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Thanks to Brad Sams at Neowin for the inspiration for the opening par.

How to get your fill of Sciencebase goodness is a post from: Sciencebase Science Blog

Red lenses – US scientists have used MRI to show that apparently the less you use your brain’s frontal lobes, the more you perceive your behaviour through rose-tinted spectacles. They publish details in the February issue of the journal NeuroImage.

Carbon dioxide trap and drop – The reduction of greenhouse gas carbon dioxide to a useful chemical industry feedstock material, carbon monoxide, can be catalysed by a ruthenium-substituted polyoxometalate according to a new study. The work holds the promise of our developing a carbon-neutral energy platform.

Cosmic coronene’s phantom spectral bands – Anomalies in the spectra of an aromatic molecule called coronene could have implications for our understanding of astrochemistry and for making nanotech devices from graphene.

A metal sponge for cleaning up nuclear waste – An inorganic material with an open framework can selectively trap caesium ions, including its 137 isotope, one of the most significant radioactive isotopes left behind after the Chernobyl nuclear reactor fire. Caesium-137 is one of the main residual sources of lethal radiation in the nuclear industry.

Narrow view of photosynthesis – Fluorescence line-narrowing and resonance Raman properties of various chlorophyll molecules have been measured in organic solvents. The work sheds new light on one of life’s most important biochemical processes – photosynthesis – and might one day allow scientists to take another step closer to emulating the reactions to trap solar energy

The long and the long of it – A novel NMR technique has measured the largest distance between two atomic nuclei using NMR, demonstrating that tritium magic angle spinning NMR could be a promising tool for structural applications in the biological and material sciences.

Making carbon dioxide useful is a post from: Sciencebase Science Blog

Compare their feelings about their chances of winning the lottery to succumbing to the toxic effects of their favourite tipple or a disease triggered by dietary whim and they may well respond, that such problems are more likely to happen to “other people”.

It’s part of the human condition we perceive the positives chances as being much more likely to happen to us than the negatives, despite the fact that the odds are usually stacked against us.

The issue of probability and its kissing cousin risk assessment is not one to be taken lightly when we are talking about the effects of pollution, genetically modified crops, the incidence of disease, nanotechnology, the impact of vaccines, and the safety of everything from vehicles to chewable children’s toys. Indeed, there are advocates for taking the precautionary principle for each and every one of these issues and many others. They feel that no matter how long the odds, avoidance, abstinence and absolute bans are the only way forward until “science” can give us a yes or no answer regarding safety in all its manifestations.

So, we hear that nanotechnology should be banned until it has been proven to be safe, or that we should avoid vaccinating our children because there is a risk of some obscure connection between a suspected contaminant or additive and an illness that may or may not happen. This is always irrespective of the risks associated with not moving forward with advances such as nanotechnology and the commonly lethal effects of the disease against which one would hope to vaccinate.

Trouble is, in the Popperian philosophy of science, this most human endeavour cannot provide a yes or a no answer to any question involving experimental data. It can only ever offer long or short odds. Unfortunately, most people outside science, and quite a few of them within, are not keen on establishing public policy, health and safety rules, and other agendas on such a basis. This has led to politicians overriding the strong advice of their retained experts in a wide range of fields in recent years and the lambasting of those experts when the rare problem does arrive.

Terje Aven of the University of Stavanger in Norway, a Professor of Risk Analysis and Risk Management, is developing a new approach to quantitative risk assessment that would be applicable to a wide range of industries and circumstances and is based on a new scientific framework. The framework is underpinned by knowledge and probabilities based on hard data, expert judgments and modeling. An important feature of the framework is identification and descriptions of uncertainties that extend beyond the probability numbers.

Fundamentally, the framework will never provide the definitive, yes-no answers that some people crave when discussing risk. However, it does offer a foundation for sensible dialogue that could help society balance the risk-benefit equation for a whole range of issues.

Terje Aven (2009). A new scientific framework for quantitative risk assessments Int. J. Business Continuity and Risk Management, 1 (1), 67-77

Science based risk assessment is a post from: Sciencebase Science Blog

In microfluidics, a droplet of acid finds its way out of a maze, while an accidental mineral could become the material of choice for magnetic tunnel junctions. In the zone between chemistry and physics, German researchers have discovered a new way to produce free electrons, which might help explain biological radiation damage, and in health PFOA emerges as a risk factor for thyroid problems.

Finally, more than half a million small molecules have found a home in Cambridge, UK thanks to a grant from the Wellcome Trust.

Find out more in this week’s Alchemist on ChemWeb.com

Early Valentine’s Alchemist is a post from: Sciencebase Science Blog

Nevertheless, Orzel uses humour and clarity to explain the ins and outs of black holes and quantum entanglement to his dog and along the way teaches us some of the fundamentals the vexed the greats, among them Bohr and Einstein.

Meanwhile, Sean Carroll takes us on a journey from Eternity to Here. This book offers a provocatively different view of time, that most elusive and fundamental of notions. Carroll points out that Einstein treated time as simply a fourth dimension in the universe a perpendicular component of spacetime. However, that assumption ignores the fact that unlike the x, y, z of space, t has a direction, heading from the Big Bang to now and into the future. Could that fact be explained by looking at what happened before the Big Bang?

Inventors and Inventions is a big book full of big ideas. It basically does what it says on the tin, in classic style. There are nice big pictures of fountain pen nibs, universal joints, lightbulbs, and band aids, all tied up with the context of their history and the lives of their inventors. In this age of Wikis and 140-character limits, it’s nice to know that someone can still produce a traditional non-fiction book of substance.

Also landing on the Sciencebase desk this month, one of those idiots books I mentioned earlier. This time it’s The complete idiot’s guide to phobias. As the name would suggest, this is a tour of an area of psychology of which many of us know a little, but few understand a lot (Psychologists aside, that is). The term phobia is too big an umbrella for a whole spectrum of mental conditions from the mild panic that some people suffer on seeing a truly harmless spider in the bath to the debilitating effects of anxiety disorders fixated on social interactions, say. Gregory Korgeski gives us a full-colour view of this spectrum.

Finally, here’s a title that will undoubtedly get the so-called intelligent design crowd What Darwin Got Wrong chomping at the bit and baying for evolutionary blood. But, it shouldn’t. This is not a book about god nor intelligent design (creationism), the authors assert. Instead, they claim to have found a fatal flaw in the science of Darwin’s approach to natural selection that should provide biology with a new perspective on evolution.

Jerry Fodor and Massimo Piattelli-Palmarini suggest that the evidence does not point to evolution taking place through a single survival of the fittest mechanism, rather that there are countless biological causes that totally eradicate “intention” from biology and evolution. If the ID crowd were perturbed by Darwin, then they should be very scared of the new guys as they remove the last vestiges of metaphysical guidance from our creation. There are no gods, no mother nature, and no grand design.

How to teach physics to your dog is a post from: Sciencebase Science Blog

The keen-eyed regulars among you will have spotted the occasional “green-tick” icon next the references I cite in my blog posts here and on the sibling sites Sciencetext and SciScoop, which flags them for the Research Blogging system.

Gratifyingly, Dr SkySkull, an editor on the RB blog frequently highlights my stuff in the Editor’s Selection section. Here’s a bunch of the most recent that drew their attention:

Balancing anonymity, privacy, and security. Having my pseudonym is fun and convenient, but how do my needs for privacy balance against the overall security of the internet and society?  David at Sciencetext gives a nice summary of the issues debated.

Fall Colors and Autumn Leaves. Before you go out to view the fall foliage this year, take a look at this post by David Bradley at SciScoop Science Forum!  Researchers are seeking an explanation as to why leaves in the U.S. mainly turn red, while in Europe they mainly turn yellow.

50 million chemicals and counting. Finally, David Bradley at sciencebase announces an unusual milestone: the Chemical Abstracts Service has logged its 50 millionth unique chemical, a mere 9 months after the 40 millionth.  But is this real progress, or an artifact of the reporting process?

We must stamp our ecological feet: Returning to Earth and its own delicate ecosystem, David Bradley of Sciencebase looks at research relating to corporate efforts at becoming “green”: are they walking the walk, or just talking the talk?

Unique urine fingerprints. With recent arguments that false DNA evidence can be manufactured in a lab, it is natural to wonder where forensic science can go next. David Bradley at sciencebase describes research that suggests that we all have a unique metabolic fingerprint — which can be detected through our urine!

Chemophobia and risk. Finally, David Bradley at Sciencebase describes a proposal to perform a more comprehensive type of chemical risk assessment, and provides some personal reflections on the subject.

Research Blogging is a post from: Sciencebase Science Blog

Melamine-tainted milk products have been pulled from convenience store shelves in southern China more than a year after hundreds of thousands of children were sickened in a massive milk safety scandal, a government spokeswoman said Monday.

I originally covered this scandal in which melamine was added to dairy products to spoof higher protein levels in baby formula milk and other foods back in 2008. Several thousand babies in China became ill, having suffered acute kidney failure, with several fatalities.

Melamine is an organic compound, a base with chemical formula C₃H₆N₆. Officially it is 1,3,5-triazine-2,4,6-triamine in the IUPAC nomenclature system (CAS #108-78-1). It is has a molecular mass of just over 126, forms a white, crystalline powder, and is only slightly soluble in water. It is used in fire retardants in polymer resins because its high nitrogen content is released as flame-stifling nitrogen gas when the compound is burned or charred.

Indeed, it is this high nitrogen level – 66% nitrogen by mass – in melamine that gives it the analytical characteristics of protein molecules. Melamine can also be described as a trimer of cyanamide, three cyanamide units joined in a ring. It is described as being harmful according to its MSDS sheet: “Harmful if swallowed, inhaled or absorbed through the skin. Chronic exposure may cause cancer or reproductive damage. Eye, skin and respiratory irritant.” Not something you would want in your infant’s milk. However, that said, the toxic dose is rather high, on a par with common table salt with an LD50 of more than 3 grams per kilogram of bodyweight.

The AP report claims that the Chinese authorities had said they would clamp down on on this toxic food fraud, but named among the culprits in the new scandals a company that was allegedly involved first time round and had been under investigation for a year.

Washington Post AP link

Melamine’s on sale again is a post from: Sciencebase Science Blog

Is this problem of heavy metal contamination killing wildlife?

At the moment, we haven’t come across any in situ analysis that provides us with a documented and a direct impact of heavy metal pollution and wildlife to the point of killing them per se in the urban scenario. However, we do have our own series of studies and related research that show an alarming range of heavy metals concentrations – in the lake bed sediments, in the water, in the fresh water fish, and in the aquatic macrophytes – exceeding established limits or guidelines.

So, there is a serious impact on the ecology?

By correlating these findings against the established probable toxic effect levels or the threshold limits for fresh water aquatic life, or against the established drinking water limits and guidelines for human consumption, livestock consumption, and even in irrigation, we can infer that most of our findings are giving a rising indication that heavy metals have indeed severely impacted the overall health of the ecology in the city’s wetlands causing severe harm on the aquatic life.

Are any particular species being affected most?

We have recorded a number of cases involving sudden mass deaths in the fresh water fish population, or a number of incidents where birds, especially migratory species such as Painted Storks and the Pelicans being found dead on the water. We are also alarmed by the dwindling sightings of indigenous water snakes such as the Green or Brown Keelback. The question at the centre of the debate now is not whether animals are dying because of the impact of polluted wetlands, but on what scale do heavy metals inflict harm on the affected aquatic life?

Is this problem of heavy metal contamination affecting people too?

It is absolutely certain that people are being affected, and in many ways. One has to bear in mind that the health impact on human beings comes from a multitude of pollutants, e.g along with heavy metals contamination we also have bacterial, pharmaceutical, and even organic pollution caused by volatile organic compounds, PCBs, etc that end up in the urban wetlands.

How come?

There is no distinction between Bangalore’s storm water drains and the city’s waste water drainage lines for the accounted portion of the sewage system. But we do know what happens! That the ground water is continually contaminated from along its sub-surface flow channels and down to the aquifers. Metals, being persistent pollutants, are found in an empirical abundance. A recent study of the Bangalore urban ground water samples by the State Government reveal significant levels of heavy metal contamination in downstream samples collected from the neighbourhoods of open and bore wells of a nearby largest industrial zone in the city.

Does this prove that people’s health is directly affected by heavy metal contamination?

Skeptics have often highlighted a lack of systematic evidence or a hot link that connects acute or chronic diseases to heavy metals in the city’s population. Yes, this may be true because Bangalore Hospitals or Medical Facilities/Institutions usually do not share their crucial data with public institutions. This is mainly due to the absence of an appropriate body that could collect, analyze and connect the dots. Nevertheless, we do have primary data based on direct interaction between us and a selected sample of people in the study area that underlines our increasing concerns for the deteriorating state of primary health in these affected localities.

What kind of direct data?

Our questionnaire survey of a sample of 1000 respondents distributed in three different geographic locations of the City (North, Central and South Zones) reveals an indirect statistical linkage between a portion of the respondents whose homes were connected to the ground water sources (in addition to the drinking water connection from the Bangalore Water and Sewerage & Supply Board) and an increase in gastrointestinal problems within a family unit over time.

For example, in the Central Zone of Bangalore City, we found that 24% of respondents had alternative access to drinking water apart from the BWSSB supply line. Specifically, almost 15% had their own bore-wells, more than 2% said they had a hand-pump dug well, 6% had open wells and over 1% said they were hiring water tankers for water supply. An interesting account here comes from the fact that 25% of respondents had gastro-intestinal problems in their family. Similar trends were found in the Bangalore South Zone. About 28% of the respondents complained about the rise in gastro-intestinal cases over time in a region where 24% of the surveyed respondents said that they had alternative and ground water sources for drinking water supply.

So what does this tell us of the ecological conditions of the City’s catchment systems?

You would only understand that when you saw a number of Government noticeboards placed along the banks of many lakes of the city warning citizens of the dangers of swimming and fishing inside these dilapidated wetlands. In some cases, the State Government has totally forbidden people from engaging in any type of fishing in those lakes as they are so severely polluted. A good example is in the lake known as the Yellamallappa Lake in north-eastern Bangalore where there is a pharmaceutical plant and a cement-grade magnesium production factory.

What else have you found in Yellamallappa?

Apart from excessive concentrations of heavy metals, we also found microbial pathogens such as E. coli, klebsiella spp, Salmonella spp, and Shigella spp. This combination is lethal and could cause a health catastrophe, albeit in the long run.

This is nothing new though, right?

The signs were already there when we conducted a survey of fishermen and their families residing along the banks of the Yellamallappa Lake in 2008. The study showed that at least 60% of respondents said that they were now forced to visit a doctor twice a month due to what they called their persistent illnesses. 45% of the respondents said they suffered from known intestinal conditions while 35% said they were often taken ill with diarrhoea. Of these, about 10% respondents said their illnesses caused them to suffer from severe vomiting on some occasions after consuming fish from the lake.

Obviously, it is not easy to determine the exact cause of their illnesses. We found out that over half of the surveyed respondents said that they would only visit a doctor in a hospital only if they fell severely sick; 45% said they would rather refer their cases to local pharmacies for an unauthorized prescription.

Are crops being affected too, leading to indirect health problems?

Other recent studies have already shown the level of heavy metals contamination in food crops and vegetables. Moreover, Bangalore lakes are increasingly being turned into illegal garbage dumps. Solid waste, including abandoned electronic waste, hospital waste, and construction waste from Bangalore’s booming real estate and construction industry which is filling any open space found wanting including wetlands. Bangaloreans are being attacked both from the water through solid waste/e-waste leachate percolating into the subterranean reservoirs and from the air through smog pollution, and most dangerously, bio-aerosols!

Leachate is a big problem?

One of our studies in Somasundarpalya Lake located in Bangalore South within the perimeters of the famous “electronic city” shows just how severe a leachate flow can be once it reaches the deltaic inflows of the lake. A comparative study of electrical conductivity underscores the levels of industrial effluent entering the lake as raw discharge laden with heavy metals ions.

If crops are being affected, the presumably livestock too?

Another immediate risk to people’s health is the grazing of livestock on vegetation lying inside the polluted basins. According to the State Government Statistics of 2007-08, Bangalore Urban is home to 159,208 heads of Cattle, 88,136 heads of sheep, 31,449 heads of Goats. Combining these figures with those of animals transported into the city for immediate meat consumption, many of these animals have to be provided with a grazing space for some time and that is where polluted basins come into the picture. Most Shrub species used as fodder such as Ipomoea spp, Eichornia crassipes, Alternanthera spp., Cyperus spp., Typha spp, etc. and different species of grass within the lakes’ shoreline perimeters are susceptible to heavy metal contamination. Plants with excessively absorbed metals may find their way into the ruminants’ bodies. The risks here can be highlighted when the meat of the affected animals ends up on someone’s table.

What can be done about it?

We have always emphasized a shift in policy and management levels, more so than in actual rejuvenation programs – an increased interaction and co-operation among various agencies (state departments concerned with environment, soil, natural resource management, public interest groups, citizen groups, agriculture, forestry, urban planning and development, research institutions, government, policy makers, etc) to enhance protective and restoration measures for Bangalore City lakes. This interaction, we feel, should include planning, environmental education and economics of urban wetlands, and urban watershed management.

Enactment of guidelines on physical restoration measures must be initiated. Without Government backed guidelines, we cannot move an inch towards a sustainable and real solution. Formation of Lake Management Guidelines, we believe, will also necessitate an immediate need to create a database on the wetland types, morphological, hydrological and biodiversity data, surrounding land use, hydrogeology, surface water quality, and socioeconomic dependence. We must converge here for a holistic, integrated, but also implementable approach.

So, what would you specifically like to see implemented?

We have called for the following:

1. Declaration of all urban wetlands as Biodiversity Hotspots through a Government Notification.
2. Rejuvenation of lakes should be done on a case-by-case basis. Not all lakes are alike and so it is wrong to view all lakes through a single lens of destructive engineering techniques.
3. Before any lake be taken up for rejuvenation, a complete Environmental Assessment (EA) Report of the current Environmental Status of the wetland should be carefully prepared and impact assessment carried out separately from a Detailed Project Report (DPR). The EA report should be produced before the special EIA environmental committee of the Government of Karnataka for analysis of the wetland system for screening, scoping and authorization. Public participation here should be encouraged and mandated before any agency takes up rejuvenation.
4. Wetlands should be protected from development zones. A buffer zone must be established between the wetlands borderline and a development zone. Even the channels that link up lakes should be protected and shielded from daily discharge of untreated sewage. We have to re-open the books of history for environmental planning and how the past municipal masters used to emphasize on a demarcation of line between a natural heritage zone and a human development rim.
5. Rejuvenation of lakes is not just an engineering matter but also equally a case of ecological conservation. It is not understood why is it that until today, most of the rejuvenation programs do not take into account the opinions of wetland ecologists. Most of the time, DPRs or the so-called Detailed Project Reports are made and submitted by civil engineers who give little preference to the ecological aspect of a wetland apart for an abstract view only. Here, a question arises: Do we rejuvenate a “Lake” or just a water “Tank”? and what are the priorities? Is it only rain water harvesting, or beatification, or structural reformation? Or also the need to maintain the wetland ecosystem and its existing life forms by maintaining the natural life of both flora and fauna? This is where most cases of remediation go wrong!
6. Desiltation may be the necessary way of removing contaminated sediments of the lake’s floor. But this method should be applied only in cases where it is deemed very necessary to do that on lakes which are gravely contaminated or ecologically speaking – dead lakes. This is because desiltation contains a grave risk of exacerbating hydrological imbalances between the surface water basin and the ground water table. Sediments on a lake’s floor play an important part as a hydrological filter and valve that manages the local surface and sub-surface water cycle. If this particular sediment layer is disturbed or physically disrupted it can lead to “perforations” – which means that the lake basin will not be able to sustain its original full tank capacity as water will uncontrollably perforate its way directly to the sub-surface layers.

Aboud S. Jumbe, & N. Nandini (2009). Heavy Metals Analysis and Sediment Quality Values in Urban Lakes American Journal of Environmental Sciences, 5 (6), 678-687

Indian urban wetland heavy metal is a post from: Sciencebase Science Blog

One example was a recent paper on Alda-1, the simplified name for N-(1,3-benzodioxol-5-ylmethyl)-2,6-dichlorobenzamide, a small organic molecule that activates the enzyme ALDH2 (aldehyde dehydrogenase 2). ALDH2 is involved in metabolising the aldehyde byproducts of other substances in the body particularly alcohol.

In September 2008, Alda-1 was touted by the media as a “new drug hope for controlling heart damage“. By activating ALDH2 it was suggested that those people who have an inactive form of that enzyme (some 40% of East Asians and people of East Asian descent) could be treated with the compound to preclude the cardiotoxicity of aldehydes formed when they drink alcohol.

More recently, the same researchers involved in the 2008 study, Thomas Hurley of the University School of Medicine in Indianapolis and Daria Mochly-Rosen, of Stanford University School of Medicine, and colleagues, have published a crystallographic study showing more details of how Alda-1 works to activate ALDH2. You can read my write-up on this work today in the latest issue of the X-ray ezine on SpectroscopyNOW.com.

However, press releases are notoriously hopeful about the actual use to which a piece of biomedical research might be put so I asked Hurley for some additional insight into the likely fortunes of Alda-1.

“Alda-1 is not ready for human trials, nor is it ever likely to be,” he told me. “Its potency is relatively low for an effective in vivo agent, especially when one accounts for its solubility.”

The compound is, as those in pharma research will have realised from the off, simply a lead compound. A compound that researchers will use as the starting point for novel and potentially more efficacious and more soluble compounds, analogues, that would be designed for testing and clinical trials.

“We have much work to do on this before clinical trials can even start to evaluate whether this is an effective strategy in vivo,” conceded Hurley, “I doubt there will anything ready for clinical application for 7-10 years, unless we get really lucky here in the next year with our analogue design and testing,” he adds.

One thing that the original media attention did get right is that Alda-1 might eventually lead to a primary clinical application in the area of cardioprotective effects. This would be rather than it being developed as a drug to allow East Asian drinkers with the ALDH2 mutation to imbibe more alcohol than their flush response, nausea, and palpitations would normally allow them.

“Its use as an activator for alcohol metabolism will, hopefully, be regulated,” Hurley told me, “There are broad ethical issues associated with an application toward reducing alcohol intolerance in the East Asian population or individuals of East Asian descent.”

He points out that pescribing a drug descended from Alda-1 to activate mutant ALDH2 would be like curing a lifestyle issue (alcohol intolerance) and replacing it with an increased risk for a devastating disease – alcoholism. “Currently, there is relatively low risk of alcohol abuse or alcoholism in those individuals who are intolerant to ethanol consumption, so ‘curing’ the intolerance is very likely to lead to an increase in the prevalence of these devastating diseases in these low risk populations,” Hurley added.

Once a drug developed for the cardioprotective benefits emerges on to the market, however, you can bet your last Yen that a blackmarket will quickly emerge where there are large populations of East Asians, for a pill that would allow otherwise lightweight drinkers to put themselves under the table without the flushing, nausea and palpitations.

Perez-Miller, S., Younus, H., Vanam, R., Chen, C., Mochly-Rosen, D., & Hurley, T. (2010). Alda-1 is an agonist and chemical chaperone for the common human aldehyde dehydrogenase 2 variant Nature Structural & Molecular Biology DOI: 10.1038/nsmb.1737

Alcoholic drug discovery truths is a post from: Sciencebase Science Blog

On at least one occasion, however, I’ve been thwarted in my efforts to provide just such a balanced point of view the issues surrounding chemical safety. Once it was a blinkered features editor on a well-known popular science magazine who simply refused to see past the word “manmade” and had already decided that if the product being discussed wasn’t derived from an extract of hemp or some other natural material and squeezed out by native bushpeople or some such nonsense then it didn’t deserve a mention in the hallowed pages of the magazine.

As a science chemistry is more than wonderful, it not only sates the inquisitive and repeatedly throws up new puzzles, it also provides us with the materials with which we have built the modern world. As with any human endeavour there is, of course, a price to pay. Many of the essential ingredients of the industrial processes on which our standard of living depends are toxic. There is no way to avoid that issue. Volatile organic compounds are a case in point and several of the most toxic are now banned substances on health and environmental grounds.

Toxicity, however, is about exposure and dose, not about blanket bans. That said, it is sometimes necessary to take a more holistic view of the potential impact of the chemical cocktails with which we surround ourselves in the workplace and in the home. Multiple-chemical sensitivity was a buzz-phrase back in the early 1990s and filled many a column inch in trade magazines such as Chemical & Engineering News (C&EN) and the now-defunct Chemistry in Britain. I’ve still got the pre-PDF “cuttings” mouldering away in a filing cabinet somewhere. But, this syndrome doesn’t seem to feature much in the trade or any other media these days, I suspect its clinical significance like so many other nebulous disorders simply didn’t stand up to close scrutiny.

However, Dimosthenis Sarigiannis and colleagues at the European Commission – Joint Research Centre, at the Institute for Health and Consumer Protection, in Ispra, Italy, seem keen to resurrect the notion that mixtures of chemicals are somehow more worrying than a single chemical acting alone.

Writing in the International Journal of Risk Assessment and Management, they assert how current risk assessments address compounds individually whereas real-life human exposure is to mixtures of chemicals present in the environment, the workplace, or consumer products. They suggest that a more connected approach to chemical risk assessment is needed.

Such an approach would combine information from environmental fate analysis, epidemiological data and toxicokinetic models to help us estimate internal exposure. This information might also be coupled to gene expression profiles to provide a signature of exposure to whole classes of toxic compounds so that we might derive a biologically based dose-response estimate. Such an approach will take into account the non-linear relationship between risk and exposure to mixtures of toxic compounds, the team explains.

The team concedes that any such model of risk-exposure will need a large data set to ensure that its predictions are statistically robust. And, I agree that we need to overhaul risk assessment in light of better understanding of how chemical mixtures affect gene expression, metabolism, and other biological processes. They also explain that a linear, additive approach to mixture toxicology is entirely outmoded given the latest evidence on non-additive effects. Again, I agree. This is not chemophobia this is rational assessment…

Sarigiannis, D., Gotti, A., Reale, G., & Marafante, E. (2009). Reflections on new directions for risk assessment of environmental chemical mixtures International Journal of Risk Assessment and Management, 13 (3/4) DOI: 10.1504/IJRAM.2009.030697

Chemophobia and risk is a post from: Sciencebase Science Blog