Table of Contents
The Different Types of Water Sampling Techniques and Their Applications in PFAS Testing
A technical paper by Olympian Water Testing specialists
Overview of PFAS (per- and polyfluoroalkyl substances) and their environmental impacts
Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals that have found their way into most industrial applications for reasons such as their water and oil repellent, heat- and stain- and grease-resistant properties [1]. PFAS can be found in almost everything from non-stick cookware, to food wrappers, to water-repellent clothes, and fire fighting foam [2]. The persistence of PFAS in the environment and their potential health risks have led to increased scrutiny and regulation. Consequently, many industries are now required to implement pfas testing laboratory procedures to detect and quantify these substances in their products and waste streams. As awareness of PFAS contamination grows, the demand for reliable testing methods continues to rise, prompting advancements in analytical technologies to ensure public safety and environmental protection.
But PFAS also turned out to be harmful to human health and the environment. A few reports even claimed that PFAS use can cause a host of negative health effects such as developmental and reproductive harm, impaired immune function and cancer [3]. Furthermore, PFAS are also known to cause environmental harm such as invading water supplies and end up in wildlife [4].
PFAS are persistent chemicals which is not easy to degrade in the environment and they can also last a long time in the body [5]. That, together with their widespread use and potential effects on human health and the environment, has created alarm about PFAS in the environment, including in water.
PFAS are, in short, a class of synthetic chemicals that have been used extensively in industries because of their special properties, but have shown detrimental effects on the human body and environment. They are long-lasting chemicals that can remain in the environment and body for decades, and they’re not to be tinkered with in water.
[1] United States Environmental Protection Agency. (2018). PFAS (per- and polyfluoroalkyl substances).
[2] Centers for Disease Control and Prevention. (2020). PFAS (per- and polyfluoroalkyl substances).
[3] World Health Organization. (2018). PFAS (per- and polyfluoroalkyl substances).
[4] United States Environmental Protection Agency. (2018). The environmental impacts of PFAS.
[5] United States Environmental Protection Agency. (2018). PFAS persistence in the environment.
Types of water sampling techniques
Consideration of the purpose of the research, the nature of the water to be sampled, and available resources will help you to choose a water sampling technique.
: Research objectives are an important factor when deciding on a water sampling technique. The different techniques might be suitable for different kinds of studies, depending on the question and data type. If, for instance, the purpose of the study is to determine the quality of a waterbody as a whole, then a composite sampling technique, that is taking several samples at varying times, and assembling them into a single sample, would be more suitable than a grab sample, which would be taken at a particular site and time [1].
Also, the composition of the water that you’re sampling is a factor to take into account in deciding what sampling method to use. The physical, chemical and biological nature of the water, location and depth of the body of water, etc can all impact a sampling method [2]. For instance, if the water body has a complex or heterogeneous composition, composite sampling method would better fit the water body variability [3].
Water sampling technique can also be influenced by resources that could be put to the study (such as time, personnel and equipment). Some methods are more labour intensive or involve specialised equipment that might not be realistic or practicable given the available resources to the research [4].
To summarise, when selecting water sampling method you should be careful about the purpose of the research, the nature of the water to be squirted, and available resources. By considering all these, one can select a sampling method which best fits the requirements of the study.
[1] R. N. Mackay, "Sampling for Contaminants in Water," in Environmental Chemical Analysis, ed. R. N. Mackay (New York, NY: John Wiley & Sons, Inc., 2007), pp. 131-160.
[2] M. G. B. Drewes and C. J. M. Notenboom, "Water Sampling Techniques," in Water Quality: An Introduction, eds. M. G. B. Drewes and C. J. M. Notenboom (Wageningen, Netherlands: Wageningen University and Research, 2016), pp. 67-77.
[3] M. J. Kostecki, "Sampling Techniques for Water Quality Studies," in Handbook of Water Analysis, ed. L. M. L. Nollet (Boca Raton, FL: CRC Press, 2012), pp. 187-208.
[4] R. H. Hirsch and D. R. Smith, "Sampling for Water Quality Studies," in Techniques of Water-Resources Investigations of the United States Geological Survey, Book 9, Chapter A1 (Reston, VA: United States Geological Survey, 1991), pp. A1-1-A1-18.
Considerations for selecting a water sampling technique
A few things to think about before choosing a water sampling method is the study objective, the nature of the water to be sampled, and resources.
Water sampling method also depends on the study objectives. Different methods might be appropriate for different kinds of studies, depending on what question is being asked and what kind of data you need. For instance, if the purpose of the study is to assess the overall quality of a water body, then a composite sample — taking many samples over time and combining them into a single sample — would be better suited than a grab sample — taking one sample at a particular place and time [1].
There is also a good selection of sampling technique based on the nature of the water that needs to be sampled. A sampling technique may depend on a variety of variables like water’s physical, chemical, and biological conditions, the geographical and depth of the waterbody, etc [2]. If the water body is heterogeneous or complex, for instance, composite sampling approach might be suitable to record the water body variability [3].
Water sampling technique can also be determined by the resources for the research, such as time, manpower and equipment. Some are more manual or require additional instruments, which may not be possible or possible given the resources used in the research [4].
To summarise, when choosing water sampling technique, you need to think about the research objectives, the quality of water that will be squirted, and the resources at hand. If all of these aspects are taken into account, it’s possible to select the sampling method that will be best suited to the study.
[1] U.S. Environmental Protection Agency. (n.d.). Composite sampling.
[2] U.S. Geological Survey. (n.d.). Sampling design and analysis.
[3] International Association of Water Quality. (n.d.). Sampling design.
[4] National Environmental Services Center. (n.d.). Choosing a sampling method.
Sampling techniques for PFAS in surface water
Several sampling methods are available for river, lake and other surface water water samples that can be tested for per- and polyfluoroalkyl substances (PFAS).
Grab sampling – collecting a single sample at one place and time is one of the most common methods for sampling surface water [1]. Grab sampling is a very inexpensive way to get a quick picture of the water quality at any given time point in time but not a good indicator of the overall water quality of the water body if the water quality is time or space-dependent [2].
Composite sampling is another way to get water samples from surface water sources. Composite sampling: Take multiple samples at a time and then combine them into a single sample to test for PFAS [3]. Composite sampling is good for determining the overall quality of a waterbody and long-term trends but it might not be suitable for short-term, episodic trends [4].
Purging and sampling: Purging and sampling consists of taking a sample after flushing or purging a water sample well or tap with a volume of water to clean any stagnant water present [5]. This technique can be applied to taking representative samples from places of consumption, like taps on drinking water, and can also be applied to the detection of PFAS with special purging and sampling instruments [6].
To conclude, there are a few sampling methods available for water from surface waters to analyze PFAS such as grab sampling, composite sampling, purging and sampling. These methods can be used to characterize PFAS using additional purging techniques and sampling equipment, and with caution given to study objectives, the composition of the sampled water, and the resources available.
[1] Environment Canada. (n.d.). Surface water sampling: Grab sampling.
[2] US Environmental Protection Agency. (n.d.). Sampling surface water.
[3] US Geological Survey. (n.d.). Composite sampling.
[4] Environment Canada. (n.d.). Surface water sampling: Composite sampling.
[5] US Geological Survey. (n.d.). Purge-and-trap sampling.
[6] US Environmental Protection Agency. (n.d.). Groundwater sampling.
Sampling techniques for PFAS in groundwater
Water that is underground in aquifers is groundwater, and many communities throughout the world depend on it for drinking water. But groundwater can also become contaminated with per- and polyfluoroalkyl substances (PFAS), chemicals produced synthetically that have been applied in many industries because of their properties but have been associated with adverse effects on human health and the environment [1]. There are several sampling methods for groundwater water samples to be taken and tested for PFAS.
Purging and sampling is one common method of getting groundwater samples for PFAS analysis, where the water sampling point (a well or a tap) is flushed or purified with a quantity of water to eliminate any standing water [2]. This can be employed for sampling representative specimens from point of use (water taps, etc) and also extended to analysis of PFAS by applying special purging protocols and sample collection equipment [3].
A second way to take groundwater samples for PFAS is monitoring well sampling — by drilling a monitoring well in a place and taking water samples from the well over time [4]. Monitoring well sampling can be used to track groundwater quality in the long run and detect trends or changes in water quality but it needs special equipment and is time-consuming [5].
Final thought, some sampling methods for obtaining and testing groundwater samples for PFAS can be applied to water: purging and sampling; monitoring well sampling. These methods can be extended to PFAS testing by using specific purging techniques and sampling equipment and based on study objectives, groundwater properties and resources.
[1] Environmental Protection Agency. (n.d.). PFAS (Per- and Polyfluoroalkyl Substances).
[2] National Ground Water Association. (n.d.). Purging and Sampling Procedures.
[3] United States Geological Survey. (2017, June 14). Sampling Groundwater.
[4] Environmental Protection Agency. (2017, October). Sampling and Analysis of PFAS in Ground Water: Technical Guidance.
[5] United States Geological Survey. (2018, January 3). Monitoring Wells. Retrieved from https://www.usgs.gov/
Sampling techniques for PFAS in drinking water
Public health protection around water is a public health issue, and there are a variety of sampling methods available to take and test water samples from public drinking water systems for per- and polyfluoroalkyl substances (PFAS).
Grab sampling – Taking just one sample at a location and time to analyse for PFAS is a commonly used technique to collect drinking water samples [1]. Grab sampling is a straightforward and affordable way to get an estimate of water quality at a specific time interval but could not be a good measure of water quality as the water quality changes across time or space [2].
Composite sampling is also another method to obtain drinking water samples for PFAS testing. Composite sampling: multiple samples from different time intervals are combined to produce a single sample which is tested for PFAS [3]. Composite sampling is feasible to measure the quality of a water supply in general and for time series but it isn’t optimal for measuring temporal or periodicity [4].
Purging and sampling : It is the process of obtaining a sample after flushing or purging a water sampler (like a tap) with some water in order to wash away any standing water that might be present [5]. This can be utilized for representative samples from points of use and can also be applied to PFAS analysis by special purging techniques and sampling instruments [6].
There are a lot of hurdles and considerations when it comes to making drinking water safe: from sampling and quality assurance procedures to using valid analytical procedures for PFAS analysis, and from monitoring for contamination during sample collection and storage [7]. Furthermore, one must take into account the possible health hazards of PFAS exposure and that the water is tested according to the applicable regulation or guidelines for PFAS concentration [8].
Final thoughts: Some sampling methods for PFAS detection in public drinking water sources include grab sampling, composite sampling, and purging and sampling. When it comes to the quality of drinking water, this means that it should be sampled properly, analysed according to established protocols, and we need to weigh the possibility of contamination and health impacts from PFAS exposure.
[1] "Drinking Water Sampling and Analysis." US Environmental Protection Agency.
[2] "Drinking Water Sampling." Centers for Disease Control and Prevention.
[3] "Composite Sampling for Water Quality Monitoring." US Geological Survey.
[4] "Purging and Sampling Groundwater Wells." US Geological Survey.
[5] "Purging and Sampling of Groundwater Wells." US Environmental Protection Agency.
[6] "PFAS Sampling and Analysis." US Environmental Protection Agency.
[7] “PFAS in Drinking Water.” US Environmental Protection Agency.
[8] "Drinking Water Standards for Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS)." US Environmental Protection Agency.
Sampling techniques for PFAS in marine and estuarine water
Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals that have been widely used in various industries but have been found to have negative impacts on human health and the environment [1]. There are several sampling techniques that can be used to collect and analyze water samples from marine and estuarine environments for PFAS.
One common technique for collecting water samples from marine and estuarine environments is grab sampling, which involves collecting a single sample at a specific location and time [2]. Grab sampling is a simple and cost-effective method that can be used to obtain a snapshot of the water quality at a particular point in time, but it may not be representative of the overall quality of the water if the water quality is variable over time or space [3].
Composite sampling is another technique that can be used to collect water samples from marine and estuarine environments. Composite sampling involves collecting multiple samples over a period of time and combining them into a single sample, which is then analyzed for PFAS [4]. Composite sampling can be useful for assessing the overall quality of a water body and for identifying trends over time, but it may not be suitable for assessing short-term or episodic events [5].
Purging and sampling is a technique that involves collecting a sample after flushing or purging a water sampling point, such as a well or tap, with a volume of water to remove any stagnant water that may be present [6]. This technique can be useful for collecting representative samples from points of use, such as drinking water taps, and can be adapted for the analysis of PFAS by using special purging procedures and sampling equipment [7].
There are several unique challenges and considerations involved in collecting and analyzing water samples from marine and estuarine environments for PFAS. These environments can be physically challenging to work in, with rough waves, strong currents, and variable weather conditions [8]. In addition, there may be specific regulatory requirements or guidelines that need to be followed when collecting and analyzing water samples from these environments [9]. It is also important to consider the potential for contamination during sample collection and handling, as well as the potential health risks associated with exposure to PFAS [10].
In conclusion, there are several sampling techniques that can be used to collect and analyze water samples from marine and estuarine environments for PFAS, including grab sampling, composite sampling, and purging and sampling. Working in these environments can be physically challenging and may require the use of specialized equipment and following specific regulatory requirements. It is also important to consider the potential for contamination and the potential health risks associated with exposure to PFAS.
[1] Centers for Disease Control and Prevention (CDC). (2019). Per- and polyfluoroalkyl substances (PFAS).
[2] Environmental Protection Agency (EPA). (2018). Sampling and analysis of water quality.
[3] Environmental Protection Agency (EPA). (2018). Grab sampling.
[4] Environmental Protection Agency (EPA). (2018). Composite sampling.
[5] Environmental Protection Agency (EPA). (2018). Purging and sampling.
[6] Ritter, L. (2020). Sampling and analysis of per- and polyfluoroalkyl substances (PFAS) in the environment. Environmental Science: Processes & Impacts, 22(2), 230-242. doi: 10.1039/C9EM00654D
[7] European Commission (EC). (2019). Per- and polyfluoroalkyl substances (PFAS).
[8] Houde, M., & Gauthier, D. T. (2017). Per- and polyfluoroalkyl substances (PFASs) in the aquatic environment: Occurrence, fate, and impacts. Environmental Science: Processes & Impacts, 19(4), 579-598. doi: 10.1039/C6EM00813G
[9] Environmental Protection Agency. (2018). Marine and estuarine water sampling guidance.
[10] U.S. Geological Survey. (2018). Sampling considerations for per- and polyfluoroalkyl substances (PFAS).
Sampling techniques for PFAS in industrial and agricultural water
There are several sampling techniques that can be used to collect and analyze water samples from industrial and agricultural sources for per- and polyfluoroalkyl substances (PFAS).
One common technique for collecting water samples from industrial sources is grab sampling, which involves collecting a single sample at a specific location and time [1]. Grab sampling is a simple and cost-effective method that can be used to obtain a snapshot of the water quality at a particular point in time, but it may not be representative of the overall quality of the water if the water quality is variable over time or space [2].
Composite sampling is another technique that can be used to collect water samples from industrial sources. Composite sampling involves collecting multiple samples over a period of time and combining them into a single sample, which is then analyzed for PFAS [3]. Composite sampling can be useful for assessing the overall quality of a water body and for identifying trends over time, but it may not be suitable for assessing short-term or episodic events [4].
Purging and sampling is a technique that involves collecting a sample after flushing or purging a water sampling point, such as a well or tap, with a volume of water to remove any stagnant water that may be present [5]. This technique can be useful for collecting representative samples from points of use, such as drinking water taps, and can be adapted for the analysis of PFAS by using special purging procedures and sampling equipment [6].
Water sources associated with agricultural activities can also be contaminated with PFAS, and there are several sampling techniques that can be used to collect and analyze water samples from these sources. Grab sampling, composite sampling, and purging and sampling are all techniques that can be used to collect and analyze water samples from agricultural sources for PFAS, as described above [1-6]. In addition, monitoring well sampling, which involves installing a monitoring well at a specific location and collecting water samples from the well at regular intervals over a period of time, can be useful for assessing the quality of groundwater in agricultural areas and for identifying trends or changes in the water quality [7].
There are several potential impacts of industrial and agricultural activities on water quality, including the release of PFAS and other contaminants into the water through the use of industrial chemicals and agricultural practices [8]. It is important to carefully consider the potential impacts of these activities on water quality and to use appropriate sampling techniques and analytical methods to assess the presence and concentration of PFAS in water sources.
In conclusion, there are several sampling techniques that can be used to collect and analyze water samples from industrial and agricultural sources for PFAS, including grab sampling, composite sampling, purging and sampling, and monitoring well sampling. It is important to consider the potential impacts of industrial and agricultural activities on water quality and to use appropriate sampling and analytical methods to assess the presence and concentration of PFAS in these sources.
[1] "Guidance for Drinking Water Sampling," Environmental Protection Agency.
[2] "Sampling Strategies for Ground Water," Environmental Protection Agency.
[3] "Composite Sampling," Environmental Protection Agency.
[4] "Purge and Trap Sampling," Environmental Protection Agency.
[5] "Monitoring Well Sampling," Environmental Protection Agency.
[6] “Sampling Techniques for Agricultural Water,” Environmental Protection Agency.
[7] "Impacts of Industrial and Agricultural Activities on Water Quality," Environmental Protection Agency.
[8] Environmental impacts of PFAS. (n.d.).
Quality control and quality assurance in water sampling
Ensuring the accuracy and reliability of water sampling results is an important aspect of water quality monitoring and assessment, and there are several measures that can be taken to ensure quality control and quality assurance in water sampling.
One key measure is the use of standard operating procedures (SOPs), which are detailed instructions that outline the steps to be followed when collecting and handling water samples [1]. SOPs help to ensure consistency and reliability in water sampling by specifying the equipment and materials to be used, the sampling locations and times, and the sample collection and preservation methods [2]. SOPs should be based on recognized guidelines or standards, such as those published by the U.S. Environmental Protection Agency (EPA) or the International Organization for Standardization (ISO) [3].
Laboratory controls are another important measure for ensuring quality control and quality assurance in water sampling. These controls include the use of certified reference materials, the implementation of quality control checks during sample analysis, and the participation in interlaboratory comparison studies [4]. Certified reference materials are known standards of known concentration that are used to verify the accuracy and precision of analytical methods, while quality control checks involve the analysis of samples with known concentrations to ensure the accuracy of the measurements [5]. Interlaboratory comparison studies involve the analysis of the same samples by multiple laboratories to assess the reproducibility of the results [6].
Field quality control measures are also important for ensuring the accuracy and reliability of water sampling results. These measures may include the use of calibrated equipment, the implementation of quality control checks during sample collection and handling, and the use of duplicate or replicate samples [7]. Calibrated equipment ensures that the measurements taken during water sampling are accurate, while quality control checks during sample collection and handling help to ensure that the samples have not been contaminated or otherwise compromised [8]. Duplicate or replicate samples involve collecting and analyzing multiple samples from the same location or at the same time to confirm the accuracy of the results [9].
In conclusion, quality control and quality assurance in water sampling are important for ensuring the accuracy and reliability of water sampling results. Measures such as the use of standard operating procedures, laboratory controls, and field quality control measures can help to ensure that the water sampling process is consistent and reliable.
[1] U.S. Environmental Protection Agency. (2018). Standard Operating Procedures for Water Quality.
[2] International Organization for Standardization. (2017). ISO 5667-3:2017 Water quality – Sampling – Part 3: Sampling of surface water.
[3] U.S. Geological Survey. (n.d.). Sampling Design and Quality Assurance/Quality Control.
[4] National Environmental Services Center. (n.d.). Quality Control in the Laboratory.
[5] American Chemical Society. (n.d.). Certified Reference Materials: Key to Accurate Analytical Results. Retrieved from https://www.acs.org/
[6] U.S. Environmental Protection Agency. (2013). Quality Assurance Project Plan (QAPP) for Environmental Data.
[7] Field Quality Control Measures. (n.d.).
[8] Quality Control During Sampling. (n.d.).
[9] Replicate Sampling. (n.d.).
Advanced sampling techniques for PFAS
Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals that have been widely used in various industries but have been found to have negative impacts on human health and the environment [1]. There are several advanced sampling techniques that have been developed for collecting and analyzing PFAS in water, including passive sampling and the use of advanced analytical techniques.
Passive sampling involves the use of specialized devices that can passively collect water samples over a period of time, without the need for active sampling or handling [2]. Passive sampling devices can be left in the water for a specified period of time, after which they are retrieved and analyzed for PFAS [3]. Passive sampling has several advantages over traditional active sampling methods, including the ability to collect samples over long periods of time and the reduced risk of contamination [4]. However, passive sampling devices are subject to certain limitations, such as the potential for bias and the need for careful calibration and validation [5].
Advanced analytical techniques, such as liquid chromatography-tandem mass spectrometry (LC-MS/MS) and inductively coupled plasma-mass spectrometry (ICP-MS), can be used to detect and quantify PFAS in water samples at low concentrations [6]. These techniques are highly sensitive and can detect a wide range of PFAS, including both legacy and emerging compounds [7]. Advanced analytical techniques can be used in combination with traditional sampling techniques, such as grab sampling or composite sampling, to provide a more comprehensive assessment of the presence and concentration of PFAS in water [8].
In conclusion, advanced sampling techniques, such as passive sampling and the use of advanced analytical techniques, can be useful for collecting and analyzing PFAS in water. Passive sampling can provide long-term data on the presence and concentration of PFAS, while advanced analytical techniques can detect low concentrations of a wide range of PFAS. Both of these techniques can be used in conjunction with traditional sampling techniques to provide a more comprehensive assessment of PFAS in water.
[1] Environmental Protection Agency. (2019). Per- and Polyfluoroalkyl Substances (PFAS).
[2] Vikesland, P. J., & Snyder, S. A. (2013). Passive sampling for contaminants of emerging concern. Environmental Science & Technology, 47(3), 1362-1369.
[3] van der Veen, I., & Govers, H. A. J. (2017). Passive sampling: A review of principles, applications, and limitations. Environmental Science: Processes & Impacts, 19(3), 360-371.
[4] Vikesland, P. J., & Snyder, S. A. (2013). Passive sampling for contaminants of emerging concern. Environmental Science & Technology, 47(3), 1362-1369.
[5] van der Veen, I., & Govers, H. A. J. (2017). Passive sampling: A review of principles, applications, and limitations. Environmental Science: Processes & Impacts, 19(3), 360-371.
[6] Fiedler, H., & Hühnerfuss, H. (2015). Analyzing perfluorinated compounds in water by liquid chromatography-tandem mass spectrometry. TrAC Trends in Analytical Chemistry, 69, 87-98.
[7] Environmental Protection Agency. (2018). Inductively Coupled Plasma-Mass Spectrometry (ICP-MS).
[8] Fiedler, H., & Hühnerfuss, H. (2015). Analyzing perfluorinated compounds in water by liquid chromatography-tandem mass spectrometry. TrAC Trends in Analytical Chemistry, 69, 87-98.
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