Greetings,

Thank you for reaching out to Extension. I am going to share two previous responses related to this question.  Please see below:

https://ask.extension.org/questions/425273 Thanks for your question about your soil's safety after railroad ties. The reason the EPA has made illegal the use of treated railroad ties in vegetable gardens is the fact that they are treated with coal tar creosote, a pesticide registered both with the EPA and the State of Oregon. The EPA's label warning is essentially "Don't touch the wood with bare skin; don't let animals or children near it; don't let it get near a water supply; don't inhale the dust; wear protective equipment when you handle it—including gloves that are "chemically impervious"; and don't burn it—the fumes can be deadly." (I quoted this from an article with a similar question to yours.)

So, then the question becomes: how long does creosote remain a risk in the soil? Although several writers indicate that plant roots do not absorb creosote, the EPA says: " If the soil in your yard was contaminated by creosote in the past, you should probably not grow food in it. You will need to wash your hands and any other exposed skin carefully after you are in contact with the contaminated soil or water outside." (Most of the dangerous exposure to creosote occurs when it leaches into the water, as well as consuming fish that have ingested it.)

So, you have a couple of options. You could have your soil tested (A & L Western Laboratories, e.g.), or you could remove the soil within a couple of feet or so of the old timbers, and replace it with uncontaminated topsoil. You could also consider building raised beds with 'clean' soil in them, with a protective net between the soil levels, which allows water and earthworms to pass through, suggested in this World Health Organization publication.

When you asked whether 'they' are safe to eat now, I'm not sure you are referring to the strawberries, the blueberries or both. However, this Extension article suggests that fruiting plants (except cucumbers and squash) are less likely to have absorbed contaminants than root crops.

Sorry I can't provide you with a simple, black-and-white answer, but environmental science research as it relates to us and our gardens is still in its infancy. Hope this is helpful. Good luck!

___________________________________________________

https://ask.extension.org/expert/questions/321261 

This is a common question and I will point the answer out in this extension publication by the University of Missouri - find the full article at: http://extension.missouri.edu/p/G6985
Here is the section of the article regarding materials (including railroad ties):

Construction materials

The choice of framework to use for walls depends on the availability and cost of the construction material and how you want the final product to look in the landscape. Treated landscape timbers and used railroad ties are popular materials. Naturally rot-resistant lumber, such as redwood or cedar, may also be used. Other possibilities include concrete blocks, bricks and stones, or synthetic lumber made of recycled plastic. A group of half barrels can make a convenient raised bed for use on a patio (Figure 3). For a consistent look, match materials to those used elsewhere in the landscape.

Generally, wood-based products are less expensive than stone or masonry materials. However, resourceful gardeners may be able to find used bricks, concrete blocks or other materials at little or no cost.

Concern has been raised about the safety of using treated lumber in food gardens. Pressure-treated lumber using CCA (chromated copper arsenate) as a preservative prompted this concern. CCA-treated wood was banned for residential use by the Environmental Protection Agency (EPA), and its production was phased out. Any remaining stock probably should not be used in raised beds for growing food crops.

ACQ (akaline copper quaternary) is an alternative preservative choice for pressure-treated lumber. Unlike CCA, it does not contain arsenic or chromium. It does, however, contain copper, which can leach into the soil from treated lumber. Although copper is an essential element for both plants and animals, excessive amounts can be harmful. A 2007 study of the safety of ACQ published in Human and Ecological Risk Assessment concluded that exposure to copper from contact with ACQ-treated wood is not expected to have adverse effects on the health of adults or children.

CA (copper azole) is another wood preservative based on the fungicidal properties of copper. Its toxicity risk should be similar to that of ACQ.

Creosote, which is used to treat railroad ties, may cause injury or death to plants that come into direct contact with it. The effect diminishes after a few years. Old, discarded ties do not injure plants (Figure 4). However, ties that are still oozing black, sticky creosote or have an intense smell may cause injury.

If you are uncertain about the safety of treated lumber, place a heavy plastic liner between the treated lumber and the soil used for growing plants to prevent direct contact of plant roots with the treated lumber. Be careful not to tear the plastic when tilling the bed.