What is Sampling Methods of Water Quality Management and Pollution Control?

Sampling Methods of Water Quality Management and Pollution Control: Are you surfing for the method of water quality management and pollution control?? Then you are in the right place as we have a complete step by step guide of the various sampling method. Relax and read to the end.

Site Selection

In sampling, first, determine why you are carrying out the project. This may be very simple or complicated depending on the results you aim to achieve.

Different goals determine the sampling designs, protocols to be used, and sampling locations (Smiley, et al., 2009). Data obtained from the sites should answer questions or hypotheses that the sampling goal sought to answer.

For instance, you may want to identify sources, types of contaminants in water, or the concentrations of a particular substance in the environment before a project. For site selection:

1. Identify the goals of the project, and understand the working of the system before choosing locations for sampling.

2. The scale of the work will determine the number of sites to collect samples from.

3. For long-term monitoring, consider the likely future plans for the sites chosen. Choose sites with no impending modifications using aerial photographs, maps, or personal knowledge of the area, GIS software, or Google earth (Benson and Dalrymple, 1984).

4. Carry out a reconnaissance survey (an initial field visit to assess the site personally) to see if the sites meet selection criteria. Sites should be easily accessible.

5. Water quality sampling for sediment and sediment-associated constituents is more difficult than sampling for other water chemistry variables because of temporal and spatial variability in transport. The point at which a sample is collected will influence sediment concentration data.

Sampling Methods of Water Quality Management and Pollution Control

1. Manual Sampling

Manual grab sampling at a single location at each sampling site is the standard method for collection of base flow (discharge derived from the seepage of groundwater in combination with upstream water through-flow without significant direct contribution from surface runoff from precipitation) samples.

Advantages of grab sampling

• It is relatively safe

• It is simple

• It is inexpensive

• It can be performed at any location

• Manual grab sampling may be the only alternative if the costs of purchasing and maintaining automatic samplers exceed available resources (Burton and Pitt, 2002).

Disadvantages of grab sampling

i. Grab sampling provides limited information on temporal (time) variability of constituents unless frequent samples are collected.
ii. Manual sampling methods also introduce human errors due to sampling.

2. Integrated sampling

This is another manual technique that collects subsamples throughout the flow cross-section to accurately determine to mean constituent concentrations.

Samples are obtained at different depths across the stream to produce accurate concentration measurements even in large streams.

Disadvantages

i. This technique requires a lot of personnel time, especially for many sites.

ii. It may be difficult to collect samples throughout the range of observed discharges.

iii. If it is necessary to enter into the stream for sample collection, safety must be an important consideration.

iv. Water samples should be collected upstream from the point of entry of the constituent of interest.

3. Automatic Sampling

The samplers are installed in the field and collect and record data automatically. They have the following advantages:

i. They use a consistent sampling procedure and simultaneously collect samples at multiple sites.

ii. Are useful where sites are distant, hard-to-reach (e.g., steep inclines), or dangerous.

iii. They are very useful for sampling during storms because they can sample throughout runoff events of various durations and magnitudes.

iv. Disadvantage: Automatic samplers require frequent maintenance (Burton and Pitt, 2002; Harmel et al., 2006a).

4. Mechanical Samplers

Mechanical samplers such as rotating slot samplers and multi-slot divisor samplers collect flow-weighted samples and estimate flow volume, allowing for the calculation of mean concentrations and mass loads.

The rotating slot sampler requires minimal maintenance, no electrical power, and collects a single flow-proportional runoff sample (Parsons, 1954, 1955; Edwards et al., 1976).