Focus
Dioxin Food Crisis in Belgium Eggs failing to hatch, baby chicks with nervous disorders, and chickens dropping like flies. That is what Belgian farmers witnessed in February and March 1999. But it wasn't until May 28, after keeping the news secret for one month, that the Belgian government announced to the public that dioxin had entered the food supply through contaminated animal feed. Immediately,
Britt E. Erickson
Analytical chemist provides a quick solution.
chickens and eggs were removed from the Belgian market. But it didn t stop there. The crisis escalated over fear that contaminated feed had also been sent to France and The Netherlands. The United States and much of Asia reacted by banning meat, eggs, and poultry products from all European Union (EU) nations until they could be proven safe.
Separation scientist Pat Sandra of the Uni- Pat Sandra versity of Ghent was angry that it took the Belgian government one month between the time it determined dioxin was in the feed and the time it confirmed it was also in chickens and eggs. "If
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Focus
Linking dioxins and PCBs Between 1929 and 1989, an estimated 1.5 million tons of polychlorinated biphenyls (PCBs), marketed under trade names such as Aroclor, Chlophen, Kanechlor, and Phenoclor, were produced worldwide, primarily for use as coolants in transformers and dielectric fluids in capacitors. PCBs also showed up in lubricants, adhesives, plasticizers, paints, and varnishes. Major production of PCBs was halted in the late 1970s because of toxicity concerns. PCBs are complex mixtures, containing isomers and compounds differing by the number of chlorine atoms attached to a biphenyl group. Altogether there are 209 PCB congeners. Analysis of PCBs is typically done by GC/MS or GC with an electron capture detector, and quantitation is often performed by selecting abundant congeners as markers and using a conversion factor to estimate total PCBs. The presof other chloroaromatics such as
you give a sample high prrority, you should be able to analyze it in at least two dayss ,ot four weeks," he emphasizes. Sandra believed the Belgian government was taking the wrong approach to solving the food crisis by looking for dioxins. "Each dioxin analysis is roughly $1700-1800 and takes a long time," hh says. In addition, most laboratories are not capable of doing dioxin analyses, which require the use of an expensive, highresolution mass spectrometer. "When I heard the news that dioxin concentrations in animal feed were 200-500 times greater than environmental levels, I immediately thought there must be high concentrations of other compounds as well, because dioxins are not primary products," says Sandra. Sure enough, something else was in the contaminated feed. Sandra had a hunch
dioxins and dibenzofurans, often complicates the analysis of PCBs. Unlike PCBs, polychlorinated dibenzo/>-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) have no known uses and have not been manufactured commercially. Dioxins and furans are generally unwanted by-products, resulting from the combustion of chlorinated compounds, such as PCBs. In the mid-1970s, dioxins were thought to come from the manufacturing of phenoxy herbicides, such as 2,4,5trichlorophenoxyacetic acid (2,4,5-T) Eventually, it became clear that dioxins and furans were coming from other sources as well including paper and pulp-bleaching mills municipal and medical waste incinerators automobile exhaust and even forest fires Like PCBs dioxins and furans occur as complex mixtures Altogether there are 75 PCDD and 135 PCDF congeners The toxicity of PCBs, dioxins, and furans is somewhat controversial. Not all congeners are considered toxic. It is difficult to assess the toxicity of PCBs because
that the source of dioxins was not incinerator residues but rather polychlorinated biphenyls (PCBs). He was able to get a sample of the feed to analyze, and bingo, he and his co-workers detected 50 ppm total PCBs (primarily Aroclor 1260). In addition, they found up to 10 ppm total PCBs in chicken fat and ~1 ppm total PCBs in eggs. Eventually, the Belgian government decided to follow Sandra's approach, making the link between dioxins and PCBs. By looking for PCBs instead of dioxins, it was able to determine which companies were affected by the contamination in a relatively short period of time. Products that were PCB-free were allowed to return to market. PCB analyses are much simpler and less expensive than dioxin analyses. "We can analyze 50 samples per day for PCBs on
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they often contain impurities, such as dioxins and furans, which can be more toxic than the PCBs themselves. However, it is generally agreed that the acute toxicity of PCBs is low. On the other hand, chronic exposure to PCBs has been shown to cause liver damage and a skin condition referred to as chloracne. Adverse effects in wildlife have also been reported due to chronic exposure to PCBs. Among the dioxins and furans, 2,3,7,8-tetrachlorodibenzo-/>-dioxin (TCDD), commonly referred to as "dioxin" in die news, is the most toxic. TCDD has recently been classified as a human carcinogen. Analysis of dioxins is often reported in terms of toxic equivalents. TCDD is given the highest toxicity equivalency factor (TEF), with a value of 1. The concentration of each dioxin is multiplied by its corresponding TEF, and the products are summed, giving the total concentration of dioxins in toxic equivalents
one instrument at a cost of roughly $150 per sample," adds Sandra. The Belgian government sent thousands of samples out to be screened for PCBs, many of which ended up in the Research Institute for Chromatography, a private facility founded by Sandra in Kortrijk, Belgium. "There we have two GC lines, giving gs the capacity of 100 samples per day." Fast PCB screening was critical in this case. Sandra believes that his method for analyzing PCBs, which includes a special way of chemically treating silica gel, is faster than the official government method. He would not elaborate on the metfiod saying that he will valldate ii so that it can be official when thetimeis right but not durrng atimeof frisis On the basis of PCB data, the Belgian government traced the source of the contam-
gian voters, outraged over the government's slow response, forced the resignation of Prime Minister Jean-Luc Dehaene of the Christian Democrats on June 14, after giving the Conservatives the majority in parliament for the first time in over a century. Meanwhile the furious EC ordered
ination back to the fat company Verkest Fat produced by Verkest during January was contaminated with high levels of PCBs and dioxins, which are believed to have come from used transformer oil. The contaminated fat was added to chicken feed and sold to unknowing farmers. All in all an estimated 80 000 kg of fat was added to —1.5 million kg of animal feed affecting'an estimated 1500 farms
vent the contamination from spreading to neighboring countries However fearing that it was
Many are calling the tnn late much r»f the incident a scandal. Euro"Our chicken is dioxin free," reads the above sign displayed in front of a world bannprt the imnnrt pean Commission (EC) chicken vendor in Amsterdam during June. J: 4. r j infill/liner regulations require all tnpnt- nnnltrv Pfgs and dairy prodnrts member states to dispose of or decontamimixed PCB-laden oil with other fats, which frntn all FIT nations PotimatpH nate all PCBs and equipment containing later went on to feed the chickens. PCBs by 2010. Rather than disposing of the The crisis couldn't have come at a in the hundreds of millions of dollars. PCBs properly, which is quite expensive, worse time—just two weeks before BelBritt Erickson is an assistant editor of some speculate that employees of Verkest gium's national and regional elections. BelAnalytical Chemistry.
Dioxin in the U.S. food supply Contaminated feed is all too familiar to Tyson Foods and other chicken producers in the United States, who suffered huge losses in July 1997 when natural clay containing dioxin was added to soybean meal as an anti-caking agent. In contrast to the high levels seen in the recent Belgian crisis, dioxin levels found in U.S. chickens during the 1997 incident were extremely low (6 parts per trillion pptr). Still the U.S. Department of Agriculture (USDA) the U S Food and Drug Administration (FDA) and the chicken producers themselves took the situation extremely seriouslv "At the time, there were no legally established tolerance limits for dioxin in foods," recalls former Tyson Foods employee Bruce Cottingham, an analytical chemist now at Central Analytical Laboratories (Belle Chasse, LA). Although USDA and FDA believed that the dioxin levels were not high enough to pose an immediate public health hazard, they decided to take action as a precautionary measure
Employees at Tyson Foods worked around the clock to determine the source of the dioxin. "We worked with a contract laboratory to prioritize samples. They ran samples from some of our feed vendors, as well as from some of our competitors. This was an industry-wide problem," remembers Cottingham. Dioxin analysis is very tricky. Only a handful of laboratories in the United States actually have the capability, and even they typically can only run 10 samples per day because an extremely complex sample preparation is required. "At one point, the U.S. poultry industry basically had the dioxin [testing] capacity of the country tied up," says Cottingham. "Because there were no guidelines, we were totally in the dark. There had not even been collaborative studies on detection limits of various dioxins," says Cottingham. As it turned out, in a fat matrix such as chicken tissue, where dioxins preferentially accumulate, the detection limit for dioxins is on the order of 1 pptr. As a result, the USDA established the limit for dioxins in food at 1 pptr, despite criticism over the lack of epidemio-
logical work to support it. "The whole issue of dioxin contamination at the levels we saw in poultry [in 1997] would have gone totally unnoticed 10 years previously, because instruments could not have detected it," says Cottingham. "Even now, if you are not specifically looking for dioxin and don't have high-priced equipment, you are not going to find it." The United States reacted to the recent food crisis in Belgium by detaining all poultry, eggs, meat, and dairy products from EU nations at the U.S. border until they could be analyzed for PCBs. The USDA's Food Safety Inspection Service, in conjunction with FDA decided that products with 0.1 ppm total PCBs would be sent to an additional laboratory for dioxin analysis. The limit of detection for FDA's official PCB method {Pesticide Analytical Manual Volume I sections 303 and 304) is 0 1 DDm Eees and frame meats fall under FDA regulations whereas meat and DOUIrrv fall under USDA regulations
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