Testing the tests

Testing strips are widely accepted as a cheap method to determine pollution of water. This method has its limitations, since it is not always possible to reliably read the colour difference – especially in the lower values. Just stating this with my vast but dated experience of testing water could expose my hubris. Therefore, I had this idea to enrich my short stroll in the Sandwell area with creating content in the field. I will compare four locations of surface water both streaming and stationary with my home tap. My tap water is monitored by South Staffs Water company, therefore the 2022 averaged results  can be referred to.

The testing strips can only go so far, however, should they work properly then they provide a good view of the water pollution. When anything organic should be tested, some strips for microbiological contamination  exist, but I did not opt in for checking these on this occasion. I will look into comparing those with other methods at a later date – for this occasion I wanted to choose an ultra-cheap widely available options. Amazon marketplace provides multiple testing strips which could be useful for this purpose. I have decided for Tespert test strips, as they provide a maximum of 19 parameters and one of which was those parameters was a bacteria test. For bacteria, two small bags with blue paper or textile fabric inside. Yellow stains of the bacteria should be drawn on the blue material after 48-72 hours in room temperature. To have a supporting evidence, I have commenced testing of each location with Salifert dissolved oxygen testing kit. This dissolved oxygen is not part of the tests of the drinking water, however, since I was checking surface fresh waters, I wanted to have a control value of some sort. Dissolved oxygen could have suggested water streaming and also indicate some of the potential microbiological life.

Sandwell is part of the Black Country. The coal mining and industrial history, together with the contemporary high population density of the West Midlands region promise that the surface waters could still be contaminated. Waters selected for checking appear clean enough from distance. The biggest goal of this test was to achieve a positive result of the bacteria test, where bacteria would be expected.

Regarding the Tespert strips, the lead, iron, nickel, copper, zinc, sulphate and ammonia were not confirmed in any tested location. This comes as a little reassuring, since the areas are used for leisure activities of local residents. A little surprise is a lack of values of nitrites and nitrates. Perhaps it is due to the area not been agriculturally exhausted as it could be in out of the town countryside. The bacteria test is a big fail, I do not have a doubt that the tested water contained a lot of microbiological life. The sample taken from the Forge Mill Lake, was collected at location under trees, where the top dirt was pushed in by the wind. I have collected from this location, because of multiple waterbirds surrounding the exposed area of the entry, expecting being fed by passers-by. Two swans noticed my location and closed the distance requesting food anyway. The water was so dirty and smelly that they did not proceed with this activity for too long. Still, neither of the bacteria tests had proven any bacteria. At this point I have to guess what sort of pollution would trigger a positive result of this test. I am dedicated to return to these areas in the future, therefore I might re-purchase these or similar tests to double check with another provider.

Water was everywhere around 180 mg/l hard, which would suggest slightly to moderately hard water, with pH just under, therefore slightly acidic. Total alkalinity had pretty much reflected the total hardness of my samples, however, the sample of my home tap water had higher alkalinity than hardness – this is perhaps not making much sense since alkalinity should be part of the hardness value, yet here it appeared twice more alkaline than hard.

Overall, I would give Tespert 4 out of 10 score. It does the job it promises, however, the microbiological tests are suspect, I will have to double-check in future. Furthermore, I had a personal issue with the multiple divided testing strips in different zip bags. I was not ready to start polluting the nature myself and therefore, I was collecting the litter for disposal latter. I had to use three to five testing strips each time at each location. Since the microbiological test supposedly did not work, I would say that these testing strips provide the worst of all worlds. Not all values are provided with the same amount of strips, with the bacteria test only providing two tests. I do not see any benefit in comparison with a Tespert tube of 125 tests.

Salifert dissolved oxygen fulfilled its expectations. Having an exotic fish tank pet on the front of its box, it gives some sort of guarantee that this test should work fine. The only downside being, this test was taking the longest. There are three different reagents which must be inserted by droplets to the sample and time intervals for waiting in between. That makes this test quiet time consuming. I measured the highest value at home. This could be due to the artificial light or enrichment of water could be caused by the pressure when leaving the tap. The lowest value in River Tame is a slight surprise. The water was streaming in the place of sample, but perhaps it could be caused be the system of canals which are flowing into the river possibly altering the microbiological potential of its water – this would further correspond with relatively the highest value of total hardness of this sample.

The dissolved oxygen can be also measured with meters for this purpose, which can be found online. Having an understanding of the oxidation processes in the water source might be a useful parameter, when determining microbiological risks. At this point, I am not convinced that such meter would benefit the basic water test for drinking water. However, soon I will be testing a meter which will be measuring oxidation-reduction potential (ORP). This could be beneficial enough, should the dissolved oxygen measurement prove to be a useful parameter, then it would be considered too. Salifert dissolved oxygen kit, I can recommend only as a cheap method for someone's aquarium, which is what it is advertised as.