When the Associated Press published results from its five-month study on the presence of pharmaceuticals in drinking water in 2008, it made headlines across the country. Drugs such as antibiotics, anti-convulsants, mood stabilizers, and cholesterol-lowering medications were found to be present in the drinking water of more than 40 million Americans.
Previous studies conducted by the U.S. Geological Survey found an average of 20 different drugs in the wastewater streams they examined—everything from caffeine to over-the-counter medications, such as ibuprofen, to rare but potent cancer chemotherapy drugs.
In addition to pharmaceuticals, contaminants such as perchlorates, pesticides, herbicides, endocrine-disrupting chemicals (EDCs), brominated flame retardants, and personal-care products have also been detected in the water supply.
Despite being referred to as “emerging contaminants,” many of these compounds have been in use for decades and their presence in water is not new. What is new, however, is our ability to measure the contaminants that exist in our water supply at very low concentrations.
While such contaminants can be found in drinking water, should they be a concern for researchers? Are these contaminants making their way from the tap into the high purity water used in the laboratory?
Analytical laboratories assessing and monitoring the presence of such emerging contaminants must ensure their laboratory water is purified to the highest degree possible, so that even minute amounts of contaminant in the purified water do not interfere with trace level analyses. Other laboratories that require a similar standard of water purity are those focusing on toxicity testing and those developing the increasingly sensitive methods for the detection of emerging contaminants and their metabolites in various matrices.
But what about life science research? Does the presence of such contaminants influence the cell-based and biological assays routinely conducted in research labs? These are difficult questions to answer. The effects of these contaminants on experimental outcomes may be so subtle that the cause of unexpected results might not be immediately traced back to the water.
Emerging contaminants can be organic molecules or ions, and they can affect experiments even if they are present in the laboratory water in very small amounts. For example, mass spectrometry is widely used in analytical and life science laboratories. This technique requires extremely pure reagents and solvents, including water, to avoid contamination of ionization chambers and interferences in mass analysis.
Another example is reversed-phase HPLC. Organic contamination of water in the mobile phase is known to cause baseline shifts and the appearance of extraneous peaks that can interfere with the spectral identification and quantitation of low-level analytes.
With DNA microarrays, the presence of organic compounds and ions in the water can hinder hybridization and interfere with the detection and measurement of genes using fluorescence. Such contaminants may also affect cell culture experiments by affecting cell growth and function or cloning efficiency.
While the presence of trace amounts of emerging contaminants may not currently be an issue in most laboratories, all researchers should remain mindful of how water quality may impact experiments. If a lab’s water-purification system is not functioning properly or is incapable of removing harmful contaminants, experimental results are likely to be affected.