Confronting the Problem of Lead in Drinking Water: What Can and Should Be Done - Global Drinking Water Management and Conservation - page 232

the water by chlorination, whereas the remaining waters are not treated (Fontenay
and Anderson 2008 ). There are 385 groundwater bodies, distributed within four
River Basin Districts.
There are about 2,700 water works that supply the Danish population of 5.5
million. The municipalities which operate 150 water utilities extract 24 times as
much water as the 2,550 privately operated water companies (Fontenay and
Anderson 2008 ). Danish authorities have found it unnecessary to cleanse the water
with carbon

lter is
required before it is drinkable. Approximately 800 million m 3 of water are
abstracted annually. Groundwater recharge averages 100 mm per year, varying
between 50 and 350 mm.
The standards of wastewater treatment are high. Over 90 percent of the aggre-
gate wastewater is treated in 216 plants, most of which are municipally operated
(Danish Ministry of the Environment and GEUS (Geological Survey of Denmark
and Greenland 2014 ). The current Danish groundwater policy is based on protec-
tion. The two most common ways are either to protect the resource of natural
groundwater or to treat wastewater to the extent that the treated water conforms to
the maximum allowable contamination levels (Hasler et al. 2005 ).
How lead is measured is important and so we repeat the

filters or add chloride; only oxidation and cleansing in a sand

findings of Hoekstra
et al. ( 2004 ) reported in the last chapter, namely that in measuring the amount of
lead in drinking water, the Danish legislation follows the use of 12 h stagnation.
Germany uses 4-h stagnation because that time protects 95 percent of their con-
sumers. Four hours stagnation covers about 80 percent of the maximum saturation
of the concentration of lead, based on the stagnation curve, while a 30-min stag-
nation covers only 30 40 percent. Random Day Time sampling and 30-min

Stagnation underestimate the real exposure by 44 and 56 percent, respectively.
In Danish groundwater samples taken in the period 1993

-

2006, lead was found
in 406 of 663 (61 percent) abstraction wells and occurred in concentrations over the
drinking water standard (5

-

g/L, value at the entrance to the property) in 10 samples
(2 percent). The average concentration was 0.6

μ

g/L and the maximal concentration

μ

measured was 35 g/L (GEUS 2007 ). In 2010, lead occurred in concentrations over

the drinking water standard (5

μ

g/L, value at the entrance to the property) in 4 of
238 samples from Danish groundwater (GEUS 2011 ).
The Danish Ministry of the Environment has

μ

financed metal release projects,
where rig testing of commonly used materials was performed at different water
works. As a result, taps must be tested for lead and cadmium release by sit-and-soak
testing in synthetic, soft water by a Scandinavian standard. This test was introduced
in the mid 1970s as a means of controlling whether illegal solders containing lead or
cadmium had been used. Nickel-chromium electroplating is accepted without lim-
itation or special requirements (Fontenayand Andersen 2008 ). Plastic products are
examined thoroughly by toxicological tests based on a review of raw materials and
production methods with the exception of parts that constitute only a minor part of