During the Network's last webinar “Water quality testing in action: Making your testing program work in the real world” there were some questions to our panelist Dr. Anna Murray that couldn't been answered because of time constraints. She answered them in written for us to share with all of you. ¡Thank you Anna!
If you missed the event, you can register to watch the recording here.
Question: Do you have updated technique for micro pollutants removal from water?
- One thing is clear with water quality testing: the number of parameters you can test is endless! The importance of prioritizing them should be determined based on their relative risk. In many low and middle income settings, the highest health risk remains diarrheal disease, which stems from microbiological contamination of water supplies. After this, there are chemical parameters like fluoride, arsenic, nitrates, lead, and other heavy metals. There are a host of emerging contaminants, microplastics, etc etc, that are difficult to test, and aren’t currently regulated even in municipal water systems in high-income countries. This isn’t to say they aren’t important, but the practical risks of these may be cancers after large volumes are consumed over a long period of time. Microbiological contamination, however, can lead to immediate health impacts that we know are detrimental to children and immunocompromised people.
- In terms of micropollutant removal, this is outside of my expertise.
There are two ways of getting an idea of the risk from a range of pollutants that do not involve lab testing - at least at first.
One is to assess the catchment. Look at possible sources of pollution. Different industries will cause different types of pollution. This is hard with very large catchments. This will give you an idea of the possible contaminants that could could then test for, reducing the number of parameters.
The other is to work out the biotic index. The number and diversity of very small animals in the water will give you an idea on how clean the water is. Polluted water can only sustain a few specially adapted species; clean water can be good for many different ones. You catch a sample of these in a net, identify them and count them.
More details on both techniques can be found in:
HOUSE, S. and REED, R., 1997. Emergency Water Sources. Guidelines for Selection and Treatment [online]. Loughborough University, UK: Water, Engineering and Development Centre. Available from: https://repository.lboro.ac.uk/articles/Emergency_water_sources_Guidelines_for_selection_and_treatment_3rd_ed_/9585170.
This is very true Brian, there are so many possible contaminants in the water that is impossible to test for everything. However, to assess the parameters to analyze based on the surrounding industries needs a deep understanding on how they work. A deep research is usually needed.