Groundwater sampling
Groundwater samples will be collected from monitoring wells by means of bailers or submersible pumps after well development; preferably after well has been allowed to set for at least 48 hours.
Samples will be sent to the laboratory and similar to soil sampling, groundwater sampling will be performed avoiding alteration of the chemical representativeness of the sample. Nevertheless, also in situ field measurements should be conducted in order to measure physicochemical parameters as pH, conductivity, temperature, etc. The amount of collected water will depend on the number and the type of compounds that will be analyzed; however the chosen laboratory should provide the correct type and number of containers. During sampling operations, bubbling must be avoided so as risk of stripping of volatiles compounds will be minimized.
The water samples should be collected directly into the appropriate containers (polyethylene, glass, amber glass bottles etc.) of different volume (e.g. 125 ml, 250ml, 500 ml or 1l), as provided by a nominated laboratory. Every sample will be collected and stored at low temperatures (4ºC) in the dark, by means of refrigerated containers or thermo insulated boxes, and send to the laboratory normally in 24-48 hours or in a time specified by the laboratory depending on the sample characteristics. Moreover, a preservative, previously specified by the laboratory, should be added to the samples.
In any case it is recommended to consult the laboratory before sampling and while sampling in order to follow strictly laboratory’s guidelines for correct sample preservation.
Each water sample container has to be labeled with an identification number and the following information:
- Site/Facility name
- Sample collection date and time
- Well type (monitoring, water supply) and number
- Name of the person who has collected the sample
- Parameters to be analyzed
In addition, photographs will be taken at the sampling locations and at surrounding areas. The photos will verify information entered in a field logbook. Each photo taken will be written in a logbook with the approximate time, date and location.
