Department of Cell Toxicology, UFZ - Helmholtz Centre for Environmental Research, Leipzig 04318, Germany.
Department of Effect Directed Analysis, UFZ - Helmholtz Centre for Environmental Research, Leipzig 04318, Germany.
Environ Sci Technol. 2020 Oct 20;54(20):13197-13206. doi: 10.1021/acs.est.0c05124. Epub 2020 Oct 2.
The identification of mixture risk drivers is a great challenge for sediment assessment, especially when taking bioavailability into consideration. The bioavailable portion, which comprises the organic contaminants in pore water and the ones bound to organic carbon, was accessed by equilibrium partitioning to polydimethylsiloxane (PDMS). The exhaustive solvent and PDMS extracts were toxicologically characterized with a battery of in vitro reporter gene assays and chemically analyzed with liquid and gas chromatography coupled to high-resolution mass spectrometry. The bioavailable fractions of mixture effects and individual chemicals were mostly lower than 0.1, indicating that more than 90% of the substances are strongly bound and would not pose an immediate risk but could potentially be remobilized in the long term. Despite 655 organic chemicals analyzed, only 0.1-28% of the observed biological effects was explained by the detected compounds in whole sediments, while 0.009-3.3% was explained by bioavailable chemicals. The mixture effects were not only dominated by legacy pollutants (e.g., polycyclic aromatic hydrocarbons (PAHs) in the bioassay for activation of the aryl-hydrocarbon receptor (AhR) and oxidative stress response (AREc32)) but also by present-use chemicals (e.g., plastic additives for binding to the peroxisome proliferator-activated receptor γ (PPARγ)), with different fingerprints between whole sediments and bioavailable extracts. Our results highlight the necessity to involve different bioassays with diverse effect profiles and broader selection of contaminants along with bioavailability for the risk assessment of chemical mixtures in sediments.
混合物风险驱动因素的识别是沉积物评估的一大挑战，尤其是在考虑生物有效性的情况下。可生物利用部分由平衡分配到聚二甲基硅氧烷（PDMS）来获取，包括孔隙水中的有机污染物和与有机碳结合的有机污染物。采用一系列体外报告基因检测对用尽的溶剂和 PDMS 提取物进行了毒理学特征描述，并采用液相色谱和气相色谱与高分辨率质谱联用对其进行了化学分析。混合物效应和个别化学品的可生物利用部分大多低于 0.1，这表明超过 90%的物质被强烈结合，不会立即构成风险，但可能会在长期内重新迁移。尽管分析了 655 种有机化学品，但在整个沉积物中检测到的化合物仅解释了观察到的生物学效应的 0.1-28%，而生物有效化学品仅解释了 0.009-3.3%。混合物效应不仅由遗留污染物（例如，生物测定中多环芳烃（PAHs）对芳香烃受体（AhR）和氧化应激反应（AREc32）的激活）主导，还由当前使用的化学品（例如，与过氧化物酶体增殖物激活受体γ（PPARγ）结合的塑料添加剂）主导，这与整个沉积物和可生物利用提取物之间的指纹图谱不同。我们的研究结果强调了在沉积物中对化学混合物进行风险评估时，必须结合不同的生物测定方法，采用不同的效应谱，以及更广泛地选择污染物和生物有效性。
