lowest observed effect concentration

例句：

1. 1. The researchers found that the lowest observed effect concentration was at a certain level of exposure.
   研究人员发现，最低观测效应浓度是在某一暴露水平。
2. 2. The study focused on the lowest observed effect concentration for various chemicals.
   该研究专注于各种化学物质的最低观测效应浓度。
3. 3. The manufacturer claims that their product has the lowest observed effect concentration in its class.
   制造商声称他们的产品在其类别中具有最低观测效应浓度。