Applications of Emerging Technologies in the Drinking Water Sector - Waterborne Pathogens: Detection Methods and Applications - page 350

Cryptosporidium is resistant to treatment by chlorine, and sampling for
its presence in drinking water is particularly complicated and lengthy. For
these reasons, there is currently no specific standard set for it under the
EU Drinking Water Directive. The directive does state that no organism
should be present that would present a threat to public health, but it does
not give any direct mention of, or guidance for, Cryptosporidium . As a result
of this, companies within the UK water industry tend to adopt a risk-based
approach to managing Cryptosporidium , assessing whether there are potential
sources of the parasite in the catchment area and putting barriers in place
to make sure it does not reach the supply in the first place. 27 In the UK,
ultraviolet (UV) disinfection is used to remove Cryptosporidium oocysts that
are resistant to normal chlorine disinfections 27 from our drinking water
supplies.
Much of the present policy for monitoring drinking water in the
UK comes as a result of disease outbreak caused by waterborne diseases.
For example, following a Cryptosporidium outbreak in 1999 from a public
groundwater, new regulations were introduced. These regulations, The Pri-
vate Water Supply regulations, now infer that authorities must measure and
regularly monitor all supplies to identify potential risk. 5 Cases of crypto-
sporidiosis (caused by the parasite) are currently still a considerable issue in
the UK. In the summer of 2012, the HPA relayed its fears in the increasing
number of cases of the illness, as 327 cases were determined between the
11th of May and the 11th of June, 2012, compared with only 82 cases for
the same period in 2011. 29
11.4.2. Legionella
Legionella bacteria are another pathogen commonly found in water. They
are able to multiply and survive at temperatures between 20 and 45 °C and
cause a fatal form of pneumonia called Legionnaire's disease if the bacteria
is inhaled in water droplets. 30 It can also cause two other illnesses, namely
Pontiac fever and Lochgoilhead fever. The bacteria are found in natural
water systems such as rivers and ponds, but they can easily get into water
systems such as those in large buildings, air conditioning systems or com-
munal showers. 31 The latest findings show that the number of confirmed
cases of Legionnaire's disease in England and Wales was 551 in 2006, 442
in 2007, and 359 in 2008, 32 demonstrating a decrease in disease occurrence
over this period. However, the disease is still a considerable health risk and
an issue within UK water supplies, and, for this reason, water systems on
commercial premises need to have a risk assessment for Legionella which