1.2.1 Sample collection
To obtain water samples a number of collectors are available. For taking samples at depth these may be quite sophisticated, but for surface waters, devices such as the pendulum beaker shown in Figure 1 are used. Once filled it is designed to automatically swing into a horizontal position on removal from the water to prevent spillage.
Figure 2 shows a procedure for sampling groundwater from a borehole on a landfill site. The level of the water is first determined by lowering an electrode on a tape measure (a and b), an alarm sounds on reaching water (which is electrically conducting due to dissolved ions). The sampling container is then lowered to the required depth and a sample removed (c).