The study recommended a minimum vertical separation distance between fracking wells and water supplies of 600m (2, 000ft).

BBC: Fracking: Untangling fact from fiction

In the specific case of maize, to ensure that seed stocks achieve 99.9% purity, a separation distance of 200 metres is required from any source of "contaminating" maize pollen.

BBC: GM trial 'no threat to organic centre'

It estimates more than 11% of the island's 68, 900 population has put their name to the petition which calls for a ban on commercial wind turbines in any Area of Outstanding Natural Beauty and a separation distance of at least 1.5km (0.9 miles) from housing.

BBC: 8,000 sign Anglesey petition against wind turbines

And one driver of that trend, says Gregory Guldner, director of the Center for the Study of Long Distance Relationships, is the perception that technology reduces the emotional separation of distance.

FORBES: Magazine Article