Moss amendment reduces persistent organic pollutant accumulation in plants

p,p'-DDE (2,2-bis(chlorophenyl)-1,1-dichloroethylene), a degradation product of p,p'-DDT (2,2-bis(chlorophenyl)-1,1,1-trichloroethane), persists in the environment due to its historical use. Cucurbita pepo spp. pepo is known for its ability to accumulate p,p'-DDE from the soil; however, the uptake mechanism remains poorly understood. Furthermore, moss species are also capable of retaining chlorinated organic compounds, which makes them valuable bioindicators for environmental research. This study assessed the effect of moss (Selaginella kraussiana) amendment on the accumulation and translocation of p,p'-DDE in the roots, shoots, and xylem sap of Cucurbita pepo ssp. pepo grown in two soils with different levels of contamination. Plants were cultivated in pots that were with or without S. kraussiana, using two soils containing 2,180-2,490 ng/g and 1,710-1,870 ng/g residual p,p'-DDE. The average p,p'-DDE concentrations in xylem sap decreased by more than 60% in moss-amended plants compared to control groups. Additionally, moss amendment reduced root and shoot p,p'-DDE concentrations by approximately 70% and 55%, respectively, compared to control groups. These findings suggest that moss amendments may reduce p,p'-DDE bioaccumulation in crops by altering contaminant bioavailability in the rhizosphere, offering a promising approach to promote food safety and minimize POP transfer through the food chain.