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CS

Information on the Environment in the CR

A-2 Water

Contents

A - 2. WATER

Table A - 2.1, A - 2.9, A - 2.10
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
  • nsolubles (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 - 2.8 Public water supply and sewerage systems

Data for the year 2006 was processed from the Questionnaire VH 8b-01 (the annual questionnaire on public water supply and sewerage systems). Data in the statistical return were provided by 1,211 respondents, i.e. 240 operators of water supply and sewerage systems and a sample of 971 municipalities of the Czech Republic that operate public water supply and sewerage systems on their own.

Data on water supply and sewerage systems for the year 2006 – includes data grossed up to the Czech Republic in total, broken down by region (NUTS 3).