Water samples should be collected from surface water bodies (lakes, rivers, streams, ponds, etc.), taking into account the velocity field in flowing water and any possible stratification in standing water. Once the location and frequency of water sampling are selected there are a set of procedures for sampling water in the natural environment (from surface water bodies) that need to be considered. Figures 7.4 and 7.5 give two examples of bottles for surface water sampling.
1. Ballast
2. Sample container
3. Supporting mesh
4. Rubber stopper
5. Suspension cable
6. Connecting cable
7. Air vent
8. Inlet
9. Vent and inlet caps
The bottle is unsealed at the sampling depth
1. Sample chamber
2. 8 3. Rubber end caps
4. Rubber pull-rod
5. Connecting and locking pin
6. Control mechanism
7. Sample outlet
The sampler is sealed by releasing the two end caps when the sampler is at the correct depth. The rubber pull-rod then contracts, pulling the end caps inwards so that the sampler is sealed at both ends
