Water sampling at the point of lake or reservoir is set according to the following provisions;
- On lakes or reservoirs with a depth of less than 10 m, water samples were taken from two points, namely at the surface and at the bottom of the lake / reservoir
- On lakes or reservoirs with depths between 10 m – 30 m, samples were taken at three points, namely the surface, the thermocline layer, and at the bottom of the lake
- On lakes or reservoirs with depths between 30 m – 100 m, the samples taken at the point, namely surface, thermocline (metalimnion), above hipolimnion layer, and the bottom of the lake / reservoir
- On lakes or reservoirs with a depth of over 100 m, the point of water sampling can be propagated as appropriate.
Sampling techniques Water
Surface water sampling technique must be adapted to the needs, because each of the different techniques for sampling and handling. Here below is a sampling technique for a variety of purposes:
For the inspection of physical and chemical properties of water:
- Prepare sampling tool in accordance with the state of water resources;
- Rinse the tool with a sample to be taken;
- Take the samples in accordance with the purposes and mix in the container while it flat;
- When samples are taken from several points, the volume of samples taken from every point must be the same.
For the inspection of dissolved oxygen:
a) Stages sampling conducted directly:
(1) Prepare the BOD bottles ± 300 mL volume were clean and the lid sharpening;
(2) Dip the bottle carefully,
(3) Fill the bottle to the brim, avoid the occurrence of turbulence and air bubbles when filling the bottle; then closed,
(4) Samples were prepared for analysis.
b) specific retrieval tool
Water samples were taken in accordance with the procedures of the use of tools.
For microbiological examination:
a) On the surface water directly
(1) Prepare a volume of 100 mL bottle and was sterilized at 120 ° C for 15 minutes or by means of other strerilisasi;
(2) Hold the bottom of the bottle and dip ± 20 cm below the water surface with the position of the mouth of the bottle opposite to the direction of flow.
b) On the surface water indirectly from bridge
(1) Prepare a sterile bottle lid wrapped in aluminum foil;
(2) Tie bottles with a strap and attach the ballast at the bottom of the bottle;
(3) Open the lid and lower the bottle slowly into the surface of the water;
(4) Pull the rope as he rolled up;
(5) Discard partially fill the bottle until the volume is ± ¾ volume of the bottle;
(6) Fuel section mouth of the bottle, then close the bottle again.
c) For the groundwater in wells
Stages Water sampling at the water surface
d) Groundwater in tap water
(1) Prepare a sterile bottle lid wrapped in aluminum foil;
(2) Open the faucet and let the water flow for 1-2 minutes;
(3) Sterilize faucet by burning mouth of the faucet until the water vapor out;
(4) Flush water again for 1-2 minutes;
(5) Open the lid and fill up to ± ¾ bottle;
(6) Fuel section mouth of the bottle, then the bottle is closed.