probable, likely, impending – but the point is, we just don’t know enough to know right now – and so it’s all possible, probable and maybe even likely.)

2) These potential differences include differences in dose metrics, absorption and distribution as a result of size and/or external modifications, mechanisms of toxicity as a result of increased access to cell matrices or generation of reactive oxygen species because of new characteristics such as increased surface area (in addition to many as yet characterized differences.)

3) Many traditional testing and detection methodology may be inappropriately applied to NP. Further, beyond the current understanding of the impacts of natural and combustion-related NP on the lung, and the toxicity of fibers related to occupational exposures (both areas of research which currently lay the foundation for NP toxicology – appropriately or not), there is consensus that data on the impacts of NP (either naturally derived or engineered) in humans and on environmental receptors is insufficient or worse, altogether lacking.

And, on that note, have a nice weekend.

Thursday, June 12, 2008


A while back I posted a few items about nanotoxicology. Back then, I must confess I didn’t know much beyond those few articles. Now that I’ve had some time to really review the nanotoxicology literature here are a few thoughts about the rapidly developing field.

The potential toxicity of nanomaterials or nanoparticles in either human or ecosystems is of concern to researchers, government, non-governmental organizations (NGOs), industry and consumers around the globe. However, even with all of the past experiences with developing and regulating chemicals – even with the knowledge that before new chemicals (or new formulations of old chemicals) blanket the earth we ought to understand their potential impacts – the health and environmental impacts of specific nanoparticles lags far behind nanoparticle technology.

I’ve also learned that although government agencies, research collaboratives and others are working to remedy this situation, the funding available for research on health and environmental effects of nanoparticles, or nanotoxicology, compared with money spent on R&D, is in the millions verses billions spent on development.

But before we despair that once again, the nanokitties have left the residents of Whoville holding the bag, nanotoxicology does have several advantages over other “ancestral” fields of toxicology including:

  • Hindsight revealing flawed strategies of the past which led to inadequate prevention and protection (though this one is quickly slipping away.)
  • The more global economy, where regulations in one country for example may impact development of a product in another (the newer EU requirements under REACH for example) in addition to greater potential for international collaboration may stretch resources beyond those that any one government might be able to contribute alone.
  • Industries wishing to convince us that in addition to the “bottom line,” they really do care about health and the environment have shown some interest, and in some cases taken leadership in the field of nanotoxicology research – or entering partnerships with environmental NGOs (for example Dupont and Environmental Defense).
  • These days, the internet provides a powerful mechanism for rapid distribution of government, NGO and academic reports, providing all stakeholders – even us peons who sit at home, our computers our only source of information - access to emerging data, technology, and publications. It will be interesting to monitor the impact of public oversight of the field as it develops.

Yet despite all of this potential, the “state of the science” on environmental and health effects research today is something of a hodgepodge. But more on that later!

Monday, June 02, 2008

Flush with drugs: a new database for common pharmaceuticals provides insight into surface water contaminantion

A while back I wrote about the “drugs down the drain” program, targeted primarily at those with unused drugs who might decide to tip those bottles of old aspirin, or unused antibiotics. Yes, yes, I know – there should be no such thing since we’re all told to complete the course. But – there have been times when amoxicillin just didn’t cut it. Those times when the kids’ ears still screamed with pain and a visit to the docs office leads to a mid-course correction - a stronger antibiotic– leaving a half-full bottle of the pink stuff in our fridge.

In these cases it’s important to dispose of the stuff properly – so they don’t end up medicating everything downstream. But what about the pain-killers, heart drugs, antidepressants, antibiotics, gastrointestinal aids that we (and here I’m using the royal WE) take daily? What happens to them when we, pardon the expression, pee?

According to a recent review (introducing a new database) by Emily Cooper and others, just published in Science of the Total Environment, “…between 30 and 90% of an administered dose of many pharmaceuticals ingested by humans is excreted in the urine as the active substance…” and “…up to 90% of drug residues may remain in effluent after [sewage] treatment…”

Although the fact that flushed drugs end up in local streams, rivers and estuaries isn’t new to me – these numbers are astounding. Just imagine if we could reclaim all those drugs. Why - in our school district that might just pull us out of the fiscal hell we've been experiencing for the past decade! And aside from all that waste (though it makes you wonder if pharmaceutical companies design them that way,) once they're in the water - they're no longer beneficial, but rather, environmental contaminants.

But wait – the astute reader (perhaps one of my astute students) might say. What about dose? Certainly the stuff gets diluted, certainly the local trout are not exposed to therapeutic doses of valium or Tylenol? Certainly not. But as the authors point out, several studies now show that chronic exposures to low concentrations can adversely impact aquatic organisms. And, don’t forget – that the Tylenol that I might send over to the local treatment plant will mix with my neighbor’s kid’s antibiotics, and the psychotherapeutics of another neighbor and …you get the picture. There’s a little bit of a whole lot of stuff going down all of our drains collectively.

So what to do with a problem so pervasive? Prioritize, prioritize, prioritize. Fortunately Cooper and co-authors introduce a new, fairly user-friendly database called “Pharmaceuticals in the Environment, Information for Assessing Risk” or PEIAR that will allow researchers and others to do just this.

After a quick tour, I found the site easy to navigate, and easy to track back to original sources, and full of useful information. However, since I’ve made a career of avoiding risk assessment I can’t comment on its utility to risk assessors. I’ll leave that to the pros.

Check it out at