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Can having glass rocks amongst the garden plants give the plants lead poisoning?

Can having glass rocks from craft store amongst my garden plants give the plants lead poisoning? my bf's ex had glass rocks everywhere in the garden. the plants, some very hearty-type plants are dying. I've dug up old roots from the palm for example, and found these damn colored rocks surrounding the roots up to 7 inches down! these are the rocks you get at a craft store for misc. - about $3-5 dollars a bag. they probably looked great in the beginning, but many of the color has faded away and now it seems 8 years later, the plants are too. There's alot of cobalt blue color in there... they seem to have kept their color the longest. thoughts on this?

Public Comments

1. It's not lead in the glass - for one thing, if they're cheap glass, they don't have an appreciable amount of lead in them - it's the fact that you've got a bed full of glass. The plants have used up all the available nutrition and their roots can't get to good soil. The same thing would have happened if you'd had river rocks or marble chips in their. The best thing to do here is dig as many of these glass stones out, recycle the glass, and put some good soil and compost in the beds.
2. Glass itself is an inert liquid- yes liquid, so there should not be any danger from the components of the glass. If these pieces have been painted to give them color, that could leach into the soil and harm the people and poison the soil for decades and decades. The problem that would concern me the most, would be the material itself. Glass, even small dense pieces could crack and shatter. That would leave tiny shards of glass in the soil that would endanger the gardeners, and again persist for a very long time. I would remove them carefully. If I had these rocks, I would use them as a decorative mulch for indoor plants. As far as the plants dying, they could have had coloring that has leached into the soil. A soil test done by a competent agency could determine that status. Finally, there is a possibility that it is the rocks themselves that are causing the plants to die. If you try to grow plants in a medium that has not nutrients and you do not add fertilizer, you are going to kill the plant..
3. Even if the glass had any lead in it it could not migrate or leach out. Crystal has lead in it and you drink out it don't you? The myth that glass is a liquid is false. If you understand thermodynamics of glass you know that it is an amorphous solid which does not display the viscosity of a liquid. This misinformation was started because glass in centuries old churches is often thicker at the bottom then at the top. But the last process in making glass in those days required spinning on a disk to make it even and smooth. This left the glass thicker at the edges and when the glass was cut into plates this thicker edge was installed at the bottom giving an illusion of flowing to the bottom.
4. Plants are actually very tolerant of lead, and don't absorb it readily. From the University of Minnesota: "Since plants do not take up large quantities of soil lead, the lead levels in soil considered safe for plants will be much higher than soil lead levels where eating of soil is a concern (pica). Generally, it has been considered safe to use garden produce grown in soils with total lead levels less than 300 ppm. The risk of lead poisoning through the food chain increases as the soil lead level rises above this concentration. Even at soil levels above 300 ppm, most of the risk is from lead contaminated soil or dust deposits on the plants rather than from uptake of lead by the plant." The accessible lead content in the glass would be far lower than 300 ppm, however, more substances than lead are added to glass that may contaminate soil. For example, that blue glass contains either cobalt or copper, dark red contains my personal favorite, selenium, etc. It may be a combination of several contaminants as opposed to just one. Also, the fact that the blue seems to have retained it's color longer likely indicates that the additives used to make it blue leach out slower than those in the glass that has lost it's color.