Unveiling plastifoamcrete: Composition, characteristics, and environmental threats of urban plastic variants

As plastic pollution research advances, novel plastic forms continue to emerge, posing new challenges for pollution control and environmental management. While coastal plastic pollution has been widely studied, urban environments remain understudied. This study introduces plastifoamcrete, a newly identified variant of plasticoncrete found in urban waste in Mexico City. Plastifoamcrete refers to fragmented pieces of concrete containing embedded microplastic Styrofoam beads, formed from the breakdown of foamed concrete during demolition and improper disposal. We analyzed 12 samples, each exhibiting various shapes and sizes (ranging from 3.56 x 3.66 to 16.18 × 10.50 cm) and signs of pitting, possibly due to bead release during construction demolition or bead shaping during foamed concrete production. Bead distribution was uneven, with abundances ranging from 395 to 1938 cm², and sizes between 0.46 and 5.8 mm. FTIR analysis confirmed their polystyrene composition. Given its friable nature, plastifoamcrete poses a risk of microplastic release and facilitates the transport of synthetic debris across terrestrial and aquatic environments. Its degradation not only can contribute to microplastic pollution but may also alter environmental pH, promote biofilm colonization, and serve as a vector for pollutant accumulation and dispersal, amplifying its ecological impact. By identifying plastifoamcrete within urban waste streams, this study broadens the scope of plastic pollution research and underscores the importance of integrating construction waste management into environmental policies.