For some, the smell brings on nausea and headaches. Others fear ‘forever chemicals’ seeping into the water

• UK and Europe’s hidden landfills at risk of leaking toxic waste into water supplies

“I just kept smelling this horrible, nasty smell … like animal excrement, and I was wondering what it was,” says Jess Brown, from Fleetwood, Lancashire.

Brown’s mother suffers from chronic obstructive pulmonary disease and she believes the smells make it worse. She also worries for her eight-year-old daughter, whose asthma worsens when the odour seeps indoors.

Exclusive: Rising flood risks driven by climate change could release chemicals from ageing sites – posing threats to ecosystems

• ‘I kept smelling a horrible nasty smell’: the risks of England’s old dumping grounds

Thousands of landfills across the UK and Europe sit in floodplains, posing a potential threat to drinking water and conservation areas if toxic waste is released into rivers, soils and ecosystems, it can be revealed.

The findings are the result of the first continent-wide mapping of landfills, conducted by the Guardian, Watershed Investigations and Investigate Europe.

Disclaimer: This dataset may contain duplicate records. Duplicates can arise from multiple data sources, repeated entries, or variations in data collection processes. While efforts have been made to identify and reduce duplication, some records may remain.

Journalismfund.eu provided funding support for the investigation.