How to test safety of soil

Hi all, My local community garden had some soil delivered by the city, but there is some concern about the potential that the soil is not safe to grow edible plants.
Is there any reliable way to test if soil is appropriate to grow edibles? My local extension school offers lots of nutrient and biomass tests, but I don't see anything about testing for contaminants.
I realize that the pool of potential contaminants in soil is inexhaustible. However, what would people recommend as basic precautions.
Thanks, Tim

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Hi Tim,
At a minimun, I would test for heavy metals and organophosphates.
Here is a site I found, not looked at closely, that describes some tests and offers services. I have no knowledge of or association with this testing service. I am sure there are many more, perhaps your County Extension Service can help.
Care Charlie

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Check heavy metals for sure. Seems that we were just talking about something that pulled heavy metals (arsenic in particular) out of the soil and then the problem became what to do with their leaves.!?? (Clay lined landfill, if I remember correctly) The organophosphates, if present, would break down fairly quickly and don't represent a long term problem, unless you drink it. The it definitely becomes a long term problem. Drinking organophosphates has become a major cause of death to indebted Indian farmers who follow the Monsanto approach to farming.

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I am not sure that shotgun testing is going to help much or be cost effective. Does this soil have no provenance? Can you follow it back to its origin and determine the risk of contaimination? Even if you identify that there is some risk it will focus your testing down to something practical and affordable.
David