Monday, November 8th, 2010
In a forthcoming article in the Proceedings of the National Academy of Sciences, Patric Allard and Monica Colaiácovo use a nemotode (round worm) system to explore how BPA damages genetic processes in animals.
BPA ranks among the highest production volume chemicals with a global annual production scale of ≈4 million metric tons. It is commonly used in the manufacture of several polymers, including polycarbonate and epoxy resins. Thus, BPA is found in a variety of items such as plastic bottles, the lining of both food and beverage cans, and dental sealants. Consistent with its widespread presence, urinary BPA is detected in >90% of the population in the United States. Higher levels of urinary BPA have been correlated with cardiovascular diseases and diabetes and may be associated with an increased risk for miscarriages.
Wednesday, October 13th, 2010
In a fascinating new article in PLOS One (open access), Daniel Nettle asks why we see social gradients in preventative health behaviors:
People of lower socioeconomic position have been found to smoke more, exercise less, have poorer diets, comply less well with therapy, use medical services less, adopt fewer safety measures, ignore health advice more, and be less health-conscious overall, than their more affluent peers. Some of these behaviors can simply be put down to financial constraints, as healthy diets, for example, cost more than unhealthy ones, but socioeconomic gradients are found even where the health behaviors in question would cost nothing, ruling out income differences as the explanation.
Socioeconomic gradients in health behavior are not easily abolished by providing more information. Informational health campaigns tend to lead to greater voluntary behavior change in people of higher socio-economic position, and thus can actually increase socioeconomic inequalities in health, even whilst improving health overall. Thus, we are struck with what we might call the exacerbatory dynamic of poverty: the people in society who face the greatest structural adversity, far from mitigating this by their lifestyles, behave in such ways as to make it worse, even when they are provided with the opportunity to do otherwise.
What are some of the possible explanations for this pattern, and are they sufficient?
Underlying socioeconomic differences in health behavior are differences in attitudinal and psychological variables. People of lower socioeconomic position have been found to be more pessimistic, have stronger beliefs in the influence of chance on health, and give a greater weighting to present over future outcomes, than people of higher socioeconomic position. These explanations seem clear.
However, they immediately raise the deeper question: why should pessimism, belief in chance, and short time perspective be found more in people of low socioeconomic position than those of high socioeconomic position? These deeper questions are at the level which behavioral ecologists call ultimate, as opposed to proximate causation
To develop more of an ultimate explanation, Nettle hypothesized that lower socioeconomic groups are subject to greater hazard or environmental harm or even simply the perception of living a more hazardous life. This, in turn, discourages healthy behavior.
To test this hypothesis, he developed a mathematical/statistical model predicting the probability of dying in a given year, which is a combination of extrinsic risks that people cannot control as well as intrinsic risks that they can control through modified health behavior. Thus, people choosing to take the time to engage healthier opportunities reduce their mortality risk. Now there’s a tradeoff, however, because the more time people choose to undertake healthy behavior, the less time is left over for leisure activities and other life events.
Overall survival is therefore a combination of all of these factors, which can easily be modeled by assuming a range of values for time spent on health vs. other activities to see what kinds of mortality outcomes arise.
Here are the interesting results he found…
Tuesday, June 1st, 2010
Two stories in today’s news:
(1) The Washington Post ran an article on the possible pesticide-child behavior link we examined in a previous post.
(2) CNN also picked up the recent report from the Environmental Working Group (video clip and printed story) on pesticide residues in produce:
The Dirty Dozen (may contain 47-67 pesticides per serving—EWG suggests buying or growing these organically)
The Clean 15 (contain fewer or no pesticides—EWG suggests you can buy these conventionally grown)
The EWG shopper’s guide.
Photo Credit: http://www.flickr.com/photos/maheshkhanna/786837829/
Sunday, May 30th, 2010
Now that hurricane season is upon us, we’re learning this week from forecasters that it’s supposed to be a bad one:
Weather Services International predicted 18 named storms, 10 hurricanes and five intense hurricanes, rated as Category 3 storm with winds of 110-130 mph, or greater.
NBC ran a segment (video clip) asking what impacts hurricanes might have on the oil spill. The clip mentions, among other things, that 2010 Atlantic sea surface temperatures are the warmest on record—not a good omen when it comes to hurricane intensity.
This is, potentially, a very serious situation for the Gulf states. If a Katrina-like storm surge were to push the oil plume onto land, we would be looking at possible oil contamination of all of the affected land areas. Imagine parking your car in your house and opening the oil pan drain plug, letting oil leak onto the floors and out onto your driveway, lawn, and streets. Now do that for every car and home along the Gulf Coast that could be impacted by storm surge where the oil plume is close to shore.
This has to be keeping people at EPA and the Gulf Coast up at night. It could be an environmental pollution disaster the likes of which we have never seen—Marshes, swamps, white-sand beaches, and coastal/vacation communities becoming a giant, oil-soaked, polluted brownfield.
One would think that witnessing this kind of unprecedented environmental disaster, and the potential for worse with the impending hurricane season, would help make the case for the transition to clean energy. Indeed, this week we have seen the oil spill mentioned by President Obama and some members of Congress as motivation for a long-term energy strategy.
Don’t hold your breath.
Even these events—as bad as they appear in real life— can be externalized from the day-to-day lives of most people in unaffected areas. Maybe that will change as this spill gets worse and we face the possibility of oil release for another few months, but right now, there is simply not enough outrage from the public demanding change in Washington, as Bob Herbert alluded to last week. And John Kerry is right, halting drilling on the Gulf Coast isn’t going to happen.
So where does all this leave us in terms of climate change, energy, and oil spills?
I’m pretty pessimistic these days. I’m not sure if anything short of a severe economic energy shock that hits ordinary people hard—similar to what we saw in 2006-2007—will bring us to a tipping point. If the U.S. returns to $4-5/gallon gasoline and home heating oil, we will start seeing environmentalists, security hawks, the energy independence crowd, green jobs advocates, and everyday citizens realign once again. Only then will there be a coalition large and loud enough to force Washington take on the political-economic might of the fossil fuel industry and their lobbyists.
If my guess is right, then we are probably still a few years away from seeing a serious move to clean energy—not until the economic recovery is further along, economies pick up speed, and the demand for oil and oil speculation kick back into high gear, causing oil prices to spike once more. Fortunately, this time around—unlike 2006-2007—we will have better technology, including electric cars, which will help make the leap easier and more sustained (provided that people can afford them).
The Gulf Coast is unfortunately poised to become collateral damage as we wait for more significant economic drivers to make the clean energy transition happen.
I’m lucky to have had the chance to travel along the coast from New Orleans to Tampa in the spring of 2005 before Katrina hit and now this oil spill happened. It’s a beautiful region. For our friends and all of the wildlife living there, let’s just hope this is a mild hurricane season and that most of the oil stays in the deep sea where it will hopefully get removed by hungry bacteria.
Photo credit: http://www.flickr.com/photos/joiseyshowaa/2392156164/
Saturday, May 22nd, 2010
Bob Herbert’s column in today’s Times forces us to look in the mirror not only with regards to the Gulf oil spill but to the political-economic foundation of social and environmental problems in general:
The response of the Obama administration and the general public to this latest outrage at the hands of a giant, politically connected corporation has been embarrassingly tepid. We take our whippings in stride in this country. We behave as though there is nothing we can do about it.
The fact that 11 human beings were killed in the Deepwater Horizon explosion (their bodies never found) has become, at best, an afterthought. BP counts its profits in the billions, and, therefore, it’s important. The 11 men working on the rig were no more important in the current American scheme of things than the oystermen losing their livelihoods along the gulf, or the wildlife doomed to die in an environment fouled by BP’s oil, or the waters that will be left unfit for ordinary families to swim and boat in.
This is the bitter reality of the American present, a period in which big business has cemented an unholy alliance with big government against the interests of ordinary Americans, who, of course, are the great majority of Americans. The great majority of Americans no longer matter.
No one knows how much of BP’s runaway oil will contaminate the gulf coast’s marshes and lakes and bayous and canals, destroying wildlife and fauna — and ruining the hopes and dreams of countless human families. What is known is that whatever oil gets in will be next to impossible to get out. It gets into the soil and the water and the plant life and can’t be scraped off the way you might be able to scrape the oil off of a beach.
It permeates and undermines the ecosystem in much the same way that big corporations have permeated and undermined our political system, with similarly devastating results.
Photo Credit: http://www.flickr.com/photos/chrisjman/3338514389/
Friday, March 19th, 2010
European bee populations are on the decline worldwide. Who cares? These bees are major pollinators of crops and therefore perform, for free, a vital ecological service worth about $U.S. 14 billion per year. Not to mention the many other species of non-crop flowering plants that reproduce with the help of insects like this.
The recent kind of decline is specific—only female worker bees disappear—and has been given the name colony collapse disorder (CCD). Nobody has figured out why this is happening. The potential list of culprits includes mites, viruses, synthetic chemicals, and other factors.
In an article this week in PLoS ONE, Christopher Mullin and colleagues explore further the potential link between pesticides and CCD.1
One third of honey bee colonies in the US were lost during each of the last three winters between ’06-’09. This alarming overwinter along with other losses of this primary pollinator, Apis mellifera L., as well as those of native pollinators, has been documented in North America and Europe. The most recent manifestation of this decline, Colony Collapse Disorder (CCD), has led to a significant collaborative effort involving several land grant universities, Departments of Agriculture and the USDA.
We have found 121 different pesticides and metabolites within 887 wax, pollen, bee and associated hive samples. Almost 60% of the 259 wax and 350 pollen samples contained at least one systemic pesticide, and over 47% had both in-hive acaricides fluvalinate and coumaphos, and chlorothalonil, a widely-used fungicide. In bee pollen were found chlorothalonil at levels up to 99 ppm and the insecticides aldicarb, carbaryl, chlorpyrifos and imidacloprid, fungicides boscalid, captan and myclobutanil, and herbicide pendimethalin at 1 ppm levels. Almost all comb and foundation wax samples (98%) were contaminated with up to 204 and 94 ppm, respectively, of fluvalinate and coumaphos, and lower amounts of amitraz degradates and chlorothalonil, with an average of 6 pesticide detections per sample and a high of 39. There were fewer pesticides found in adults and brood except for those linked with bee kills by permethrin (20 ppm) and fipronil (3.1 ppm).
The 98 pesticides and metabolites detected in mixtures up to 214 ppm in bee pollen alone represents a remarkably high level for toxicants in the brood and adult food of this primary pollinator. This represents over half of the maximum individual pesticide incidences ever reported for apiaries. While exposure to many of these neurotoxicants elicits acute and sublethal reductions in honey bee fitness, the effects of these materials in combinations and their direct association with CCD or declining bee health remains to be determined.
The high frequency of multiple pesticides in bee collected pollen and wax indicates that pesticide interactions need thorough investigation before their roles in decreasing bee health can be either supported or refuted. The large number of studies to date, are limited by being done on mostly one compound at a time, as well as using whole colonies where the timing of contaminated pollen intake and its utilization by the colony are difficult to interpret as a causal relationship. Laboratory studies have clearly indicated sublethal impacts on honey bee learning, immune system functioning, and synergism of insecticide toxicity by fungicides, yet combinations of herbicides with fungicides and insecticides in 3 or more component mixtures have not been studied.
The widespread occurrence of multiple residues, some at toxic levels for single compounds, and the lack of any scientific literature on the biological consequences of combinations of pesticides, argues strongly for urgent changes in regulatory policies regarding pesticide registration and monitoring procedures as they relate to pollinator safety. This further calls for emergency funding to address the myriad holes in our scientific understanding of pesticide consequences for pollinators. The relegation of bee toxicity for registered compounds to impact only label warnings, and the underestimation of systemic pesticide hazards to bees in the registration process may well have contributed to widespread pesticide contamination of pollen, the primary food source of our major pollinator. Is risking the $14 billion contribution of pollinators to our food system really worth lack of action?
1Christopher A. Mullin, Maryann Frazier, James L. Frazier, Sara Ashcraft, Roger Simonds, Dennis vanEngelsdorp, Jeffery S. Pettis (2010). High Levels of Miticides and Agrochemicals in North American Apiaries: Implications for Honey Bee Health PLoS ONE
Monday, March 1st, 2010
How do you turn a male frog into a female frog that breeds with other male frogs? Expose them to herbicides that are routinely sprayed on agricultural fields worldwide.
Last year, Tyrone Hayes from UC Berkeley gave a talk at Bowdoin about his career’s work studying the impacts of endocrine-disrupting chemicals on amphibian development.
This week’s Early Edition of the Proceedings of the National Academy of Sciences features some of this research.1
Atrazine is one of the most widely used pesticides in the world. Approximately 80 million pounds are applied annually in the United States alone, and atrazine is the most common pesticide contaminant of ground and surface water. Atrazine can be transported more than 1,000 km from the point of application via rainfall and, as a result, contaminates otherwise pristine habitats, even in remote areas where it is not used. In fact, more than a half million pounds of atrazine are precipitated in rainfall each year in the United States.
In addition to its persistence, mobility, and widespread contamination of water, atrazine is also a concern because several studies have shown that atrazine is a potent endocrine disruptor active in the ppb (parts per billion) range in fish, amphibians, reptiles, and human cell lines, and at higher doses (ppm) in reptiles, birds, and laboratory rodents. Atrazine seems to be most potent in amphibians, where it is active at levels as low as 0.1 ppb. Although a few studies suggest that atrazine has no effect on amphibians under certain laboratory conditions, in other studies, atrazine reduces testicular volume; reduces germ cell and Sertoli cell numbers; induces hermaphroditism; reduces testosterone; and induces testicular oogenesis. Furthermore, atrazine contamination is associated with demasculinization and feminization of amphibians in agricultural areas where atrazine is used and directly correlated with atrazine contamination in the wild.
Using an experiment where his team exposed frogs to a 2.5 parts per billion atrizine solution, here’s what they found:
Atrazine-exposed males were both demasculinized (chemically castrated) and completely feminized as adults. Ten percent of the exposed genetic males developed into functional females that copulated with unexposed males and produced viable eggs. Atrazine exposed males suffered from depressed testosterone, decreased breeding gland size, demasculinized/feminized laryngeal development, suppressed mating behavior, reduced spermatogenesis, and decreased fertility. These data are consistent with effects of atrazine observed in other vertebrate classes. The present findings exemplify the role that atrazine and other endocrine-disrupting pesticides likely play in global amphibian declines.
The main implication of this chemically induced sex switching is that it has the potential to disrupt breeding and contribute to the amphibian declines observed worldwide:
Although many studies have focused on death from disease and its role in global amphibian declines and sudden enigmatic disappearances of populations, virtually no attention has been paid to the slow gradual loss of amphibian populations due to failed recruitment. The present study suggests several ways that exposure to endocrine disruptors such as atrazine may lead to population level effects in the wild and contribute to amphibian declines. Certainly, the inability to compete for females and the significant decline in fertility in exposed males, as reported in the present study, will have a direct impact on exposed populations.
1Hayes, T. et al (2010) Atrazine induces complete feminization and chemical castration in male African clawed frogs (Xenopus laevis). Proceedings of the National Academy of Sciences. doi:10.1073/pnas.0909519107
Friday, February 19th, 2010
How much does pollution (and other environmental impacts) from corporations cost each year? These costs, borne by society rather than corporations, are called negative externalities. An example is the cost of medical expenses and the loss of forests caused by air pollution.
The Guardian is running a story by Juliette Jowit suggesting that the total cost of externalities for the 3,000 largest companies in the world could be as much as $US 2.2 trillion in 2008. As the story points out, that’s a lot:
Excerpts (links by Jowit):
Later this year, another huge UN study – dubbed the “Stern for nature” after the influential report on the economics of climate change by Sir Nicholas Stern – will attempt to put a price on such global environmental damage, and suggest ways to prevent it. The report, led by economist Pavan Sukhdev, is likely to argue for abolition of billions of dollars of subsidies to harmful industries like agriculture, energy and transport, tougher regulations and more taxes on companies that cause the damage.
“What we’re talking about is a completely new paradigm,” said Richard Mattison, Trucost’s chief operating officer and leader of the report team. “Externalities of this scale and nature pose a major risk to the global economy and markets are not fully aware of these risks, nor do they know how to deal with them.”
“It’s going to be a significant proportion of a lot of companies’ profit margins,” Mattison told the Guardian. “Whether they actually have to pay for these costs will be determined by the appetite for policy makers to enforce the ‘polluter pays’ principle. We should be seeking ways to fix the system, rather than waiting for the economy to adapt. Continued inefficient use of natural resources will cause significant impacts on [national economies] overall, and a massive problem for governments to fix.”
Another major concern is the risk that companies simply run out of resources they need to operate, said Andrea Moffat, of the US-based investor lobby group Ceres, whose members include more than 80 funds with assets worth more than US$8tn. An example was the estimated loss of 20,000 jobs and $1bn last year for agricultural companies because of water shortages in California, said Moffat.
Tuesday, November 17th, 2009
The field of nanotechnology is exploding, and many materials, such as titanium (Ti), are being shrunk and used in consumer products like sun tan lotions, cosmetics, and toothpaste.
It has been traditionally thought that inert materials like Ti won’t cause health issues because they don’t react with molecules in our cells. New research from UCLA’s Jonsson Comprehensive Cancer Center published in Cancer Research suggests that this conventional wisdom may be flawed.
Ti appears to migrate throughout the body, causing DNA/chromosome breakage and inflammation (both of which are linked to cancer) and oxidative stress causing cell death. Rather than chemically reacting with molecules in cells, the high surface area of the tiny particles appears to cause cell molecules to change.
The manufacture of TiO2 nanoparticles is a huge industry, Schiestl said, with production at about two million tons per year. In addition to paint, cosmetics, sunscreen and vitamins, the nanoparticles can be found in toothpaste, food colorants, nutritional supplements and hundreds of other personal care products.
Once in the system, the TiO2 nanoparticles accumulate in different organs because the body has no way to eliminate them. And because they are so small, they can go everywhere in the body, even through cells, and may interfere with sub-cellular mechanisms.
Sunday, November 15th, 2009
Every day, we are exposed to a cocktail of synthetic chemicals from consumer products. How harmful are these? In an earlier post, I described how risk analysis is an important scientific process for determining exposure, effects, and overall risk of these chemicals.
One thing missing from these analyses is how people respond to information about their chemical exposure. In a recent issue1 of the Journal of Health and Social Behavior, Rebecca Altman and colleagues addressed this by analyzing what they call the “exposure experience” of women in Cape Cod, MA—an area with elevated breast cancer rates.
What did they find?