羊角月牙藻在制药废水毒性评价中的应用

以羊角月牙藻(FACHB-271 Selenastrum capricornutum)作为测试生物,分别采用EC₅₀(半数抑制浓度)、TU_a(急性毒性单位)和LID(最低无效应稀释度)指标对某制药厂污水处理站4个工艺节点和总出水排放口的水样进行急性毒性效应评价. 结果表明:地下调节池(工艺节点①)水样EC₅₀为15.12%±3.82%,TU_a为6.6,LID为16,为极毒/中毒废水；地上调节池(工艺节点②)水样EC₅₀为15.81%±1.04%,TU_a为6.3,LID为16,为极毒/中毒废水；中间沉淀池(工艺节点③)水样EC₅₀为62.12%±3.83%,TU_a为1.6,LID为8,为中毒/低毒废水；二级沉淀池(工艺节点④)水样EC₅₀为89.10%±1.43%,TU_a为1.1,LID为4,为低毒废水；总出水排放口水样EC₅₀＞100%,TU_a＜1,LID为1,为无毒或微毒废水. 经过各污水处理工艺节点后,制药废水对羊角月牙藻的急性毒性逐级减弱,并且毒性指标与ρ(COD_Cr)具有较好的线性关系. 研究还发现,采用毒性指标LID表征该制药废水的生物毒性,对废水样品的毒性分辨能力更强. 

Application of Selenastrum capricornutum in a Pharmaceutical Wastewater Toxicity Assessment

A green algae species (Selenastrum capricornutum, FACHB-271) was applied to study the acute toxicity of wastewater from a pharmaceutical manufacturer. Wastewater samples were collected from four treatment process nodes and the effluent of a pharmaceutical wastewater treatment. The acute toxic effects were evaluated by the level of EC50 (concentration for 50% of maximal effect), TU_a (acute toxic unit) and LID (lowest ineffective dilution). The samples from the underground and ground regulating pool were extremely/moderately toxic. Underground (process node 1):EC₅₀=15.12%±3.82%, TU_a=6.6, LID=16; Ground (process node 2):EC₅₀=15.81%±1.04%, TU_a=6.3, LID=16); the primary setting pool wastewater (process node 3), EC₅₀=62.12%±3.83%, TU_a=1.6, LID=8, was moderately/low toxic; the secondary setting pool wastewater (process node 4), EC₅₀=89.10%±1.43%, TU_a=1.1, LID=4, was low toxic; the effluent sample, EC₅₀ > 100%, TU_a＜1.0, LID=1, was not/slightly toxic. The results showed that the toxicity of wastewater samples was reduced gradually after each treatment, and a linear relationship was found between toxicity index and ln ρ(COD_Cr). In addition, the index, LID, can represent the toxic levels of wastewater samples more clearly.