"(...) nearly 900 tons of unexploded munitions are recovered each year by Belgian and French farmers after ploughing their fields."
"Authorities estimate that if they continue working at the current rate, it could take anywhere from 300 to 700 years to complete."
"A 20 hectare contaminated site abandoned by the French Society of Munitions Recovery, which went bankrupt in 2006. No one knows the effect this pollution is causing and no one known when or how it will be cleaned up."
For more details (in french) : http://oliviersainthilaire.com/?page_id=38