The use of commercial formulations of deltamethrin in toxicological tests gives greater accuracy to them and the presence of humificated material can minimize the deleterious effects of deltamethrin on soil. The humic acid structure also suffers modifications and fluorescence, a high sensibility technique, is able to evidence these changes. The humic acids were obtained according to IHSS methodology. After, they were analyzed via fluorescence by Kalbitz and Milori methods. Commercial formulations were assessed with and without the active principle.  According to Kalbitz, the samples just with the dispersant (without the active principle), had a little variation on the humification degree, with little increase on the sample to which it was added hummus from filter cake. For the entire commercial formulation samples a variation on the humification degree was observed. The sample that received orange pill hummus presented higher rates. According Milori methodology, the formulation samples without the active principle suffer a variation on the humification degree. Besides, the sample that suffers more variation was the one with no additional hummus. For the entire formulation samples an increase on the humification degree was observed, mainly on the sample to orange pill hummus was added. After the addition of the entire formulation, that is, with deltamethrin, an increase on the humification degree was observed for all samples. This is due to the presence of nitrogen (present in the deltamethrin molecule) which in turn acts as a source food in the first moment. In the samples that did not contain deltamethrin, the hummus addition caused a decrease on the humification degree. The addition of fresh material provoked this decrease, because the organic matter is more diluted. In the samples that received deltamethrin, an increase on the humification degree was observed, so, probably, the pyrethroid masked the hummus addition. So, the deltamethrin causes more significant changes in humic soil structure than the surfactants present in the commercial formulation.

Influence of the presence of humus in the humification degree of soil contaminated by commercial deltamethrin via fluorescence spectroscopy

248th National Meeting (2014)

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