Dissemination of acrylamide monomer from polyacrylamide-based flocculant use--sand and gravel quarry case study

Aggregate quarries play a major role in land settlement. However, like all industrial operations, they can have impacts on the environment, notably due to the use of polyacrylamide (PAM)-based flocculants, which contain residual acrylamide (AMD), a carcinogenic, mutagenic, and reprotoxic monomer. In this study, the dissemination of AMD throughout the environment has been investigated in a French quarry. The presence of AMD has been determined in the process water and in the sludge, as well as in the surrounding surface water and groundwater. From the results of several sampling campaigns carried out on this case study, we can (a) confirm that the AMD contained in the commercial product is found in the quarry's water circuit (0.41 to 5.66 μg/l); (b) show that AMD is transported to the surrounding environment, as confirmed by the contamination of a pond near the installation (0.07 to 0.08 μg/l) and the presence of AMD in groundwater (0.01 to 0.02 μg/l); and (c) show that the sludge in both the current and former settling basins contains AMD (between 4 and 26 μg/kg of dry sludge). Therefore, we demonstrated in this case study that using PAM-based flocculants leads to the release of AMD to the environment beyond the treatment plant and creates a reserve of AMD in sludge basins.