Following up on the story about house dust representing a potential source for exposures to persistent chemicals, here is an article care of Environmental Health News that examines the relationship between occurrences of non-Hodgkin’s lymphoma and organochlorine compounds in house dust. The paper (abstract available free) was published this month in Epidemiology.
The authors observe that the incidence of non-Hodgkin’s lymphoma has increased over time (a display of the trend can be found here). A depressed immune system is a risk factor for NHL, and potential effects of PCBs on the immune system is a concern for human health.
The study examined the relationship between excess risk of NHL with indoor exposure to PCBs and DDE in house dust. A trend of increased risk with increased PCBs concentrations was observed, though less so with DDE. The PCB congeners reported in the abstract are judged by EPA to be of “highest concern” because of abundance in the environment, elevated toxicity or inducers of liver function enzymes that activate the toxicity of other xenobiotics.
It’s probably not a strong association, but it is important to keep in mind that these aren’t the only toxic substances, not to mention allergens, with a potential exposure pathway from household dust. More aggressive cleaning is identified as a method to reduce exposure to allergens in dust that trigger asthma attacks. Would it also reduce chemical exposures?
Jorn Barger’s wonderful Robot Wisdom Weblog recently returned (after having gone mysteriously missing for over a year). From it, I’ve linked to a great article by Edward Tufte about how the findings of primary studies gradually lose their power and meaning, when they become repackaged and redistributed by secondary organizations (journalists, public relations firms, think tanks, nongovernmental organizations, governmental agencies, and on and on – see the posts from the previous couple of days):
In repackagings, a persistent rage to conclude denies the complexities, ambiguities and uncertainties of the primary evidence. A substantial selection bias also operates: news wins out over olds, as recency of evidence decides relevance of evidence.
You must see the original to get the subtext behind the phrase “rage to conclude”, which is a wonderful quote from Flaubert.
According to Tufte, secondary organizations filter and inevitably corrupt the evidence-based findings in a primary report, as they summarize, simplify, synthesize and spin the material to suit their particular needs. While not mentioned, I’m certain that blogs would also fall into this category. Readers continually need to ask themselves if what they are getting from any source truly constitutes information. A definition of information that I have found useful is in James Q. Wilson’s book Bureaucracy:
. . . a full, accurate, and properly nuanced body of knowledge about important matters. . . .
Paraphrasing Wilson, often what we get instead is:
. . . a torrent of incomplete facts, opinions, guesses and self-serving statements about distant events.
Tufte says that consumers of evidence should stay reasonably close to primary sources and to secondary reporters and synthesizers who provide unbiased interpretations (note that in practice this could be a bit difficult, because it requires taking the time to compare original source and secondary compilation, and the original source might be technical and difficult to understand – time and ease of understanding being two reasons for turning to secondary sources). Signs of an untrustworthy source are denial of access to primary evidence or repackaged reports that always support a party line.
I get the sense that Tufte feels not being scrupulously intellectually honest in how one writes, describes or summarizes another’s work is inherently corrupting. Using examples of corporate communications and government intelligence agencies, he notes that in distorting and spinning evidence to others, we may start to do something worse – lying to ourselves.
The Washington Post reports that levels of exposure to lead and metabolites from second-hand smoke have decreased, and quotes the CDC director as saying “[t]hese data help relieve worry and concern”. The Post however fails to cite the other conclusion about lead, that children of black and Mexican-American families, who are lower in the socio-economic spectrum, and live in urban housing constructed before 1950, are showing no decline in blood-lead levels.
Other newspapers choose to focus on the same message as the Post, which is “exposures are decreasing”. The LA Times chooses to focus on the other side of the message, that exposures are widespread with unknown health significance. The STATS web site at George Mason University, which “monitors the media to expose the abuse of science and statistics before people are misled and public policy is distorted,” (sort of an ACSH in academic garb) beats up the LA Times for distorting the story from CDC’s report, significantly without saying a word about distortions of the Washington Post kind. STATS then uses the CDC report to take a sideswipe at this study evaluating the possibility that phthalate exposures could result in alteration of sex ratios in humans; an object lesson of why we don’t put statisticians in charge of evaluating environmental risks to human health – alterations in sex ratios in response to environmental exposures is a matter warranting further examination.
The most sensible thing said in the press about the CDC’s report, quoted here from the LA Times article is:
"The report in general shows that people — kids and adults — are exposed to things that aren't intended to be in their body," said Dr. Jerome A. Paulson, an associate professor of pediatrics at the George Washington University School of Medicine and Health Sciences who specializes in children's environmental health. "In and of itself, that is a concern. Whether it's harmful or not we can't tell from this particular study."
This is why they are called “xenobiotics”.
With the different interests spinning the results to fit their needs (it’s nothing to worry about/it’s a real problem) and the press having a problem getting an accurate story out, there’s little wonder that this issue is very confusing to many people. There are some reasons for optimism – phasing out lead in gasoline, nonsmoking campaigns, and suspending use of aldrin and dieldrin as insecticides, seem to have resulted in exposure reductions. There are some reasons for concerns still – lead exposures remain elevated in some groups, exposures to phthalates are widespread and are not well understood. And, there are the exposures that CDC program is still getting around to, such as brominated fire retardants.
I’ve taken the stance that if we want to have the nutritional benefits of fish such as salmon, without pollutant exposures or introductions of exotic species, we should try to develop sustainable ways of farming fish. While the following story is more about sea birds, it has implications for other species feeding high on the ocean foodchain.
From BoingBoing, I was alerted to a story about elevated findings of dead birds observed during recent coastal surveys. A suspected cause reported in the Seattle Times is warming of the ocean “apparently caused by a lack of upwelling” that also brings up cold, nutrient-rich deep water that feeds the marine foodchain. (BoingBoing is less circumspect, stating that “[f]or reasons that mystify scientists, ocean temperatures are rising, which is killing off the plankton. As a result, animals higher on the food chain are facing mass starvation.”)
I don’t think either rendition gets the story entirely right – actually, what is thought to be the case is that warming of the ocean from climate changes promotes stratification in the water column, suppressing upwelling. While increased surface winds can mitigate this effect, if the winds aren’t sufficient, then the upwelling doesn’t occur. This stratification has coincided with poor habitat for Pacific Northwest salmon, herring, anchovies and smelt, which I suppose would eventually have an impact on the bird populations
None of the stories about this event have shown the data, so here they are. What seems to have sparked all of the interest is the data from the second quarter of 2005, which show a noticeable increase in the number of dead birds across all of the beaches surveyed.
From the perspective of this blog, the birds are just a symptom – this occurrence represents another reason why it might not be the best idea to rely on wild fish to meet dietary needs. Recall that fish consumption is recommended to maintain adequate intake of omega-3-fatty acids that promote cardiac health. However, fish consumption, particularly farmed fish, contributes to exposure to persistent organic pollutants such as dioxins. Consumption of wild fish is associated with lower dioxin exposures, and the recommendation has been made that people favor consumption of wild fish. However, speaking for salmon, with all of the existing pressures (streamflow modifications from dams and agricultural water use, habitat loss, climate change impacts) maybe reducing fishing pressure would be a good idea to assist recovery of natural populations. More information on climate change and impacts to PNW salmon populations can be found in the proceedings of this recent symposium.
Fish farming has its problems, but are those solvable through application of best practices? More on that later.
Just some confirmation of something I posted last month – liquid fuels from biomass such as corn consume more in terms of energy and material inputs than they produce in fuel value. This comes from no less of an authority than David Pimental of Cornell.
Risk Contribution Theory in Lead Exposure Litigation
I found this to be an interesting piece of information because of the potential for widespread impacts with litigation for a wide range of common substances suspected of developmental, behavioral or neurological adverse effects. It has also been interesting in seeing how environmental health issues intersect with the law, as people grapple with finding remedies for problems that, by the nature of epidemiological and environmental health investigative methods, cannot be attributed to specific causes. It’s also been an interesting exercise in reading legal opinions, and trying to navigate around the technicalities to clearly understand and express what they are saying.
The Wisconsin Supreme Court ruled that a 15-year-old boy can sue manufacturers of lead-based paints for his neurological disorders, even though he can’t prove which company manufactured the pigments that he was exposed to. He alleges that the exposures occurred in two houses, built in 1900 and 1905, where he lived as a young child. While he has settled with the owners of the houses, he is still pursuing damages from the manufacturers under the “risk contribution theory of liability”, first adopted in diethylstilbestrol litigation many years ago. In the DES case (Collins vs. Eli Lilly), the plaintiff had vaginal cancer related to her mother taking DES during pregnancy. However, in order to pursue the claim of negligence on the part of the manufacturer, she had to be able to be able to identify the manufacturer or seller of the specific pills taken by her mother, which she was unable to do. In Collins, the court relaxed the plaintiff’s burden to identify the specific manufacturer under the “risk contribution” theory of liability.
Under this theory, the diethylstilbestrol plaintiff needed only to show that a "defendant drug company produced or marketed the type of [diethylstilbestrol] taken by [her] mother" in connection with her claims for both negligence and strict-liability.
Note that the court making the DES ruling didn’t seem to need convincing that the DES exposure was the cause of the plaintiff’s vaginal cancer,
Faced with the certainty that the woman injured by her mother's use of diethylstilbestrol would have no "remedy at law for her injuries" unless the traditional identification-rule was modified. . . Collins relied on article I, section 9 of the Wisconsin Constitution ("Every person is entitled to a certain remedy in the laws for all injuries, or wrongs which he may receive in his person, property, or character."), and decided to "fashion[] a method of recovery for the [diethylstilbestrol] case which will deviate from traditional notions of tort law."
The appeals court declined to apply the risk contribution theory to the Thomas case, however, the case was heard in the Wisconsin Supreme Court. The background for the Supreme Court’s decision was that the companies manufacturing lead-based paints had known about the risks for many years, and had conspired to conceal them. More about that topic can be found in Rosner’s and Markowitz’s book Deceit and Denial, which is discussed further here. The New England Journal of Medicine’s review of Deceit and Denial provides a good introduction to the lead issues addressed in the book.
The legal opinions for this case also mention the “conspiracy” and “enterprise liability” theories – I plan to post on those later.
What’s interesting about this lawsuit is there are several other classes of toxic substances in commerce, where it might be possible that the “risk contribution” theory could apply. These include PBDEs and other fire retardants, PFOA, phthalates and PCBs (not too sure how this would apply to dioxins and furans or mercury, though). If the weight of evidence of adverse human health effects for these substances rises to the level of serious consideration in the courts, we could be hearing more about risk contribution in the future.
Originally posted July 3rd, lost by Blogger on July 4th.
By now most everyone has heard the controversy about publishing a study modeling the potential public health impact of a bioterrorism event involving contaminating the milk supply with botulinum toxin. The Department of Health and Human Services had asked the Proceedings of the National Academy of Sciences to delay publication of the paper, because it highlighted vulnerabilities to the dairy industry that the government thought might be useful to terrorists. Thankfully the Proceedings elected to publish the paper, which was based on publicly accessible information and contained several recommendations for increasing the security of the food supply.
While food producers in general are probably unwilling to have the safety of food highlighted in this manner, opening these issues up for public debate is a critical part of homeland security. Sadly, the government’s response to the terrorist threat to critical infrastructure has been to restrict public access to information, thus taking away the most effective tool for enforcing security in critical infrastructure (most of which is privately held) – public pressure.
The inattention to safety relative to the magnitude of the problem, along with penchant for secrecy, is the same whether we’re talking about the food supply or chemical manufacturing. With regard to chemical plant security, we’re still seeing conclusions such as this being published (in February 2005), more than three years after 9-11.
In contrast to the low probability of chemical terrorism, possible consequences for human health and the environment from such an event could be severe. Moreover, limited evidence suggests that chemical facilities may be “soft targets,” lacking in adequate safeguards against criminal and terrorist attacks.
Voluntary industry guidelines, originally thought to be the key to maintaining chemical security are no longer considered sufficient to keep the nation’s chemical plants safe from potential terrorist attack, according to the Department of Homeland Security. Regulations and enforceable performance standards are now seen as necessary. A recent report published by the Center for American Progress further highlights this issue:
More than three years after the attacks of 9/11, our nation's chemical manufacturing and transport facilities remain extremely vulnerable to terrorism. Voluntary approaches have failed to accomplish what our national security requires, leaving us with no choice: The administration must put aside its ideological resistance to federal action, overcome private sector inertia, force a change in the status quo, and put into place new safety measures. In this, the first in a series of papers on protecting our critical infrastructure, the Center for American Progress sets out a 12-month action plan to reduce the risks posed by the nation’s chemical facilities.
There might be more progress in these efforts if the public were more aware of the vulnerabilities and their consequences. Whether it realizes it or not, the government has a vested interest in public debate about how our society can be attacked, and what should be done about it. This represents the best way to bring pressure to both private industry (which controls most of the critical infrastructure such as chemical manufacturing and food processing) and government agencies to take protective measures.
More resources on chemical safety from OMBWatch can be found here.
On this Fourth of July, Paul Krugman informs us about an advocacy group, the Center forConsumer Freedom, which tells us that “food liberty -- just one of the many important areas of personal choice fought for by the original American patriots -- is constantly under attack.” The Center for Consumer Freedom is funded by a “coalition of restaurants, food companies, and consumers working together to promote personal responsibility and protect consumer choices”. According to Krugman, this includes Coca-Cola, Wendy’s and Tyson.
So now some people will say anything to justify eating whatever crap pleases them never mind the consequences, or justify the profits made selling the crap, including branding anyone speaking out about it as unpatriotic. Would it be un-American of me to remind the Center for Consumer Freedom that it was Ben Franklin who said:
