Geoscience Reference
In-Depth Information
ic compounds. Some examples of these are gasoline, solvents, pesticides, latex paint, and
plastics. When chlorine combines with organic debris, like dead leaves, it makes carcinogenic
(cancer-causing) compounds called trihalomethanes (THMs). Boiling your water will kill mi-
croorganisms but will usually have no effect on chemical or radioactive pollutants. Distillation
will kill all kinds of microorganisms, but simple distillers will not remove volatile organic com-
pounds since they evaporate and condense along with the water vapor. To remove volatile or-
ganic compounds, more advanced distillers include either fractional distillation or an activated
carbon cartridge to remove these pollutants. The common reverse osmosis (RO) systems,
which include activated carbon filters, will remove most organic compounds and heavy metals
(see the section on water treatment).
Disinfecting Your Water
Contrary to popular opinion, clear, sparkling water is often unsafe for drinking. Even springwa-
ter may not be safe. Deep-water springs from gravel or sand sources are usually safe, but may
be contaminated by runoff from agricultural fertilizers, septic systems, sewer lines, and so on.
Springs emerging from rock crevices can be exit points for underground streams carrying pol-
lutants from far-off sources. When unsure about the source of your water, it is safest to boil,
chemically treat, or filter the water through a certified water filter.
Boiling all your daily drinking water is time and energy consuming, and will not remove
bad tastes, odors, or toxic chemicals. Most chemical treatments leave an aftertaste and should
be used with care to ensure the proper concentration and contact time for the temperature of ap-
plication, plus they will not remove toxic chemicals or bad tastes and odors. Traditional iodine
and chlorine water treatments, except for the relatively new two-part chlorine dioxide water
treatment products (trade names Aquamira, Micropur, and MMS), do not provide guaranteed
protection from
Cryptosporidium
cysts, which have been found to survive a twenty-four-hour
soak in undiluted household bleach. Portable filters can rapidly process surface water into pot-
able water and, if they have a carbon block inside the filter, they will remove bad tastes, odors,
and many chemical contaminants, but some filters may not purify as well as their labels lead
you to believe. When your water source is highly questionable, the safest method for portable,
fast, reliable water disinfection is to combine either chemical or UV treatment with bacteriolo-
gical filtration, or to simply use the chlorine dioxide-based products, which will kill all organ-
isms in five to fifteen minutes. Recommended methods for sterilizing and disinfecting water
are summarized below.
