VOC
Volatile Organic Chemicals (VOCs) are carbon-containing compounds that evaporate easily from water into air at normal air temperatures. (This is why the distinctive odor of gasoline and many solvents can easily be detected.) VOCs are contained in a wide variety of commercial, industrial and residential products including fuel oils, gasoline, solvents, cleaners and degreasers, paints, inks, dyes, refrigerants and pesticides.
The category of VOC (Volatile Organic Chemical) includes a number of chemicals that are both man-made and naturally occurring. Water from wells and utilities may contain some of these contaminants. Some VOCs are pesticides, herbicides, or insecticides that seep into the ground water after application. Other VOCs enter the water supply through industrial or other waste disposal. This category also includes total trihalomethanes, which are a by-product of chlorination.
The information below is from from the Multi-Pure Corporation:
Volatile Organic Chemicals (VOC's) are contaminants that may be found in drinking water supplies across the nation. VOC's are those organic chemicals (pesticides, herbicides, and other chemicals) that are "readily vaporizable at a relatively low temperature" (Webster's Collegiate Dictionary). With no visible characteristics, smell, or taste, VOC's are virtually undetectable in drinking water by the consumer. The only way to know if your water has VOC's is to have it tested or to obtain test results from local public water supplier. VOC's are often toxic and pose intimidating health risks.
|
||
| Almost every region in the U.S. has VOC's in the water supplies. Urban areas may get VOC's from industrialization, and rural areas may get VOC's from agriculture. Also, 90% of U.S. drinking water is chlorinated (and most likely contains disinfection by-products); thus, VOC's are practically everywhere. In a recent study by the Environmental Working Group, 28 of 29 cities tested were found to have herbicides or pesticides in their tap water. |
Some Common Sources of Volatile Organics
|
||||||||||||||||||||||||||||||||||||||||||||||||
The table above is from http://www.health.state.ny.us/environmental/indoors/voc.htm/ List of common VOCs that can be found in water supplies.
|
||||||||||||||||||||||||||||||||||||||||||||||||
Treatment of VOCs. The treatment of choice for most volatile organics is activated carbon filtration. Adsorption capacity of carbon varies with each individual chemical, and some carbons are better than others at VOC treatment. Coconut shell carbon is generally regarded as best in VOC reduction. Reverse osmosis can also remove up to 80% of VOCs, and aeration used in conjunction with activated carbon can be very effective. With carbon filtration, significantly longer contact time is usually required for VOC reduction than for dechlorination.
|
||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||||||