Dioxin

What is Dioxin? Dioxin is a common name given to a group of persistent and very toxic chemicals, also known as dioxins and furans. These chemicals include 75 chlorinated dibenzo dioxins and 135 chlorinated dibenzo furans. The most toxic of these compounds is 2,3,7,8-tetrachlorodibenzo-p-dioxin, also known as TCDD. The other 209 dioxin and furan chemicals, or congeners, are less toxic than TCDD by orders of magnitude of 0.5, 0.1, 0.01, or 0.001, relative to the toxicity of TCDD. For this reason, dioxin in the environment is measured and reported in terms of TCDD equivalents, which are the actual concentrations of each dioxin or furan congener multiplied by its relative toxicity. The amount of dioxin in a sample is the sum of the concentration of TCDD and TCDD-equivalents.

2,3,7,8-TCDD

2,3,7,8-TCDF

Where does it come from and how does it affect me? Dioxin is a by-product of many chemical, manufacturing, and combustion processes. The use of chlorine in a chemical process or the combustion of a chlorine-containing material (such as plastic) results in the formation of dioxin. For this reason, we see dioxin in our surface waters and sediments near effluent outfalls, and in our surface soils and grasses down-wind of incinerators and factories. Distribution of dioxin from the “source” is only the first in a long line of concerns regarding dioxin because of what happens once it enters the environment. Dioxin is referred to as a persistent and bioaccumulative toxic substance, meaning it stays in the environment a long time and it works its way up various food chains. Grazing animals, from rodents to bovine, may feed down-wind of incinerators and accumulate dioxin in their fat cells over their life cycle. This has been demonstrated in numerous studies involving testing of beef and cows milk. Dioxin, from factory outfalls, is assimilated by aquatic microorganisms then magnifies up the food chain in larger fish, which are in turn eaten by bears, birds of prey, sea mammals, and humans. According to the USEPA, 90% of human exposure to dioxin occurs through consumption of meat, dairy products, and fish. What is worse is that dioxin is transmitted to nursing infants through mothers milk. For these reasons, dioxin has been quoted as being the “Darth Vader of toxic chemicals”. The scientific community has known about the serious implications of dioxin in the environment for years. A recent EPA study determined that the lifetime risk of getting cancer from dioxin is between 1 in 1,000 to 1 in 10,000 (acceptable lifetime cancer risk for a given chemical typically ranges from 1 in 10,000 to 1 in 1,000,000.). The EPA study concluded that, as a society, we have been accumulating dioxin and dioxin-like chemicals in our bodies to the extent that we may soon start to see adverse health affects as a result. Dioxin exposure has been linked to infertility, birth defects, impaired child development, decreased testis size, and thyroid changes. It can cause endometriosis, decreased sperm count, and reduced testosterone levels.

FRONTIER ANALYTICAL LABORATORY 5172 Hillsdale Circle * El Dorado Hills, CA 95762 Tel (916) 934-0900 * Fax (916) 934-0999 [email protected]

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What are people doing about it? Now that USEPA is getting more serious about dioxin, there is greater incentive to control it through the legislative process. The momentum on dioxin control is picking up now that the word is out. Governmental agencies are placing restrictions on dioxin emissions at factory stacks and effluent outfalls. Community groups and local officials are pressuring regulators to require dioxin studies at hazardous waste cleanup sites. With this increased enforcement comes the need for monitoring. For years, factories and incinerators have been required to routinely monitor air emissions and water discharges for a variety of pollutants excluding dioxin. Dioxin has finally hit the radar screen for the same reason that other toxic substances have been in the limelight – prolonged exposure to dioxin poses adverse health affects. What are implications to analytical laboratories? Analytical requirements for dioxin are unique compared to other routinely monitored substances. Because it is toxic at much lower concentrations than other pollutants and dioxin analysis requires speciation of many congeners, the analytical requirements are far more sophisticated and sensitive. For instance, most toxic chemicals are commonly measured in parts per million (ppm) and parts per billion (ppb) whereas dioxin is commonly measured in parts per trillion (ppt) and parts per quadrillion (ppq). Also, carcinogens like benzene are commonly regulated at 1 to 5 parts per billion (ppb) whereas dioxin is regulated at 1 part per trillion (ppt) and lower. As a result, dioxin analysis is significantly more costly than that for other toxic pollutants. The high cost for analysis partially explains the long-standing resistance to regulate it. What are the common analytical methods? There are currently 8 analytical methods that are routinely used for the determination of dioxins and furans: EPA Method 1613, EPA Method 8290, EPA Method 8280, EPA Method 613, EPA Method 23, EPA Method TO-9, NCASI Method 551, and CARB Method 428. These methods are quite similar in respect to one another and cover a variety of matrices. EPA Method 8280 and EPA Method 613 are low resolution with results in the ppb to ppt levels and are written to cover just about any matrix other than air media. EPA Method 23, EPA Method TO-9, and CARB Method 428 are air methods and are high resolution methods with results reported in the ppt to ppq levels. EPA Method 1613, EPA Method 8290, and NCASI Method 551 are all high resolution methods with results in the ppt to ppq levels and are also written to address a variety of matrices; soil, aqueous, tissue, effluent, solids, etc. What are the QC requirements for testing? Each set of samples is required to have a reference method blank (MB) and an ongoing precision and recovery (OPR) or laboratory control sample (LCS). In addition, a matrix spike/matrix spike duplicate (MS/MSD) may be required. All QC samples are prepared and analyzed using the same procedure as the rest of the sample batch. All QC samples are run with each sample batch, not to exceed 20 samples in a given 12-hour period. The MB is analyzed to demonstrate freedom from laboratory contamination. The OPR or LCS is analyzed to demonstrate method precision and accuracy. An OPR or LCS is prepared by adding a known quantity of dioxin standard to a MB. The results must fall within method specific acceptance criteria.

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If the MB, OPR, or LCS does not meet method specific criteria, the entire sample batch is reextracted and re-analyzed. The MS/MSD are analyzed to demonstrate method precision and accuracy on a particular sample matrix. A MS/MSD is prepared by adding a known quantity of dioxin standard to duplicate samples. The relative percent difference between the MS and MSD should be < 50%. Additional QC can consist of running duplicate samples. For duplicate samples, the relative percent difference should be < 50%. Are there specific tests an analytical laboratory must perform prior to testing for dioxins and furans? Yes. There is an array of procedures a laboratory must follow prior to being certified for dioxin and furan analysis. The most common tests are MDLs (method detection limits), IPRs (initial precision and recovery), and performance evaluations (PE). MDLs are performed to determine the minimum concentration of an analyte that can be measured and reported with 99% confidence. A known amount of native standard is added to seven reference matrix method blanks, typical spike levels are that of the lowest point of a calibration curve. These spiked matrix method blanks are then prepared and analyzed following the laboratory procedure for processing samples. MDLs must be performed prior to the first time a method is used and any time a method or instrumentation is modified. IPRs are analyzed to demonstrate acceptable precision and accuracy. A known quantity of native standard is added to four reference matrix method blanks, typical levels are that of the mid point of the calibration curve. The IPRs are then prepared and analyzed following the laboratory procedure for processing samples. IPRs are performed prior to the first time a method is used and whenever a method, instrumentation, or personnel change occurs. PE samples are analyzed to demonstrate laboratory accuracy. PE samples are prepared and analyzed following the laboratory procedure for processing samples. PE samples usually contain a known concentration of method analytes that has been analyzed by multiple laboratories to determine statistically the accuracy and precision that can be expected when a competent analyst performs a method. Analyte concentrations are unknown to the analyst. What is the difference between detection limits (DLs) and reporting limits (RLs)? Both methods of reporting are sample size biased. A reporting limit (RL) is calculated using the lowest point of the calibration curve. Any detection of an analyte below this level is disregarded. In dioxin and furan analysis, only EPA Method 1613B refers to reporting limits. All other dioxin and furan methods refer to detection limits (DLs). A detection limit is the lowest possible amount of an analyte that is not detectable for that sample. These levels can vary based on chemical and matrix interferences, sample sizes, and instrument performance. Detection limits are only reported when an analyte is not present in the sample. When using the detection limit methodology, any positive detection of an analyte that meets the criteria must be reported, even if it is below the lowest point of the calibration curve. A specific qualifier is assigned to any positive that is reported below the lowest point of the calibration curve.

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Where can I get additional information on Dioxin? Aside from conducting Internet searches, check out: “How to Start to Stop Dioxin Exposures in Your Community,” an article providing basic information on the sources and health effects of dioxin and what can be done to curb production of and exposure to dioxin. {http://www.enviroweb.org/issues/dioxin/dioxin.htms] “Dioxin Exposure and Health,” an article by the European Commission on what is being done to study sources of and levels of dioxin in the European Union. [http://europa.eu.int/comm./environment/dioxin/] “EPA Links Dioxin to Cancer,” a 16 May 2000 Washington Post article summarizing USEPA’s findings from their draft assessment report on dioxin. [http://washingtonpost.com/wp-dyn/articles/A139082000May16.html] “The USEPA Dioxin Exposure Initiative,” an article discussing the initiative’s study, whose primary goal is to quantitatively link dioxin sources to general population exposure. [http://www.epa.gov/ncea/dei.htm] “Japan agrees to cleanup pollution near U.S. Navy base,” a CNN.com 2000 March 17 article about how Japan’s Environmental Protection Agency charged the owners of a private incinerator with causing dangerously high dioxin emissions. The discovery resulted in a temporary shutdown of the incinerator, installation of emission controls, and long-term ambient air monitoring. [http://www.cnn.com/2000/ASIANOW/east/03/16/cohen.japan/index.html] You can also contact: Frontier Analytical Laboratory 5172 Hillsdale Circle El Dorado Hills, CA 95762 Tel: 916-934-0900 Fax: 916-934-0999 Email: [email protected]

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