Sunday 5 February 2012

Debate: Fluoridating Tap Water

I was inspired by Ada's previous article to search for more information on this subject. This is part of a very long article from the Globe and Mail which discusses the debate surrounding fluoridating tap water:


Nearly a half-century after water fluoridation became widespread, a small but growing number of medical officials and environmentalists are again raising concerns over the practice.
Recent research is suggesting that fluoride may be connected to a number of serious conditions, including the development in teenage boys of osteosarcoma, the rare bone cancer that killed Canadian icon Terry Fox, reduced intelligence levels in children, and impaired thyroid function.
In Waterdown, Ont., a suburb of Hamilton, Cindy Mayor has approached her city council and asked that it stop fluoridation for the area's 500,000 residents. "Here we are, mass-medicating with a drug," she says. The activist frets that fluoridation could be one reason for the growing number of people being treated for lowered thyroid hormone levels.
She isn't alone in worrying about fluoride, placed in many municipal water supplies to make teeth more resistant to decay.
While those complaining about fluoride were often portrayed as a kooky fringe - typified by the 1964 movie classic Dr. Strangelove, in which a demented U.S. general feared fluoridation was a communist plot - fluoride criticism has recently gone mainstream.
Although the research linking the chemical with serious conditions is disputed, critics of fluoridation say that at the least it indicates a review of the practice needs to be conducted.
A review is even more pressing, in the view of critics, because scientists now believe that the main protective action from fluoride does not come from ingesting the chemical, with the teeth absorbing it from inside the body, but from direct absorption through topical application to teeth.
This means swallowing water is a far less effective way to fight cavities than brushing with fluoridated toothpaste. That may explain the steep decline in cavity rates observed in industrialized countries since the 1970s, irrespective of whether they fluoridate water. Almost all of Europe does not, and yet has seen a sharp reduction in dental caries.
"I think there is a much broader understanding that there might be some legitimate concerns with fluoride," said Richard Wiles, executive director of the Washington-based Environmental Working Group, a public-interest group that has been lobbying the U.S. National Institutes of Health to provide a second opinion on fluoridation.
About 13.5 million Canadians, or about 43 per cent of the population, live in communities with fluoridated tap water, but almost no fluoridation is done in British Columbia or Quebec, according to Health Canada.
The EWG worries that the public is being overexposed to fluoride, and says water is the easiest source to eliminate.
Fluoridation is based on research from the 1940s, and Mr. Wiles contends that it wouldn't be able to pass a modern risk assessment used for drugs or pesticides.
"We took a look at the science and it was really apparent to us that the current levels of fluoride exposure were unsafe," he said.
The view on fluoride's potential downside is rejected out of hand by Health Canada, as well as the Canadian Dental Association.
"The fluoridation of drinking water supplies is a well-accepted measure to protect public health that is strongly supported by scientific evidence," Health Canada said in an e-mailed statement.
Nonetheless, the department said it is currently studying the recent scientific findings and may adjust the amount it recommends for water.
The Canadian Dental Association also endorses fluoridation. "It's among the greatest public-health measures that has ever been put in place, right up there with vaccination," said Darryl Smith, president of the association.
Dr. Smith worries that if fluoridation critics have their way, it will lead to a loss in the hard-won gains against tooth decay. Currently, about half of the children in Canada younger than 11 don't have cavities.
Although health authorities are confident fluoridation is a good idea, they haven't been very good at picking the optimum dose.
Many jurisdictions have, with little fanfare, recently cut the amount they add, to minimize chances that children will get dental fluorosis, or mottled teeth.
The cuts have been substantial enough to suggest that previous levels to which the public was exposed for more than three decades were too high. Toronto's drinking water, after several reductions, now contains half the fluoride it did before 1999, while the province of Quebec cut the recommended amount by 42 per cent in 2004.
Fluorosis, if severe, causes unsightly staining of teeth, but in mild cases the result is white streaking that many dentists consider cosmetic. During the 1990s, anywhere from 20 per cent to 75 per cent of children were afflicted in fluoridated areas.
Both Toronto and Quebec fluoridate below the level Health Canada believes is optimum: 0.8 to 1 part per million fluoride to water. Toronto is at 0.6 ppm.
Among the recent studies, the most worrisome is the possible association with childhood osteosarcoma.
The disease, the cause of which is unknown, is fatal in about one-third of cases and almost always leads to amputations.
The research indicates that fluoride exposure among boys, but not consistently among girls, during a critical period of bone growth from age 5 to 10 makes them more susceptible to the bone cancer during their teenage years.
Scientists are on the lookout for effects on bones, because they absorb half the fluoride people ingest.
A paper outlining the finding was published in 2006 in the journal Cancer Causes & Control and produced by Harvard University researchers.
Researchers found that boys aged 6 to 8 who were exposed to more fluoridated water were about four times more likely to develop the cancer than those exposed to lower levels. The researchers called their results "remarkably robust."
Although similar findings in young male rodents have been seen in laboratory experiments, other studies that investigated lifetime human exposure to the chemical did not detect any association with osteosarcoma.
The EWG's Mr. Wiles said these findings are the kinds of research clues that should cause governments to consider listing the chemical as a probable carcinogen.

Wednesday 25 January 2012

How Much Oxygen Does One Tree Produce?

You've probably heard that trees produce oxygen, but have you ever wondered just how much oxygen one tree makes? The amount of oxygen produced by a tree depends on several factors, but here are some typical calculations.
 
The atmosphere of the Earth has a different composition from that of other planets in part due to the biochemical reactions of Earth's organisms. Trees and plankton play a big role in this. You've probably heard that trees produce oxygen, but have you ever wondered how much oxygen that is? You'll hear a range of numbers and ways of presenting them because the amount of oxygen produced by a tree depends on the species of tree, its age, its health, and also on the tree's surroundings. According to the Arbor Day Foundation, "a mature leafy tree produces as much oxygen in a season as 10 people inhale in a year." Here are some other quoted figures regarding the amount of oxygen produced by a tree:

"A single mature tree can absorb carbon dioxide at a rate of 48 lbs./year and release enough oxygen back into the atmosphere to support 2 human beings."
- McAliney, Mike. Arguments for Land Conservation: Documentation and Information Sources for Land Resources Protection, Trust for Public Land, Sacramento, CA, December, 1993


"One acre of trees annually consumes the amount of carbon dioxide equivalent to that produced by driving an average car for 26,000 miles. That same acre of trees also produces enough oxygen for 18 people to breathe for a year."
- New York Times

“A 100-ft tree, 18" diameter at its base, produces 6,000 pounds of oxygen."

"On average, one tree produces nearly 260 pounds of oxygen each year. Two mature trees can provide enough oxygen for a family of four."
- Environment Canada, Canada's national environmental agency
"Mean net annual oxygen production (after accounting for decomposition) per hectare of trees (100% tree canopy) offsets oxygen consumption of 19 people per year (eight people per acre of tree cover), but ranges from nine people per hectare of canopy cover (four people/ac cover) in Minneapolis, Minnesota, to 28 people/ha cover (12 people/ac cover) in Calgary, Alberta."
- U.S. Forest Service and International Society of Arboriculture joint publication



Monday 16 January 2012

The water you're drinking; is it really safe?

To be specific, the TAP water your drinking; safe or not? while it typically is safe here and now in Canada, there was a time in a farming town in western Ontario called Walkerton where the water was contaminated by a strain of  O157:H7 E. Coli Bacteria in may 2000. the E. Coli comes from the intestines of healthy cattle and can result in permanent kidney damage or be fatal to humans if they eat it in undercooked hamburger, unpasteurized milk or contaminated water. At least seven people died directly from drinking the E. coli contaminated water, and about 2,500 became ill. Investigators suspect run-off from cattle manure as a probable source of the E. coli in the water. This hasn't been the only case of poor water testing in Canada; In the spring of 1996, hundreds of people in Collingwood, (an hour's drive from Walkerton) become ill after Cryptosporidium, a parasite linked to animal feces, contaminated the drinking water. In 2001 a similar outbreak in North Battleford, Saskatchewan caused by Cryptosporidium affected at least 5,800 people. while no one dies in both of these cases, it is another highlight on Ontario's poor water testing and regulations then. Now of course, with the affect that it had on the people of Walkerton and elsewhere, the government has since tightened up, including enacting the clean water act of 2006, which protects existing and future sources of drinking water. so with that please don't be considering stocking up on crates of bottled water, that is a whole other story of its negative effects on the environment and our bodies. Our water now is relatively safe if you ignore the fluoride which can cause toxicological side-effects so just remember how people just couldn't be sure 12 years ago in the small town of Walkerton, Ontario the next time you're getting water from the tap.

Do you believe the Walkerton tragedy could have been prevented? if so, what are the steps you think could have been taken to prevent this tragedy from happening?

Read here for more details:
http://www.thecanadianencyclopedia.com/articles/macleans/walkerton-tragedy
*http://www.cbc.ca/news/canada/story/2010/05/10/f-walkerton-water-ecoli.html

Sunday 15 January 2012

Nitrogen Dioxide, Ozone & Lead Partner to Increase Pollution Dangers to Urban Children

I thought that this article may be an interesting one to post since it related to things that we have been discussing in class. I thought that problems with lead paint only pertained to the past, but I guess I was wrong!




The adverse health effects of ozone (O3) and nitrogen dioxide (NO2) have been known for decades. The Clean Air Act was established in 1963, but ambient a quality was not regulated until 1970, and by 1971 EPA had established one hour National Ambient Air Quality Standard (NAAQS) of 0.08 ppm for both O3 and nitrogen dioxide. Nitrogen dioxide and ozone are two of the major outdoor ambient chemical pollutants affecting asthmatics. In addition, nitrogen dioxide plays a role in formation of acid rain, contributes to global warming, and hampers the growth of plants. Ground-level ozone interferes with a plant's ability to manufacture (photosynthesize) and store food, and lowers plant resistance to disease.
Just when we think that we are getting a handle on the entire criminal record of these two compounds, scientists from the University of California, Irvine have linked them to another environmental and health outlaw, lead (Pb). In an abstract published in Environ. Sci. Technology, October 14, 2009 (article ASAP) R. D. Edwards, N. L. Lam, L. Zhang, M. A. Johnson and M. T. Kleinman from the School of Medicine, University of California, Irvine reported that nitrogen dioxide (NO2) and ozone (O3) from vehicles emissions react with surfaces painted with lead based paint and increase the release of lead. According to Edwards, paint is made of two basic components: pigment granules and an unsaturated polymeric binder that holds them together. O3 and NO2typically react with unsaturated compounds. Edwards and colleagues suspected that this characteristic might make lead pigment granules become deposited in house dust or be more available to children's hands in urban environments where O3 and NO2 are frequently in high concentration.
The researchers coated stainless steel with a thin layer of lead based paint and exposed them to NO2 and O3. They then evaluated the coated surfaces using reflectometry and scanning electron microscopy. They also wiped the surfaces and calculated the amount of lead on the wipes. Edwards and his colleagues reported that NO2 and O3 changed the surfaces' morphology and significantly increased the amount of lead that can were wiped off them.
The results of this research suggests that a lot more emphasis must be placed on eliminating lead based paint from the urban environment and lowering the emission of O3 and NO2 in American cities that are still remediating old buildings and in developing nations where lead based paint is still being sold.






Roberta Barbalace. Nitrogen Dioxide, Ozone & Lead Partner to Increase Pollution Dangers to Urban Children. EnvironmentalChemistry.com. Dec. 3, 2009. Accessed on-line: 1/15/2012
http://EnvironmentalChemistry.com/yogi/environmental/200912_nitrogen_dioxide_ozone_and_lead_endanger_children.html
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Thursday 12 January 2012

The Clean Air Act

You've probably heard about the Clean Air Acts and can figure out they have something to do with air pollution, but what else do you know about Clean Air Act legislation? Here's a look at the Clean Air Acts and answers to some common questions about them.

The Clean Air Act is the name of any of several pieces of legislation aimed at reducing smog and other types of air pollution.

In the United States, the Clean Air Acts include the Air Pollution Control Act of 1955, Clean Air Act of 1963, Air Quality Act of 1967, the Clean Air Act Extension of 1970, and Clean Air Act Amendments in 1977 and 1990. State and local governments have passed supplemental legislation to fill in gaps left by the federal mandates. The Clean Air Acts have addressed acid rain, ozone depletion, and the emission of atmospheric toxins. The laws have included provisions for emissions trading and a national permits program. The amendments established requirements for gasoline reformulation.
In Canada, there have been two acts with the name "Clean Air Act". The Clean Air Act of the 1970s regulated the atmospheric release of asbestos, lead, mercury, and vinyl chloride. This Act was replaced by the Canadian Environmental Protection Act in the year 2000. The second Clean Air Act (2006) was directed against smog and greenhouse gas emissions.

In the United Kingdom, the Clean Air Act of 1956 legislated zones for smokeless fuels and relocated power stations to rural areas. The Clean Air Act of 1968 introduced tall chimneys to disperse air pollution from the burning of fossil fuels.

Impact of the Clean Air Acts
The legislation has led to the development of better pollution dispersion models. Critics say the Clean Air Acts have cut into corporate profits and have led companies to relocate, while proponents say the Acts have improved air quality, which has improved human and environmental health, and have created more jobs than they have eliminated.

Saturday 19 November 2011

TM 1st response

Great start Dolkar and some interesting questions: "four main diseases would be; diarrhea, lower respiratory infection, unintentional injuries, and malaria". I would be very interested to read what your group finds out and discusses about respiratory infections as this reads as if it might be due to environment. I wonder why they used the term "unintentional injuries"!  

Friday 18 November 2011

Diseases and Environment; There is a link?

In this article i was reading by larry west, he says that according to a report by the World Health Organization (WHO) nearly a quarter of all diseases are linked to the environment. the four main diseases would be; diarrhea, lower respiratory infection, unintentional injuries, and malaria. what do you think the factors would be to get these diseases? where do you think they would most commonly occur? in the article, they mention preventative measures that all seem obvious to us, but what other measures do you think we could take to prevent diseases from our environment? according to the article, if these steps were taken the amount of deaths every year linking to diseases caused by the environment would be drastically reduced.
read the article here: http://environment.about.com/b/2007/05/10/nearly-a-quarter-of-all-disease-linked-to-environment-by-who-report.htm