ISO/DIS 18957:2025

This document describes a laboratory test method to determine the aerobic biodegradation of plastic materials exposed to seawater using accelerated conditions. Furthermore, this document describes the general requirements of the apparatus and the procedures for using this test method. The biodegradation is determined by measuring the oxygen demand in a closed respirometer or by measuring the CO2 evolved during mineralization of the plastic materials by microorganisms in the seawater. This test method is designed to give an early indication of the potential biodegradability of plastic materials in marine environment. In addition, for the purpose of promoting the development of biodegradable plastics, this document also provides a method for measuring the biomass components produced by metabolizing the test resin before it is completely mineralized to CO2, that enables to evaluate the potential biodegradability considered by carbon flow by the sum of the degree of biodegradation based on O2 and/or CO2 analysis and the degree of conversion to biomass in much shorter period of time than full mineralization. This method is not suitable to assess the degree of disintegration of plastic materials caused by abiotic factors like heat or UV radiation.