| Popis: |
The toxicity of the organophosphorous insecticides thiometon and disulfoton as well as some of their degradation products was determined using Daphnia magna, Photobacterium phosphoreum (Microtox ® ) and an acetylcholinesterase (AChE) activity assay. For comparison, the toxicity of the organophosphorous insecticides dichlorvos, fenitrothion, parathion, etrimfos, propetamphos and quinalphos was measured. Although disulfoton and thiometon have a similar molecular structure they showed different inhibitory effects on D. magna and P. phosphoreum . Some of their degradation products (PO analogs) were stronger inhibitors of AChE than the parent compounds and showed also higher toxicity in the bioassay with D. magna. D. magna was less sensitive to the degradation products lacking the sulfur containing side-chain and to the low molecular weight sulfur compounds. A toxicological model was used to predict the toxicity of disulfoton and thiometon and their degradation products in soil leachates in the D. magna and P. phosphoreum bioassays. The predictions were based on the toxicity of the single compound and the concentration of each compound in the leachate. The predictions made showed good correlations with the determined toxicity for both bioassays. |
