A pathogenic organism is an organism that causes disease. In the case of waterborne diseases, this can be protozoa, bacteria or viruses.
Some micro-organisms (e.g., Giardia lamblia) can form cysts that allow the organism to live for a period of time without food, water or oxygen. The cyst protects the body from the harshest conditions and makes it much more resistant to desiccation, heat, chemicals, mechanical stresses such as crushing or vibration, ultraviolet and ionizing radiation than an unprotected body. Parasitic species can survive outside the host due to cysts.
In the wild or on a long-distance journey, it is unusual to be exposed to all five types of contamination simultaneously. Use common sense and do your research to find out what you might encounter.
Visible turbidity that can be removed by coarse filtration
Dead fish and vegetation are obvious signs of severe chemical pollution. However, chemical pollution is often less severe and the signs are much more subtle. By doing a little research before your trip, you can assess whether you are visiting an area where chemical pollution is likely to be a problem (for example, whether you will be near sulphide mines or whether there is a lot of farming).
The presence of waterborne pathogens is often linked to the presence of people and pets in the water (and water contaminated by their faeces). In many places where there has been little or no human activity, livestock or farm animals, the water may be pathogen-free and safe to drink. However, remember that we cannot know for sure without testing the water. So, for this there must be water filter plants in today’s household.
Even if locals drink the water, remember that they have been doing so for many years and may have acquired immunity to pathogens that we may not have encountered before.
Pre-trip research will also help you to determine what waterborne pathogens are possible, likely or endemic in the country you are travelling to. This type of testing can easily be combined with pre-travel vaccination testing, if required.
Addressing water contamination
Methods exist to treat turbidity, parasites, bacteria, viruses and chemical contaminants.
However, no single method is suitable for treating all these contaminants. There are also many water purification products on the market that use some of these methods. Due to this proliferation of products and their marketing, potential users may face some confusion as to which method is "best". The best solution depends on the circumstances.
In the following articles, I will examine the various methods in more detail, including advantages and disadvantages and application tips.
Authors using water purification pumps
The author uses a water purification pump that combines filtration and chemical treatment. Photo: Amanda Quaine.
Here I go back to first principles.
To make things as clear as possible, the following important points should be remembered:
Coarse filtration will remove turbidity;
Microfiltration removes larger pathogenic organisms (protozoa and some bacteria);
Boiling destroys all pathogenic organisms (regardless of their height);
Some filtration techniques (activated carbon) can remove some chemical contaminants;
Some chemical treatments (chlorine, iodine) destroy many pathogenic organisms (especially bacteria and viruses), while others (chlorine dioxide) inactivate all organisms.
It can therefore be concluded that a combination of filtration and appropriate chemical treatment or boiling will remove all or some of the specific contaminants. Understanding these basic principles will enable you to make an informed decision, independent of marketing influences, and to choose the best solution for your circumstances. Further details on the different methods, their advantages and disadvantages will be given in the following articles.