④ The 3rd layer of groundwater is less polluted. About 25% of the samples
exceeded the limits of permanganate index, volatile phenols, ammonia, nitrite
and total coliforms, mostly by less than 3.5 times, except for total coliforms.
In summary, the 1st and 2nd layers of groundwater under the landfill seriously
exceeded the standard limits of conventional indicators, some by more than 20
times. Heavy metal indicators including iron, manganese and arsenic are exceeded.
In particular, the iron indicator is exceeded by more than 70 times of the standard
and the other two indicators are both exceeded by more than 3 times of the standard.
The 3rd layer of groundwater is in fairly good conditions. Some indicators are
exceeded slightly, which however may be related with the local groundwater
background value. None of the volatile organic compounds indicators of the
groundwater at the landfill site and in the surroundings exceeded the limits as
provided in Chinese national standard “Standards for Drinking Water Quality” or
the groundwater standard of North Carolina, USA.
Legend
Scope of key working areas
Scale (m)
Contour of ammonia-nitrogen concentration
in 3rd aquifer
Boundary of the scope where ammonia-nitrogen
concentration in the 3rd aquifer exceeds the limit
Fig. 5.49 Map showing the distribution of ammonia-nitrogen concentration in the 3rd layer of
groundwater at the landfill site
5.5 North China
261
exceeded the limits of permanganate index, volatile phenols, ammonia, nitrite
and total coliforms, mostly by less than 3.5 times, except for total coliforms.
In summary, the 1st and 2nd layers of groundwater under the landfill seriously
exceeded the standard limits of conventional indicators, some by more than 20
times. Heavy metal indicators including iron, manganese and arsenic are exceeded.
In particular, the iron indicator is exceeded by more than 70 times of the standard
and the other two indicators are both exceeded by more than 3 times of the standard.
The 3rd layer of groundwater is in fairly good conditions. Some indicators are
exceeded slightly, which however may be related with the local groundwater
background value. None of the volatile organic compounds indicators of the
groundwater at the landfill site and in the surroundings exceeded the limits as
provided in Chinese national standard “Standards for Drinking Water Quality” or
the groundwater standard of North Carolina, USA.
Legend
Scope of key working areas
Scale (m)
Contour of ammonia-nitrogen concentration
in 3rd aquifer
Boundary of the scope where ammonia-nitrogen
concentration in the 3rd aquifer exceeds the limit
Fig. 5.49 Map showing the distribution of ammonia-nitrogen concentration in the 3rd layer of
groundwater at the landfill site
5.5 North China
261