Combined toxicity interactions and contribution of three N-DBPs to Vibrio qinghaiensis sp.-Q67
Three nitrogenous disinfection by-products(N-DBPs),bromoacetonitrile(BAN),dibromoacetonitrile(DBAN)and dichloroacetamide(Dichloroacetamide,DCAM),were selected as research objects,and three binary mixture systems(BAN-DBAN,BAN-DCAM,DBAN-DCAM)and one ternary mixture system(BAN-DBAN-DCAM)were designed by the direct equipartition and uniform design ray methods,respectively.The time-dependent microplate toxicity analysis(t-MTA)was used to systematically determine the toxicity of the three N-DBPs and their mixture systems against Vibrio qinghaiensis sp.-Q67,Q67.A concentration addition(CA)model was applied to analyze toxicity interactions within mixtures,and the dose reduction index(DR1)method was used to characterize the contribution of individual components to the combined toxicity interactions.The results showed that the concentration-effect curves of BAN,DBAN and DCAM on Q67 were"S"-shaped with obvious acute toxicity,and the long-term toxicity was higher than the acute toxicity.BAN-DCAM mixture showed antagonism,the BAN-DBAN showed synergism,while the DBAN-DCAM and BAN-DBAN-DCAM appeared both antagonism and synergism.The three binary mixture systems,except BAN-DCAM,showed synergistic effects with different intensities at the early stage of exposure.In the BAN-DBAN-DCAM system,DRImax,DBAN(=258.706)＞DRImax,BAN(=38.166)＞DRImax,DCAM(=2.658),so the contribution degree of the three N-DBPs to the synergistic effects was presumed to be followed by DCAM＞DBAN＞BAN.
nitrogenous disinfection by-productsVibrio qinghaiensis sp.-Q67combined toxicityinteractiondose reduction index
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维普
