A better question would be, "is there a mechanism for plants to take up the large molecules that could be leached into the water from the plastic." The answer to that is, "no."

Gutters are typically made of pvc.

Also, keep in mind that gutters are used for growing veg hydroponically. The internet is awash with stories of people who tried to use gutters with normal potting soil and hand watering and failed miserably.

I believe one of the issues with gutters and traditional soil based gardening is the depth. Those gutters are not very deep. I was going to grow strawberries in them, but decided to build simple containers using cedar fence boards. The total cost for a 6' cedar container was less than $10. You can see my unfinished versions here: http://forums2.gardenweb.com/discussions/4455060/m=23/feedback-on-strawberry-planters-i-built

The main reason I was interested in trying it was the height. Due to age and back surgery bending a lot is no longer an option. I could put the gutters around the top of my garden fence. Safety was my first concern. I have looked on the bottom for the triangle with the # on it- but I don't see one. Honestly, I don't understand plant science enough to know if the plant can take up anything that leaches into the soil. Thanks for all the comments. I might just do regular pots sitting up on an outdoor table-they are deeper and they are rated.

i use a metal gutter, and i just put my small pots in the gutter. not growing veg, but they are great for starter plants … and young hosta and other assorted stuff. I have it spanning my pergola legs at about shoulder height … IWFM