AC condensate is basically distilled water, and the moment that is condenses on the coils in your air conditioner. At that moment it is free of all dissolved materials.

After that it runs across the outside of the copper coils, that are usually assembled with lead based solder, into a (probably) an open galvanized collection pan, where bacterial and dust can accumulate, then out of the pan down a copper, flexible plastic or PVC pipe to where ever it is discharged.

Texas A&M Extension has done work with rainwater and AC condensate collection to help deal with drought. In fact several buildings have been outfitted to use the AC condensate for landscape irrigation.  It is also commercially recommended in large buildings in humid climate where large amounts of water might be generated. Generally it is considered "grey water", since I the collection mechanism is not regularly cleaned and serviced.

http://water.tamu.edu/water-resources-homeowners/

http://urbanlandscapeguide.tamu.edu/irrigation1.html

Since the water has nothing dissolved, it is usually "happy" to accept materials into solution. This could include the lead and heavy metal which you are concerned about. Generally, it appears that reliable sources recommend this water for surface and subsurface landscape and ornamental irrigation, to avoid the possibility that these materials or undesirable bacterial become available to humans.  In all cases I reviewed, AC condensate is NOT recommended for direct human consumption. 

There are also plenty of "un-vetted" sources that recommend unconditionally for irrigation of vegetable gardens, etc.....I

Almost any water that we have access to, unless it has been carefully distilled is likely to have some  variety of contaminates, even lead at very low levels. It is possible that the AC condensate can be contaminated with bacteria, fungus, dust and the materials that could be on the dust as well as small amounts of heavy metal and chemicals from the device itself. (Although equipment manufacters could product coils and connects that would not introduce heavy metal.)

I could find not documentation that AC condensate was necessarily contaminated with heavy metal, so I suspect that it is unlikely that your former use of the condensate for the production of vegetable is unlikely to have an effect on you. However, in the future, it would seem prudent to use the AC condensate on non-edible plants. I am sure that you could have a sample of the water evaluated for heavy metals, if you wanted or needed to continue to use it for edible food production.

You may wish to contact your local extension office, to get help with evaluating the AC condensate as a source for irrigation of edible plants. Follow this link and click on "find an office near you".

https://extension.tennessee.edu/Pages/default.aspx