Contaminated soils can become a secondary atmospheric source instead of a passive sink
WHAT THE EVIDENCE SAYS
Measurements of DDTs, HCHs and PCBs in air and soil across agricultural, urban and industrial sites showed strong spatial and seasonal variation. Concentrations were often elevated in warmer pre-monsoon and monsoon periods, and fugacity calculations indicated that some contaminated soils can act as secondary emission sources that remobilize persistent pollutants into the atmosphere.
WHY IT MATTERS / OUR READ
Legacy contamination is dynamic. A soil that stores pollutants in one season can become a source in another, so risk assessment and monitoring need to account for exchange processes rather than treating old residues as permanently immobilized.
CAVEATS / UNCERTAINTY
The study covers three Pakistani cities and source attribution is inferential. Concentration reporting in the early article version contains formatting irregularities, so the edition avoids over-interpreting exact ranges and focuses on the robust seasonal/exchange pattern.
SOURCE
Scientific Reports — primary study
View original evidence ↗
Air–soil measurements across agricultural, urban and industrial landscapes in Khyber Pakhtunkhwa found warmer-season POP elevations and fugacity evidence of remobilization from some soils.
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