Abstract

Pollution is one of the major environmental issues that affect human beings. Metalworking fluids are widely used in many industries. There are many chemical components such as amines and biocides in the metalworking fluids, which cannot be biologically treated, and disposal is still a problem. Often chemicals are tested for toxicity individually, however, there are interactions between combinations of chemicals. Hence, in this research, chemicals that are commonly used in metalworking fluids, are tested in combination as part of a factorial experimental design. Three types of commercially available biocides (A14, AEF, AOX - coded due to commercial rights), two amines (Monoethanolamide - MEA, Triethyl olamine - TEA), and an emulsifier (blinded because of commercial rights) were tested. A bacterial biosensor E.coli HB101 was used to assess toxicity. A total of 63 tests were carried out. It was found that the toxic responses do not align with predictions based on the sum of the responses to individual compounds. Instead, there are interactions that cause synergistic or counter effects. For example, biocides A14 and AEF were found to be lethally toxic; biocide AOX and MEA were found to be slightly toxic. The combination of MEA, AEF, A14 was found to be the most toxic of the 63 possible combinations. However, when AOX was added, the toxicity level decreased in indication that toxicity was mitigated. This study shows that understanding the combinatorial toxicity could help to inform eco-design and promote sustainable biological treatment at the end of product life.

Keywords: Combinatorial Toxicity, Biocide, Biosensor, Amine