ABSTRACT
CONTENTS 1.1 Introduction ........................................................................................................................... 2 1.2 General Aspects of Sampling and Sample Handling ..................................................... 3
1.2.1 Initial Considerations ............................................................................................. 3 1.2.2 Spatial Aspects ........................................................................................................ 3 1.2.3 Temporal Aspects ................................................................................................... 3 1.2.4 Number of Samples................................................................................................ 5 1.2.5 Sample Volume ....................................................................................................... 5 1.2.6 Storage and Conservation ..................................................................................... 6
1.2.6.1 Contamination.......................................................................................... 6 1.2.6.2 Loss ............................................................................................................ 6 1.2.6.3 Sorption ..................................................................................................... 7 1.2.6.4 Recommended Storage ........................................................................... 8 1.2.6.5 Quality Control in Water Sampling...................................................... 8
1.3 Sampling Strategies for Different Ecosystems ................................................................. 8 1.3.1 Lakes and Reservoirs ........................................................................................... 13 1.3.2 Streams and Rivers............................................................................................... 15
1.3.2.1 Location of Sampling within the Stream ........................................... 15 1.3.2.2 Description of the Longitudinal Gradient ......................................... 15 1.3.2.3 Temporal Changes of Water Quality ................................................. 16 1.3.2.4 Using Sediments to Integrate over Time ........................................... 17
1.3.3 Estuarine and Marine Environments ................................................................ 17 1.3.4 Urban Areas........................................................................................................... 18
1.4 Sampling Equipment.......................................................................................................... 20 1.4.1 General Comments ............................................................................................... 20 1.4.2 Manual Sampling Systems .................................................................................. 20
1.4.2.1 Simple Sampler for Shallow Water..................................................... 20 1.4.2.2 Sampler for Large Quantities in Shallow Water .............................. 20 1.4.2.3 Simple Sampler for Deepwater ........................................................... 20 1.4.2.4 Deepwater Sampler (Not Adding Air to the Sample)..................... 21 1.4.2.5 Deepwater Sampler for Trace Elements (Allowing Air
to Mix with the Sample) ....................................................................... 21 1.4.3 Systems for Sampling the Benthic Boundary Layer
at Different Depths................................................................................................ 23 1.4.3.1 Deepwater (>50 m) ............................................................................... 23 1.4.3.2 Shallow Water (<50 m)......................................................................... 23
1.4.4 Automatic Sampling Systems ............................................................................... 23 1.4.4.1 Sampling Average Concentrations ....................................................... 24 1.4.4.2 Sampling Average Concentrations-Sampling Buoy........................ 24 1.4.4.3 Event-Controlled Sampling of Industrial Short-Term
Contamination.......................................................................................... 24 1.4.4.4 Rapid Underway Monitoring ................................................................ 25 1.4.4.5 Event-Controlled Sampling: Surface Water Runoff from
Agricultural Land .................................................................................... 27 1.4.4.6 Other Considerations Regarding Automatic
Sampling Equipment............................................................................... 27 1.4.5 Extraction Techniques............................................................................................ 29
1.4.5.1 Liquid-Liquid Extraction of Large Volumes ...................................... 30 1.4.5.2 Solid-Phase Extraction Techniques....................................................... 30 1.4.5.3 Passive Sampler Devices ........................................................................ 34
1.4.6 Concentration of Contaminants in Suspensions and Sediment...................... 38 1.4.6.1 Suspended Particle Sampler for Small Streams.................................. 39
Acknowledgment......................................................................................................................... 41 References ..................................................................................................................................... 42
The quality of output from an environmental sampling project is limited by whichever is the weakest component-sampling or analysis. Progress in analytical protocols, including the development of new and more sophisticated techniques described elsewhere in this handbook, results in the taking of samples increasingly becoming the quality-determining step in water quality assessment [1,2]. Conclusions based on laboratory results from the most careful analysis of water samples may be invalidated because the original collection of the samples was inadequate or invalid. Poor sampling design or mistakes in sampling technique or sample handling during the sampling process inevitably lead to erroneous results, which cannot be corrected afterward [3-7].
