Portable Water Purifier Considerations
- It is widely known that Giardia and/or Cryptosporidia have been found in water supplies essentially in every country of the world. Therefore, you should always protect against parasitic cysts and you should insist on 100% reduction. When one cyst can infect, 99.9% may not be good enough, especially when there is no known treatment for Cryptosporidia.
- Pesticides and herbicides, and possibly other chemicals, can be present anywhere downwind or downstream from major agricultural and industrial areas hundreds of miles away. These contaminants concentrate in streams, rivers and lakes and sometimes are intentionally added for weed and aquatic life control. (Water Pollution Biology, P.D. Abel, John Wiley & Sons, 1989.)
- In the USA , asbestos fibres can be found in very high numbers of more than a million fibres per litre in most western and in some eastern wilderness waters. Even though trace amounts of these chemicals may not make you ill, no one wants to drink asbestos fibres if they can easily be avoided.
- Micron ratings must be absolute to be meaningful, and precise measurements are essentially impossible to make. Micron ratings pertain only to physical removal or straining of particles, so absolute micron ratings are only one means of evaluation of effectiveness. Removal of pesticides, herbicides, tastes, odours, most colours and solvents require other purification (separation) mechanisms. Some product claims confuse retention ratings by listing the size of microbes killed rather than the actual retentions. For example, .01 microns, the size of some viruses, is stated for some iodine products but actual retention may be 100X bigger at 1.0 micron. Many units, even those with very low micron ratings, have little or no ability to remove anything other than particles.
- According to US Federal regulations "Pesticide" products rely on chemically poisoning organisms (pests) while "Devices" rely on physically removing them. All products carry a US EPA Establishment Registration Number. "Pesticide" products also must carry a second EPA registration number for the "Pesticide" being used. So, decide if you want to use a "Device" or a "Pesticide" product for your water purification needs, and be sure to check the label to choose the right type. In certain applications, it may be desirable to use a "Pesticide" to pretreat water. Complete removal of the "Pesticide" is very desirable after enough kill time has elapsed.
- Iodine used directly or from iodine resins is not effective against Cryptosporidia and larger pathogens, and most iodine resin based systems require double pass through for effectiveness against viruses, especially at low water temperatures. Some iodine resin systems require 10 minutes of hold or kill time, in addition to double pass through, to achieve 99.99% reduction of viruses. There is no practical way to know if a water source contains pathogens. This means that for consistent virus and perhaps for bacteria reduction, when using iodine resin systems, all water should be pumped through twice, and then held for 10 additional minutes. It is essential that carbon post filters not be used, as they stop pesticidal action. The General Ecology First Need® portable water purifier removes cysts, bacteria, viruses and viral toxins in a single pass - without chemicals or hold time.
So, now that you know why you need to purify and some background, you can review the requirements for a portable purifier and select the right one for your individual outdoor recreation needs...
Selecting a Portable Water Purifier
Portable Water Purifier Requirements