Many suggest that soils with lead levels above 300 ppm should be either replaced or covered over with raised beds. Adequate amounts of organic matter and the proper soil pH both can minimize plants contact with soil borne lead. While all plants do uptake some of those heavy metals your greatest contact would be eating root crops from lead contaminated soil when the lead adheres to the surface of the plant root.

Here is a link that might be useful: about lead in soil

I would do some more soil tests and try to zero in on where the majority of the contamination is. No need to remediate the whole yard if most of the contamination is right next to the house.

late at night & I'm tired, so haven't googled to be sure, but it seems like that after Hurricane Katrina, people in the New Orleans area were advised to plant turnips & then discard the entire plants to decontaminate the soil.

I wish you the best.

Compost has long been recognized as an effective remedial control against high lead levels. And yours are not all that high - the EPA considers 0-500 ppm low risk, 500-1000 ppm moderate risk.

By both increasing soil pH above 6.5 or by adding a rich phosphorous source, you will create conditions that will bind the lead and prevent it being taken up by plants. It is also important to know that very few plants take up lead from the soil in any significant amount. Since altering soil pH can be difficult and usually temporary, supplying phosphorus may be easier to accomplish - and well-aged compost, chicken manure and fish bone meal are excellent oprganic sources. The phosphorus binds with the lead to form pyromorphite crystals, a form of lead which is non-toxic (not bio-available) to humans and animals.

The primary risk of lead contaminated soils is physical contact with the soil itself. Much of this can be eliminated by just common sense - wear gloves when working in the soil, remove shoes when going indoors, keep small children from playing in the dirt and wash up well after gardening. Many vegetables and fruits will be perfectly safe when grown in lead contaminated soils. Uptake is minimal for most plants types - virtually nonexistant in fruiting plants so plant things like fruit trees, cane berries and plants with accessory fruits like tomatoes, peppers, squash etc. In leafy greens the biggest danger is from dirt splashed onto the leaves--not so much from lead inside the plant (possible exception is spinach). So wash your leafy greens well! Root crops pose the highest risk, as they will uptake some lead and the dirt is present on the skin of the root. So if lead is present in your native soil, always peel root crops or grow them in imported soil (raised beds).

Thanks for the replies. I'm still wading through this but so far so good:
http://www.epa.gov/superfund/lead/products/FINAL%20TRW%20Lead%20Committee%20Gardening%20Recommendations.pdf

Sounds like the lab is estimating total Pb content based on their extractable Pb test, but if you really want to know, you should have a total Pb test done to really answer your questions. That procedure involves digesting the entire sample to destroy all organic matter and most of the mineral matrix, freeing up all the Pb present.

300 is not that bad, although it's not great. As noted above EPA considers 400 safe for residential (including gardening). My state uses 260. So if it's really 300 you're right in that range. Keep in mind it's based on statistics, and risks increase relatively linearly with concentration, so if you're over some limit, it doesn't mean everyone is going to be poisoned, but rather an increased level of risk.

The above posts are all good advice particularly about washing soil off the outside of vegetables and people. I wouldn't worry about wearing gloves as an adult, but I would try to limit kids exposure to bare soil and make sure they wash up asap afterwards. Passive ingestion from hands and flying dust is the major intake pathway. Avoid that and you'll be fine. And if you have kids under 6 AND your soil total Pb turns out to be 300 or above, you might want to have them tested. It's easy to do at their next doctor visit, or your local health agency might do it for free.

Nothing like hard data to clarify things!

Good luck and keep us posted.