Heavy metals, phthalates, characterizing elements, CO2 concentrations and pH and hardness levels were measured in forty samples of bottled mineral waters. In some samples arsenic, manganese, mercury and selenium were present in higher concentrations than permitted by Italian law. No significant release of phthalates from containers in PET was observed. In the same samples, toxicity tests with Daphnia magna were carried out. Toxicity levels, expressed as % of immobile organisms, ranged from 0 to 100%; generally the highest toxicity values were found in the hardwaters.