Risk assessment of hydrophobic organic compounds (HOCs) is difficult because maintaining a well-defined exposure during aquatic toxicity testing is challenging due to the limited water solubility and various loss processes such as volatilization, biodegradation and sorption. Passive dosing techniques help to overcome these challenges by providing a well-controlled and solvent-free exposure. In this study, the algal growth inhibition test (DIN EN ISO 8692) was converted into a miniaturized passive dosing setting. For this purpose, biocompatible O-rings were used as substance reservoirs and loaded with polycyclic aromatic hydrocarbons (PAHs). The growth inhibition of the microalgae Raphidocelis subcapitata induced by single PAHs (log K_OW 3.24–5.91) was investigated. In addition, recreated PAH mixtures were tested representing field compositions of the pore water North Sea sediments. Some of the single PAHs revealed strong growth inhibiting effects on the algal growth, while the recreated mixture compositions had slightly lower effect on the growth inhibition in the highest concentrations. Overall, the toxicity of the PAHs generally increased with the maximum chemical activities (a_max) of the PAHs and the inhibition data could be fitted with one maximum chemical activity response curve. Therefore, the miniaturized passive dosing approach appears as a promising practical and economical method that can be used for toxicity testing of the different trophic levels to improve comprehensive risk assessment.

疏水性有机化合物 (HOC) 的风险评估很困难，因为在水生毒性测试期间保持明确的暴露是具有挑战性的，因为水溶性有限以及挥发、生物降解和吸附等各种损失过程。被动给药技术通过提供良好控制和无溶剂的暴露来帮助克服这些挑战。在这项研究中，藻类生长抑制测试 (DIN EN ISO 8692) 被转换为小型被动给药设置。为此，生物相容性 O 形环被用作物质储存器并装载多环芳烃 (PAH)。单一 PAHs对微藻Raphidocelis subcapitata的生长抑制作用(log K _OW3.24–5.91) 进行了调查。此外，对代表孔隙水北海沉积物的现场组成的再生 PAH 混合物进行了测试。一些单一的多环芳烃对藻类生长有很强的生长抑制作用，而再造的混合物组合物在最高浓度下对生长抑制作用略低。总体而言，多环芳烃的毒性通常随着多环芳烃的最大化学活性（a _max）而增加，抑制数据可以用一条最大化学活性响应曲线拟合。因此，小型化被动给药方法似乎是一种很有前途的实用且经济的方法，可用于不同营养级的毒性测试，以改善综合风险评估。