Archives for the month of: August, 2012

From Harvard Gazette:

Life evolved in a toxic world long before humans began polluting it, according to a University of Massachusettsenvironmental toxicologist, who added that understanding life’s evolutionary response to environmental poisons can help people to fight destructive effects.

Emily Monosson, an adjunct professor in the UMass Department of Environmental Conservation and author of the book “Evolution in a Toxic World,” said that an understanding of both how rapidly and how slowly life can evolve to fight toxic pollutants is largely missing from toxicology, which is the science of understanding the effects of poisons on life, particularly human life.

Monosson, who spoke Thursday at Harvard’s Haller Hall in an event sponsored by the Harvard Museum of Natural History, said lessons from our evolutionary past that might help us avoid trouble have been ignored by toxicologists and industry alike.

Monosson said she wrote the book in an effort to get toxicologists to think differently about their field, which she said still uses tools that are 40 years old and badly need updating.

“The basic point of doing this book is to get toxicologists to look differently at our field,” Monosson said. “Toxicology needs to change.”

Examples abound on the ramifications of rapid evolution, she said. Bacteria reproduce so fast that they quickly evolve resistance to drugs used to treat disease, resulting in frightening new ailments such as multidrug-resistant tuberculosis. Similarly, insects can rapidly evolve resistance to pesticides, and weeds can evolve resistance to herbicides.

“Roundup Ready” soybeans offer an example where a better understanding of the rapidity of evolution might have helped, Monosson said. The soybean was genetically modified to be resistant to the herbicide Roundup, which could then be sprayed on soybean fields, where it would kill weeds but not the soybeans. Officials believed that the weeds would not become resistant to Roundup. But after blanket applications, it appears that some resistance is evolving.

Slow evolutionary change also holds lessons for toxicologists and industry, Monosson said. Estrogen receptors help to control the body’s use of the critical reproductive hormone. Some industrial chemicals bond with the receptor, widely disrupting reproduction of an array of creatures.

Estrogen receptors are highly conserved, meaning they are widespread among many kinds of creatures and have changed extremely slowly over time, an indication of their evolutionary importance. An understanding of that importance would have helped officials predict that chemicals interfering with them would have widespread and deleterious environmental effects, Monosson said.

“There’s a lot of problems we could have avoided if we understood the power of evolution in the presence of toxic chemicals,” Monosson said.

It is unknown how humans today will respond to the many chemicals, usually at low levels, that our bodies are carrying. Some of these chemicals may be harmless alone but could have interactions with other chemicals in our bodies, Monosson said.

“Those chemicals in us today weren’t in our grandparents,” Monosson said. “If we take an evolutionary approach to understand how systems evolved to detoxify chemicals, maybe we can learn how to do it [ourselves].”

A toxic Earth is nothing new to life, Monosson said. When life began 3.8 billion years ago, there were poisons all around. Besides the presence of metals and other toxins in the environment, early microbes were bombarded from above. The early Earth had little oxygen in the atmosphere and no protective ozone layer to shield the microbes from ultraviolet (UV) rays.

In response, early life evolved an enzyme, photolyase, to repair the UV damage to DNA. That enzyme, though lost in most mammals, remains widespread in other types of creatures.

Another early example involved oxygen, which is very reactive and on the early Earth acted like a poison. Life has since evolved to handle and depend on oxygen. One strategy evolved to break down hydrogen peroxide, a highly toxic chemical that forms naturally in the presence of oxygen, water, and UV rays. Early life developed an enzyme called catalase to detoxify hydrogen peroxide, accelerating the natural breakdown process from weeks to a fraction of a second.

In the future, climate change promises to alter the range of many creatures, putting them in new environments to which they’ll have to adapt. The ozone hole is exposing creatures to higher levels of UV radiation than they’re adapted to handle. And human-generated pollutants continue to be released into the environment, presenting an environmental challenge for a wide array of creatures.

Some, like Hudson River fish that have evolved to thrive despite the presence of polychlorinated biphenyls (PCBs), will evolve their own solutions, but others may need human intervention to handle an environment whose toxicity is changing much more rapidly than in the past.

“The problem today is that in a blink of time, we changed the Earth,” Monosson said. “We’ve added a lot of new synthetic chemicals and redistributed a lot of natural chemicals.”

Read entire article here.

Image by Kris Snibbe/Harvard Staff Photographer.

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Dr. Sanjay Gupta compares how the U.S. and the European Union regulate chemicals.

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CNN’s Dr. Sanjay Gupta explains why a 1976 toxic chemical law may be putting Americans at risk.

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From :

NRDC’s Larry Levine describes the successful, decades-long battle to clean up General Electric’s toxic PCBs from the Hudson River and gets a tour of the cleanup project with EPA.

We dump billions of tons of carbon pollution into the atmosphere each year. As a result, the concentration of carbon dioxide has increased by 40%. Excess carbon dioxide traps excess heat in the atmosphere. Excess heat causes extreme heat waves, droughts, and storms.

This year’s extreme weather follows last year’s. The last twelve months were the hottest on record for the United States. Texas saw its hottest and driest summer on record in 2011 by a wide margin, and research published recently shows that carbon pollution dramatically increased the probability of such extreme heat and drought. The data are in. This is what global warming looks like.

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This ScienCentral News video describes new research suggesting how tiny particles from vehicle emissions can cause heart disease and other problems.

From the Myrtle Beach Sun News: Mutant fish: A puzzle in the water (by Claudia Lauer, September 29):

Longtime Bucksport residents know every curve in the dirt road leading to the Bull Creek boat landing.

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Fishing and wading in the muddy waters is almost second nature for generations of residents who grew up as river folks, but something in the creek is starting to worry some residents.

A U.S. Geological Survey study released in September 2009 reported that 90 percent of the largemouth bass pulled from the creek during the study had male and were developing female reproductive cells. A year after the study was finished, residents still have questions about the effects of the fish on people and whether something in the water — the same water filtered for drinking water for many Horry County residents — is causing what biologists call endocrine disruption, which makes reproduction for the fish more difficult.

The problem is not confined to Bull Creek, but the Pee Dee Basin had the highest incidence of intersex fish in the study. The study looked at river basins all over the country and found that about half of them had some instances of intersex fish. The only river basin examined that didn’t show any problems was Alaska’s Yukon River Basin. In parts of the Mississippi River in Minnesota and the Yampa River in Colorado, 70 percent of the smallmouth bass had female signs. Scientists and residents say more research must be done to determine which of the many possible environmental contaminants to the water may be causing the issue in the fish and whether it’s something being done locally or upstream.

Steve Howell, like many of the lifelong residents, feels some ownership in the creek that he, his family and his friends have fished for generations.

“What about taking baths, drinking the water, cooking and etc. with the water from your tap that is coming straight out of the same river that is highly contaminated that it is screwing the fish up?” Howell said. “Since it is affecting the fish in such drastic ways as this, then what is it going to do to humans over a period of time, and why isn’t anyone or any group doing a study to try and find out?”

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A number of contaminants have been suspected as the cause of the endocrine disruption. Researchers are studying the effects of livestock farming, of industrial chemicals, and of hormones and other chemicals that find their way into waste water. Hormones and birth control pills have become more commonplace and leave the human body in our waste.

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Howell said he plans to continue fishing in the creek, but he’s wary of what the long-term effects could be.

“You want to know what is happening because if the water is doing that to the fish, then what happens to us?” he said. “What happens to women who are pregnant or babies that aren’t born yet? You want to know what they’re doing to make sure we’re safe and whether there’s more happening other than here’s this study and we don’t know why it’s happening or what it means.”

Read the entire article here.

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