First question is why H2S kits? What I meant to say was that there are a number of water tests that use H2S chemistry. Do you have more details (a spec) of the type of H2S test you want? If not then what do you want the tests to do i.e. the level of sensitivity (yes/no or more idea of the level of contamination)? Regards, Nick
Like Nick, my initial thought was also why H2S? Though I have come across wells that stank of rotting eggs, I understood that it was harmless in itself, just unpleasant to drink, and anyway it would all evaporate off after a few hours if the water was left standing.
I then Googled it and came across details of a test kit that used H2S as an indicator of faecal pollution - http://www.etc.murdoch.edu.au/pages/h2s.html And I guess that this is what is required rather than a test for H2S itself.
More information from the website is as follows;
A simple, easy to use water testing kit, developed for aboriginal communities.
Safe drinking water is one of the primary requirements for healthy life. Epidemics arising from waterborne diseases are a global health problem. About eighty percent of all infectious diseases throughout the world are water related. Microbial pollution of drinking water is due to the presence of faecal matter in the water supply. It is impossible to test water for each and every microorganism of faecal origin. Water is therefore tested for suitable microbial indicators such as coliform bacteria which is present in the faecal matter of warm blooded animals including humans. Coliform bacteria have been generally accepted as the indicators of faecal pollution. Another organism present in faecal matter is sulphate reducing bacteria that have been found to occur in high numbers of up to a thousand million organisms per mg of human faeces, which is almost the same as coliform bacteria and hence shall be considered as an indicator.
A method to test this was refined and modified... based on the detection of H2S reducing bacteria originally developed by Manja et al (1982). A test kit to test the bacteriological quality of water had been developed to conduct the test on-site. This is very suitable for the remote communities... The test kit is now being introduced to Aboriginal Communities. The test is very simple and does not require technically trained personnel to conduct the test. As part of the kit, RADG has produced a video and training book, which are self-explanatory. It is economical compared to all other tests in terms of cost of chemicals, transportation, and storage. As there is no need for incubation at a constant temperature, the kit uses a cheap yoghurt maker as the incubator to heat up to 35 degrees Celsius. The method works best at 35 degrees even though it will work between 18 and 40 degrees Celsius. The medium has indefinite shelf life and does not need to be stored in a refrigerator, unlike other chemicals. The kit will have great application in developing countries and has the potential to be an internationally appropriate technology.
I hope that this helps.
If you do actually need to test for H2S in itself there are a range of companies on line advertising test kits. This can be as simple as strips to dip in the water. How these relate ... (more)
H2S is very common in groundwater. It is usually created by the action of sulphate reducing bacteria in the aquifer/groundwater. It is common in groundwater where there is either a lot of sulphate from say evaporite deposits/gypsum, or rocks that contain pyrite or other metal sulphides (limestones, shales, metamorphic rocks), or in areas of volcanic activity/sulphur fumaroles etc. The metal sulphides in sediments and metamorphic rocks are broken down (weathered) by groundwater containing oxygen in the recharge zone. The sulphides become soluble sulphates. The groundwater subsequently moves deeper into, or along, the flow system and the redox potential changes. It becomes anoxic. The sulphate reducing bacteria, which are common and harmless members of the biofilms found in aquifers, then, under these reducing conditions, use the oxygen in the sulphate ion, as a part of their metabolism, and dissolved H2S is the by-product.
The most sensitive test equipment is the human nose. We can smell H2S down to very low levels of less than 0.1ppm.
Hach ( http://www.hach.com ) produce simple field testing kits that use a silver nitrate reagent on a filter paper and Alka-Seltzer tablets to drive off the H2S from the water sample in a small bottle. These test kits are quite accurate and very robust and have been around for over 35 years. However the human nose can still smell H2S when the test kits give a zero reading.
The golden rule with H2S is that if you can smell it you are probably alright. Our noses can smell H2S up to about 6-8 ppm. Above these levels the H2S cauterises, or overloads the sensors in our noses. H2S is more poisonous than hydrogen cyanide. Higher levels of H2S in a confined space can kill you, but if you can continue to smell it you are probably safe. You might feel a bit sick or woozy.
I once fell over and just managed to crawl out of a depression on a still night in the desert in Arabia. H2S had been de-gassing from the discharge water from a long pump test on a deep borehole, pumped into the depression. I smelled the H2S as I approached the lip of the depression, but lost the smell as I went down into it to take a flow meter reading on the discharge pipe. After a few minutes I felt dizzy, fell over, and just had enough wit to realise what was happening, and crawl up to the fresh air outside the lip of the depression. I had a banging headache for the next few hours.
H2S in a water supply is usually not a problem if the water is pumped and splashed into an open topped tank or reservoir. Aeration is a standard treatment process for H2S. However the water may still be unpleasant to drink because the H2S is often associated with high levels of manganese, iron and other metals. These may precipitate when the water is aerated. The water can be discoloured ... (more)
I followed the link but there’s nothing on the website which gives this method any more credibility than the numerous presence/absence tests for bacteria which are already available. Even if, as they claim, they are able to isolate faecal contamination by this method, unless something is published which shows how they might quantitatively relate their results to levels faecal contamination (equivalent to E. coli/100 ml). I can’t see this being a very useful addition to the analytical toolkit. We generally don’t go around condemning water supplies because of the presence of faecal contamination – we need at least a semi-quantitative method from which we can evaluate risk. In our context, we’re usually satisfied with levels of E. coli less than 10/100 ml.
Thanks for the link anyway. Perhaps someone might buy a kit and subject it to a thorough comparison with other methods…
Safe drinking water is one of the number one necessities for healthful lifestyles. Epidemics arising from waterborne diseases are an international health trouble. approximately 80 percent of all infectious diseases for the duration of the world is water associated. Microbial pollution of consuming water is because of the presence of faecal count number within the water supply. it's miles impossible to test water for each and each microorganism of a faecal starting place academic writing tips. Water is therefore tested for suitable microbial indicators including coliform bacteria that is a gift in the faecal relies on warm-blooded animals which includes humans. The coliform microorganism was generally popular because of the indicators of faecal pollution. another organism present in faecal depend is a sulphate lowering microorganism that has been observed to arise in excessive numbers of as much as one thousand million organisms in line with mg of human faeces, which is almost the same as coliform bacteria and therefore will be taken into consideration as a hallmark.
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