is the modern day pressure treated wood safe for vegtable gardens?

Question

The old pressure treated wood contained arsenic and was not safe but I understand that has been removed, should i use this in my vegetable garden or not?

Answer 1

Wood decays when it gets wet. Although redwood and cedarheart woods have a natural resistance to decay and termites, most other woods that come into contact with soil or water will rot and lose strength.

In an effort to improve durability, resistance to wood-eating insects and decay fungi, wood has been chemically pressure- treated to increase its useful service life.

In the past, lumber impregnated with chromated copper arsenate (known as CCA) was used for playground equipment, retaining walls, decks and raised vegetable garden beds.

It boasted longer life than rot-resistant species like redwood, you could buy it almost anywhere, and manufacturers said the treatment chemicals, though toxic, safely stayed put in the wood.
The main plus for gardeners was that the chemicals didn't harm plants, unlike creosote and pentachlorophenol, two previously popular wood preservatives.

But then, word started getting out that treated woods in general, and CCA-treated wood in particular, were not safe to use. There was concern that the arsenic in CCA-treated wood was not bound up in the wood and, in fact, migrated into the surrounding soil.

In January 2004, the wood treating industry voluntarily withdrew CCA-treated lumber for common residential use. Although the EPA has not concluded that there is unreasonable risk to the public from these products, it suggests any reduction in exposure to these is desirable.

Alternative pressure-treated wood products are currently available, such as amine or alkaline copper qua and copper azole and more will be offered in the future

Arsenic is a naturally occurring element widely distributed in the earth's crust. In the past it has been used in many products, including pigments, insecticides, and herbicides. Because of its potential for poisoning, most uses of arsenic have been discontinued or severely restricted. Exposure to large amounts of arsenic can lead to serious illness or death.

Ongoing exposure to smaller amounts over a long time can cause many different adverse health effects including skin changes, cardiovascular problems, and increased risk of several forms of cancer.

So how much arsenic leaches into the soil from CCA lumber? More to the point, how much gets taken up by vegetables?

The chemicals impregnated in CCA-treated lumber do have good resistance to leaching, but there is some loss of chemicals into surrounding soil. There appears to be an initial surge of leaching during the first rainy season, and then the wood settles down to a slow release of small amounts, decreasing slightly over time.

Once arsenic is in the ground, it doesn't migrate much. Where there is leaching, arsenic levels drop quickly with distance from the wood, usually reaching background levels within a few inches in raised beds.

Arsenic may accumulate in very tiny amounts in vegetables grown immediately adjacent to the treated lumber, but the vegetables would still be considered safe to eat by U.S. Public Health Service standards.

The U.S. EPA has concluded that CCA-treated lumber does not pose an unreasonable risk to the public and there is no reason to prematurely remove structures or other items constructed with this material.

Here are some common "bottom line" approaches to using CCA-treated lumber:

Seal it: Paint or stain treated deck or play equipment to bind loose particles and slow leaching of metals to soil and water. Use stains that penetrate wood with no sanding or scraping that would release CCA to the environment. Apply sealant every year or two.

Cover it: Put a tablecloth on picnic tables. Place a sheet or blanket on decks or benches used as play areas for young children.

Cut it: Work only in well-ventilated areas. Wear air filter mask, goggles and gloves when sanding or cutting the treated wood. Consider using recycled plastic lumber for new construction or repairs.

Line it: For wooden dividers in gardens, place plastic between wood rails and plants.

Dispose it: CCA-treated wood is not considered a hazardous material and can be disposed of in your regular garbage pick-up or ordinary trash collection. However, do not burn treated wood in open fires, stoves, fireplaces, or residential boilers.

Be prudent: Do not use treated wood where CCA would contaminate food or animal feed (e.g., garden compost, bee hives, mulch, cutting boards, counter tops, animal bedding).

Answer 2

Pressure-treated wood is wood that has had toxins pushed into it under pressure. In some places you can still get copper-chromium-arsenic treatments while others have move on to arsenic-free chemistry. They all leach to some extent. Bottom line is that the wood is treated with insecticide and fungicide and so cannot be used for organic veggies. You can find a durable hardwood and watch it slowly rot away or use masonry or plastic for your borders. Or you can use the treated wood and forget about "organic" claims.

Answer 3

Can't touch Jewels response, but I like the recycled plastic wood. Works fine, lasts a LONG time.

Answer 4

No, treated wood is highly poisonous. I worked at a lumber yard b4 and i had to wash my hands everytime i handled it...if you do use it keep it elevated above the wood with something.

Answer 5

Unfortunately, It's still too risky.

http://www.ecologycenter.org/factsheets/pressure-treated_wood.html