First Evidence and Source of Quaternary Phosphonium Compounds in Soil and Indoor Dust around a Manufacturing Plant

Organophosphorus pollutants pose significant threats
to both human
health and natural ecosystems due to their widespread use and toxicological
effects. In addition to the well-known organophosphorus pesticides
and organophosphate esters, quaternary phosphonium compounds (QPCs)
are widely utilized, highly productive, and toxic. However, their
environmental presence and behavior are not well understood. Using
the cheminformatics toolkit in Python, 25 QPCs were screened as target
analytes from a chemical industry database based on their characteristic
structural features. Among them, 16 QPCs were detected in soil (range:
2.61–5.84 × 103 ng/g), and 11 QPCs were found
in indoor dust (range: 4.89–1.71 × 103 ng/g)
near a manufacturing plant. A point-source distribution pattern was
observed in the soil, while indoor dust concentrations showed a distance-dependent
attenuation. The spatial distribution suggests that the manufacturing
plant is a significant source of QPCs in the surrounding area, with
eight QPCs being reported for the first time. Human exposure assessment
via dust ingestion indicated estimated daily intakes well below acceptable
thresholds, suggesting limited immediate risk. This study highlights
QPC manufacturing plants as a significant source of environmental
contaminants and underscores the need for greater attention to plant-released
QPCs and their potential health effects.