Ecotoxicological assessment of metalworking fluids using the Allium cepa test procedure

Metalworking fluids (MWFs), which have a long history of use in industry and are in constant and ever-increasing use in parallel with advancements in mechanisation, are emulsions prepared with water. MWFs prepared as a 1/20 (MWF: water) mixture in practice, contain a large amount of water within their structure, and may become an aquatic toxic mixture in an ecosystem. In this study, half maximal effective concentration (EC₅₀) values for MWFs were determined using the Allium cepa test, an accepted ecotoxicological biomonitor, and test solutions were prepared (1/250, 1/500 and 1/1000). Depending on the MWF ratio at each concentration, a decrease in the mitotic index (MI), irregularities in the phase distribution and aberrations in the chromosomes were observed. When the amount of MWF in the water increased, chromosomal abnormalities such as stickiness were observed to occur; whereas abnormalities such as c-mitosis, fragments, bridges, vagrants and micronucleus increased as the amount of the MWF decreased. Over a second 24-h period, it was observed that values, in particular MI, showed a tendency to return to normal.