Wiiliam D. Marshall of McGill University is looking at ways of using supercritical CO2 for converting persistent and toxic molecules s uch as polychlorinated biphenyls (PCB's) into harmless byproducts.
A supercritical fluid is a substance above its critical temperature (TC) and critical pressure (Pc). The critical point (which for carbon dioxide occurs at a very elevated pressure of 7380 kPa and at 31.1°C) represents the highest temperature and pressure at which the substance can exist as a vapour and liquid in equilibrium. (see diagram below). Supercrtitical carbon dioxide is already routinely used in industry as an alternative to carcinogenic solvents that were once used, for example, to decaffeinate tea and coffee. see link
Last year, Federal Express planned to replace all of its 44 000 vehicles with diesel-electric trucks. These would cut smog-producing emissions by 90%.
In Denmark, a 1994 law obliges all national and local governments to use recycled products. Six years later, 10 of 14 counties had developed policies for purchasing green products.
Non-wood alternative fibers are making a comeback as sources of paper. These include hemp (which had been used for 2000 years prior to the industrial application of Keller's wood-based technique of the late 19th century), kenaf and agricultural residues. Unlike wood, agrifibres are lignin-free, and so require less energy and additives.
(Source: Worldwatch Institute. State of the World:2004. Norton. 2004.)
From Scientific American: August 2003
A growing body of data suggests that environmental contaminants may not always be poisonous--
they may actually be good for you at low levels. Read article.
Here's a summary of a Jan. 2005 discussion of the same topic on the radio program Quirks and Quarks.
(To listen to the entire program, click here)..
"A radical and largely forgotten idea has been dusted off, polished up and reintroduced to the scientific world. The idea, as toxicologist Dr. Michael Dourson from the consulting firm of Toxicology Excellence for Risk Assessment explains, is that small amounts of chemicals, just below the toxic levels, may actually provide some benefit to our systems. This theory, called hormesis, has been championed by Dr. Edward Calabrese, a toxicologist from the University of Massachusetts at Amherst. He's gathered a mass of data that he says show that many toxins, in animal or plant experiments, produce benefits at certain low doses."
"Not all researchers agree that hormesis is a common or general response, though. Dr. Daniel Krewski, director of the McLaughlin Centre for Population Health Risk Assessment at the University of Ottawa, thinks that, while hormesis is an interesting phenomenon and may occur in some circumstances, many toxins are probably poisonous at even the lowest levels. He says his work with radiation, for example, doesn't seem to support the idea of hormesis. Dr. Devra Lee Davis, professor of Epidemiology and the director of the Center for Environmental Oncology at the University of Pittsburgh Cancer Institute, thinks hormesis could be a dangerous idea. Hormesis suggests that low doses of carcinogens aren't toxic. She doesn't believe the science supports this idea, and she's concerned it might be taken as an excuse for increasing the allowable levels of these toxins in the environment."
This is by no means fresh news, but it's still valid information regarding the benefits of quitting smoking.Source: American Cancer Society
There are now about 25000* humpback whales, over 60 times the amount present in 1963, according to a Brisbane conference of marine biologists specializing in humpbacks. Since 1949, commercial whaling had caused the number of such whales to decrease from 12 500 to 400 in a period of only 14 years.
These 66 000 pound mammals are well-known for their singing, an intricate sequence of sounds lasting as long as half an hour, longer than any mammalian courtship song, including man, whose hit mush-songs typically last less than 6 minutes. Each song consists of repeated motifs of syllables that are used to produce six basic themes. The variation sung by an individual whale is unique, although groups of whales in given areas sing similar compositions. Males are the only singers,diverting competing males and attracting females with indications of their prowess and learning ability.
Note this total is lowe than the one reported at http://en.wikipedia.org/wiki/Humpback_whale#_note-breiwick
Levels of atomic Cl were on the decline for the first time according to an announcement by US scientists at the
National Oceanic and Atmospheric Administration. Such free radicals are responsible for destroying ozone.
This was not a surprising result since the amount of CFC's released into the air in the USA was reduced by 52% between 1988 and 1994. The reason behind the decline was the Montreal protocol of 1987 in which a host of countries agreed to reduce the use of ozone-depleting chemicals by 50% by the end of the 20th century. Some pessimistic environmentalists had knocked the agreement as being too little, too late, but evidently it had better than expected positive results less than 10 years later. Things should get even better because the United States formally banned the use and manufacture CFC's in 1996. Other countries had passed similar legislation.
Page Maintained by E. Uva; firstname.lastname@example.org