METHOD OF DETERMINING SOIL TOXICITY BY METHOD OF BIOTESTING WITH USE OF HOLOTRICHS PARAMECIUM CAUDATUM EHRENBERG Russian patent published in 2013 - IPC G01N33/24 

FIELD: agriculture.

SUBSTANCE: method includes extraction of soil sample with water, filtration to obtain a clear solution with pH of 7.0-8.2. Preparation of scale of dilution of the extract and determining the toxicity of the sample on test-reaction of the infusoria. Then the soil is repeatedly extracted with aqueous of acetone. Filtration and extraction with hexane is carried out, lower hexane fraction is drained and repeated extraction is carried out with new portion of hexane. The hexane extract is evaporated to dryness, ethanol is added, it is covered and infused, with subsequent transfer to the colloidal solution by dilution of ethanol extract to the concentration with 2% aqueous solution of the preparation of dry bile of cattle at a concentration of 0.01%. The scale of dilution is biotested on test-reaction of the speed of contraction of secretory vesicles of the infusoria, and the level of toxicity of the soil sample is estimated by the values of toxicity of water-soluble fraction and water-insoluble of DDT.

EFFECT: improvement of accuracy of estimation of biotesting due to inclusion into the composition of detectable substances of DDT hardly soluble in water.

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