Automation of the Ames Assay Scoring and Assessment of Water Samples for Mutagenicity

Potable water contain various chemicals, compounds and disinfection by-products. The presence of these substances can result in mutagenic risk to the public, highlighting the need for surveillance. This study evaluated the mutagenic potential of source water and drinking water from two South African drinking water treatment plants. The study also investigated the high-throughput scoring of the Salmonella typhimurium Ames mutagenicity assay with frameshift and base-pair mutations. Two different scoring approaches were used including visual manual scoring and using the automatic image scanning platform. No mutagenic risk was detected for both TA98 and TA100 bacteria regardless of metabolic activation. Grab sampling may have missed any transient mutagenic events. Despite the limitations, automatic scanning of the microtiter plates ensured consistent, reliable and accurate results that can be reviewed. The outcomes of the study show effective mitigation of mutagenic risk by the treatment plants and deliver public reassurance of drinking water. The advantageous combination of automated scoring technologies, as demonstrated in this study, provides a scalable and standardized monitoring programme for mutagenic risk. Regulatory frameworks would benefit from a mutagenic risk monitoring programme, given the myriad health risks involved in exposure to environmental mutagens.