Information in the Environment in the Czech Republic
A-2. Water | Contents |
A - 2. WATER
Table A - 2.1, A - 2.10, A - 2.11 Quality of water in water courses
Selected pollutants
- biological oxygen demand (BOD5): the amount of oxygen consumed for aerobic biochemical decomposition of organics, contained in water for five days under standard conditions
- chemical oxygen demand (CODCr): the amount of oxygen (O2) as determined by the dichromate method
- insolubles (NL): substances determined by filtering water and drying up the residue at 105 °C
to constant weight
Determination of water quality in streams
The profile refers to a place where measurements are carried out.
Pollution degree classification:
I - very clean water
II - clean water
III - polluted water
IV - heavily polluted water
V - very heavily polluted water
Indicator (v mg/l) | Class |
 | I. II.III.IV.V. |
| BOD5 | <2<5<10<15>15 |
| CODCr | <15<25<35<55>55 |
| N-NO3 | <1,0<3,4<7,0<11,0>11,0 |
| N-NH4 | <0,3<0,5<1,5<5,0>5,0 |
| TP (total phosphorus) | <0,03<0,15<0,4<1,0>1,0 |
Classification according to CSN 75 7221.
Table A - 2.2 to A - 2.9 Public water supply and sewerage systems
Production of water includes both invoiced and uninvoiced water. The sum of these two items may differ from figures for total production, by water supplied from or to other organizations.
Public water supply and sewerage systems: water supply and sewerage systems run
by municipalities.