Emerging contaminants in the water we drink
Posted: 14 October 2016 | | No comments yet
People consume water from a wide variety of sources within the aquatic ecosystem and the control of contamination is an important issue, not only for human health, but also for the environment as a whole. The role fertilisers and pesticides play in changing aquatic ecosystems across the world is such a well-documented concept that it is taught in most schools, but the scope of water contamination extends far beyond algal blooms and insect population depletions.
The way the water we drink is treated depends on where in the world we are. Many countries have put in place very detailed regulations and controls for drinking water.
How is drinking water treated differently in Europe compared with the rest of the world?
Unlike treated tap water in Europe, the bottled water consumed comes almost exclusively from natural sources – the most common being natural mineral waters which constitute approximately 82% of consumed water. Approximately 15% are spring waters and only about 3% are table waters (treated bottled water). These natural waters cannot be altered or disinfected and, thus, must be of a high quality in the first place, being drinkable ‘from the source’. To ensure this quality is maintained, the European Union issues directives that all member states must adhere to.
The European concept of ‘original purity’
The lack of alteration or disinfection stems from a 1972 proposal put forward in the Codex Alimentarius stating that a new approach for mineral water was to be considered in Europe. This proposal suggested that the inherent difference between bottled mineral water and ‘ordinary drinking water’ was the water’s ‘original purity’. At the time there had been long-standing public discussions regarding the microbiological safety of bodies of water, particularly in southern European states where higher levels of microbes lead to increased chlorination.
The conclusion of the Codex was that mineral waters must be properly microbiologically assessed at their source, in order to determine if the water was safe for human consumption in an unaltered state. This led to the publication of the Codex Standard for Natural Mineral Waters 108-1981. The outcome of the implementation of this standard has forced manufacturers to protect the entire catchment area of their water source and, while this originally focused on contamination from microbes, improved chemical characterisation techniques have led to the expansion of the ‘original purity’ concept to now also include chemical contaminants.
The rest of the world
In the rest of the world, however, non-mineral water sources are more common. Glacial and surface water can be consumed because the legislation and regulations allow for disinfection and contaminant removal. Theoretically, even wastewater could be treated to be drinkable, although this is not very common.
Contaminants in water
Although the way water is sourced varies in different areas of the world, the underlying threat of contamination remains the same. In Europe natural sources must be shown to be contaminant free and in the rest of the world, processed water must not exceed certain threshold levels, or values are limited to be potable. The contaminants themselves come from a variety of sources and can include a range of organic micropollutants, including the following: