Evaluation of Phenolic Foam's Toxicity Used in Floral Arrangements

Abstract

The study investigates the characterization and toxicity of two types of phenolic foams: Floral (FF) and Hydroponic (HF), used in floral arrangements and hydroponic structures. These foams contain a resin with a free phenol content ranging between 5.0% and 8.0%, a substance harmful to plant development and ecosystem contamination. Methods such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and gas chromatography-tandem mass spectrometry (GC-MS/MS) are used for characterization. Acute exposure ecotoxicological tests are conducted with Daphnia magna for the FF sample and lettuce seeds (Lactuca sativa) for both FF and HF samples. Results reveal structural similarities between the foams and phenolic resin, including the presence of residual free phenol at concentrations of 180 ppm in FF and 73 ppm in HF, and possibly different additive treatments between samples. The FF sample had a half maximal effective concentration (EC₅₀, 48 h) = 15.4 ± 2.7 g L⁻¹ for D. magna. Surprisingly, the HF sample proves more toxic to L. sativa than FF, suggesting a potential influence of additives released from the sample's composition beyond the free phenol. This study shows that improper phenolic foam disposal can harm both aquatic and land ecosystems.