Distilled water is a highly purified form of water, with most impurities removed. While pure distilled water itself does not support bacterial growth, contamination can readily occur during handling and storage, allowing bacteria to establish and multiply.
The Science Behind Distilled Water’s Purity
Distilled water undergoes boiling and condensation, effectively removing minerals, organic matter, and most contaminants, including microorganisms. This process results in nearly pure H₂O with very low levels of dissolved solids.
Bacteria require specific nutrients and an energy source to grow and reproduce. In pure distilled water, these essential nutrients are absent or negligible, making it an inhospitable environment for sustained bacterial growth.
Sources of Bacterial Introduction
Despite its initial purity, distilled water is highly susceptible to external contamination once exposed. Airborne particles, including dust and microbial spores, can readily settle into open containers. Unsterilized containers or surfaces, and handling with unwashed hands, can introduce bacteria. Cross-contamination from other water sources also poses a risk.
Even a small amount of organic matter or minerals from these contaminants can provide minimal nutrients for some bacteria to survive or slowly grow. Once introduced, bacteria can form biofilms, slimy layers that adhere to surfaces within the container, providing a protective environment for further growth.
Potential Consequences of Bacterial Growth
Bacterial growth in distilled water poses concerns depending on its application. In laboratory experiments, contamination interferes with results and compromises scientific findings. For medical procedures, using contaminated distilled water carries an infection risk, necessitating strict protocols and sterile handling.
If contaminated distilled water is consumed or used in devices like humidifiers or CPAP machines, it can lead to health risks. While the human digestive system can often neutralize ingested microorganisms, the respiratory tract lacks these defenses. Inhaling aerosolized bacteria from these devices can cause respiratory issues or other infections, especially for individuals with compromised immune systems.
Guidelines for Maintaining Purity
To minimize bacterial contamination, store distilled water in sealed, clean, opaque containers. Opaque containers prevent light exposure, which can encourage microbial growth. Avoid reusing containers that previously held other liquids without thorough cleaning and sterilization.
Proper hygiene during handling, such as washing hands before pouring, helps prevent bacterial introduction. Use distilled water promptly after opening or transferring it from its original sealed container to limit exposure to potential contaminants. Regularly inspecting containers for signs of damage or contamination, such as cloudiness or unusual odors, helps ensure the water’s continued purity.