High-Throughput Transcriptomics of Water Extracts Detects Reductions in Biological Activity with Water Treatment Processes

The presence of numerous chemical contaminants from industrial,
agricultural, and pharmaceutical sources in water supplies poses a
potential risk to human and ecological health. Current chemical analyses
suffer from limitations, including chemical coverage and high cost,
and broad-coverage in vitro assays such as transcriptomics
may further improve water quality monitoring by assessing a large
range of possible effects. Here, we used high-throughput transcriptomics
to assess the activity induced by field-derived water extracts in
MCF7 breast carcinoma cells. Wastewater and surface water extracts
induced the largest changes in expression among cell proliferation-related
genes and neurological, estrogenic, and antibiotic pathways, whereas
drinking and reclaimed water extracts that underwent advanced treatment
showed substantially reduced bioactivity on both gene and pathway
levels. Importantly, reclaimed water extracts induced fewer changes
in gene expression than laboratory blanks, which reinforces previous
conclusions based on targeted assays and improves confidence in bioassay-based
monitoring of water quality.