What are POPs, PCPs, and PFAS, and why has their use in products been restricted? What are common test methods to make sure that these substances do not exceed permissible levels?
Chemical testing is an essential process in ensuring the safety of various products and materials that we use in our daily lives. Among the many chemicals that require testing, POPs, PCPs, and PFAS are some of the most critical and widely studied. In this article, we will discuss what these chemicals are, why they require testing, and the products that are most commonly tested for these chemicals.
POPs
Persistent organic pollutants (POPs) are a group of organic chemicals that are characterized by their resistance to environmental degradation, ability to bioaccumulate in the food chain, and toxicity to humans and wildlife. Some examples of POPs include:
- Polychlorinated biphenyls (PCBs) - These are a group of synthetic organic chemicals that were widely used as coolants and lubricants in electrical equipment and as flame retardants. They are highly toxic and persistent, and have been found to cause a range of health problems, including cancer, developmental delays, and immune system dysfunction.
- Dioxins - These are a group of highly toxic compounds that are formed as byproducts of various industrial processes, such as waste incineration and paper production. They are known to cause cancer, reproductive and developmental problems, and immune system dysfunction in humans and animals.
- Polybrominated diphenyl ethers (PBDEs) - These are a group of flame retardant chemicals that have been widely used in furniture, electronics, and other products. They are persistent and bioaccumulative, and have been found to cause developmental and neurological problems in children, as well as thyroid and liver damage.
- Chlorinated pesticides - These include chemicals such as DDT, chlordane, and hexachlorobenzene, which were widely used in agriculture to control pests. They are persistent and toxic, and have been linked to cancer, reproductive and developmental problems, and immune system dysfunction in humans and animals.
- Polycyclic aromatic hydrocarbons (PAHs) - These are a group of chemicals that are formed during the incomplete combustion of organic materials, such as coal, oil, and wood. They are carcinogenic and have been linked to respiratory problems, cardiovascular disease, and developmental problems in children.
There are many other chemicals that are considered POPs, including some pesticides, herbicides, and industrial chemicals. These chemicals are typically regulated by national and international organizations, such as the Stockholm Convention on Persistent Organic Pollutants, due to their persistence, toxicity, and potential for environmental and human harm.
PCPs
Polychlorinated phenols (PCPs) are a group of toxic organic chemicals that have been used in a variety of industrial and agricultural applications. Some examples of PCPs include:
- Pentachlorophenol (PCP) - This is one of the most widely used PCPs and has been used as a wood preservative, herbicide, and pesticide. It is highly toxic and has been linked to cancer, reproductive problems, and immune system dysfunction in humans and animals.
- Tetrachlorophenol (TCP) - This is another commonly used PCP that has been used as a wood preservative and in the production of other chemicals. It is toxic and can cause skin and eye irritation, respiratory problems, and liver and kidney damage.
- Trichlorophenol (TCP) - This is a PCP that has been used as a fungicide, herbicide, and disinfectant. It is toxic and can cause skin and eye irritation, respiratory problems, and liver and kidney damage.
- Chlorophenols - This group of PCPs includes a range of different chemicals that have been used in various industrial and agricultural applications. They are toxic and can cause a range of health problems, including skin and eye irritation, respiratory problems, and liver and kidney damage.
PCPs are persistent and can bioaccumulate in the environment and in the food chain, leading to potential harm to humans and wildlife. As a result, their use has been restricted or banned in many countries.
PFAS
Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that have been used in a wide range of industrial and consumer applications due to their unique properties, such as water and oil repellency, heat resistance, and non-stick properties. Some examples of PFAS include:
- Perfluorooctanoic acid (PFOA) - This is a PFAS that has been widely used in the production of non-stick coatings, such as Teflon. It is persistent and has been found to accumulate in the environment and in the bodies of humans and animals. PFOA has been linked to cancer, reproductive and developmental problems, and immune system dysfunction.
- Perfluorooctanesulfonic acid (PFOS) - This is another commonly used PFAS that has been used in the production of non-stick coatings, as well as in firefighting foams and other applications. It is persistent and has been found to accumulate in the environment and in the bodies of humans and animals. PFOS has been linked to cancer, reproductive and developmental problems, and immune system dysfunction.
- Perfluorobutanesulfonic acid (PFBS) - This is a PFAS that has been used as a replacement for PFOS in some applications, such as in firefighting foams. It is also persistent and has been found to accumulate in the environment and in the bodies of humans and animals. While there is less information available about the health effects of PFBS compared to PFOA and PFOS, studies have suggested that it may also be harmful to human health.
- Perfluorononanoic acid (PFNA) - This is a PFAS that has been used in various industrial applications, such as in the production of coatings and plastics. It is persistent and has been found to accumulate in the environment and in the bodies of humans and animals. PFNA has been linked to developmental problems in children and may also be linked to cancer.
PFAS are considered to be emerging contaminants of concern due to their persistence, potential for bioaccumulation, and toxicity to humans and wildlife. Many countries have introduced regulations to restrict or ban the use of certain PFAS in consumer products, and there is ongoing research to better understand their health and environmental impacts.
Test methods for POPs, PCPs and PFAS
There are several test methods that can be used to measure the levels of POPs, PCPs and PFAS in products. Among the most commonly used ones are GC-MS, LC-MS and ELISA. The choice of method depends on the specific substance being tested for, the sample matrix, and the level of sensitivity and specificity required.
Gas chromatography-mass spectrometry (GC-MS)
Gas chromatography-mass spectrometry (GC-MS) is a widely used analytical technique for the detection and quantification of POPs, PCP and PFAS in products. The GC-MS method involves two main steps: separation of the analytes and detection of the separated analytes.
In the first step, the sample is introduced into the GC column, which separates the analytes based on their physical and chemical properties, such as boiling point, vapor pressure, and polarity. The column is typically made of a long, thin tube coated with a stationary phase that interacts with the analytes in the sample. The analytes are then carried through the column by a flow of inert gas, such as helium or nitrogen. As the analytes pass through the column, they are separated based on their different interactions with the stationary phase, and they emerge from the column as individual peaks.
In the second step, the separated analytes are detected and quantified by mass spectrometry. In this step, the analytes are ionized and fragmented into smaller fragments, which are then separated and detected based on their mass-to-charge ratio (m/z). The resulting mass spectra provide information about the identity and quantity of the analytes in the sample.
GC-MS is a highly sensitive and specific method for the detection of POPs, PCPs, and PFAS in products. The method can detect very low levels of these chemicals in complex matrices, such as food, water, and soil. However, GC-MS requires specialized equipment and trained personnel, and it is a relatively time-consuming and expensive method compared to other analytical methods, such as ELISA.
Liquid chromatography-mass spectrometry (LC-MS)
Liquid chromatography-mass spectrometry (LC-MS) is another widely used analytical technique. This method is similar to GC-MS, but it involves the separation of the analytes using a liquid chromatography column instead of a gas chromatography column. In this method, the sample is first extracted from the product using a suitable solvent and purified using solid phase extraction or other sample cleanup methods. The resulting sample is then injected into an LC column, which separates the analytes based on their physical and chemical properties, such as polarity and size. The analytes are then detected and quantified by mass spectrometry in the same manner as GC-MS.
LC-MS is a highly sensitive and specific method for the detection of POPs, PCPs, and PFAS in products. It can detect very low levels of these chemicals in complex matrices, such as food, water, and soil, and it can provide structural information about the analytes, which can help identify and confirm the presence of these chemicals in a sample. LC-MS is also a relatively fast method compared to GC-MS, as the sample preparation step is simpler and requires less time. However, LC-MS also requires specialized equipment and trained personnel, and it is generally more expensive than other analytical methods, such as ELISA.
Enzyme-linked immunosorbent assay (ELISA)
This method is commonly used for the detection of specific POPs, such as dioxins and furans, in food and environmental samples. In ELISA, the sample is treated with antibodies that specifically bind to the target PCP, POP or PFAS. The bound substance is then detected using a colorimetric or fluorescent assay. ELISA is a relatively simple and cost-effective method for detecting the chemicals listed above, and it can be used to screen large numbers of samples in a short period of time. However, it is generally less sensitive than other analytical methods, such as GC-MS and LC-MS, which can detect lower levels of PCPs, POPs or PFAS in products. Therefore, ELISA is often used as a preliminary screening method, followed by the aforementioned more specific and sensitive confirmatory methods, to confirm the presence of PCPs in a product.
Testing labs for POPs, PCPs and PFAS
In order to carry out the test methods explained above, a qualified testing laboratory is needed. This lab not only needs the equipment to perform e.g. a GC-MS, but it also needs qualified staff that is familiar with the respective test method. This is why not all chemical testing labs will be able to offer all testing procedures listed above, but possibly only some of them, or even none at all.This is why finding a suitable testing service provider for POPs, PCPs and PFAS in a specific product can be challenging at times. One way of finding suitable chemical testing labs is a free request using the testxchange online platform. Here, users can complete a brief digital request form to describe the POP, PCP or PFAS analysis that they need. In the next step,this request is shared with several potential laboratories automatically. These testing labs can then respond to the request and provide the user with quotes for the chemical testing that is needed.