“When the water is abstracted from the ground,” he continues, “all those things can change again. It’s understanding the impact of the water flowing through the ground and the water being abstracted from a source that’s important, and doing that in such a way that purity is retained in the product,” he explains.
The method for locating an aquifier is geographically dependent and often involves a combination of factors. For example, geological maps of the UK have been produced in quite some detail over the past century. These maps make it easier to look for water, as specific rock types generally yield good quantities of water.
Other areas, such as India or the Middle East, still have uncharted geological territory to understand. In cases where the geological understanding is poor, it’s necessary to map the geology using a combination of methods, such as acquiring remote sensing data from satellites or more detailed rock analysis in the field.
Once a source has been located, it must pass a series of tests before it can be used for bottling purposes. The initial temperature test is an indicator of how well-protected the water is. This will vary depending on whether the water source is shallow or deep.
Dr Horobin elaborates on other tests which are usually conducted at the water source: “We tend to measure a selection of characteristics such as pH, conductivity, total dissolved solids (TDS), nitrate and turbidity, which effectively means the cloudiness of the water.
“We also tend to measure conductivity in the field because it’s straightforward to perform, and the testing equipment is sensitive enough to quickly analyse the mineral contents in the water.”
However, as Dr Horobin is quick to point out, most things are measured in the laboratory, where the accuracy of the equipment is much better and guarantees the quality of the water.
Testing of the source should be part of everyday operation. A datalogger can be left in the borehole to measure water levels and temperature at frequent intervals. If a datalogger is unavailable, then someone from the HACCP team should check the source at least daily. Even if a datalogger is being used, a HACCP team member will still need to collect a water sample for laboratory analysis, as well as gather information on the temperature, conductivity and pH (among other things relevant to the particular source). As each source is different, it’s difficult to generalise about what needs to be tested at a particular water source.
“Specific aspects of shallow bottled water sources should be measured more frequently, as shallow aquifers are more likely to be influenced more rapidly by rainfall,” says Dr Horobin. “In contrast, deep sources such as Buxton in the UK are more protected.”
Other parameters to look for would be the major and minor ions. The major ions and the dry residue are usually listed on the back of the bottle. The minor ions include naturally occurring fluoride, ammonium, sulphide and metals such as manganese and iron. The water also needs to be tested for its microbiology, as well as contaminants that are more a product of human endeavour.
A particular group of contaminants that’s a headache for anyone in the bottle water business is pesticides, as they don’t break down easily, and stay in the environment for a long time. Another issue is that they’re bio-accumulative, which means that the body absorbs the toxin faster than it can get rid of it.
Pesticides present a particular risk, which is one of the reasons why the limit set for such contaminants in food and drink is so low. For example, the Who drinking water limit for Atrazine, a common pesticide found in the environment, is 0.003mg per litre (which is equal to three parts of Atrazine per billion parts of water).
Once initial testing is complete, the water may need to be treated depending on the particular requirements. This treatment can encompass anything, from a basic filter to remove sediment, submicron filters or ultraviolet light (UV) to remove bacteria and Reverse Osmosis (RO) systems to remove minerals.
The type of testing allowed depends on whether the product is a natural mineral water or a spring water. Regulations pertaining to the treatment of spring water in terms of the extent of treatment are less strict than for mineral water. A spring water would often go through a filter and then be put through UV filtration. Alternatively, a company could use RO to remove all minerals from the water, followed by an artificial remineralisation process.
Aquafina, produced by PepsiCo, is an example of a brand of purified bottled water that uses a combination of charcoal filtration, chlorination and dechlorination, RO and ozonation. EU regulation prohibits the use of RO for mineral water because it would change the natural composition of the water. A mineral water is usually treated with a micron filter in order to remove sediment present during the production process.
So, the laboratory has given the source 10 out of 10, a treatment system has been set up, the production plant is up and running and each member of the HACCP team has been allocated a role, but how does it work in practice? Dr Horobin gives an example from microbiology: “In order to determine whether the microbiology at source is OK, you might think you can measure the microbiology in the water as it moves to the processing plant, but this is impossible to do for all the water. Another issue is that it can take three days before the result is known. Therefore, finding a suitable surrogate is the better option.”
In a treated water, this alternative could be the level of chlorine that can be measured constantly online. Within a HACCP plan, the critical control point would be where the chlorine is measured.
It’s not possible to measure the microbiology of water at all times, particularly packaged water just before it’s bottled. However, it is possible to identify critical control points within the system to minimise potential disruption. For example, if chlorine levels drop below a certain threshold, this will at least alert you to a problem early on within the production process.
Dr Ric Horobin is water and environment director at Zenith International.
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