IANAC (I am not a chemist, and certainly not an organic chemist <shudder>) but I know that contamination by former dry cleaning sites (almost always near built

IANAC (I am not a chemist, and certainly not an organic chemist <shudder>) but I know that contamination by former dry cleaning sites (almost always near built up areas, in small parades of shops, often near schools, gardens, etc) is a very serious problem. In the past, such businesses frequently dumped waste into drains, soak-always, pits, or in fact anywhere other than paying to have it treated properly. Probably the only other thing I’m aware of that you might possibly encounter is the site of a former leather tannery, although these were not generally sited near houses due to the overpowering smell and obvious unsightlyness.