Are there any grounds for that (given concentrations and everything)? Are those concentrations high enough for any long-term impact? And how far do those heavy metals travel through groundwater (maybe, soil filters it out at some point, idk). Please cite academic publications, if any are available.
[1]: 'Electronic waste management approaches: An overview', Waste Management, no. 33.
However, in our age of infinite memory and the computer screen being able to show more than 20 columns or 20 rows at a time, I think we can agree on leaving the undefined, general term "heavy metal" to music and discussing the toxicity of each substance, one by one.
Since you seems keen to read books, I suggest you have a look at the first 50/60 pages of this book: "Contaminant Hydrogeology" by Fetter, 1999 for a quick overview of the topic.