Cationic acrylamide-based polyelectrolytes (cPAM) are widely used in industry. They can be designed for optimal performance in a specific application, but this opportunity means the environmental safety of all different alternatives needs to be addressed. Both the inclusion of environmental toxicity as a design variable and the establishment of relationships between structure and ecotoxicity are thus current challenges. The aim of this study was to assess whether structural variables such as molecular weight, charge density and the integrative intrinsic viscosity parameter can be used to predict the environmental safety of cPAMs, as well as if these relationships are stable when the biological models change. Five cPAMs comprising molecular weight and charge density gradients were tested against bacteria, microalgae, macrophytes and daphnids. While correlations were found between physical properties of cPAMs as expected, no clear ecotoxicity patterns could be identified. All cPAMs can be classified as harmful to aquatic life on the basis of the responses elicited in the most sensitive organisms, microalgae and daphnids. Unicellular bacteria were the least sensitive eco-receptors possibly due to cell wall structure or the protective effect of the ionic strength of the test medium. The macrophytes were also tolerant to cPAMs exposure, which may be related to exposure avoidance mechanisms. The order of toxicity of cPAMs depended on the test organism, preventing the establishment of stable structure-ecotoxicity relationships. Therefore, the study leads to the overall generalist recommendation of relying on the most sensitively responding test organisms when developing new (eco)safe-by-design cPAMs.

阳离子丙烯酰胺基聚电解质（cPAM）在工业中被广泛使用。可以将它们设计为在特定应用中实现最佳性能，但是这种机会意味着需要解决所有不同替代方案的环境安全问题。因此，将环境毒性纳入设计变量以及建立结构与生态毒性之间的关系都是当前的挑战。这项研究的目的是评估结构变量（例如分子量，电荷密度和综合特性粘度参数）是否可用于预测cPAM的环境安全性，以及当生物学模型改变时这些关系是否稳定。测试了五种由分子量和电荷密度梯度组成的cPAM，以对抗细菌，微藻，大型植物和蚤类。虽然发现cPAMs的物理性质之间存在相关性，但无法确定明确的生态毒性模式。根据在最敏感的生物，微藻和水蚤中引起的反应，所有cPAM都可以归类为对水生生物有害。单细胞细菌是最不敏感的生态受体，可能是由于细胞壁结构或测试介质离子强度的保护作用所致。大型植物还耐受cPAMs的暴露，这可能与避免暴露的机制有关。cPAMs的毒性顺序取决于测试生物，从而阻止建立稳定的结构-生态毒性关系。所以，