Evaluation of the impact of construction products on the environment by leaching of possibly hazardous substances

Construction products are in contact with water (e.g., rain, seepage water) during their service lifetime and may release potentially harmful compounds by leaching processes. Monitoring studies showed that compounds attributed to construction products are found in storm water and the receiving bodies of water and that the release of biocides in urban areas can be comparable to the input of pesticides from agricultural uses. Therefore, a prospective risk assessment of such products is necessary. Laboratory leaching tests have been developed by the Technical Committee CEN/TC 351 and are ready to use. One major task in the future will be the evaluation of the leaching test results, as concentrations found in laboratory experiments are not directly comparable to the field situations. Another task will be the selection of compounds to be considered for construction products, which are often a complex mixture and contain additives, pigments, stabilization agents, etc. The formulations of the products may serve as a starting point, but total content is a poor predictor for leachability, and analysis of the eluates is necessary. In some cases, non-targeted approaches might be required to identify compounds in the eluates. In the identification process, plausibility checks referring to available information should be included. Ecotoxicological tests are a complementary method to test eluates, and the combined effects of all compounds—including degradation products—are included. A bio test battery has been applied in a round robin test and was published in a guidance document. Published studies on the ecotoxicity of construction products show the tests’ suitability to distinguish between products with small and larger effects on the environment.