Over the years as I dig my vegetable plot I have found bits and pieces of old household waste, i.e. pieces of old china, glass, small chunks of burnt coal, etc. Once I found a small scrap of lead. The property used to belong to a house dating from about 1830 and I think my plot is sited on top of an old household tip. My concern is more about possible contamination from dioxins or the like from the remains of coal fires than about the small annoyance of a few bits of china or glass. Also, for some years our neighbours used to burn garden clippings. and some bits of household waste and the smoke would drift across the ground. More dioxins?