When you hear people talk about lead poisoning hazards, one of the first things that comes to mind is peeling paint chips in poorly maintained innercity apartments. Probably the last that would come to mind are vinyl-backed baby bibs. Which is what makes the story in last Friday's Chicago Daily Herald such a stunner.
Reporter Steve Zalusky interviewed a suburban grandma who apparently triggered a major investigation by the Center for Environmental Health, based in Oakland, Calif. Seems the grandmother had heard a news account about an investigation by that group, which had turned up lead in plastic lunch boxes. It caused her to wonder whether just any plastic might be contaminated.
So, she bought a test kit and used on her grandson's baby bib. When it tested positive for the toxic heavy metal, she bought more bibs and tested those as well. All came from a Chinese supplier for Wal-Mart, Zalusky says.
In a new report that the Center for Environmental Health released last week, Caroline Cox, its research director, noted that over the past 6 months, her group had purchased more than 50 brands of vinyl baby bibs and screened them. It then sent 18 that tested positive to an independent lab for further analysis.
The report said that vinyl portions of four "contained significant amounts of lead, above 600 parts per million." Cox explained that her group used that cutoff "because the Consumer Product Safety Commission classifies paints with more than 600 parts per million of lead as 'banned hazardous products.'” One subsequently tested bib from a Wal-Mart brand actually contained a whopping 9,700 parts per million lead.
On May 2, the Oakland Center announced that as a result of legal action it had taken, Wal-Mart will no longer sell the bibs, at least in California. When regulators in Illinois and New York learned of the problem, they negotiated with Wal-Mart for it to cease selling the bibs in their states as well.
However Cox's group found, Wal-Mart was not the only company selling lead-tainted bibs. A few other major companies distributed bibs that also tested positive. For now, the Center for Environmental Health recommends, worried parents should test any vinyl bibs their youngsters are using and substitute non-vinyl versions where lead is found.
The good news: At least this is an avoidable hazard. It's not like powdered lead wafting in open windows of buildings that lack air conditioning--something that Arlene Weiss, a consulting toxicologist with Environmental Medicine, in Westwood, N.J., documented last year.
I interviewed her at the Society of Toxicology meeting in San Diego. In the March 25, 2006 Science News, I note that the federal limit for lead in house dust is 40 micrograms per square foot of swabbed area. I then cited a study that Weiss and her colleagues had published 1 month earlier documenting that this lead limit "can be exceeded on [indoor] surfaces near windows in New York City after only 3 weeks of dust accumulation" from outdoor sources.
The choice there: Keep the windows tightly closed and swelter in the summer heat--or vacuum and damp-wipe all surfaces daily.
Monday, May 7, 2007
Hormonal Fireworks?
Remember the old TV commercial: It's not nice to fool Mother Nature? Well that's what environmental hormones do--fool our bodies, or those of the critters around us, into taking biochemical directions from pollutants. Perchlorate is one such pollutant with a relatively recently recognized hormonal alter ego. A new report finds aquatic animals may encounter dramatic spikes in exposure to perchlorate following pyrotechnic displays.
Perchlorate is an ingredient of many rocket fuels, which is why Air Force bases can become perchlorate-rich environments. The compound also appears to help boost ceremonial rockets--firecrackers--into the sky. Unfortunately, our bodies mistake perchlorate for thyroid hormones. Ands because thyroid hormones play important roles in growth and neural development, exposure to this pollutant has the potential to do some pretty dastardly things.
For instance, I wrote a story for Science News, last August, that showed perchlorate masculinized certain female fish. So dramatic were the impacts that scientists initially mistook affected females for males. Several of these macho moms even displayed male-courtship behavior and produced sperm. Clearly, that was not something Mother Nature had intended. At a minimum, it could jeopardize reproduction in affected populations.
In the new study, researchers measured perchlorate concentrations in an Oklahoma lake over which fireworks were displayed. The scientists sampled the water before and for weeks after July 4 fireworks rained the rocket ingredient into the water. What they found is that concentrations peaked within a day of the pyrotechnic display, then disappeared. However, it could take almost 3 months for the pollutant to vanish.
To understand how it vanished, the scientists took some lake water back to the lab and added perchlorate to it. As long as the water housed its normal complement of aquatic microbes, the pollutant disappeared. It seems these bugs chow down on it--and how quickly they eliminate the perchlorate can depend on water temperature. However, when the researchers sterilized the water--killing its microbes--the perchlorate showed no signs of disappearing. The findings will appear in an upcoming issue of Environmental Science & Technology. Subscribers can see the article early online.
Although most concentrations in the new study were well below a part per billion, in one instance the peak maxxed out at 44 ppb. For perspective, the latter is within the range that perturbed the reproductive development of fish in the story I wrote last year.
I guess we'll just have to hope that our pyrotechnic displays don't coincide with pivotal developmental periods of nearby fish. Oops...aren't there places--like Disney World, for instance--where fireworks occur year-round?
Perchlorate is an ingredient of many rocket fuels, which is why Air Force bases can become perchlorate-rich environments. The compound also appears to help boost ceremonial rockets--firecrackers--into the sky. Unfortunately, our bodies mistake perchlorate for thyroid hormones. Ands because thyroid hormones play important roles in growth and neural development, exposure to this pollutant has the potential to do some pretty dastardly things.
For instance, I wrote a story for Science News, last August, that showed perchlorate masculinized certain female fish. So dramatic were the impacts that scientists initially mistook affected females for males. Several of these macho moms even displayed male-courtship behavior and produced sperm. Clearly, that was not something Mother Nature had intended. At a minimum, it could jeopardize reproduction in affected populations.
In the new study, researchers measured perchlorate concentrations in an Oklahoma lake over which fireworks were displayed. The scientists sampled the water before and for weeks after July 4 fireworks rained the rocket ingredient into the water. What they found is that concentrations peaked within a day of the pyrotechnic display, then disappeared. However, it could take almost 3 months for the pollutant to vanish.
To understand how it vanished, the scientists took some lake water back to the lab and added perchlorate to it. As long as the water housed its normal complement of aquatic microbes, the pollutant disappeared. It seems these bugs chow down on it--and how quickly they eliminate the perchlorate can depend on water temperature. However, when the researchers sterilized the water--killing its microbes--the perchlorate showed no signs of disappearing. The findings will appear in an upcoming issue of Environmental Science & Technology. Subscribers can see the article early online.
Although most concentrations in the new study were well below a part per billion, in one instance the peak maxxed out at 44 ppb. For perspective, the latter is within the range that perturbed the reproductive development of fish in the story I wrote last year.
I guess we'll just have to hope that our pyrotechnic displays don't coincide with pivotal developmental periods of nearby fish. Oops...aren't there places--like Disney World, for instance--where fireworks occur year-round?
Sleepless Kids Stat
Sleep "is an important but underrecognized component of wellness in children," Columbia University researchers note in a recent supplement to the prestigious journal Pediatrics. That's why it's disturbing that their new nationally representative survey of U.S. children finds that "[a]pproximately 15 million American children are affected by inadequate sleep." Many of these children also had mood disorders--chiefly depression--headaches, and allergies. Moreover, the scientists found, contrary to many smaller studies, this one documented that childhood sleep deprivation "transcends all culture."
Source: Smaldone, A, J.C. Honig, and M.W. Byrne. 2007. Sleepless in America: Inadequate Sleep and Relationships to Health and Well-being of Our Nation's Children. Pediatrics 119, Supplement 1(February):S29.
Source: Smaldone, A, J.C. Honig, and M.W. Byrne. 2007. Sleepless in America: Inadequate Sleep and Relationships to Health and Well-being of Our Nation's Children. Pediatrics 119, Supplement 1(February):S29.
Swimming in Hormones
Does the idea of drinking or swimming in hormones appeal? Probably not. However, a new report finds that hormones excreted by livestock not only end up in their manure, but also run off into the nation's waterways as rains wash through manure-treated fields.
So what? Hormones are terrifically powerful chemicals, agents designed to be biologically active in trace quantities. Their role: to orchestrate the body's every function, telling each tissue when it's time to turn genes on—or off. Let loose a signal at the wrong time and havoc can ensue. Which is why littering waterways can do a number on fish and other aquatic life.
In the new study, Jeanne Kjær of the Geological Survey of Denmark and Greenland and her colleagues measured concentrations of estrogens—female sex hormones—running off of fields that had been fertilized with pig manure. Levels of the hormones were in the low nanograms per liter—that's parts per trillion. Remember, though, these chemicals are designed to work at vanishingly tiny concentrations. Indeed, they often exert a stronger effect at low doses than at higher ones.
Measurable amounts of the sex hormones continued to leach off of fertilized fields for up to 3 months, the scientists will report in an upcoming issue of Environmental Science & Technology. Their article was published early online, last Saturday.
Feminization of male fish has been reported in many waters. I've covered those reports plenty myself in stories for Science News. Most of those reports pointed toward estrogens excreted by humans—and released into waters from sewage-treatment plants—as the likely source of any gender-bending effects witnessed in wildlife.
The new data imply that agriculture could be a substantial additional source of such contamination. Indeed, the authors argue, their findings "indicate an urgent need for further research into the risk of estrogen contamination of the aquatic environment" by manure-fertilized fields.
So what? Hormones are terrifically powerful chemicals, agents designed to be biologically active in trace quantities. Their role: to orchestrate the body's every function, telling each tissue when it's time to turn genes on—or off. Let loose a signal at the wrong time and havoc can ensue. Which is why littering waterways can do a number on fish and other aquatic life.
In the new study, Jeanne Kjær of the Geological Survey of Denmark and Greenland and her colleagues measured concentrations of estrogens—female sex hormones—running off of fields that had been fertilized with pig manure. Levels of the hormones were in the low nanograms per liter—that's parts per trillion. Remember, though, these chemicals are designed to work at vanishingly tiny concentrations. Indeed, they often exert a stronger effect at low doses than at higher ones.
Measurable amounts of the sex hormones continued to leach off of fertilized fields for up to 3 months, the scientists will report in an upcoming issue of Environmental Science & Technology. Their article was published early online, last Saturday.
Feminization of male fish has been reported in many waters. I've covered those reports plenty myself in stories for Science News. Most of those reports pointed toward estrogens excreted by humans—and released into waters from sewage-treatment plants—as the likely source of any gender-bending effects witnessed in wildlife.
The new data imply that agriculture could be a substantial additional source of such contamination. Indeed, the authors argue, their findings "indicate an urgent need for further research into the risk of estrogen contamination of the aquatic environment" by manure-fertilized fields.
Smoke and Wind
Pass by any major urban office building, these days, and you're likely to see at least a few souls commiserating outside the entrance about their forced eviction from smokefree offices whenever they feel an urge to light up. However, such nicotine addicts may find their lives constrained even more, if regulators get wind of new research published this month in the Journal of the Air & Waste Management Association.
Stanford University scientists wondered whether exiling smokers to the outdoor environment actually contributed substantially to pollution there. So, they set up continuous particle sensors to tally the tiny smoke particles in areas frequented by cigarette and cigar smokers--these were typically parks, outdoor cafes, sidewalks, and restaurant patios.
The bottom line: Sitting or standing downwind of a smoker could fill your breathing space with substantial amounts of smoke. How much? Within 1.5 feet of smokers, one could encounter upwards of 1,000 micrograms per cubic meter in air of fine particles. These are the type that can be inhaled deeply into lungs.
Admittedly, that was a maximum value. More typical ones were 200 to 500 micrograms per cubic meter of air. Still, Neil E. Klepeis and his colleagues report, concentrations at 1.5 feet downwind of an outdoor smoker were comparable to indoor concentrations found in smokers' homes. The big difference: Once an outdoor smoker puts out his or her cigarette, nearby air concentrations plummet to virtually zero. In homes, however, air isn't diluted as effectively as outdoors, so smoke remains aloft within rooms for hours after stubbing out a cigarette.
This is the first peer-reviewed data on systematic measurements of outdoor tobacco smoke. The study's authors conclude: "these data--that outdoor tobacco smoke levels can be substantial under certain conditions--[are] vital to the development of outdoor tobacco-control policy."
Of course, they're only telling us nonsmokers what we have been observing anecdotally: that outdoor air all too often fails to effectively dilute tobacco pollution. I'd say these data should begin discussions about whether even outdoor cafes need to consider offering us--especially patrons with small children--access to truly smokefree zones.
Stanford University scientists wondered whether exiling smokers to the outdoor environment actually contributed substantially to pollution there. So, they set up continuous particle sensors to tally the tiny smoke particles in areas frequented by cigarette and cigar smokers--these were typically parks, outdoor cafes, sidewalks, and restaurant patios.
The bottom line: Sitting or standing downwind of a smoker could fill your breathing space with substantial amounts of smoke. How much? Within 1.5 feet of smokers, one could encounter upwards of 1,000 micrograms per cubic meter in air of fine particles. These are the type that can be inhaled deeply into lungs.
Admittedly, that was a maximum value. More typical ones were 200 to 500 micrograms per cubic meter of air. Still, Neil E. Klepeis and his colleagues report, concentrations at 1.5 feet downwind of an outdoor smoker were comparable to indoor concentrations found in smokers' homes. The big difference: Once an outdoor smoker puts out his or her cigarette, nearby air concentrations plummet to virtually zero. In homes, however, air isn't diluted as effectively as outdoors, so smoke remains aloft within rooms for hours after stubbing out a cigarette.
This is the first peer-reviewed data on systematic measurements of outdoor tobacco smoke. The study's authors conclude: "these data--that outdoor tobacco smoke levels can be substantial under certain conditions--[are] vital to the development of outdoor tobacco-control policy."
Of course, they're only telling us nonsmokers what we have been observing anecdotally: that outdoor air all too often fails to effectively dilute tobacco pollution. I'd say these data should begin discussions about whether even outdoor cafes need to consider offering us--especially patrons with small children--access to truly smokefree zones.
Thursday, May 3, 2007
More Fat Stats
Researchers at the Beltsville (Md.) Human Nutrition Research Center have just released data on fat-consumption trends over the past 3 decades, based upon a representative survey of the U.S. population. The good news is that overall fat intake is down--from a high of about 45 percent of calories in the late '70s, to about 37 percent of calories today. However, despite the message that saturated fats tend to be the least healthy, the new data show that even today, more than half of U.S. adults derive 10 to 15 % of their calories from sat fats. Younger adults--those 20 to 50 years old--consumed the highest quantities--on average, more than 100 grams per day among men, and more than 75 grams per day among women.
What's the biggest contributor of fats to the adult diet? Desserts, at 11%, should come as no surprise. However, it turns out that pizza, burritos, and tacos were equally big contributors. Next on the list--above bacon even: regular salad dressings, butter, and margarines.
Source: "Levels and Sources of Fat in the Diets of Adults" by Alanna J. Moshfegh, Joseph D. Goldman and Randy P. LaComb, at the Experimental Biology '07 meeting this week in Washington, D.C.
What's the biggest contributor of fats to the adult diet? Desserts, at 11%, should come as no surprise. However, it turns out that pizza, burritos, and tacos were equally big contributors. Next on the list--above bacon even: regular salad dressings, butter, and margarines.
Source: "Levels and Sources of Fat in the Diets of Adults" by Alanna J. Moshfegh, Joseph D. Goldman and Randy P. LaComb, at the Experimental Biology '07 meeting this week in Washington, D.C.
Wednesday, May 2, 2007
No Flavor? It's Scents-less
You know how foods taste strange, or indeed, rather flavor-less when you have a head cold? Well, some people are born with a permanent genetic impairment that prevents their nose from ever picking up scents, volatile cues that are critical to experiencing a food's full flavor. Over the past year, Washington, D.C., physician Robert I. Henkin, began homing in on what underlies the problem for most afflicted individuals. Two days ago, the genial neurologist reported his findings--and a partial cure--at the Experimental Biology '07 meeting, in Washington, D.C.
For most of his patients, their scentsless existence traces to a lack of growth factors in nasal mucus. These proteins are needed to support the health of sensory cells in tissue lining the inside of the nose. In their absence, those sensory cells can become impaired or disappear, he noted.
Afflicted individuals can sense that there are odors around, and their general intensity, but can't distinguish between them, Henkin explains. Their taste buds work fine, so they can detect salt, sweet, bitter, and sour. But they'd never discern the difference between a strawberry flavor and straight sugar, because the primary berry essence is a scent.
Once he realized what was missing in the mucus, Henkin's team at the Taste and Smell Clinic began treating people with drugs--generally phosphodiesterase inhibitors--that help the body make adequate amounts of the missing proteins. Months may go by before nasal secretions become anywhere near replete enough to rescue scent-sensing cells. Once they do, his patients suddenly find themselves bathed in a complex world of strange, wondrous, and often enticing odors.
At the meeting, Henkin reported data from the first 25 patients treated. Even with long-term drug therapy, their mucus growth-factor concentrations never reached normal levels, he told me, "but they get close to it." More to the point, these people get to lead richer, safer lives. Indeed, he notes, some patients had become sickened in the past by not detecting the smell of spoiled foods.
After our talk, I tried to imagine a world devoid of the smells of coffee, chocolate, newly mown grass, or a freshly bathed infant. Who would willingly give that up?
Which explains why Henkin's patients tend to stick with their drug therapy, despite the side effects it can bring, such as increased anxiety or a racing heart rate.
Oh, he did mention one additional therapeutic drawback: weight gain. It seems that once his patients wake up the world of smells, the flavors of their foods can seduce them into downing larger portions.
For most of his patients, their scentsless existence traces to a lack of growth factors in nasal mucus. These proteins are needed to support the health of sensory cells in tissue lining the inside of the nose. In their absence, those sensory cells can become impaired or disappear, he noted.
Afflicted individuals can sense that there are odors around, and their general intensity, but can't distinguish between them, Henkin explains. Their taste buds work fine, so they can detect salt, sweet, bitter, and sour. But they'd never discern the difference between a strawberry flavor and straight sugar, because the primary berry essence is a scent.
Once he realized what was missing in the mucus, Henkin's team at the Taste and Smell Clinic began treating people with drugs--generally phosphodiesterase inhibitors--that help the body make adequate amounts of the missing proteins. Months may go by before nasal secretions become anywhere near replete enough to rescue scent-sensing cells. Once they do, his patients suddenly find themselves bathed in a complex world of strange, wondrous, and often enticing odors.
At the meeting, Henkin reported data from the first 25 patients treated. Even with long-term drug therapy, their mucus growth-factor concentrations never reached normal levels, he told me, "but they get close to it." More to the point, these people get to lead richer, safer lives. Indeed, he notes, some patients had become sickened in the past by not detecting the smell of spoiled foods.
After our talk, I tried to imagine a world devoid of the smells of coffee, chocolate, newly mown grass, or a freshly bathed infant. Who would willingly give that up?
Which explains why Henkin's patients tend to stick with their drug therapy, despite the side effects it can bring, such as increased anxiety or a racing heart rate.
Oh, he did mention one additional therapeutic drawback: weight gain. It seems that once his patients wake up the world of smells, the flavors of their foods can seduce them into downing larger portions.
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