region, while the lowest value (0.195–0.209 mg/L) was
found in the Southwest region.
This phenomenon can be explained as follows: in the
South East region, it has the natural features of lush vegetation
and abundant rainfall, and well-developed social and
economic characteristics. The drinking water sources are
located at lower reaches of the Changjiang River and the
Pearl River. Therefore, there are many possible pollution
sources. While in Southwest region, the drinking water
sources are located at the upper reaches of the Changjiang
River and the Pearl River, where less pollution sources
were existent.
In river, the concentrations of ammonia change seasonally
(Fig. 3). According to the data collected in 2007,
ammonia levels from January to March were obviously
higher than the other months. The highest value was found
in February, and the lowest value was found in May and
November. The changes of ammonia levels were related to
the seasonal quantity of water in the river.
In lake/reservoir drinking water sources, ammonia originates
from industries, agriculture and domestic wastewater
drainage. Between 2005 and 2008, there was no obvious
variation in ammonia levels in different regions. It is due
to the closed and semi-closed nature of the lake/reservoir
drinking water sources, large quantity of water, and the
long cycle of water exchange. The highest value (Table 2)
of annual ammonia was found in the Southwest, Northwest
and North regions, and the lowest value of annual ammonia
was found in the South East region. As shown in Fig. 3,
the ammonia concentrations varied seasonally, according
to the climatic characteristics of the regions. The highest
values of ammonia were found in different month in
different regions.
In underground drinking water sources, between 2005
and 2008 year, the ammonia levels were varying in different
regions. It is due to the geological permeability and the
natural features of regions. The highest value (Table 2) of
annual ammonia was found in the North and Northwest
regions, and the lowest value of annual ammonia was
found in the Southwest region.
There was no obvious seasonal change in ammonia
concentrations (Fig. 3). Groundwater exists in the pore