~dGossip
~tLiving near traffic pollution tied to heart deaths
~w2010-07-27
According to the results from a recent study, middle-aged and older
adults who live near high-traffic roads may have a heightened risk of
dying from heart disease -- but the odds seem to go down if they move
to a less-travelled neighbourhood. Although according to the
researchers, the findings did not prove that traffic pollution is the
reason for the excess heart disease deaths. However, they do add to
evidence tying vehicle-produced pollutants to the risk of dying from
heart problems. In May, the American Heart Association (AHA) released
a report stating that recent studies have "substantially
strengthened" the evidence that air pollution from traffic, industry
and power generation is a risk factor for heart attack, stroke and
deaths from cardiovascular causes. The evidence most strongly points
to particles known as fine particulate matter, which is produced from
burning gasoline and other fossil fuels. The AHA recommends that
people with established heart disease and other at-risk individuals - including the elderly and people with risk factors for heart
disease, like diabetes and high blood pressure -- try to limit their
exposure to congested roadways and spend less time outside on days
when air quality is poorer. During the new study, researcher Wen Qi
Gan and colleagues at the University of British Columbia analysed
data on more than 450,000 Vancouver-area residents between the ages
of 45 and 85. They detected that over nine years, residents who
consistently lived within roughly 500 feet of a highway or within 165
feet of a major road were more likely to die of heart disease than
those who lived farther from high-traffic roadways. In addition, the
researchers discovered "two new twists" to what's been known about
the relationship between traffic and heart disease deaths, explained
senior researcher Dr. Michael Brauer, a professor of environmental
health at the university. That is, the risk of heart disease death
declined among residents who moved away from high-traffic roads
during the study period, while it increased among those who moved
closer to congested roads. "It's sort of like what we see with
smoking cessation," Brauer said. "The associated disease risks are
lower in former smokers," compared with persistent smokers. The
results are based on 450,283 middle-aged and older adults with no
known heart disease at the outset. Approximately 53,000 persistently
lived within 500 feet of a highway or 165 feet of a major road over
the nine-year study.
In total, 607 -- or just over 1 percent -- died of heart disease
during that period; that compared with 0.7 percent of the more than
328,000 people who persistently lived farther from traffic. The
researchers were able to account for a number of other factors that
could explain any connection between living near major roads and
having a higher risk of dying from heart disease -- including
residents' age, neighbourhood income levels and any diagnoses of
diabetes or major lung disease. The researchers found that living
near a highway or major road was still linked to a 29 percent higher
risk of heart disease death, versus living farther away. Among people
who either moved away from or closer to a major road, the risk of
heart disease death was also somewhat elevated -- but lower when
compared with residents who persistently lived near busy roads. In
addition, the researchers used air pollution data to show that people
living close to highways and major roads would have been exposed to
higher levels of particulate matter, nitrogen dioxide and other
traffic-related pollutants. The findings do not prove that air
pollution was the reason for the higher risks. Brauer said that
traffic noise, for example, might be involved. Furthermore, the
researchers had no information on certain key factors in heart
disease risk, including people's smoking habits and weight. However,
a body of research has now linked air pollution exposure to the risk
of heart disease death, Brauer pointed out. He also added that the
evidence suggests that traffic pollution may be a particular risk. A
"big question," Brauer said, is whether exposure to air pollution is
linked to the initial development of heart disease -- or whether its
association with heart disease death reflects an effect mainly on
people with existing heart problems. Researchers believe that air
pollutants may trigger heart attacks, strokes or other cardiovascular
"events" in vulnerable people by causing inflammation in the blood
vessels and irritating the nerves of the lungs. Brauer suggested that
people view traffic pollution as one of the range of factors that may
influence their heart disease risk -- which includes exercise and
diet habits, smoking and the presence of any health conditions that
contribute to heart disease, like diabetes, high blood pressure and
high cholesterol. Living near major roads does not mean a person is
destined for heart disease. Brauer noted, living in a low-traffic
area does not mean a person can slack on following a healthy
lifestyle.
Reuters Health, 15 July 2010
a
href="http://www.reuters.com/news/health">http://www.reuters.com/news
/health</a>
~dGossip
~tBADGE, made from BPA, reacts with food
~w2010-07-27
A new research report has suggested that leftover residues of a
compound made from bisphenol A (BPA) for use in food can linings
reacts with sugars, proteins and other parts of food to form new
molecules. According to the new study published in the Journal of
Agricultural and Food Chemistry, a main component of food can linings
forms new chemicals when it reacts with different parts of food.
BADGE, which is short for bisphenol A diglycidyl ether, is produced
from bisphenol A and is a building block of certain types of resins
that coat food and drink cans. Like its parent compound, BADGE has
endocrine disrupting properties. The researchers from The Netherlands
and Great Britain found that BADGE residue left over from
manufacturing of the can coating can react with sugars, proteins and
other small molecules – for example ethanol in beer. The findings
demonstrate how critical it is to understand the extent of chemical
migration from resin linings into the can's contents and what happens
to the compounds once they interact with the food and beverage. This
is important because of the implications for food safety. The
European Union bases its regulations for how much BADGE can migrate
from food primarily on the reaction between BADGE and water. However,
according to the findings from the latest study, BADGE-water reaction
only accounted for as much as 26 percent of the "disappearing" BADGE
the researchers added to samples of canned tuna, apple puree and
beer. Some of the remaining BADGE could be detected as BADGE-glucose
and BADGE-amino acid reaction products. Even when the additional
BADGE products were considered, it was still not possible to account
for all of the BADGE added to the food. The researchers believe that
BADGE can form products with larger, high-molecular-weight
carbohydrates, fibres and proteins that would be difficult to detect
directly with the methods they used. This was the case for proteins.
When the researcher mixed BADGE with insulin, a large protein, the
BADGE was effectively invisible. However, when they broke down the
protein into its component parts, then the BADGE products could be
detected. Although large molecules like the insulin-BADGE product
would probably be too large to be absorbed by the body at first, it
is possible that after they break down into smaller molecules in the
stomach, then exposure to BADGE would be likely. The BPA-like
chemical backbone of BADGE was not changed by reactions with food
molecules. During this study, the researchers did not investigate
whether the structural similarity of these products to BADGE and BPA
might lead to similar harmful effects attributed to BPA or if the
BADGE products might be related to levels of BPA that have been
detected in most of the U.S. population. For the study, BADGE was
added to two types of canned food – tuna in sunflower oil and apple
puree – and three drinks – an ale, a stout, and a lager. Spiked and
nonspiked controls were recanned, homogenised and then analysed three
weeks later using liquid chromatography.
Environmental Health News, 19 July 2010
<ahref="http://www.environmentalhealthnews.org/">http://www.environme
ntalhealthnews.org/</a>
~dGossip
~tNational Oceanic and Atmospheric Administration Finds PM and Black
Carbon in Air near Gulf Spill
~w2010-07-27
National Oceanic and Atmospheric Administration (NOAA) scientists
said their data on air quality measurements taken in June in the
vicinity of the Deepwater Horizon/BP oil spill area are consistent
with those of the U.S. Environmental Protection Agency and the
Occupational Safety & Healthy Administration. The new NOAA report
provides a summary of the levels of nearly 100 air pollutants
measured with sophisticated air sampling instruments onboard a WP-3D
research aircraft. During the analysis, the researchers detected
common air pollutants including ozone, nitrogen oxides and carbon
monoxide, in amounts typical of urban areas in U.S. cities. However,
15 to 70 kilometres downwind from the oil spill, concentrations of
certain hydrocarbons were much higher than found in typical polluted
air. Particulate matter downwind of the oil slick was comparable to
concentrations in moderately polluted urban air, but the particles
were almost entirely organic material, as opposed to those typically
found in urban particulate matter. In addition, the researchers
measured large amounts of black carbon in smoke from a controlled
burn of crude oil on the water. “Data from the NOAA flights are
providing an important detailed and independent set of air quality
data to assess air quality risks of workers at sea and the public
ashore,” said A. R. Ravishankara, director of the Chemical Sciences
Division of NOAA’s Earth System Research Laboratory, who led the
study. NOAA scientists measured the air pollutants in four areas,
including in the immediate vicinity of the spill, downwind from the
spill, and along the Mississippi, Alabama and Florida coastlines. In
addition, they measured “background” air in an area far from the
spill to serve as a control sample. In analysing the levels of the
pollutants, scientists compared them to typical concentrations of a
polluted U.S. urban area. The near-shore measurements, 30 to 40
kilometres from shore, demonstrated pollution concentrations
generally lower than those typically found in urban areas. The
background air was relatively free of pollution from the oil spill.
The report offers a highly detailed snapshot of the concentrations of
hydrocarbons and other organic chemicals, particulate matter, ozone,
carbon monoxide, nitrogen dioxide, peroxyacetyl nitrate and a host of
other air pollutants in the Gulf in early June. Measurements were
taken from as low as 60 meters above sea level and up to 1,000 meters
above sea level, with most flight tracks being about 150 meters above
the Gulf.
Environmental Protection News, 22 July 2010
<a href="http://www.eponline.com">http://www.eponline.com</a>
~dGossip
~tFlame retardants in house dust match residents' blood levels
~w2010-07-27
A new study has reported that people living in houses with higher
levels of flame retardant chemicals in the dust have themselves
higher levels of the chemicals in their blood. This finding
implicates dust as a major exposure source for the compounds. The
mystery of why some people have higher levels of certain flame
retardants in their bodies than others may hinge on simple house
dust, according to the new study by a team of U.S. researchers.
Previous research indicates that dust and food are major sources of
exposure to PBDE chemicals yet questions remained regarding the
importance of dust as a source. In the new study, the role of dust is
clarified because it is the first research to compare levels of flame
retardants in house dust with levels in the people who live in the
same house. The researchers report that while some foods do harbour
PBDEs, eating and breathing dust seems to be the main source of
exposure in the United States. Dust, then, may provide an easy and
accurate way to predict exposures in the people who live in the home,
the researchers explain. This is in contrast to some European
countries. PBDE levels are remarkably lower in dust samples collected
in Europe compared to the United States, possibly because many PBDEs
were banned there years ago. For example, in Belgium and Germany, no
associations are found between PBDE levels in dust and in people's
blood. Furthermore, levels vary across the United States. The highest
levels of PBDEs are measured in Californians. The state has the
strictest fire safety standards in the nation, and therefore, flame
retardant use is high. Many consumer products contain PBDEs. During
fires, the chemicals slow down burning of the electronics, carpeting,
textiles, mattresses and upholstered foam furniture that contain
them.
In the United States, several PBDEs have been phased out of use
because of concerns for the toxic and hormonal effects of these
chemicals. However, older products such as carpets and furniture that
contain these types continue to release them as they age. In
addition, products with these chemicals can still be imported and
sold. In rodents, certain PBDEs can affect brain development and
thyroid hormone levels as well as having endocrine disruptor
activities. That is, they can act like or prevent the normal action
of hormones in those animals. Additional studies in humans suggest
that higher levels of some PBDEs in the body can lead to altered
hormone levels. During the new study, the researchers collected used
vacuum cleaner bags from 50 households in Massachusetts and examined
the contents for the presence of over 30 PBDEs. At the same time,
blood samples from 12 adult couples were collected and tested for
several of the PBDE types found in the majority of the house dust
samples. The levels and types measured show that PBDEs are a large
component of indoor dust. Total PBDE concentrations averaged 4,742
nanograms per gram (ng/g) and ranged from 980 to 44,546 ng/g. Of
those measured, six were not detected in any house, three were found
in a small number of houses – less than 30 percent – and the rest
were found in the majority of the dust samples. Thirteen PBDEs were
detected in every house sampled. Three of those – BDE 47, 99 and 100
– had related levels in dust and in blood. That is, houses with high
levels of these chemicals in dust samples were likely to have
occupants with high levels of the chemicals in their blood. Gender
had a similar strong association; men with high levels in their blood
were likely to live with women who also had high levels in their
blood.
Environmental Health News, 23 July 2010
<ahref="http://www.environmentalhealthnews.org/">http://www.environme
ntalhealthnews.org/</a>
~dGossip
~tHeart risk factors less common in fish lovers
~w2010-07-27
The results from a new study have suggested that middle-aged and
older men who eat fish every day are less likely than infrequent fish
eaters to develop a collection of risk factors for heart disease,
diabetes and stroke. At this stage it is unclear whether it is the
fishy diet itself that is contributing to the health benefits. But,
the researchers say, the results are in line with studies showing
that omega-3 fatty acids -- found most abundantly in oily fish like
salmon, mackerel and albacore tuna -- may have heart benefits.
Clinical trials have demonstrated that omega-3s can lower
triglycerides (a type of blood fat), and a prescription medication
containing the fats -- sold as Lovaza -- is sometimes used to treat
very high triglyceride levels. In addition, the researchers have
suggested that fish oil supplements can help lower blood pressure and
may reduce the risk of death among people with established heart
disease, according to the National Institutes of Health. During the
new study, of 3,500 Korean adults ages 40 to 69, the researchers
found that men who had a serving of fish each day were 57 percent
less likely than those who dined on fish less than once per week to
develop metabolic syndrome over three years. Metabolic syndrome
refers to a collection of risk factors for diabetes, heart disease
and stroke -- including abdominal obesity, high blood pressure, high
blood sugar, low HDL cholesterol and high triglycerides. The syndrome
is typically diagnosed when a person has three or more of those
traits, and the National Health and Nutrition Examination Survey, a
major study, found that it can double the risk of heart attack and
stroke. Previous studies have detected an association between higher
fish intake and a lower risk of some individual components of
metabolic syndrome. However, the current study is the first to
demonstrate an association with the collection of risk factors,
according to the researchers, led by Dr. Inkyung Baik of Kookmin
University in Seoul. The researchers found that of 232 men who said
they ate fish every day at the study's outset, 29 -- or about 12
percent -- developed metabolic syndrome over the next three years. Of
the 190 men who said they ate fish less than weekly, 16 percent
developed metabolic syndrome. When Baik's team considered other
factors -- including the men's income and education, body weight and
lifestyle habits such as smoking and exercise -- daily fish
consumption was linked to a 57 percent lower risk of metabolic
syndrome versus less-than-weekly consumption. However, there was no
such association seen among women. The reason for the gender
discrepancy is not clear.
The researchers speculate that, as a group, women may not have gotten
enough omega-3 fatty acids from fish to show a reduction in the risk
of metabolic syndrome. Men in the top 10 percent for omega-3 intake
from fish typically got 786 milligrams (mg) per day, while their
female counterparts got 563 mg. In addition, men in that top omega-3
group showed a lower risk of metabolic syndrome than those in the
bottom 10 percent -- which, according to Baik's team, supports the
theory that it is the fats that explain the connection between fish
and the risk of metabolic syndrome. However, this type of study
cannot by itself prove cause-and-effect. "Our findings need to be
confirmed by other investigators," Dr. Chol Shin, one of the
researchers on the study and a professor at Korea University Ansan
Hospital, said. And in general, it is not yet clear what the optimal
daily intake of omega-3 fatty acids might be, Shin noted. In the
U.S., there is no recommended daily allowance set for EPA and DHA,
the two major omega-3 fatty acids, writes registered dietitian
Gretchen K. Vannice, in an editorial published with the study.
However, she adds, the American Dietetic Association and other groups
have suggested a daily allowance of anywhere from 250 to 500 mg of
EPA and DHA, based on the overall body of research into omega-3s and
heart health. Two servings of fatty fish per week would be enough to
achieve those levels, Vannice notes. Furthermore, that fits in with
the current advice from the American Heart Association that adults
strive to eat two servings of fish, preferably fatty varieties, each
week. However, even if eating fish regularly does help reduce the
risk of metabolic syndrome or its components, it would be only one of
many factors involved. A healthy weight, not smoking, regular
exercise, and a balanced diet rich in fruits, vegetables, high-fibre
foods and "good" unsaturated fats are all considered important.
Reuters Health, 20 July 2010
a href="http://www.reuters.com">http://www.reuters.com</a>
~dGossip
~tSmog Might Trigger Cell Death in the Heart, Study Finds
~w2010-07-27
At the recent American Heart Association's Basic Cardiovascular
Sciences 2010 Scientific Sessions -- Technological and Conceptual
Advances in Cardiovascular Disease, researchers reported that an
earlier study in rats provided the first direct indication that a
major component of smog might trigger cell death in the heart. The
study found that exposure to ground-level ozone over several weeks
increased the activity of a substance that triggers cell death in the
heart. Ozone (O3) is a highly reactive gas made up of three oxygen
molecules. In the upper atmosphere, it protects Earth from the sun's
radiation. However, O3 becomes a major component of smog when it
forms near the ground through reactions between sunlight, nitrogen
oxides and hydrocarbons from fossil fuels and industrial processes.
"Several epidemiological studies have linked air pollution to the
development of cardiovascular disease, but air pollution contains
hundreds of chemicals and those studies were unable to separate out
the effects of individual components," said Rajat Sethi, Ph.D., an
assistant professor in the Department of Pharmaceutical Sciences at
the Texas A&M Health Science Centre Irma Lerma Rangel College of
Pharmacy in Kingsville, Texas. "Our study looked for direct evidence
of the role of ozone alone in cardiac dysfunction by creating a
controlled environment." During the study, the researchers tested
four groups of 10 rats living in clear plastic-glass boxes. The first
two groups were exposed for eight hours a day to 0.8 parts per
million (ppm) of O3 for either 28 or 56 consecutive days. The other
two groups were exposed to 28 days or 56 days of clean, filtered air
for eight hours per day. After the eight hours of testing, all the
rats experienced 16 hours of clean air overnight. The results
demonstrated that the hearts of the O3-exposed rats had increased
levels of tumour necrosis factor-alpha (TNF α), an indication of
inflammation compared to hearts of the control rats. Increased TNF α
levels have been linked to a drop in levels of a heart-protective
protein called Caveolin-1 (Cav1). Scientists believe Cav1 protects
the heart by binding to a chemical called p38MAPK alpha (p38MAPK α),
which is known to be a cell death signalling chemical, Sethi said.
The researchers found that Cav1 levels decreased in the hearts of
rats exposed to O3 compared to the hearts of control rats who
breathed filtered air. "We believe the decreased levels of Cav1 make
more unbound p38MAPK α available for telling the heart cells to die.
That link between Cav1 and O3 has never been shown in the heart,"
Sethi said.
Science Daily, 22 July 2010
<a href="http://www.sciencedaily.com">http://www.sciencedaily.com</a>
~dGossip
~tZinc sprays dull sense of smell in some users
~w2010-07-27
New research has concluded that homeopathic zinc nasal sprays don't
fight colds, and they probably cause some people to lose their sense
of smell. "Increased Food and Drug Administration oversight of
homeopathic medications is needed to monitor the safety of these
popular remedies," Drs. Terence M. Davidson and Wendy Smith of the
University of California, San Diego, and the Veterans Affairs San
Diego Health System write in the July issue of the Archives of
Otolaryngology -- Head and Neck Surgery. Homeopathic remedies contain
tiny amounts of certain substances mixed with inactive ingredients.
While the FDA requires people dispensing homeopathic drugs for
"serious disease conditions" to be licensed, Davidson and Smith note,
regulation of over-the-counter products is virtually nonexistent.
While over-the-counter zinc gluconate sprays remain a popular cold
remedy, a number of well-designed studies have shown that the sprays
don't work, the researchers point out. There's also growing evidence
that zinc nasal sprays could dull people's sense of smell, or even
eliminate it, possibly permanently, they add. During the new study,
the researchers investigated whether zinc sprays could actually be
causing users to lose their sense of smell by examining 25 people who
lost their sense of smell soon after using zinc gluconate gel. All
had sought care at the university's Nasal Dysfunction Clinic. In
addition, they reviewed the medical literature on the relationship
between zinc use and olfactory problems. The researchers used a set
of nine requirements known as the Bradford Hill Criteria to determine
whether zinc caused the patients' olfactory problems. Researchers
developed the criteria in 1965 so they could test whether tobacco
smoking causes lung cancer without having to perform a large - and
unethical - study in which they assigned some people to smoke. The
seven criteria require that several people in different parts of the
world see the same relationship, which the effect occurs soon after
the potential cause, and other findings. The researchers discovered
that the zinc-olfaction relationship fulfilled all nine criteria. For
example, people report a loss of sense of smell within minutes to
hours after using the spray; also, the relationship between zinc use
and loss of sense of smell has been reported by several independent
groups of researchers. "Based on our analysis, it appears evident
that intranasal zinc can and does cause anosmia," the clinical term
for loss of sense of smell, the researchers say. Right now, they add,
homeopathic remedies aren't required to follow FDA rules on
expiration dating or laboratory testing to confirm that they actually
contain the active ingredients they claim, at the stated strength.
"Protecting our patients from the potential risks of intranasal zinc
medications and other homeopathic drugs, especially ones with limited
therapeutic benefit, should be a high priority of the FDA," Davidson
and Smith conclude.
Reuters Health, 21 July 2010
a
href="http://www.reuters.com/news/health">http://www.reuters.com/news
/health</a>
~dGossip
~tGulf Oil Dispersants Unlikely to Be Endocrine Disruptors and Have
Relatively Low Cell Toxicity, Tests Find
~w2010-07-27
Government researchers have reported that eight of the most commonly
used oil dispersants used to fight oil spills, such as the massive
episode in the Gulf of Mexico, appear unlikely to act as endocrine
disruptors -- hormone-like substances that can interfere with
reproduction, development, and other biological processes. In
addition, the tested dispersants had a relatively low potential for
cytotoxicity (cell death), with JD-2000 and SAF-RON GOLD showing the
least potential. The researchers were from the U. S. Environmental
Protection Agency and the National Institutes of Health Chemical
Genomics Centre. The study was published in the journal Environmental
Science & Technology. Richard Judson and colleagues note that more
than 1.5 million gallons of dispersants have been used so far in the
Deepwater Horizon spill. These detergent-like chemicals break up oil
slicks into small drops. Scientists are concerned that some
dispersants contain ingredients that turn into endocrine disruptors
in the environment, and could harm marine mammals, fish, and humans.
But only limited toxicity testing data is available on currently-used
dispersants, and this is only results from the first round of EPA
dispersant testing, they state. With an urgent need for such
information in the Deepwater Horizon spill, the scientists applied a
rapid screening method using mammalian cells to determine the eight
dispersants' potential to act as endocrine disruptors and relative
toxicity to living cells. The dispersants included a type widely
being used to treat the Gulf oil spill. None of the substances showed
significant endocrine disruption activity and cytotoxicity was not
seen until dispersants were tested at concentrations above 10 parts
per million, the scientists said. However, they note that "there are
other routes by which chemicals can cause endocrine disruption, as
well as other types of toxicity that have not been tested for here."
Science Daily, 22 July 2010
<a href="http://www.sciencedaily.com">http://www.sciencedaily.com</a>
~dGossip
~tChemicals higher, thyroid hormone lower in pregnant women near ewaste recycling
~w2010-07-27
Yet another study has raises concerns regarding e-waste recycling and
its effects on human health following a new report, which found that
pregnant women in China who live nearer the facilities have higher
levels of toxic chemicals and depressed levels of thyroid hormones.
Pregnant women who live in areas close to electronic waste
dismantling sites have higher exposures to persistent organic
pollutants and depressed thyroid hormone levels than those who live
farther away from the facilities, a new study that compares women in
two regions of China, has found. Despite the fact that they have no
interactions with the e-waste facility, the recycling activities
affect the women living adjacent to the sites. This study raises
concerns about e-waste practices and health effects on both the
mothers and the developing foetuses. This is the first study to
evaluate the levels of these three groups of pollutants in people who
live near e-waste recycling sites and to determine their effect on
thyroid hormone levels. The results of this study mostly agree with
findings from the few prior studies that have also looked at the
effects of the chemical groups – either alone or in pairs – on
thyroid hormones. PCBs and PBDEs are widely-used chemicals found in
electronic products. PCDDs/Fs are typically formed when the
electronic products containing these chemicals burn – as sometimes
happens during their gutting and recycling. These chemicals have been
either banned or phased out from use due to persistence,
bioaccumulation and toxicity concerns. Yet, the compounds are still
present in residential areas and in consumer products. Electronic
waste recycling – including burning, acid leaching and dismantling –
can release the pollutants into the air, water and soil where people
can be exposed to high levels. All of the chemicals measured affect
thyroid regulation in animal exposure studies. Several of these
studies document significant associations between exposure to the
contaminants and depression of thyroid hormone levels in both
children and adults. Steady thyroid hormone levels are critical to
the developing foetus, particularly for physical and mental
development. Low thyroid hormone levels can cause delays and brain
and nervous system problems.
During the study, the researchers examined 50 pregnant women who
lived in two different regions in southeast China for at least five
years. One region is a well-known e-waste recycling area (zone A), in
which recycling has been going on for more than 25 years. The second
region represents a control reference site (zone B) and is located
more than 250 kilometres away from the first region. Researchers
measured the levels of about 17 chlorinated dioxins (i.e. PCDDs and
PCDFs), six polychlorinated biphenyls (PCBs) and six polybrominated
diphenyl ethers (PBDEs) in cord blood collected during delivery.
Thyroid hormone levels – T3, thyroxine (T4) and thyroid stimulating
hormone (TSH) – were measured in the women’s blood samples taken
during the sixteenth week of pregnancy. The results demonstrated that
in general, women living near the recycling facilities had higher
body burdens – and thus, higher exposures – to all three chemical
classes than the women who lived farther away. Median concentrations
of PCDDs/Fs, PCBs and PBDEs in cord blood collected from those who
live close were 3 times, 5.4 times and 1.4 times higher,
respectively, than the levels measured in cord blood collected from
women who lived farther away. Furthermore, total thyroxine and
thyroid stimulating hormone (TSH) were significantly lower in women
nearer the recycling activities. The researchers found that as
PCDDs/Fs and PCBs levels increased, levels of T4 decreased. This
association was statistically significant. The researchers concluded
that the findings from the latest study suggest that further research
into human health effects of both employees in e-waste sites and for
people living in cities with e-waste facilities from exposure to
chemicals released during e-waste practices is warranted.
Environmental Health News, 20 July 2010
<ahref="http://www.environmentalhealthnews.org/">http://www.environme
ntalhealthnews.org/</a>
~dGossip
~tRecreational Pool Disinfectants Linked to Health Problems
~w2010-07-27
Splashing around in a swimming pool on a hot summer day may not be as
safe as you think. According to the finds from a new study by
researches at the University of Illinois, the application of
disinfectants in recreational pools is linked to previously published
adverse health outcomes such as asthma and bladder cancer. Each year,
339 million visits take place at pools and water parks across the
United States. Not only is swimming fun, but it's also the second
most popular form of exercise in the country. Because of this,
disinfection of recreational pools is critical to prevent outbreaks
of infectious disease. However, Michael Plewa, U of I professor of
genetics, said negative outcomes can occur when disinfection byproducts form reactions with organic matter in pool water. Pool water
represents extreme cases of disinfection that differ from the
disinfection of drinking water as pools are continuously exposed to
disinfectants. "All sources of water possess organic matter that
comes from decaying leaves, microbes and other dead life forms,"
Plewa said. "In addition to organic matter and disinfectants, pool
waters contain sweat, hair, skin, urine, and consumer products such
as cosmetics and sunscreens from swimmers." These consumer products
are often nitrogen-rich, causing concern that they may contribute to
the generation of nitrogenous disinfection by-products, Plewa added.
When mixed with disinfectants, these products may become chemically
modified and converted into more toxic agents. These disinfection byproducts can mutate genes, induce birth defects, accelerate the aging
process, cause respiratory ailments, and even induce cancer after
long-term exposures.
In this study, collections from public pools and a control sample of
tap water were evaluated to identify recreational water conditions
that could be harmful to your health. During the new study, a
systematic mammalian cell genotoxicity analysis was used to compare
the water samples. Plewa said this sensitive DNA technology examined
genomic damage in mammalian cells, allowing researchers to
investigate damage at the level of each nucleus within each cell. The
study compared different disinfection methods and environmental
conditions. The findings proved that all disinfected pool samples
exhibited more genomic DNA damage than the source tap water, Plewa
said. "Care should be taken in selecting disinfectants to treat
recreational pool water," Plewa advised. "The data suggest that
brominating agents should be avoided as disinfectants of recreational
pool water. The best method to treat pool waters is a combination of
UV treatment with chlorine as compared to chlorination alone." Plewa
recommends that organic carbon be removed prior to disinfection when
the pool water is being recycled. Furthermore, swimmers can help
reduce the genotoxicity of pool water by showering before entering
the water. Pool owners should also remind patrons about the potential
harm caused by urinating in a pool. These simple steps can greatly
reduce the precursors of toxic disinfection by-products, Plewa said.
Science Daily, 22 July 2010
<a href="http://www.sciencedaily.com">http://www.sciencedaily.com</a>
~dGossip
~tNew membrane makes fresh water from sea and sewage feasible
~w2010-07-27
A special membrane turns salty sea water into fresh water, paving the
way for large-scale desalination that would provide desperately
needed drinking water. The technology, developed by researchers at
Yale University, can clean and purify water from oceans, salty ground
water or sewage water with far less energy input than currently is
required to do a similar job. The membrane may be a big step forward
in reaching the goal of reliable and affordable sources of fresh
water. Finding sustainable sources of clean drinking water is a major
global challenge, especially in most of the developing world. The
need is apparent in both urban areas, due to growing population and
demand, and rural regions, where sometimes scarce water supplies are
quickly drying up. As fresh water becomes more scarce, desalination
and filtering will be increasingly necessary to satisfy the world’s
unquenchable thirst for this precious commodity. Yet, neither of the
existing desalination technologies – distilling sea water vapours by
boiling then collecting the water vapours or reverse osmosis where
water is pushed through membranes to filter the salt – are feasible
on a large scale. Both require high amounts of energy to either boil
the water or create pressure. A newer approach does not require
external heat or pressure but lacks an adequate membrane to filter
the water. The technique uses a mixture of dissolved carbon dioxide
and ammonia gas in water on one side and salty or dirty water on the
other side of the membrane. The gas/water mixture draws the clean
water through the membrane and leaves the salt and dirt on the other
side. A small amount of heat is then applied to drive off the carbon
dioxide and ammonia, leaving just pure, fresh water. However, no
current membranes can stand up to the ammonia. Now, researchers
report that they have developed one – a thin-film composite forward
osmosis membrane. They describe the new development in the journal
Environmental Science and Technology. The membrane is permeable
enough to allow water to flow freely through it but resistant enough
to keep the ammonia and chemicals in sewage from passing through it.
This landmark development is a beginning. More research is required
to bring down the costs of the membranes and make this technology
accessible in all parts of the world.
Environmental Health News, 20 July 2010
<ahref="http://www.environmentalhealthnews.org/">http://www.environme
ntalhealthnews.org/</a>
~dGossip
~tKey Finding: Many Pathogenic Fungi Use the Same Entrance to Invade
Host Cells
~w2010-07-27
In a new study, researchers have discovered that many deadly
pathogens use the same protein to gain access to the cells of a
potential host. The new findings could have implications for blocking
infections by agents ranging from wheat rust to malaria. Pathogenic
fungi, such as flax rust and soybean rust, and similar pathogens
known as oomycetes, such as the organism behind the Irish potato
famine and sudden oak death, make similar proteins to disarm their
hosts' defences. But to work, these effector proteins need to first
make their way inside of a cell. Up until now, researchers did not
know, in the first place, how these compounds were able to break in.
The new study, published in the journal Cell, describes how these
blights do it. To infect a plant, pathogenic fungi and oomycetes make
a protein called RXLR—a type of effector protein—which enters plant
host cells and blocks the plant's defences. However, the new research
shows that both of these types of organisms are able to insert their
effector proteins inside the cell by binding with a single type of
lipid on the host cell's surface. This union allows the effector
protein to be carried into the cell through the cell wall, where it
can start doing damage. "Even though they're very different, they're
using a similar mode of entry," says Shiv Kale, a National Science
Foundation graduate research fellow at Virginia Tech's Virginia
Bioinformatics Institute and lead author of the new paper, of the
various plant pathogens. The "key" that the pathogens use to get into
host cells is a lipid known as phosphatidylinositol-3-phosphate (or
PI-3-P). That such different organisms would make use of a single
lipid was a surprise to Kale and his colleagues. And although PI-3-P
had been described before, "that lipid is predominantly on the inside
of the cell," Kale says, so finding it on the exterior surface of the
cells was "really exciting." Even though the universality of the
lipid use was unexpected, "it makes sense from an evolutionary
standpoint," Kale explains. If the single key could give pathogens
access to a multitude of hosts, the talent would be worth keeping
around, leading Kale to conclude that the pathogens' mode of entry is
probably "ancient and highly conserved." The single common technique
for entry could be salutary for humans and the crops we depend on,
though, as researchers in agriculture and medicine strive to find the
best ways to block fungal and oomycete infections.
"The finding is no doubt a breakthrough in host–pathogen
interaction," Takao Kasuga and Lynn Epstein, both of the Department
of Plant Sciences at the University of California, Davis, noted in a
joint e-mail. "We now know how pathogens' effector proteins are
delivered into host cells." These lipid receptors were not just found
on the surface of the plant cells tested by Kale and his colleagues,
but on some animal cells as well—including human lung epithelial
cells. Kale is hopeful that the findings might someday be put to use
in new treatments that could suppress PI-3-P and block the pathogen's
path. "It seems that if you can find a target for this entry
mechanism, you could develop a therapeutic," he says. Such a
medication might be useful to patients who have compromised immune
systems and fall prey to fungal infections that healthier individuals
can usually fight off, such as those with AIDS who are more
susceptible to cryptococcal meningitis, a fungal infection that can
attack the nervous system. However, the new data did not illuminate
whether any of the host's biological processes would be interrupted
if the binding capabilities of their cells' external PI-3-P were
inhibited, Kale says. And not everyone is sure blocking the host's
binding lipid is going to be a simple approach. The substance in
question is "a ubiquitous and extremely important part of the cell
membrane," Kasuga and Epstein noted. "Manipulating and blocking of
effector–PI-3-P interactions without interfering with PI-3-P
functions in healthy cells may be a challenge." More broadly, the
findings could help to shed light on other scourges, such as malaria.
Red blood cells, which malaria infects, have not been shown to have
PI-3-P on their surfaces. Nevertheless, the malaria parasite
Plasmodium seems to have developed a similar mechanism for entering
the cells, Kale notes. Furthermore, examining various entry methods
of pathogens, researchers like Kale hope to zero in on an early,
possibly universal step in the infection process. Currently,
scientists from various disciplines are designing new trials to start
putting these findings to work in agricultural and medical realms.
Kale notes that this sort of basic discovery, although minute, is
just the kind of jumping-off point many basic science researchers
dream of. He hopes that eventually preventive treatments will "have
some benefit to humanity because of it."
Scientific American, 23 July 2010
<a href="http://www.sciam.com">http://www.sciam.com</a>
~dGossip
~tBetter Sampling Needed in Wastewater Monitoring
~w2010-07-27
A new study by Australian researchers has shown that improper
sampling protocols to detect pharmaceuticals, personal care products,
and illicit drugs in sewage can lead researchers to misestimate the
chemicals' concentrations or miss the pollutants altogether. The new
study was published in the journal Environmental Science &
Technology. Chemical contaminants appear and disappear over time in
wastewater, so whether or not researchers detect them depends on when
and how frequently scientists collect samples. Scientists want to
quantify the flux of pharmaceuticals, personal care products, and
illegal drugs through sewage systems to determine how much we release
into the environment and to improve sewage plants treatments.
However, many scientists lack the instruments that can monitor these
contaminants' dynamics with sufficient time resolution, says
environmental engineer Christoph Ort of the University of Queensland
in Australia. In a separate study, Ort and colleagues examined 87
recent papers that studied 267 different sewer sites, and found that
the authors didn't cite or heed internationally-accepted sampling
practices. Researchers often collected samples too infrequently and
then pooled all their samples together for analysis; in doing so,
they lost all information about the dynamics of a compound over time
and possibly missed pollutants. In the present study, Ort and
colleagues illustrate the point by tracking a medical-imaging
contrast agent at a sewage treatment plant that served 100,000
inhabitants. Based on how frequently doctors use the chemical, the
investigators estimated that at most one or two people in that
population would excrete the compound into the sewage system during a
weekday. Then, the researchers monitored the wastewater over a fourhour time period. To ensure that they didn't miss a single toilet
flush, they collected 120 samples, each consisting of two minutes of
wastewater flow. When they analysed the samples by mass spectrometry,
the contrast agent only showed up in 30. If they had sampled less
frequently, the scientists may have missed its presence completely.
Scientists often resort to improper sampling because of expense or
logistical limitations, says chemist Bruce Brownawell at Stony Brook
University in New York, but this study highlights its pitfalls: "It
makes us vigilant about paying attention to the sampling methods."
Chemical & Engineering News, 23 July 2010
<a
href="http://pubs.acs.org/cen/news">http://pubs.acs.org/cen/news</a>
~dGossip
~tVitamin C helps fight cancer
A new study, led by Associate Professor Margreet Vissers of the
University of Otago’s Free Radical Research Group, is the first real
evidence of a connection between vitamin C and tumour growth.
Associate Professor Vissers says “Our results offer a promising and
simple intervention to help in our fight against cancer, at the level
of both prevention and cure”. The new study was published in the
journal Cancer Research. The role of vitamin C in cancer treatment
has been the subject of debate for many years, with many anecdotal
accounts of the beneficial role of vitamin C in both the prevention
and treatment of cancer. In previous studies, Associate Professor
Vissers has demonstrated the vitamin’s importance in maintaining cell
health and hinted at its potential for limiting diseases such as
cancer. In her latest research, she investigated whether vitamin C
levels were lowered in patients with endometrial tumours. The study
examined whether the cancer cells had low vitamin C levels and
whether this correlated with tumour aggressiveness and resistance to
chemotherapy. Associate Professor Vissers and her colleagues
discovered tumours were less able to accumulate vitamin C compared
with normal healthy tissue, and that this related to the ability of
the tumour to survive and grow. Tumours with low vitamin C levels had
more of a protein called HIF-1 which allows them to thrive in
conditions of stress. The findings are significant as they show, for
the first time, a direct relationship between HIF-1 and vitamin C
levels in tumours and suggest it would be beneficial for people with
cancer cells to have more vitamin C. This could help limit the rate
of tumour growth, increase the responsiveness to chemotherapy and may
prevent the formation of solid tumours.
Science Alert, 19 July 2010
<a
href="http://www.sciencealert.com.au">http://www.sciencealert.com.au<
/a>
~dGossip
~tResearchers Model Personal Pollution Exposure
~w2010-07-27
In a new study, researchers have concluded that people's diet, not
their local environment, best determines their pollutant loads.
Environmental toxicologists would like to better predict how much
organic chemical pollution settles into our bodies, but two
roadblocks stand in their way. Scientists don't know the exact
emission rates of these chemicals or how quickly they biodegrade in
the environment. A new study sidesteps these data gaps and finds that
people's diets matter more than their local environment. Organic
contaminants, such as plasticisers and pesticides, make a long,
complicated trip through the environment to us. "This complexity
leads to great variability in human exposure between ecosystems,"
says Emma Undeman, an environmental chemist at Stockholm University
in Sweden. For example, even though pollution emissions in the Arctic
are very low, people who live there accumulate greater levels of
harmful chemicals than people living in higher-emitting temperate
regions. Undeman and her colleagues wanted to find a novel way to
predict this variability that overcame toxicologists' two roadblocks.
They started by asking a question: If different ecosystems, such as
the tropics or the Arctic, had identical emission levels and you
compared people's contaminant loads in each region, how would they
differ? To answer their question, the scientists combined two models:
one that calculates how chemicals move in an ecosystem and one that
analyses how the chemicals behave in that region's food chain. The
models took into account environmental factors such as temperature
and precipitation along with details about people's diet from each
region.
With their linked-up models, the researchers set pollution emission
rates equal for all ecosystems and estimated a person's average
pollutant exposure in each region. They then normalised each region's
estimates to that of the temperate zone to create an exposure
susceptibility index, which allowed them to rank exposures for each
region. Not surprisingly, the Arctic came out on top. But the gap
between the Arctic and other regions was larger than expected: A
person living in the Arctic is about 520 times more susceptible to
some pollutant exposures than a person eating a mixed diet in the
temperate zone, the scientists estimated. Surprisingly, diet was the
key factor, Undeman says. "The Arctic is a very susceptible
environment because people there eat seal, which is a very good
exposure vector for chemicals," she says. Seals and other marine
mammals pack a high pollutant load because they live longer and feed
on predatory fish that bioaccumulate contaminants. Because vegetables
sit at the bottom of the food chain and amass fewer pollutants,
vegans in temperate zones were the least susceptible, the researchers
concluded. Frank Wania, an environmental chemist at the University of
Toronto, Scarborough in Canada and a co-author of the study, says
that these calculations show that policymakers can't take risk
assessments for the well-studied temperate region and apply them
elsewhere, because the risks vary by several orders of magnitude. Tom
McKone, an environmental health scientist at the University of
California, Berkeley, agrees that these susceptibility calculations
could be powerful tools for policymakers: "It takes a complicated set
of processes and integrates it into a single number that makes
sense."
Chemical & Engineering News, 22 July 2010
<a
href="http://pubs.acs.org/cen/news">http://pubs.acs.org/cen/news</a>