Belgian Dioxin ProMED Digest v99n155

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DIOXIN IN MEAT, POULTRY & EGGS - BELGIUM (06) ********************************************
A ProMED-mail post

[see also:
Dioxin, chicken & eggs contaminated - Belgium (04) 990610224844 Dioxin contamination, pigs - Belgium 990604100400 Dioxin in meat, poultry & eggs - Belgium (05) 990609225447 Dioxin poultry ban lifted - Belgium (02) 990613231838]

Date: Wed, 30 Jun 1999 11:23:31 +0200
From: Debora MacKenzie


One month after a crisis broke out over dioxin contamination in Belgian food and livestock feed, it is still not known exactly what toxins were present, how much was there, how much food was contaminated, and where it went. A government has fallen over the issue, but little science is being done, and government regulators in countries that have banned Belgian food imports are wondering if and when they can lift the bans. This is an update on the event. I am writing in a personal capacity. My views do not necessarily express those of the publications for which I work.

To recap what we know: about 8 litres of used PCB, probably from a transformer, ended up in an 80 tonne batch of recycled fats subsequently used to make animal feed, mainly for chickens, in mid- January 1999. It was sold as recycled animal fat, but contained vegetable oil too. There has been talk of motor oil but that is probably a confusion. 

One theory of how this happened involves public recycling depots for used frying fat, which also have containers for used motor oil. 
PCBs shouldn't have been in either. But it is possible that someone heading for the motor oil bin trying to quietly dispose of transformer oil instead dumped it in the used food oil. Other theories are that the PCBs were dumped deliberately or accidentally by a waste dealer; or that a heat transfer pipe using PCBs as the circulating fluid leaked, as in the Yusho incident in Japan [1968] and the Yu Cheng incident in Taiwan.

Belgium is currently investigating several recycling companies other than their initial suspects. In February 1999 chicken farmers noticed that some laying hens were sick and dead, some chicks were failing to hatch, and some that did hatch had "neurological symptoms", probably impaired movement. One of the PCDFs in the mix was one for which the toxicity in birds is very high, as per the re-evaluation of relative congener toxicity done in 1998 by Martin Van den Berg et al, Env Health Perspectives, v106 pp 775-790, Dec 1998. 

It is possible that we would never have found out about this incident were that not the case. If the fat had been fed to cows, there would probably have been no symptoms, and in any EU country but Germany, which actively monitors milk for dioxins, the event might not have been detected for months.

The Belgian farmers went to their feed companies, the feed companies called their insurance people, they called in a veterinary inspector, and he looked for everything, mainly nutrient deficiencies. Then in April 1999 he wondered if it might be dioxins -- a lucky stroke of insight as dioxins are usually suspected only in grazing animals exposed to incinerator deposits. He sent a sample of feed, and a dead laying hen, to RIKILT-DLO, the Dutch national lab for food quality in Wageningen, the Netherlands, choosing them partly because VITO in Mol, the only lab in Belgium accredited for dioxin analysis, specialises in milk. RIKILT's web site is <http://www.rikilt.dlo.nl>

Toxicity for mixtures of dioxins and dioxin-like compounds, is expressed as toxic equivalency, or TEQ, a figure arrived at by multiplying the concentration of each congener present by its known relative toxicity. RIKILT found 958 TEQ pg/g fat PCDDs and PCDFs (mostly the latter) in the chicken, and 781 ng TEQ per g of feed. The pattern of congeners resembled the Yusho incident in 1968 in Japan, especially the PCDFs, so RIKILT concluded that the origin was PCB contamination, and calculated the ratio of PCB to fat on this basis. PCBs have now been confirmed by direct measurement. These are the only numbers available for feed contamination, apart from the PCBs noted below.

The feed companies told the government in late April 1999. It asked for another analysis. RIKILT tested 2 eggs, intended for hatching, and a laying hen. The eggs tested at 713 and 266 pg/g fat TEQ, the chicken 741 pg/g fat TEQ. Another 10 chicks were also tested and were contaminated -- levels have not been released. 
They were probably collected in April 1999, but the scientists who tested them aren't sure.

On 26 May 1999 Belgium informed its neighbours and the European Commission as required by law. The Commission is launching court action over the delay.

Belgium pulled chickens and eggs off the market, then products made with eggs. Then they found cows and pigs had got the feed so they pulled beef and pork, and stopped exporting milk on order of the Commission though it was still sold in Belgium. They took Belgian butter off the market, though some report finding it in supermarkets. Indeed much depended on the cooperation of retailers -- I saw egg waffles on snack shelves in small shops which certainly were not removed during the crisis. Bins were set up for people to dump banned food, but many people did not use them, and at least some of what was dumped was spirited away.

The government tried to determine what feed companies bought the fat, what farms bought their feed, and what farms didn't and could therefore be exonerated so as to get food back on the market. This was in the middle of a federal election campaign. The government defeat on 13 June 1999 was widely attributed to anger over the delay in informing the public about the dioxin contamination.

The numbers cited above are the only measurements of dioxins in chickens from the period of probable maximum contamination of which I or anyone I have talked to is aware. Analyses now being done intensively at laboratories throughout Belgium and the region are aimed at making sure food available now is clean. RIKILT has found no evidence of contamination in any recent Dutch or Belgian food. No other data has been released.

As PCBs cost less to analyse than dioxins, and this can be done by many laboratories in Belgium, the Belgian government has commissioned extensive PCB analyses on recent food. It is not being analysed quantitatively for total PCBs, but for a standard set of seven congeners being used as a marker for this incident. We don't know how much toxicity in food contaminated by the incident can be attributed to PCBs as no one has yet done a full congener analysis -- and the 7 standard congeners are not the co-planar dioxin-like types for which we have toxic equivalency factors from which TEQ is calculated.

Without sampling and testing of food from February and March 1999, we will never know how contaminated the food was, how much and what kinds of food were contaminated, or where it was distributed. Apparently one Belgian institute has plans to try and collect such samples, but it is only starting now.

The only other measurement of contamination I have been able to acquire is from a private Belgian laboratory, which found 332 - 519 micrograms PCBs (7 congeners) per gram fat in feed. The ratio between this and known dioxin values gram for gram in the RIKILT measurements is about right, I am told. It is not clear from the records that have been obtained when this feed was sampled.

The European Commission's scientific committee on food in an opinion dated 16 June 1999 said dioxin-like PCBs accounted for 80 per cent of the TEQ in food contaminated by the Belgian incident. This means that the 900 pg/g TEQs for dioxins that may have existed in eggs during the period of probable peak contamination is only a fifth of the total toxicity. But the committee based that rough estimate on known ratios of the seven congeners analysed to other congeners in Aroclors 1245 and 1260, thought to resemble the original contaminant mixture, making this a very rough estimate. Their report at 
http://www.europe.eu.int/comm/dg24/health/sc/scf/index_en.html is largely concerned with whether to let Belgian milk back onto the EU market.

The 80 tonnes of fat thought to be behind all this was enough to make 1600 tonnes, or 10 million chicken-days, of feed. It is not clear whether the authorities have been attempting to account for all 80 tonnes of the fat in the records of the feed companies, or all 1600 tonnes of feed that could have been made from it. Sales records are not enough to trace the contamination, because of a widespread practice of making sales without paperwork.

Is this incident over? Everyone I have talked to says this was a one- off, that one 80 tonne contaminated batch of fats was the problem, and it has probably been eaten. Probably the contamination has already gone through the food chain insofar as it affected chickens, which have a fast turnover rate.

But some of the contamination fed to cows and hogs may still be there and may not have gone through humans yet. No data have been released as to whether there have been any elevated levels of PCBs or dioxins found in meat, apart from general statements that meat produced recently is clean.

There have been no elevated levels in recent milk, beyond Europe's usual background, which could be due to batch dilution.

Meanwhile Austria, moved to do some analyses by this incident, found dioxin in some domestically produced pig feed. Levels were much lower than in Belgium, and the feed has been impounded. 
Details are at
http://www.bmlf.gv.at/presse/fpresse.htm, in German. 
Dioxins are given as 2 - 6 pg TEQ per g of feed, much less than the few values reported for Belgium. I do not know if the Austrians have done any pork analyses.

The Europeans' dioxin plight is not unique. An article to appear in the journal Environmental Research in October will report among the first published measurements of the levels of dioxins in chickens during a dioxin-in-feed incident in the southern US 2 years ago. Levels were a tenth those in Belgium, but the contamination appears to have lasted for years, and was only picked up because of a one-off survey of dioxins in food undertaken by EPA and USDA. Some details may be found in New Scientist, 26 June 1999, on the web at
http://www.newscientist.com/ns/19990626/focus.html

There are plans for health surveys in Belgium to follow up this incident, but these will be of little use without data on the extent and nature of the contamination. A breast milk survey might be informative, but there would be 'noise' problems -- levels in western Europe are already high -- and unless the high levels of some PCDFs can be taken as a signature, it would be impossible to say whether any observed increases in dioxins or PCBs were caused by this incident. This is especially true as this is not the first time Europe has been affected by dioxins in feed. Dioxin-laced citrus pulp was discovered in 1997 to be affecting milk cattle. As in the US episode concentrations were lower than the few we know about from Belgium, but affected a larger area for a longer time. 
Some details of this are in the New Scientist article cited above.

- ---
Debora MacKenzie,
Europe correspondent,
New Scientist.
d.mackenzie@chello.be
...............................tg/jw

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End of ProMED Digest V99 #155
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