Compounds released from unused biodegradable mulch materials after contact with water

Biodegradable plastics (BDP) are an alternative to environmental and economical drawbacks of PE agricultural mulches. They are intended to biodegrade into the soil or in compost. BDP materials certified as biodegradable in soil or in compost have passed ecotoxicity biotests after biodegradation, but most BDP ecotoxicity studies do not provide insights on the components these materials may release. The present work aims to characterize the compounds released from BDP to water solutions before biodegradation. New unused BDP, one paper mulch for agricultural use, a control without any material, and one non-degradable PE mulch, were incubated in a water solution for identification of the released compounds through GC-MS, NMR and UPLC-MS/MS. All BDP released compounds and modified the pH of the solution, with differences depending on the composition of the material. A diversity of compounds used in the formulation of the materials, and their derivatives, were identified in most solutions; mostly, but not exclusively, adipic acid, 1,4-butanediol, lactic acid, glycerol, terephthalic acid, mono and disaccharides, or fatty acids; some were also quantified. Results prove BDP to interact with the environment and to release compounds well before biodegradation may be acknowledged. They are also a step forward towards identifying the links between reported changes in plant development and specific compounds or compound mixtures, and towards a more sustainable and targeted selection and use of BDP for mulching specific plant species in agriculture. (C) 2020 Elsevier Ltd. All rights reserved.