Cleaning dishes is a daily activity in every household, which does not receive special attention by most people. Only a few of them follow the instructions and dosage. The purpose of our research was to determine the residual amount of surfactants – sodium dodecyl sulphate (SDS) on different materials after manual dishwashing. Besides, it was our task also to study the effect of roughness of the material on the amount and toxicity of SDS. To determine the amount of residue of SDS a spectrophotometric method employing methylene blue was applied. Toxicity measurements of SDS residues were done by measuring the inhibition of luminescence of Vibrio fischeri bacteria. The results obtained showed that on the wooden plate and cup there were the highest residues of SDS compared to other materials like: plastic, porcelain, stainless steel and glass plate and/or cup. The residues of SDS were on average higher by 30% on cups, compared to plates. That proved that the rougher is the material and the deeper is the dish, the more residues remain on them. The amount of remaining SDS on dishes after manual dishwashing caused from 3 to 4% inhibition of luminescence bacteria, while a 99% of luminescence inhibition was detected in the water in which the dishes were washed indicating the toxicity of discharged water in normal household.
B.04 Guest lecture
COBISS.SI-ID: 5501035