Answer: There are two "camps" on this subject. There are those who cite studies showing that, indeed, some of the materials in treated wood such as railroad ties, do leach into the soil. On the other side are studies showing that no leaching occurs. Since there is no definitive answer, I usually recommend people err on the side of caution and not use these materials in their gardens. As far as whether or not your soil is contaminated, I would recommend you have a soil test done. Contact your local Extension Service regarding a soil test kit. Explain your situation and request they test for copper, chromium, and arsenic (and whatever else they recommend). Alternatives to treated lumber or railroad ties include cedar, hemlock, and "timbers" made from recycled plastic.
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