Comments on: Plastic goods for your compost heap

A biotech firm and agricultural giant ADM plan to sell the biodegradable plastic for eco-conscious consumers next year.
Photos: Natural plastics for eco-conscious consumers

[c|net Reader]

Is It Really Better?

OK, so traditional plastic is made from petroleum and it doesn't degrade (or do so very slowly). Traditional plastic can be recycled.

The questions I have are:

1. Is there any side effect on the environment from the modified corn starch when it degrades? Just because they call it "green" and make it from plant materials doesn't make it good for the environment. After all, petroleum comes from plants, too.

2. What is the total cost? There's energy expended to retrieve and refine petroleum, and energy is needed to produce and recycle traditional plastics. Likewise, there are effects from growing, harvesting, and refining corn plus those of creating Mirel. On balance, which is better?

3. How practical is Mirel? For example, under what conditions does Mirel degrade? Will a water spill cause a leak? What if it's left outside? How long before the container is useless? Can Mirel be used only for dry goods? If it's used for frozen foods, will melting ice/frost be a problem? Can it be used for medical supplies?

I'm sure there are other questions, but these are the sorts of things I'd like c|net to share with us. Most of these green stories simply convey ideal notions rather than asking tough questions and comparing the whole picture. I'd like to see more in the future.

[c|net Reader]

Typo

"(or do so very slowly)" should have been "(or does so very slowly)" of course.

[mlamonica]

Some answers from reporter

1. As I understand this, it's made from plain old corn starch so there won't be any unknown environmental effects as products degrade.

2. I don't have a detailed analysis of the two separate processes of making plastics from oil and plastics from petroleum, but on balance, it appears that plant-based plastics take less energy over its lifecycle. Just looking at disposal, a plant plastic will degrade with no effort (and creates fertilizer), whereas recycling takes additional energy. And, as you point out, extracting and refining oil and creating plastics is very energy-intensive.

There are other potential benefits as well, when you consider that a lot of plastic is not recycled and simply remains an environmental pollutant for a long time.

3. Mirel can be used for liquid containers, even boiling water and won't degrade. The process takes months, depending on thickness, but decomposition will only happen if the plastic is buried in soil or in bodies of water where microbes can eat away at it.

Finally, I think you raise a good point about our green tech coverage overall. Many products aim to be environmentally friendly but nearly everything will have some sort of drawback or limitation. We can try to lay out the pros and cons and introduce more analysis.