Infants are widely exposed to a class of chemicals that might be harmful to their
reproductive systems. That’s according to new research published today/this week
(Monday, February 4th, 2008) in the journal Pediatrics. Mark Brush reports – the
chemicals are known as phthalates:
Transcript
Infants are widely exposed to a class of chemicals that might be harmful to their
reproductive systems. That’s according to new research published today/this week
(Monday, February 4th, 2008) in the journal Pediatrics. Mark Brush reports – the
chemicals are known as phthalates:
Phthalates are everywhere. They’re used to make plastics softer. And they’re used in
perfumes, shampoos, and lotions to help the product absorb into your skin.
Researchers at the University of Washington found that infants had higher concentrations of phthalates in their urine if their mothers used baby lotions, shampoos and powders.
Dr. Sheela Sathyanarayana led the study. She says it can be hard to avoid phthalates:
“In terms of personal care products and cosmetics, we don’t know. The products are not
labeled to contain phthalates in them, and so it’s very, very difficult to kind of counsel
families about what to do.”
Sathyanarayana says more study is needed to determine human health effects. Animal
studies have shown that the chemicals can change hormone levels, leading to
reproductive problems in males.
She's cute, but what about all those diapers? (Photo by Mark Brush)
Elizabeth Parise holds 5-month-old Jack (a "diaper-free baby") on his potty. (Photo courtesy of DiaperFreeBaby)
7-month-old Jack adjusts his underwear as he sits on the potty. (Photo courtesy of DiaperFreeBaby)
There’s a reason more than 90% of American parents choose disposable
diapers over cloth. Nothing beats the convenience of disposable
diapers. But what about their effect on the environment? Reporter
Mark Brush has two little ones at home and decided to take a closer
look at the question:
Transcript
There’s a reason more than 90% of American parents choose disposable
diapers over cloth. Nothing beats the convenience of disposable
diapers. But what about their effect on the environment? Reporter
Mark Brush has two little ones at home and decided to take a closer
look at the question:
My wife and I didn’t hesitate in our decision about diapers. We went
with disposables from the start.
(Sound of baby crying)
Raising kids can be hard work. The convenience of disposable diapers
was just too much to pass up. But what does that decision mean for the
environment? I mean, if I do the math, we’ve got a three-year-old who’s
out of diapers. And a one-year-old who’s going through three or four a day now. Over
the years, we’ve dumped about 5,480 diapers into a nearby landfill.
Five thousand four hundred eighty. Going with disposables can’t be
good, can it?
Well, as it turns out, the answer is pretty darned complicated. There
have been several studies done on diapers and the problems they create.
Most recently, a study was done on diapers by the Environment Agency in
Great Britain.
It compared disposable diapers with cloth diapers washed at home, and
cloth diapers from a diaper service. In the end, they said, there were no clear
winners. So disposables aren’t so bad, right?
Well, not so fast, says Greg Keoleian. He’s the co-director of the
Center for Sustainable Systems at the University of Michigan. Keoleian
says it all depends on where you live:
“In evaluating life cycle results you should look at local conditions.
For example if you’re in an area where water is scarce, like let’s say
Arizona, then you want to weigh that factor more heavily in your
decision.”
Keoleian says since I live in an area where landfill space is short,
and where water is plentiful… I might want to consider cloth diapers,
so, I bring the idea home to my family:
(Mark:) “What do you think, Andrea? Do you think we should try cloth
diapers?”
(Andrea:) “No.”
(Mark:) “Why?”
(Andrea:) “‘Cause you might have to send me to the Looney bin.”
(Eli:) “Well, Mom, then you don’t have to through them away.”
(Andrea:) “That’s true, you’ve got a good point.”
(Eli:) “You only have to wash them.”
(Andrea:) “Yep, that’s true. And you know what, my Mom and Dad always
washed all of our diapers. She was a better woman than I am…
(laughing)”
(Sound of baby crying)
But today, the choices are different than they were for our parents. It’s not just about cloth vs. disposable anymore. There are tons of different choices. For instance, I went down the street to our friend
Melissa’s house.
She and her husband have a two-year-old. They’ve tried out a bunch of
different diapers including one you can flush down the toilet. The
point of the G-diaper, Melissa says, is to treat the waste – rather than simply throwing
it in your garbage can:
“So then when you go to change him… you take it out… and then you put it
in the toilet and they give you a swish stick. And then you swish it
as it’s flushing – therefore you won’t clog up your toilets. Now, I did
notice that when I used these in public restrooms and I didn’t have my
swish stick I would kind of clog up the toilet sometimes… it all
depended on the toilet. So for going out, the G-diapers for me didn’t seem
to be such a good idea because I hated clogging up the toilets (laughs).”
Melissa says after problems like this, she eventually switched to a kind of disposable diaper
that’s supposed to be better for the environment.
Now, if you really want to think outside the box, there’s another choice that might come in handy. It’s a practice called Diaper Free: No diapers. Parents help their infants go to the toilet when nature calls. Erin LaFreniere is a sort of local expert on the Diaper Free method:
“Diaper Free is a little bit misleading because people think you’re not
wearing a diaper, oh that must be horrible, how can you deal with the mess, that’s not sanitary. And really, diaper
free really means not being stuck with diapers all the time.”
LaFreniere says parents still use diapers, just not as often. They
learn how to pick up on their infant’s cues, and when it’s time they
take them to the bathroom. She says cutting back on diapers is a side
benefit. For her, learning how to communicate with her baby was more
important.
But, I don’t know. I can’t imagine the diaper free idea going over well at home. I mean, our lives are really busy and it’s hard enough for us to keep up. Disposable
diapers are just too convenient.
I guess it’s like a lot of decisions people make in their lives:
convenience will often trump a slight benefit to the environment.
And experts I talked to said if we take a look at all the impacts we have on the
environment, diapering is pretty low on the list. So, my wife and I can do right by the environment somewhere else in our lives.
Air deposition is when air pollution settles out into lakes and streams and becomes water pollution. (Photo by Lester Graham)
We’re continuing our series, Ten Threats to the Great Lakes. Our guide through the series is Lester Graham. In this report he explains one of the threats that experts identified is air pollution that finds its way into the Great Lakes:
Transcript
We’re continuing our series ‘Ten Threats to the Great Lakes’. Our guide through the
series is Lester Graham. In this report he explains one of the threats is air pollution that
finds its way into the Great Lakes:
It’s called ‘Air Deposition.” Melissa Hulting is a scientist at U.S. Environmental
Protection Agency. We asked her just what that means:
“Air deposition simply is just when materials, in this case pollutants, are transferred from
the air to the water. So, pollutants in particles can fall into the water. Pollutants in rain
can fall into the water, or pollutants in a gas form can be absorbed into the water.”
So, it’s things like pesticides that evaporate from farm fields and end up in the rain over
the Great Lakes. PCBs in soil do the same. Dioxins from backyard burning end up in the
air, and then are carried to the lakes
One of the pollutants that causes a significant problem in the Great Lakes is mercury. It
gets in the water. Then it contaminates the fish. We eat the fish and mercury gets in us.
It can cause babies to be born with smaller heads. It can cause nervous system damage
and lower IQ in small children if women of childbearing age or children eat too much
fish.
One of the notable sources of mercury is from power plants that burn coal.
(Sound of coal car)
Railroad cars like this one empty their tons of coal at power plants all across the nation.
More than half of the electricity in the nation is produced at coal-burning power plants,
and with a 250-year supply, coal is going to be the primary fuel for a while.
One coal producing state is acknowledging that mercury is a problem. Doug Scott is the
Director of the Illinois Environmental Protection Agency. He says coal is important to
the energy mix, but we need to reduce pollutants such as mercury as much as possible.
“The policy of the state has been to try to work with the power plants to try to burn
Illinois coal as cleanly as you can. Now, that means a lot more equipment and a lot more
things that they have to do to be able to make that work, but we’re committed to trying to
do both those things.”
And, Scott says the federal government’s mercury reduction program does not go far
enough soon enough, but the electric utility industry disagrees.
Dan Riedinger is spokesman for the Edison Electric Institute, a power industry trade
organization. Riedinger says, really reducing mercury emissions at power plants just
won’t make that much difference.
“Power plants contribute relatively little to the deposition of mercury in any one area of
the country, including the Great Lakes, and no matter how much we reduce mercury
emissions from power plants in the Great Lakes Region, it’s really not going to have a
discernable impact in terms of improving the levels of mercury in the fish people want to eat.”
“Relatively little? Now, that flies in the face of everything I’ve read so far. Everything
I’ve read, indicates coal-fired power plants are a significant contributor to the mercury
issue in the Great Lakes and other places.”
“It’s really not quite that simple. Power plants are a significant source of mercury
emissions here in the United States, but most of the mercury that lands in the Great
Lakes, particularly in the western Great Lakes is going to come from sources outside of
the United States.”
Well, it’s not quite that simple either. The U.S. EPA’s Melissa Hulting agrees some of
the mercury in the Great Lakes comes from foreign sources, but recent studies show
some mercury settles out fairly close to the smokestacks. She says you can blame both
for the mercury in your fish.
“You blame the sources that are close by and you blame the sources that are far away.
The bottom line with mercury is that we’re all in this together and it’s going to take
everybody reducing their sources to take care of the problem.”
Taking care of the problem is going to take some money, and that will mean we’ll all pay in
higher utility bills. The Illinois EPA’s Doug Scott says it’ll be worth it if we can reduce
mercury exposure to people.
“We know what the issue is. It’s not a matter of us not understanding the connection
between mercury and what happens in fish, and then what happens in humans as a result
of that. We understand that. We know it, and we also know to a great degree what we
can do to try to correct the problem, and so, it’s a matter of just going out and doing it,
and so I’d like to think it’s something that can be done sooner rather than later.”
And since Great Lakes fish have elevated levels of mercury, sooner would be good.
It’ll take a while for the mercury already there to work its way out of the ecosystem and
return to more normal levels.
Women marching on behalf of a campaign to remove phthalates and other chemicals from cosmetics. (Photo courtesy of the Breast Cancer Fund)
Teri Olle and her daughter, Natalie Olle Comerford, enjoy playing dress-up with cosmetics, but they choose to use products with fewer chemicals. (Photo by John Comerford)
There are new concerns that products we use every day to keep us clean and make us beautiful may contain toxic chemicals. The targets are things like shampoos, deodorants, hair dyes and cosmetics. Some companies are taking these concerns seriously and giving themselves a makeover. The Great Lakes Radio Consortium’s Julie Halpert has this story:
Transcript
There are new concerns that products we use every day to keep us clean and make us beautiful may contain toxic chemicals. The targets are things like shampoos, deodorants, hair dyes and cosmetics. Some companies are taking these concerns seriously and giving themselves a makeover. The Great Lakes Radio Consortium’s Julie Halpert has this story:
(Sound of woman and child talking)
Teri Olle is playing dress-up with her two-year-old daughter, Natalie, in the family’s bathroom. Teri is applying lotions to her daughter’s chubby cheeks, while Natalie puts lipstick on her mother.
Little girls like Natalie have been playing dress-up for generations. But Natalie’s game is slightly different. She’s using nail polish, lipsticks and creams made without man-made chemicals.
That’s because her mother is an environmental activist who lobbies against toxic chemical use. With cosmetics, her biggest fear is a group of chemicals called phthalates. Phthalates increase the flexibility of plastic and keep nail polish from chipping.
“Phthalates are testosterone-suppressing synthetic hormones, essentially. And they’ve been linked with all sorts of developmental problems, including, most dramatically, a set of male genital defects that show themselves as birth defects in infant boys.”
Last month, scientists released the first study on male babies. They found a strong link between high levels of phthalates exposure in pregnant women and damage to their sons’ reproductive tract. Studies like this, and others on lab animals showing possible links to reproductive problems, prompted the European Union this past March to ban two types of phthalates from all products sold in Europe. The states of California, New York and Massachusetts are also considering similar plans.
Olle is five months pregnant with her second child. She doesn’t know if she’s carrying a boy, but she says chemicals in cosmetics could be risky for any fetus. So she’s not taking any chances.
“For me, as a person, if someone said to me, ‘You can either use this product that may cause a genital defect in your baby boy or not’, I would think most people would go, ‘Really, we probably shouldn’t be using these products.'”
And it’s not just phthalates that could be a problem. Environmentalists say that the ingredients in cosmetics haven’t been evaluated for health or safety effects. The Food and Drug Administration doesn’t do that kind of testing. And in 60 years, it’s banned only nine ingredients. So there are other chemicals, like coal tars used in hair dyes and formaldehyde used in nail polish, that might cause health problems as they’re absorbed by the skin into the bloodstream.
Because of these concerns, a group of environmentalists called the Campaign for Safe Cosmetics has convinced 136 natural cosmetics companies to sign a pledge to check for potentially toxic chemicals and eliminate them.
One of those companies is Avalon Organics. Over the past year, Avalon’s spent two and a half million dollars to reformulate their products and switch to more natural alternatives. Gil Pritchard is the company’s President and CEO. He says the jury’s out on whether these chemicals definitely cause harm. Even so, he didn’t hesitate to make the investment.
“It’s convincing enough for me and our company to exercise what we call a precautionary principle – to adopt it and say look, we may not have direct scientific evidence, but there’s enough evidence here to say whoa, I can feel the heat from the stove. I don’t need to put my finger on and burn myself to know that that’s one of the likely outcomes.”
But not all companies feel this way. Procter & Gamble, in Cincinnati, Ohio, has not signed the pledge. Nor have any other major cosmetic companies. Tim Long is a company spokesman. He says environmentalists are blowing this issue way out of proportion.
“The amounts of most of these ingredients that the activists have concerns about are, in fact, extremely small and at the doses used in our products, there’s no scientific evidence to support that they’re resulting in any harm to consumers.”
Long says Procter & Gamble complied with the EU directive and took the banned phthalates out of all of its products both in Europe and the U.S. But he says that wasn’t necessary, since phthalates, along with all other cosmetic ingredients, simply aren’t dangerous. He says his company wouldn’t be using them if they were. And the FDA says that these cosmetics are safe.
Environmentalists say that more research needs to be done to better understand the effect of chemicals used in cosmetics on the body. But Teri Olle says that with so many natural alternatives available, it makes sense to be careful.
“When I became pregnant, I definitely became more conscious of what I was putting on my body. I mean, if you’re supposed to avoid soft cheeses and cake batter, it certainly can’t be good for you to be spraying petrochemicals on your body. That definitely can’t be good for the baby.”
So when the baby’s born this September, instead of using products with man-made chemicals, Teri Olle will be spreading diaper rash ointment with beeswax and apricot oil on her newborn baby.
Babies and children are frequently in contact with dust. Some scientists worry that potentially-harmful chemicals found in household dust will result in negative health effects. (Photo by Jason Sellers)
Chemicals that are suspected of being hazardous to human health are being found in household dust. The chemicals are flame retardants used in everything from carpet padding to TV sets. The Great Lakes Radio Consortium’s Mark Brush has more:
Transcript
Chemicals that are suspected of being hazardous to human health
are being found in household dust. The chemicals are flame retardants
used in everything from carpet padding to TV sets. The Great Lakes Radio
Consortium’s Mark Brush has more:
The chemicals are known as poly-brominated-diphenyl-ethers, or PBDEs.
Scientists already knew that these flame retardant chemicals where found in
food. Now researchers are finding the chemicals, in household dust.
Heather Stapleton is a research chemist at the National Institute of
Standards and Technology. She authored a study recently published by the
American Chemical Society.
“I went out and collected some house dust samples from areas within the
Washington D.C. metropolitan area, and brought these samples back to the lab
and just did a preliminary measurement looking at PBDE’s in the house dust
samples and found surprisingly high levels in the house dust.”
Researchers are most concerned about how the chemicals affect developing
babies. Babies have more contact with household dust than the rest of us.
The chemicals have been found to cause developmental and nervous system
damage in rats and mice.
A new study found that pregnant women living in areas with high levels of fine particulate matter (p.m.) give birth to babies that weigh less on average than those born to mothers in areas with low levels of fine p.m. (Photo by Stephen
Rainer)
Cars, trucks and coal-fired power plants contribute to fine particle pollution, or soot. That type of pollution can be harmful for adults with heart or lung problems, and kids with asthma. A new study suggests that the pollution can also affect developing babies. The Great Lakes Radio Consortium’s Rebecca Williams has more:
Transcript
Cars, trucks, and coal-fired power plants contribute to fine particle pollution, or soot. That type of pollution can be harmful for adults with heart or lung problems, and kids with asthma. A new study suggests that the pollution can also affect developing babies. The Great Lakes Radio Consortium’s Rebecca Williams has more:
This study was the first to look at fine particle pollution and developing babies in the U.S. Researchers looked at more than 18,000 babies that were carried to full term in California. They found that mothers living in areas of high exposure to fine particles had babies that weighed about an ounce less than mothers living in low exposure areas.
Tracey Woodruff is a senior scientist with the Environmental Protection Agency. She co-authored the study in the journal Pediatrics. Woodruff says an ounce is a small difference in birth weight, but it’s significant enough to merit more research on particulate matter – also known as “p.m.”
“This is one more piece of information about adverse health effects of p.m., which is feeding into the larger literature, which is leading EPA to embark on a number of different activities to try to reduce the levels.”
Woodruff says future research should look at whether fine particle pollution is related to premature births.
For the Great Lakes Radio Consortium, I’m Rebecca Williams.
Meredith Buhalis and her daughter Zoe. Meredith's breast milk was tested for PBDEs as part of a study by the Environmental Working Group. (Photo by Meredith Buhalis)
Couch cushions often have PBDEs in them... (Photo by Nicholas Sales)
...and so do TVs. Are there any health effects from being surrounded by these chemicals? (Photo by Craig Young)
Flame retardant chemicals help make our lives safer.
The chemicals are designed to keep plastics and foam from
catching on fire, but the flame retardants are worrying some
scientists because these chemicals are turning up in people’s
bodies, sometimes at alarmingly high rates. The Great Lakes
Radio Consortium’s Mark Brush has more:
Transcript
Flame retardant chemicals help make our lives safer. The chemicals are designed
to keep plastics and foam from catching on fire. But the flame retardants are
beginning to worry some scientists because these chemicals are turning up in
peoples’ bodies. Sometimes at alarmingly high rates. The Great Lakes Radio
Consortium’s Mark Brush has more:
If you take a look around your house, you can find a lot of things that have
flame retardant chemicals in them. They’re in your television set, the cushions
in your couch, and the padding underneath your carpet. They’re known as poly-bromiated-diphenyl
ethers, or PBDEs. And they’re either mixed in or sprayed on plastics and foam to keep a fire
from spreading.
Five years ago a Swedish study found these chemicals were accumulating in women’s breast
milk. Studies in the U.S. followed, and researchers also found PBDEs in Americans, but at
even higher levels. In fact, Americans have some of the highest levels ever measured. And
over time, the levels have been going up.
(sound of baby)
Meredith Buhalis was one of those people measured in a study by an envrionmental organization
called the Environmental Working Group. Buhalis and 20 other first time moms sent in samples
of their breast milk. When the samples were tested, all of them had some level of PBDEs in
them. Buhalis says when she read the results she didn’t know what to think.
“I guess I kind of read the results and the study was like, ‘Oh, well that sort of sucks.’
I wish I knew more about what that meant. ‘Cause I don’t. You know, they don’t know what
that means.”
Scientists don’t know how or if the chemicals affect human health. And some scientists
think the government and the chemical companies aren’t doing enough to look into PBDEs.
(sound of typing)
In his office at the University of Texas in Dallas, Dr. Arnold Schecter is working on an
article about the flame retardants. He’s been studying toxic chemicals for more than thirty
years. He and some of his colleagues think PBDEs are a lot like another type of chemical…
“It reminds us of PCBs. PCBs structurally are similar to the PBDEs. So there is the worry,
or the concern, that they may have many, if not all, the toxic effect that PCBs have on humans.”
So far the data on PCBs strongly suggest that the chemicals can cause cancer in humans as
well as other human health effects such as damage to the nervous and immune systems. The
companies that manufacture the flame retardants say it’s not fair to compare PBDEs with
PCBs. They say the chemicals are vastly different.
But no one really knows whether the chemicals are similar in the way they affect human
health. That’s because no one’s studied the human health effects of PBDEs.
“Unfortunately, there are no published human health studies and I don’t believe any have
been funded by the federal government to date. Nor by industry, nor by any foundations,
which is a bit different than the situation with PCBs and dioxins years ago when many
studies were being funded.”
Some animal studies suggest that the chemicals can permanently disrupt the hormone and
nervous systems, cause reproductive and developmental damage, and cause cancer. All that
makes scientists such as Dr. Schecter especially concerned about the most vulnerable
population – developing babies.
Because of the concerns, the biggest manufacturer of these chemicals in the U.S. has agreed
to stop making two of the PBDE formulations that were found to accumulate in people. Great
Lakes Chemical says production will stop by the end of this year. The chemicals will be
replaced with another type of brominated flame retardant.
The Bromine Science and Environmental Forum is a trade group that represents companies
that make the flame retardants. Peter O’Toole is the group’s U.S. Director. He says so
far the amount of chemicals found in people doesn’t concern the companies, but the upward
trend does.
“And again, it wasn’t of alarming numbers, but the manufacturer was concerned that these
numbers were going up nonetheless. And they thought it was prudent, and they talked to the
EPA and EPA thought it was prudent if there was some sort of mutual phase out of those materials.”
Dr. Schecter says he commends the company for taking this step. But he says even though these
two formulations will be phased out, the flame retardants are already in our environment now.
He says his research has found high levels of PBDEs by wiping the plastic casing on television
sets, and in the dust found in homes. He says what’s in our homes now isn’t going to vanish,
so we need to figure out how the chemicals get into us, so we can avoid potential health problems.
For its part, the U.S. Envrionmental Protection Agency says large-scale human health studies
take a long time to develop. An agency spokesperson says the EPA first needs to learn how a
person becomes highly exposed. After that, they say researchers will be able to ask the question,
“for the highly exposed people, are there any health effects?”
(sound of baby)
That leaves people such as Meredith Buhalis, with a lot more questions than answers.
“We are thinking of having another baby, and I think I would really like to know more about
PBDEs. I think about it when I think about that.” (to her daughter) “Oh thank you. Hi, baby.
Hi, Zoe.”
The Federal government doesn’t plan to regulate the chemicals anytime soon. But some states
aren’t waiting for more studies. A handful of states have placed restrictions on certain
types of PBDEs. And in other states, legislation is pending.
For the Great Lakes Radio Consortium, I’m Mark Brush.
Researchers have found a potential toxin in our food. The Great Lakes Radio Consortium’s Mark Brush has an update on the ongoing concern over brominated flame retardants:
Transcript
Researchers have found a potential toxin in our food. The Great Lakes Radio
Consortium’s Mark Brush has an update on the ongoing concern over brominated
flame-retardants:
Brominated flame-retardants, or PBDEs are used to prevent fires in
everything from couch cushions to computer components. Several studies have
shown that there are higher amounts of these chemicals in Americans than in
people anywhere else in the world.
Researchers from the University of Texas recently tested 32 food items from major
supermarket chains in their area. They published their findings in the journal Environmental Science and Technology. They found that all products with
animal fat in them, and one soy-based infant formula, were contaminated with PBDEs.
Dr. Arnold Schecter headed up the study. He says the human health effects have yet to
be understood:
“We don’t know whether these levels by themselves or in combination with
other chemicals could be causing human health effects. And, you know, we’re
particularly worried about the most sensitive population, before birth,
nursing infants, and the elderly, or people with special health problems.”
Experts say they’re concerned about these chemicals because they behave a
lot like PCBs, which are known to cause multiple health problems in humans.
For the Great Lakes Radio Consortium, I’m Mark Brush.
Biologists are looking at how a shark
in a Great Lakes region aquarium gave
"virgin birth" last year. Photo courtesy of
Belle Isle Aquarium, Detroit.
A female shark in an aquarium in the Great Lakes region has apparently given virgin birth. Four shark eggs hatched last year and three of those babies are now growing normally. As the Great Lakes Radio Consortium’s Celeste Headlee reports, it may be some time before the cause can be determined, but the event is still a surprise for biologists:
Transcript
A female shark in an aquarium in the Great Lakes region has apparently given virgin birth. Four
shark eggs hatched last year and three of those babies are now growing normally. As the Great
Lakes Radio Consortium’s Celeste Headlee reports, it may be some time before the cause can be
determined, but the event is still a surprise for biologists:
Biologists have a technical term for virgin birth. It’s called parthenogenesis. Doug Sweet is the
Curator of Fishes at the Belle Isle Aquarium in Detroit. He says parthenogenesis is common in
invertebrates and some amphibians.
“Most vertebrate animals, the females will produce eggs even if the male is not around. And it’s
just a matter of… it’s a chemical trick, basically, to get that egg to develop into an individual
without a sperm activating it.”
But parthenogenesis has been totally unheard of for sharks, until now. Last year, the Henry
Doorly Zoo in Omaha, Nebraska, announced they thought a Bonnethead shark there had
reproduced by parthenogenesis. The baby lived less than 12 hours, though, and genetic tests were
inconclusive.
But when Doug Sweet saw the press release from the Henry Doorly Zoo about a possible virgin
birth, he thought he’d try an experiment. Sweet decided to incubate the eggs of his two female
bamboo sharks. Four of the eggs developed. Sweet says the sharks were acquired by the
aquarium before they had reached sexual maturity, and they have never been exposed to a male.
He says the likely conclusion is that these sharks are reproducing by parthenogenesis.
Two other explanations, though highly unlikely, are that the shark has both testicular and ovarian
tissue, and fertilized its own eggs or that sharks are capable of storing sperm for years and even
passing it down to their offspring. Sweet has sent small clippings from the sharks’ fins to the
Henry Doorly Genetics Lab. Testing has already begun, but Sweet says it could take more than a
year to get the results. In the meantime, Sweet says the facts remain the same: a female shark
has given virgin birth. If it is parthenogenesis, he says, it will have important implications for
biologists around the world.
“Parthenogenesis just hasn’t been considered to happen in sharks; it’s never been recorded. It may
be happening all the time out there, so this is kind of breaking news in the shark world.”
The two adult bamboo sharks and the offspring are currently on exhibit at the Belle Isle
Aquarium in Detroit.
For the Great Lakes Radio Consortium, I’m Celeste Headlee.
States are struggling with ways to warn people, especially women of childbearing years and children, about the hazards of eating too much sport fish contaminated with toxic chemicals.
Health officials are trying to get the word out about contaminants in sport fish. But the issue is complicated. So, it’s difficult to give people an easy answer on how to reduce the health risk. The Great Lakes Radio Consortium’s Lester Graham reports:
Transcript
Health officials are trying to get the word out about contaminants in sport fish. But the
issue is complicated. So, it’s difficult to give people an easy answer on how to reduce
the health risk. The Great Lakes Radio Consortium’s Lester Graham reports:
Sport fish contain contaminants such as PCBs, pesticides, and mercury. But the amount
of contaminants in a fish depends on the body of water, the species of fish, and
even the age of the fish. So, there are very few general guidelines. That makes it difficult for
health officials to tell people what’s best for them.
Faith Shottenfeld is with the New York State Department of Public Health. She says safe
consumption levels vary.
“For some fish, a meal a week, a meal a month. You certainly can talk in general
about eating smaller fish because as you move your way up the food chain, you
know, the bigger fish eat the little fish so they get more and more and more chemicals,
but there are some examples of smaller fish that are highly contaminated.”
Shottenfeld notes that children and women of childbearing age are at more risk
from ill effects of the contaminants in fish than men. She says the best bet is to talk to someone
who’s familiar with your state and area’s fish consumption advisories.
For the Great Lakes Radio Consortium, this is Lester Graham.
