What Is Groundwater?
Groundwater analysis determines water quality in specimens taken from observation or supply wells. The well must be purged as defined in the standard before sampling; stagnant well water does not represent the aquifer.
Purpose of Groundwater
The purpose is to determine groundwater's natural quality, monitor plume migration at contaminated sites, and assess compliance with groundwater quality standards.
Which Products Is Groundwater Applied To?
- Observation and monitoring wells
- Drinking and irrigation wells
- Contaminated-site monitoring points
- Vicinity of a landfill
- Vicinity of an industrial facility
In Which Sectors Is Groundwater Used?
Standards Related to Groundwater
- TS ISO 5667-11 (guidance on sampling of groundwaters)
- TS EN ISO 5667-3 (preservation and handling of samples)
- TS EN ISO 17294-2 (determination of elements by ICP-MS)
- TS EN ISO 10304-1 (anions by ion chromatography)
- TS EN ISO 15680 (volatile organic compounds — purge-and-trap GC-MS)
Groundwater Conditions
- Well purging
- Stagnant water is purged before sampling; continued until field parameters stabilise
- Field measurements
- pH, conductivity, temperature, dissolved oxygen and redox potential are recorded
- Pumping rate
- Low-flow pumping reduces loss of volatile compounds
- Water level
- The static water level is measured before sampling
Equipment for Groundwater
- Low-flow sampling pumps
- Multi-parameter field probe and flow cell
- Water level meter
- ICP-MS and GC-MS
- Purge-and-trap system
Sample Requirements for Groundwater
- Sampling is the largest component of total uncertainty in environmental analysis. The specimen container, preservation (acidification, cooling, storage in the dark), fill method and time to reach the laboratory are all defined in the standard; if any one is not met, the result loses its validity. Sampling must be carried out by authorised personnel per a written plan.
- Well purging records and field parameters must be reported
- For volatile compounds, specimens must be taken in vials filled without air bubbles
- Well coordinates, depth and screen interval must be provided
Duration of Groundwater
Fieldwork depends on the number of wells and purging time. Laboratory analyses take several working days per the parameter list; volatile organic and pesticide screens take longer.
Groundwater Procedure
- 1Well information and the static water level are recorded.
- 2The well is purged per the standard.
- 3Field parameters are monitored until they stabilise.
- 4Specimens are taken in containers suited to the parameter and preserved.
- 5It is delivered to the laboratory via cold chain.
- 6Analyses are performed and results compared against quality standards.
Groundwater Acceptance Criteria
2006/118/EC defines groundwater quality standards for nitrate and pesticides; threshold values for other pollutants are set by member states. Site-specific target and intervention values are used at contaminated sites. Applicable values are confirmed from current legislation.
Evaluation of Results
A specimen taken without purging represents water that has stood in the well and equilibrated with the atmosphere; it does not show the aquifer's real quality. This is the most common error in groundwater monitoring. Results should also be assessed as a time series, not a single occasion.
Groundwater Report
- Well identification, coordinates, depth and screen interval
- Static water level and purging records
- Saha parametreleri
- Method, result and limit of quantification for each parameter
- Quality standards compared against
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- 2006/118/EC Groundwater Directive
- 2000/60/EC Water Framework Directive
- 91/676/EEC Nitrates Directive
Environmental Analysis — What Does This Testing Field Cover?
The section below describes the field that the Groundwater test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Environmental analysis determines the presence and concentration of pollutants in water, soil, waste, air and flue gas samples. The output of this family is usually part of a permit, a declaration or an inspection file; the result has direct legal consequences.
In this family SAMPLING is half the result, and this is the feature that most sets the field apart. A sample taken at the wrong time, in the wrong container, under the wrong preservation or from the wrong point gives an invalid result no matter how well it is analysed in the laboratory. In waste water a grab sample and a composite sample give different information; in soil, surface and depth produce different results. Sampling therefore has its own standards and its own accreditation scope.
On the water side, physico-chemical parameters (pH, conductivity, turbidity, COD, BOD, suspended solids), ions, heavy metals, organic pollutants and microbiological parameters are measured. Drinking water and waste water carry different parameter sets and different limits; the same laboratory method leads to a different decision under the two regimes.
In soil and waste, heavy metals, hydrocarbons, PAH and PCB compounds and LEACHING BEHAVIOUR are determined. The leaching test carries a logic peculiar to this field: it is not the total amount of a pollutant in soil but the fraction that can pass into water that determines the environmental risk. Waste classification and the disposal decision rest largely on this test.
On the emissions side, dust, sulphur dioxide, nitrogen oxides, carbon monoxide, oxygen, moisture and total organic carbon are monitored in flue gas. Measurement is made on site under operating conditions and must represent the plant's actual operating regime; a measurement taken at low load does not show the emissions at full capacity.
Continuous measurement systems are a separate body of work. In large plants emissions are monitored continuously and the accuracy of these systems is verified periodically by comparison with independent measurements; the quality assurance framework governs this.
Noise and vibration measurements complete the environmental impact side of the field: environmental noise mapping, workplace noise exposure and vibration exposure measurements produce evidence for both environmental and occupational health legislation.
Method groups in this field
Sampling
Separate sampling standards for water, waste water, soil, waste, flue gas and ambient air; grab, composite and continuous sampling techniques.
Water physico-chemical
pH, conductivity, turbidity, colour, suspended solids, COD, BOD, TOC, alkalinity, nitrogen and phosphorus species.
Elemental analysis
Determination of heavy metals and trace elements in water, soil and waste by ICP-OES and ICP-MS.
Organic pollutants
Volatile organic compounds, PAH, PCB and organochlorine pesticides by GC-MS; hydrocarbon oil index.
Flue gas
Measurement of dust, SO2, NOx, CO, O2, moisture and total gaseous organic carbon; quality assurance of automated measuring systems.
Leaching and waste characterisation
Leaching tests and waste classification parameters; the basis for the disposal decision.
Commonly confused in this field
- An analytical result cannot be used on its own without the sampling record; the time, point, conditions and chain of custody are part of the report.
- Total content and leachable amount give different information; in waste classification, leaching behaviour is what counts.
- Emission measurement must be made under representative operating conditions of the plant; a result taken at partial load is misleading.
- Drinking water and waste water limits are defined in different legislation; the same parameter carries a different threshold under the two regimes.
- A sample from a single point does not represent the whole area; assessment of a contaminated site requires a grid-based sampling plan.
Which decisions these results support
- Compliance with environmental permits and discharge limits
- Quality assurance of continuous emission measurement systems
- Contaminated site assessment and the remediation decision
- Waste classification and selection of the disposal method
- Workplace exposure measurements and occupational health obligations
Related Tests
Frequently Asked Questions About Groundwater
Why does well purging matter so much?
Water standing in the well casing does not represent water coming from the aquifer: because it has contacted the atmosphere, its oxygen level, redox state and metal solubility have changed. A result taken without purging is misleading.
Does a single analysis show whether there is pollution?
No. Groundwater quality varies seasonally, and a contaminant plume moves over time. Assessment requires data from multiple points and multiple periods.