Tannins & Lignins can cause bad odors and discoloration in a raw-water supply. Corrective treatments can result in unhealthy levels of disinfection byproducts. Safe Home offers a few kits that provide drinking water testing for tannin/lignin in city or well water supplies.

Parameter Type: Drinking Water Testing for Volatiles

Parameter Name: Tannin/Lignin

What it is and Where it Comes From:

Tannins and lignins are organic compounds found in plants and trees, particularly in bark, leaves, and seeds.  By volume, 25-30% of pine needles are composed of tannins and lignins, for instance. When these plants decompose in the environment, the hardy tannic and lignic enzymes are among the last to break down (due to bacterial resistance), and they give many water bodies and streams a naturally rusty color. Tannins were used extensively in leather tanning and dyeing and contribute to the pollution still found in some older manufacturing sites.  On the plus side, tannins released from wood provide many of our favorite flavors in wine, smoked meats, and cheese.  The puckery taste of fruits like cranberries and persimmon come from tannins.  Unripe fruits are strongly tannic. Lignins are even more resistant to breakdown than tannins.  In the paper and pulp industry, lignins make up about 20% of the pulpy mash that becomes paper.  Lignins cause paper to yellow, so fine paper has the lignins removed. The re-release of too many tannins and lignins into the downstream environment is something pulp, and paper mills must guard against. Tannins and lignins in the water treatment industry can pose a problem by reacting with chlorine to produce new compounds called disinfection byproducts (in this case, trichloromethanes) that are suspected carcinogens.  Water treatment plants must find workarounds to this undesired situation, such as removing tannins and lignins before treatment, or using something other than chlorine to disinfect the water. Drinking water testing gives you several benefits like peace of mind, identifying contaminants in your water, and insight into health concerns. Safe Home offers Laboratory drinking water testing kits for tannin/lignin, allowing you to collect your water sample and ship it directly to our EPA-Certified Laboratory. This platform of drinking water testing for tannin/lignin will give you an accurate level based on the lowest level of a parameter our instruments can detect (Method Detection Level). Safe Home drinking water testing for physical properties can be used for city and well water supplies. Drinking water testing should be done any time you notice a significant change in your water quality.

Health Effects:

While water affected by tannins does not pose any health or safety risk when consumed or used in the home, it can create some unique problems. Besides the unappealing color, affected water can have a plant-like, musty odor to it and will have an unpleasantly tangy aftertaste when consumed. The tea-like color also works similarly to a dye and has the potential to permanently stain laundry and even porcelain fixtures and dinnerware in your home. Preforming drinking water testing routinely for contamination can ensure safe levels to protect yourself and your family.

Solutions to Contaminant Levels:

After drinking water testing, what are my treatment options? Common tannin treatment uses an organic scavenging anion exchange resin. The anion resin is sensitive to hardness, so most systems include a water softener as pretreatment. The water softener extends the life of the anion resin and increases tannin absorption. Anion exchange resin systems should be regenerated occasionally with a baking soda and saltwater solution to improve the effectiveness of the resin. When cleaning is needed, the water will have a “fishy” odor caused by the fouled anion resin. Anion exchange resin systems can also change the chloride, alkalinity, and sulfate levels of the water, so you may wish to monitor these substances more closely once the system is installed. Oxidation and filtration are another method to remove tannins but is not as simple as anion exchange and softening. Contact a water treatment expert in your area for assistance. It should be noted that tannins can sometimes interfere with equipment used to treat other water problems. For example, the resins or medias in iron filters, cation exchange filters and neutralizing filters can become coated by the tannins and may no longer work properly. It may be useful to test for tannins (using the “clear glass” method described above) before installing these types of water treatment devices. Who do I need to contact to find out more information about water quality in my area? Every community water supplier must provide an annual report to its customers, known as a Consumer Confidence Report (CCR). The report provides information on your local drinking water quality, including the water’s source, contaminants found in the water, and how consumers can get involved in protecting drinking water. How often does the local public water system preform drinking water testing? Frequency of drinking water testing depends on the number of people served, the type of water source, and types of contaminants. Certain contaminants are tested more frequently than others, as established by the Safe Drinking Water Act. You can find out about levels of regulated contaminants in your treated water for the previous calendar year in your annual Consumer Confidence Report (CCR).


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