KKA 5101

A Healthy Biodiversity Offers Many Natural Services

2009-04-28T16:01:00.004+08:00

Biodiversity is the variation of life forms within a given ecosystem, biome, or for the entire Earth. Biodiversity is often used as a measure of the health of biological systems. The biodiversity found on Earth today consists of many millions of distinct biological species, which is the product of nearly 3.5 billion years of evolution. A healthy biodiversity provides a number of natural services for everyone:

Ecosystem services, such as:

- Protection of water resources

- Soils formation and protection

- Nutrient storage and recycling

- Pollution breakdown and absorption

- Contribution to climate stability

- Maintenance of ecosystems

- Recovery from unpredictable events

Biological resources, such as:

- Food

- Medicinal resources and pharmaceutical drugs

- Wood products

- Ornamental plants

- Breeding stocks, population reservoirs

- Future resources

- Diversity in genes, species and ecosystems

Social benefits, such as:

- Research, education and monitoring

- Recreation and tourism

- Cultural values

That is quite a lot of services we get for free guys!

The cost of replacing these (if possible) would be extremely expensive. It therefore makes economic and development sense to move towards sustainability.

A report from Nature magazine also explains that genetic diversity helps to prevent the chances of extinction in the wild (and claims to have shown proof of this).

To prevent the well known and well documented problems of genetic defects caused by in-breeding, species need a variety of genes to ensure successful survival. Without this, the chances of extinction increases.

And as we start destroying, reducing and isolating habitats, the chances for interaction from species with a large gene pool decreases. Now, decision is in your hand. Think about it!

“Self-healing” Polymer May Facilitate Recycling of Hard-to-dispose Plastic

2009-04-28T15:37:00.004+08:00

Guys, I have good news to tell you here. The researchers in Netherlands are reporting development of a new plastic with potential for use in the first easy-to-recycle computer circuit boards, electrical insulation, and other electronics products that now wind up on society's growing heaps of electronic waste.

Antonius Broekhuis and colleagues note in the new study that so-called thermoset plastics are widely used in consumer electronics due to their hardness and heat resistance. These plastics, however, contain additives and reinforcement materials that make them almost impossible to recycle. So-called thermoplastics, in contrast, are softer and can be remelted easily. As a result, thermoset plastics often end up in landfills or incinerators, where they can contribute to pollution. Scientists have long-sought a simple, inexpensive process to make these plastics recyclable, but they have been largely unsuccessful until now.

Broekhuis and colleagues describe development of a new type of thermosetting plastic that can be melted and remoulded without losing its original heat-resistance and strength. The scientists showed in laboratory tests that they could melt granules of what they term a "self-healing" polymer and reform them into uniform, rigid plastic bars. They also showed that the plastic could be remoulded multiple times, setting the stage for a new generation of recyclable plastics.

Landfill Cover Soil Methane Oxidation Underestimated

2009-04-28T15:19:00.003+08:00

Well, I got something to share about landfill here guys. A landfill, also known as a dump (and historically as a midden), is a site for the disposal of trash materials by burial and is the oldest form of waste treatment. Historically, landfills have been the most common methods of organized waste disposal and remain so in many places around the world. Landfilled waste decomposes in the absence of oxygen and results in the production of methane. Landfills are classified as the second-largest human-made source of CH₄ in the U.S. Additionally, landfill gas contains numerous non-methane hydrocarbons that are either volatilized directly from waste materials or produced through biochemical reactions during waste degradation.

Microbial methane oxidation reduces the emissions of methane and other volatile hydrocarbons from landfills. Determining the importance of this process is one of the major uncertainties in estimating national or global CH₄ emissions from landfills. Landfill gas that is not collected passes through landfill cover soils on the way to being released to the environment. Bacteria in the soil consume methane and other volatile hydrocarbons that are produced by decomposition in the underlying waste by reacting it with oxygen.

A value of 0 to 10% oxidation has been recommended by the Intergovernmental Panel on Climate Change guidelines for national greenhouse gas inventories. Currently, for regulatory purposes the USEPA has recommended a default value for landfill cover CH₄ oxidation of 10% due to the uncertainty involved and the lack of a standard method to determine oxidation rate.

Drs. Jeffrey Chanton, David Powelson, and Roger Green of Florida State University and Waste Management Inc. reviewed and compiled literature results from 42 determinations of the fraction of methane oxidized and 30 determinations of methane oxidation rate in a variety of soil types and landfill covers. The results were published in the March-April issue of the Journal of Environmental Quality.

The means for the fraction of methane oxidized upon transit across the differing types of soil covers ranged from 22% in clayey soil to 55% in sandy soil. The overall mean fraction oxidized across all studies was 36% with a standard error of 6%. For a subset of fifteen studies conducted over an annual cycle the fraction of methane oxidized ranged from 11 to 89% with a mean value of 35 ± 6%, a value that was nearly identical to the overall mean.

The literature summarized in this paper indicates that the fraction of methane oxidized in landfill cover soils is considerably greater than the default value of 10%. Of the 42 determinations of methane oxidation only four reported values of 10% or less. One reported a value of 10%. This particular study was the first to report a well constrained value for the fraction of methane oxidized in a specific landfill, and because of this, it has received undue weight in the determination of regulations. The default value of 10% should be updated based upon technological advancements in soil engineering and state of the practice applications in cover design as well as recent studies detailed journals such as Journal of Environmental Quality.

Paper, Plastic, or Something Better ???

2009-03-23T14:46:00.003+08:00

The next time the clerk at your favourite grocery store asks whether you prefer “paper or plastic” for your purchases, consider giving the truly eco-friendly response and saying, “neither.”

Plastic bags end up as litter that fouls the landscape, and kill thousands of marine mammals every year that mistake the floating bags for food. Plastic bags that get buried in landfills may take up to 1,000 years to break down, and in the process they separate into smaller and smaller toxic particles that contaminate soil and water. Furthermore, the production of plastic bags consume millions of gallons of oil that could be used for fuel and heating.

Is Paper Better Than Plastic?

Paper bags, which many people consider a better alternative to plastic bags, carry their own set of environmental problems. For example, according to the American Forest and Paper Association, in 1999 the U.S. alone used 10 billion paper grocery bags, which adds up to a lot of trees.

Reusable Bags Are a Better Option.

But if you decline paper and plastic bags, then how do you get your groceries home? The answer, according to many environmentalists, is high-quality reusable shopping bags made of materials that don’t harm the environment during production and don’t need to be discarded after each use. (You can find a good selection of high-quality reusable bags online at reusablebags.com. In addition, many organic grocery stores and consumer co-operatives carry reusable shopping bags).

Experts estimate that 500 billion to 1 trillion plastic bags are consumed and discarded annually worldwide, more than a million per minute.

Here are a few facts about plastic bags to help demonstrate the value of reusable bags, to consumers and the environment:

* Plastic bags aren’t biodegradable. They actually go through a process called photodegradation—breaking down into smaller and smaller toxic particles that contaminate both soil and water, and end up entering the food chain when animals accidentally ingest them.

* According to the Environmental Protection Agency, more than 380 billion plastic bags are used in the United States every year. Of those, approximately 100 billion are plastic shopping bags, which cost retailers about $4 billion annually.

* According to various estimates, Taiwan consumes 20 billion plastic bags annually (900 per person), Japan consumes 300 billion bags each year (300 per person), and Australia consumes 6.9 billion plastic bags annually (326 per person).

* Hundreds of thousands of whales, dolphins, sea turtles and other marine mammals die every year after eating discarded plastic bags they mistake for food.

* Discarded plastic bags have become so common in Africa they have spawned a cottage industry. People there collect the bags and use them to weave hats, bags and other goods. According to the BBC, one such group routinely collects 30,000 bags every month.

* Plastic bags as litter have even become commonplace in Antarctica and other remote areas. According to David Barnes, a marine scientist with the British Antarctic Survey, plastic bags have gone from being rare in the late 1980s and early 1990s to being almost everywhere in Antarctica.

Some governments have recognized the severity of the problem and are taking action to help combat it.

Strategic Taxes Can Cut Plastic Bag Use.

In 2001, for example, Ireland was using 1.2 billion plastic bags annually, about 316 per person. In 2002, the Irish government imposed a plastic bag consumption tax (called a PlasTax), which has reduced consumption by 90 percent. The tax of $.15 per bag is paid by consumers when they check out at the store. Besides cutting back on litter, Ireland’s tax has saved approximately 18 million liters of oil. Several other governments around the world are now considering a similar tax on plastic bags.

Governments Use the Law to Limit Plastic Bags.

More recently, Japan passed a law that empowers the government to issue warnings to merchants that overuse plastic bags and don’t do enough to “reduce, reuse or recycle.” In Japanese culture, it is common for stores to wrap each item in its own bag, which the Japanese consider a matter of both good hygiene and respect or politeness.

Companies Making Tough Choices.

Meanwhile, some eco-friendly companies, such as Toronto’s Mountain Equipment Co-op are voluntarily exploring ethical alternatives to plastic bags, turning to biodegradable bags made from corn. The corn-based bags cost several times more than plastic bags, but are produced using much less energy and will break down in landfills or composters in four to 12 weeks.