Persistent Legacies in the Soil
Dichlorodiphenyltrichloroethane (DDT) is perhaps the most salient example of a persistent toxicant with a global footprint. Although it has been banned for agricultural use in Europe and the US since the 1970s, it remains a critical tool globally for malaria vector control under the specific exemptions of the Stockholm Convention. Toxicologically, DDT and its primary metabolites (DDE and DDD) are remarkably stable and lipophilic, allowing them to sequester in soil organic matter and adipose tissue for many decades.
Recent European soil surveys indicate that DDT residues are still present in significant, detectable amounts in agricultural lands, particularly in parts of Southern and Eastern Europe. These “residual depots” in the ground act as a latent environmental burden; they can be re-mobilised into the atmosphere or water through tilling, erosion, or extreme weather events, entering the food chain half a century after their last application. Because DDT is a confirmed endocrine disruptor and has been linked to long-term neurodevelopmental effects in epidemiological studies, its continued presence in the soil profile necessitates ongoing toxicological monitoring. It serves as a stark reminder that in environmental toxicology, the term “banned” does not equate to “absent”.