Drinking Water? Drinking Plants!

In North America, we often don’t even think about the safety of our drinking water – we take it for granted.  Advanced water treatment plants remove disease-causing microbes from our water, allowing us to quench our thirst without getting sick.  In many regions of the globe, safe drinking water is scarce; further these regions often don’t have the resources to eliminate microbes from water, creating a need for a cheap, easy way of cleaning water.  Boutilier et al. (Boutilier et al., 2014, PLoS ONE 9: e89934) report a potential solution: using pine trees.

Trees such as pine have a vascular system – much like our veins (however trees do not have a pump such as our heart).  The vascular system of a tree has two components: the xylem and the phloem.  The xylem acts as a series of interconnected tubes that bring water from the roots of a tree to the leaves.  None of the individual xylem tubes extend completely from the roots to the leaves – water has to travel sideways between tubes to make the full journey, and does so through small openings between the tubes (red circles in figure below).

These small openings are protected by little membranes that allow only water and very small particles through, acting, in effect, as a filter.  Boutilier et al. capitalized on this idea by testing if the xylem of pine could filter out harmful bacteria.  They used sections of pine branches connected to tubing to act as a filter (see picture below), and filtered red-dyed water and bacteria-infested water with the xylem.  Their results were fantastic: the red water was very clear and at least 99.9% of the bacteria were removed – all without costly equipment and chemicals.  Moreover, one small section of xylem could filter enough water for one person per day!

This breakthrough is just in its initial stages – while using wood could be a sustainable and cheap way to provide safer drinking water (note: this method cannot filter out viruses or chemicals, however water-borne bacteria are especially deadly in impoverished regions), there’s the possibility that it could promote deforestation.  So the solution is to make sure that this water filtration method is implemented with sustainable forestry management, which should be enough to provide reduce water borne illnesses in areas too poor or remote to have advanced water treatment facilities.

Stay safe and stay informed,