Just to contribute to this very interesting topic
Years ago my mums sister got cancer and in her latter stages one of my sisters who heard of geopathic stress lines had our aunts house checked and a stress line was found.
Basically the guy doing this geopathic stress test goes around like a water diviner and he detected an underground stream going through the house and it was going through under her bed and disturbing the natural field, so the bed was moved and she lived longer than doctors thought she would, her husband died several years before also from cancer (tumour).
Apparently from what I understand if one finds such an anomaly going through your house one is recommended to put copper tubing around the house with a small flow of water going through it and this is supposed to cancel out the effect of the distorted field caused by the underground stream (note copper tubing is placed in the ground).
Copper is also supposed to be very good at deterring slugs and snails, apparently if one puts up a copper barrier the little guys have to go somewhere else to feed, apparently its like an electric fence to them and if its to small the little fellows just sort of limbo over it, I haven't tried it out yet and will try it out this summer to see if its true.
Also regarding copper intake, liver is a good source for copper but only organic liver.
Anyway just my two cents