Taking a water sample and sending it to the lab seems like groundwater sampling should be easy. However, the reality is that the process requires great care, as small omissions can lead to flawed findings and unwelcome delays (or wastes). Here’s a simple step-by-step overview.
1) Prepare the equipment
Bottles, tubing and pumps should be clean; bottles should be labelled and suitable for the parameters being tested. The sampler will also check health and safety and confirm the Well ID.
2) Measure water levels
Recording the groundwater level in the monitoring well with a dip meter. This allows monitoring seasonal changes and determines whether the well is acting as it should. For Groundwater Remediation, contact //soilfix.co.uk/services/groundwater-remediation
3) Purge the well
Groundwater samples are collected as the pumped water level at various sampling depths is allowed to stabilise, and stagnant well water has been removed (purged) in order for the sample to better represent groundwater within the formation. This is a regular practice done over monitoring “stabilisation” readings while pumping out a set volume.
4) Monitor field parameters
When purging takes place, the pH, temperature and dissolved oxygen are carefully watched along with conductivity. But when those start levelling out, then you are usually looking at the water being pretty fair.
5) Collect the sample
For samples – collect into the appropriate bottles, sometimes with preservatives: put in a cool box. Before delivery to the lab, a rigorous chain of custody is completed.
How samples get contaminated
Typical problems are clogged tubing or bottles, touching the rim of the bottle mouth with your finger when sampling from the tube, too short spacing between samples – before stabilisation, stirring up sediment in the well and keeping samples excessively warm. Cross-contamination may also occur when reusing equipment from well to well without proper decontamination.