Abstract

Background

Zinc oxide nanoparticle (nZnO) and chemicals with different mode of action (MOA, i.e., narcotic and reactive) were frequently detected in the Yangtze River. Organisms are typically exposed to mixtures of nZnO and other chemicals rather than individual nZnO. Toxicity of nZnO is caused by the dissolution of Zn²⁺, which has been proved in the field of single toxicity. However, it is still unclear whether the released Zn²⁺ plays a critical role in the nZnO toxicity of nZnO–chemicals mixtures. In the present study, the binary mixture toxicity of nZnO/Zn²⁺ and chemicals with different MOA was investigated in acute (15 min) and chronic (12 h) toxicity test upon Vibrio fischeri (V. fischeri). The joint effects of nZnO and tested chemicals were explored. Moreover, two classic models, concentration addition (CA) and independent action (IA) were applied to predict the toxicity of mixtures.

Results

The difference of toxicity unit (TU) values between the mixtures of Zn²⁺–chemicals with those of nZnO–chemicals was not significant (P > 0.05), not only in acute toxicity test but also in chronic toxicity test. The antagonistic or additive effects for nZnO-chemicals can be observed in most mixtures, with the TU values ranging from 0.75 to 1.77 and 0.47 to 2.45 in acute toxicity test and chronic test, respectively. We also observed that the prediction accuracy of CA and IA models was not very well in the mixtures where the difference between the toxicity ratios of the components was small (less than about 10), with the mean absolute percentage error (MAPE) values ranging from 0.14 to 0.67 for CA model and 0.17–0.51 for IA model, respectively.

Conclusion

We found that the dissolved Zn²⁺ mainly accounted for the nZnO toxicity in the mixtures of nZnO–chemicals, and the joint effects of these mixtures were mostly antagonism and additivity. CA and IA models were unsuitable for predicting the mixture toxicity of nZnO–chemicals at their equitoxic ratios.

中文翻译：

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氧化锌纳米颗粒与化学剂对费氏弧菌的混合毒性

摘要

背景

长江中经常发现氧化锌纳米粒子（n ZnO）和具有不同作用模式的化学物质（MOA，即麻醉和反应性）。有机体通常暴露于n ZnO和其他化学物质的混合物，而不是单独的n ZnO。n ZnO的毒性是由Zn ²⁺的溶解引起的，这已在单一毒性领域得到证明。但是，尚不清楚释放的Zn ²⁺是否在n ZnO-化学混合物的n ZnO毒性中起关键作用。在本研究中，n ZnO / Zn ²⁺的二元混合物毒性并在费氏弧菌（V. fischeri）的急性（15分钟）和慢性（12 h）毒性试验中研究了具有不同MOA的化学物质。探索了n ZnO和受试化学品的共同作用。此外，两个经典模型，浓度增加（CA）和独立作用（IA）用于预测混合物的毒性。

结果

Zn ²⁺化学品与n ZnO化学品的混合物之间的毒性单位（TU）值的差异不显着（P  > 0.05），不仅在急性毒性试验中，而且在慢性毒性试验中。对n的拮抗作用或加和作用可以在大多数混合物中观察到ZnO化学物质，在急性毒性试验和慢性试验中，TU值分别为0.75至1.77和0.47至2.45。我们还观察到，在组分的毒性比之间的差异很小（小于约10）的混合物中，CA和IA模型的预测精度不是很好，平均绝对百分比误差（MAPE）值在CA模型分别为0.14至0.67和IA模型为0.17-0.51。

结论

我们发现，溶解的Zn ²⁺主要是n ZnO-化学物质混合物中n ZnO毒性的原因，这些混合物的共同作用主要是拮抗作用和可加性。CA和IA模型不适合预测n ZnO-化学品在其等毒比下的混合物毒性。