The international Landfill Owners Organisation (LOO) scientific
committee has issued a warning that discarded electronics is causing a
problem. Research has shown that copper salts leaching mainly from
printed circuit conductors is arresting the anaerobic bacterial
decomposition of organic material co-deposited in the landfills.

LOO is asking the World Health Organisation to call on governments to
ban copper in the manufacture of printed circuits, because the increased
quantities of undecomposed organic matter in landfills is causing a
proliferation of rats. Studies in eight countries have shown the rat
population to have increased by an average of 128 per cent in landfills
containing discarded electronics, compared to similar landfills with no
electronics. This problem has been exacerbated by considerably lower
levels of lead in landfills with electronics, compared with similar
studies made 10 years ago. It is believed that the higher lead levels
helped to lower the rat population.

http://www.loosciencecom.org/reports/report20090401

Brian