This International Standard specifies a semi-static method for the determination of the effects of contaminants on growth and survival of young snails, usually Helix aspersa aspersa Müller. The animals are exposed via the cutaneous and digestive route using a test substrate (artificial or natural soil according to the objective of the study) to which defined amounts of the following are added: - substances or preparations; - soils (contaminated or of unknown quality) or waste materials. A static method may be implemented in addition to the semi-static method (optional). This method is described in Annex A. This method does not apply to volatile substances, i.e. substances for which the Henry constant, H, or the air/water partition coefficient is over 1, or for which the vapour pressure is over 0,013 3 Pa at 25 °C. This test takes into account the possible change in the test substance, preparation, soil or waste material because the test mixture is prepared and renewed every 7 days during the 28-day test period.