Testing for PCB Congeners & Aroclors
ALS Environmental performs number of test procedures for the presence of PCBs. Including EPA Methods 600/4-81-045 for oils; 608 for waste water and 1668 and 8082 for solid, and aqueous samples such as sediment and tissue. Air samples can also be tested by NIOSH Method 5503 as well as EPA TO-4A (high volume sampler), TO-10A (low volume sampler and TO-10A M (wipes). Please click on the method of interest for information about the reporting limits for these methods and other pertinent information.
PCBs were first isolated in the 1880s from coal tar extracts, and commercial production of PCBs began in the 1920s. Their usefulness was tied to their chemical stability, low flammability and excellent electrical insulating properties. This stability also explains their persistence in the environment. The compounds were in widespread use throughout most of the 20th century in industrial transformers and capacitors, electrical devices of all kinds, fluorescent light fixture ballasts, insulation materials, adhesives and tape, caulking, plastics, and some floor finishes to mention a few. However, the toxic effects of PCB exposure were observed as early as 1933. In animals, PCBs have been shown to cause cancer and a number of serious non-cancer health effects on various systems in the body including the endocrine system, immune system, reproductive system, nervous system, and others. In the 1970s, PCB production was banned in the United States and regulations concerning the presence of PCBs in the environment were promulgated.
PCBs were typically synthesized by chlorinating biphenyl with chlorine gas, substituting chlorine atoms for hydrogen atoms on the biphenyl molecule. Individual chlorinated biphenyl molecules are called congeners. Individual congeners are identified by the number and position of the chlorine atoms around the biphenyl rings. There are 209 possible PCB congeners ranging from the mono-substituted 2-chlorobiphenyl to the fully-substituted decachlorobiphenyl. Varying the conditions of this chlorination process produced different mixtures of congeners with different physical properties. These mixtures were sold as products called Aroclors.
The only North American producer, Monsanto Company, marketed PCBs under the trade name Aroclor from 1930 to 1977. These were sold under trade names followed by a four digit number. The first two digits generally refer to the number of carbon atoms in the biphenyl skeleton (for PCBs this is 12), the second two numbers indicate the percentage of chlorine by mass in the mixture. Thus, Aroclor 1260 has 12 carbon atoms and contains 60% chlorine by mass. An exception is Aroclor 1016, which also has 12 carbon atoms, but has 42% chlorine by mass. Different Aroclors were used at different times and for different applications. In electrical equipment manufacturing in the USA, Aroclor 1260 and Aroclor 1254 were the main mixtures used before 1950, Aroclor 1242 was the main mixture used in the 1950s and 1960s until it was phased out in 1971 and replaced by Aroclor 1016.
EPA Method 8082
EPA Method 8082 is the most common analytical method used for the analysis of PCB Aroclors and a short list of PCB congeners in samples of solids, sediments, tissues and liquids. This method uses a capillary dual column gas chromatography with electron capture detection (GC/ECD). The Aroclors are identified by characteristic peak patterns. Improvements can be made to this method to allow some individual or homologue congener identification with much lower detection limits. Typical reporting limits range from 0.033 mg/Kg in soils to a range roughly ten times lower (2 µg/Kg) by using advanced analytical techniques. In waters, typical reporting limits are 0.01 – 1.0 µg/L with low level limits ranging around 0.005 µg/L.
EPA Method 608
EPA Method 608 is a wastewater method used to analyze samples for PCB Aroclors and organochlorine pesticides also using a capillary dual column GC/ECD. EPA Method 608 is also only used on wastewater samples.
EPA Method 600/4-81-045
EPA Method EPA 600/4-81-045 is a capillary dual column GC/ECD method to test for PCB aroclors in oils. The aroclors of interest are those considered the most commonly manufactured in the US: aroclors 1016, 1221, 1232, 1242, 1248, 1254 and 1260.