Human exposure to dioxins and furans and the contribution of municipal waste incinerators to the contamination of the environment in the Netherlands

Met literatuurgegevens kan de humane belasting met dioxinen en furanen in Nederland geschat worden op 12 pg 2,3,7,8-TCDD en op 116 pg 2,3,7,8-TCDD equivalenten (TEQ) per persoon per dag. Dat is 50% van de Tolerable Daily Intake (TDI) van 4 pg 2,3,7,8-TCDD per kg lichaamsgewicht. 98% van deze belasting blijkt via de voeding plaats te vinden, terwijl de overige 2% van inhalatie, dermale bloostelling en ingestie van dioxinen en furanen uit lucht of uit gecontamineerde bodem komt. De bijdrage aan dioxinen en furanen uit vliegstof van afvalverbrandingsinstallaties in Nederland kan geschat worden op 4-5% voor plantaardige produkten en 10-30% voor melk, vlees en eieren. Lokaal kan deze belasting met dioxinen en furanen ten gevolge van vliegstof via gecontamineerde groenten en melk resulteren in een geschatte maximale extra opname van 240 pg TEQ per persoon per dag. In deze gevallen bedraagt de totale belasting 5.5 pg TEQ per kg lichaamsgewicht per dag, waarmee de TDI circa 1.4 maal overschreden worden.Abstract not availableDGM/A DGM/

[Chicken-embryo test. Fase II. Determination of the relative toxicity of eleven 2,3,7,8-chlorosubstituted dioxines and furanes, and three planary OCB's.]

Abstract niet beschikbaarIn order to evaluate the risk of samples contaminated with mixtures polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and planar biphenyls a chicken embryo bioassay is in development at our Institute. In this bioassay the toxic potency of these compounds is determined by means of the ethoxyresorufin-deethylation (EROD) activity in the microsomal fraction of the chicken embryo liver. The experiments showed a large variation between the basal EROD activities, and the maximal induced EROD activities. The slope for most dose curves was similar. The relative toxicity factors in the chick embryo test determined, were compared to the international (i)-TEFs. The EROD induction by the tetra- and penta-dioxins and -furans showed higher TEF in the chicken embryo compared to the (i)-TEF, and the hexa- and heptachlorinated congeners are undervalued in the chicken embryo assay. Then the chicken embryo assay was used to evaluate the additive aspect of the TEF principle. The results showed that additivity of the congeners was responsible for the EROD induction at a low dose.HIGB VVP VHI;DGM/SVS RIV

Toxicity of a flue ash for fuinea pigs and rats and the bioretention of 2,3,7,8-chlorine substituted dioxins and furans from a flue ash and a flue ash extract in rat liver

In dierexperimenteel onderzoek met cavia's en ratten werd de toxiciteit van een vliegstof bepaald. Doseringen van 2.5, 5 en 10% vliegstof in het voer bij de cavia en de rat resulteerde na 14 dagen in dosis-gerelateerde verminderde groei, afname van lever- en thymusgewicht, inductie van microsomale leverenzymen en bioretentie van 2,3,7,8-TCDD in de lever. Hogere doseringen bij ratten resulteerde in sterfte en macroscopische veranderingen in de maag. Er werd geconcludeerd, dat bij lagere doseringen de zeventien 2,3,7,8-chloor-gesubstitueerde dioxinen en furanen in vliegstof voor de effecten verantwoordelijk zijn, terwijl bij hogere doseringen vliegstof effecten van metalen manifest worden. Biobeschikbaarheidsonderzoek met het vliegstof en een extract van vliegstof bij ratten toonde sterke selectieve bioretentie van de zeventien 2,3,7,8-chloor-gesubstitueerde congeneren in de lever. Er werd geconcludeerd, dat de retentie van deze zeventien congeneren niet afhankelijk was van de samenstelling van het mengsel en ook niet van de concentratie van het congeneer in dat mengsel, maar wel van de matrix van het vliegstof.Abstract not availableDGM/A DGM/

[Exposure of mature Turks in the Netherlands to dioxine and related connections by diet.]

Abstract niet beschikbaarIt is known, that emissions from incinerators can cause elevated levels of dioxins and related compounds in cow's milk fat and beef. Later on it was shown that a local contamination of mutton from these sources was also likely to occur. As the consumption of mutton by the general Dutch population is negligible, that finding did not cause any problem. On the other hand, one can predict a potential problem for a population with a significant intake of mutton, such as Dutch inhabitants from foreign origin. Therefore a food consumption survey with adult Turkish men and women was carried out by the Agricultural University Wageningen. At the same time the concentration of (i)-TEQ in mutton near incinerators and from background area was determined by the National Institute of Public Health and Environmental Protection in Bilthoven. The original data from the food consumption survey were used to calculate the intake of (i)-TEQ and (pcb)-TEQ by the Dutch Turks, applying concentrations of dioxins and furans, and planar PCB's from the previous study with the general Dutch population. So a series of individual intake figures was established from which the median intake and its 95 percentile of the adult Turks was computed. The results showed a daily intake of 2,3,7,8-chloride substituted dioxins and furans of 84 pg (i)-TEQ (95%: 171), equivalent with 1.13 pg (i)-TEQ/kg .day (95%: 2.32). For planar PCB's the corresponding figures are 110 pg (pcb)-TEQ (95%: 221), equivalent with 1.48 pg (pcb)-TEQ/kg.day (95%: 2.99). It was concluded, that these figures are simular with the results from the previous study with the general Dutch population, and that there was no exceeding of the Dutch Tolerable Daily Intake (TDI) of 10 pg TEQ/kg.day for the Dutch Turks. The study showed however that butter, sheep and beef, and in a lesser degree cheese from cow's milk fat contributed most to the total intake, as for the general Dutch population milk products and cheese, and food items with various fats from food industry were most significant. A scenario analysis showed an exceeding of the TDI of 1% of the adult Dutch Turks, if mutton was contaminated with 13 pg TEQ/g. fat and 5% for mutton with 18 pg TEQ/g.fat. Levels up to 20 pg (i)-TEQ/g.fat are determined, and as incinerators do also emit planar PCB's the total dioxins and related compounds in mutton can be higher then 20 pg TEQ. So, local contamination of mutton could have unacceptable consequences for the Dutch Turks. As a result of the local contamination of cow's milk fat near incineration processes, measures to reduce emission of (i)-TEQ are forced by law. These measures will reduce the concentrations of dioxins and related compounds in mutton at the same time, thus controlling major sources of exposure for the general polulation will also be effective for the exposure by dutch Turks.WVC (HIGB) VROM LNV Interdepartementale Coord. Comm. Dioxin

Dioxins and PCB's in foodstuffs. Results from supplementary research

Betreft de resultaten van een onderzoek in het kader van project Dioxinen en PCB's in Voeding in de periode 1991-1995. De verschillende studies zijn uitgevoerd om onzekerheden met betrekking tot de meetgegevens die in 1991 zijn gebruikt voor berekening van de inname van dioxinen en planaire PCB's door de Nederlandse bevolking, nader te onderzoeken. De resultaten worden weergegeven van onderzoek naar de gehalten van de zeventien 2,3,7,8-chloorgesubstitueerde dibenzo-p-dioxinen (PCDD's) en dibenzofuranen (PCDF's) en drie non-ortho 3,3',4,4'-chloorgesubstitueerde (planaire) PCB's in voedingsprodukten die bij de berekening van de innamen in 1991 nog niet waren meegenomen (wild, graan, groenten en fruit) en aanvullend onderzoek naar de gehalten in consumptiemelk, visolien en schapevet. Het aanvullend onderzoek naar gehalten dioxine en verwante verbindingen is vervolgens gebruikt om een her-evaluatie uit te voeren van de resultaten van het onderzoek naar de blootstelling van de Nederlandse bevolking aan TEQ, zoals gerapporteerd in 1991. Door aanpassing van de concentraties op basis van het aanvullend onderzoek, in combinatie met de oorspronkelijke consumptiegegevens bleek, dat de mediane dagelijkse blootstelling via de voeding 14% lager is, dan volgens de berekening uit 1991. Dit wordt voornamelijk veroorzaakt door de aanpassing van het gehalte TEQ in industriele olien en vetten, wat voortvloeit uit de resultaten van het onderzoek aan visolie.Results are presented of supplementary studies performed in the framework of project Dioxins and PCBs in Foodstuffs in the period 1991-1995. The various studies have been carried out to investigate uncertainties in the measurement data used in calculations of the intake of dioxins and planar PCBs by the general population of the Netherlands by the consumption of food. Results are presented from measurements of the levels of the seventeen 2,3,7,8-chlorine substituted dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and three non-ortho substitued (planar) PCBs in foodstuffs that were not included in the calculation of the intakes in 1991 (game, cereals, vegetables and fruits). In addition, results are included from supplementary studies on levels of these compounds in consumer's milk, fish oils and mutton. Results from these studies have subsequently been used to re-evaluate the results of the study on the intake of 2,3,7,8-TCDD equivalents (TEQs) by the general population, as reported in 1991. The supplementary studies resulted in some changes in nation-wide representative concentrations in Dutch foodstuffs. By combining this information with the original consumption data, the median daily exposure to TEQs appeared to be 14% lower than according to the calculations from 1991. This is primarily caused by the change of the concentrations of TEQs in the food group of industrial oils and fats, which resulted from the study on fish oils.HIGBVWS/VV

De WHO-consultatie inzake Toxiciteits Equivalentie Factoren voor Dioxinen: een commentaar

De WHO-consultatie inzake Toxiciteits Equivalentie Factoren voor nioxine-achtige PCB's heeft geresulteerd in het vaststellen van interim TEF's voor, in totaal, 13 congeneren. Daarmee is de consultatie aanzienlijk successvoller geweest dan van te voren werd gepland en verwacht. Dit rapport gaat nader in op enkele problemen die gedurende de consultatie naar voren kwamen. Met name de beschikbaarheid van geschikte experimentele gegevens, de selectie van de relevante dioxine-achtige PCB-congeneren maar ook van eventuele andere stoffen, de wijze waarop de TEF's tot stand zijn gekomen en de analytisch-chemische consequenties van de nieuwe TEF's worden belicht.The recent WHO consultation on Toxic Equivalency Factors for PCBs has resulted in the establishment of interim TEF values for 13 congeners. By achieving this the meeting has exceeded prior objectives and expectations. The present report adresses some of the problems encountered in the process of deriving the TEFs. Specifically, the availability of appropriate experimental data, the selection of dioxin-like PCBs and possible other chemicals, the derivation process itself and analytical implications of the new TEFs are dealt with.HIG

[Chicken-embryo test. Phase III. Availability of 2,3,7,8-TCDD in the chicken embryo.]

Abstract niet beschikbaarAt the Institute are chicken embryos used to develop an experimental bioassay to investigate the Toxicological Equivalency factors (TEF) of individual dioxins and furans, and mixtures of congeners using the TEF principle. The bioassay should be used to determine the toxic potency of a mixture with dioxin related compounds, within the objective of future risk assessment of these compounds for the public health. In this study, the concentration 2,3,7,8-TCDD within the egg had to be determined after a single injection of 101 ng 2,3,7,8-TCDD, or 505 ng 2,3,7,8-TCDD per egg. That was achieved by analyzing the various samples, using gas chromatography, with an ECD (Electron Capture Detector). The clean up of these samples was done by a extraction of total fat with toluene, and a additional purification with active carbon (Carbosphere) and alumina. The recovery of the seventeen 2,3,7,8-chlorine substituted dioxins and furans was in a range of 60 to 120% with a mean value of 79%. The total amount of 2,3,7,8-TCDD, that was regained from the egg, 48 hours after exposure, was in a range of 17 to 123% of the total dose injected. That revovery appeared to be dose related. It was concluded, that the manual method of exposure by a single injection is not very accurate, and needs improvement. The retention of 2,3,7,8-TCDD in the chicken embryo's liver was not dose related, nor affected by a injection in the air sac or egg fluid. It was between 4 and 8% of the retrieved quantity. Furthermore, the analysis showed a retention in the yolk, of 75% of the retrieved quantity. So, it can be seen, that the major amount of (lipophilic) chemical is absorbed by the yolk, that containsa rather high concentration of fat. That has its consequences for the lowest external dose possible, that will cause a detectable EROD induction, that is used as the marker for the toxic potency of the dioxin related compounds in this test system. The high absorption will may be aslo cause problems for the interpretation of the results of the chicken embryo assay for risk assessment in reference to the public health.HIGB VVP VHI DGM/SVS RIV

[Chicken-embryo test. Phase I. Development of methods to investigate the TEF of dioxines and furans.]

Abstract niet beschikbaarChicken embryos were used to develop an experimental bioassay to investigate the Toxicological Equivalency Factors (TEF) of dioxines and furans, and mixtures using the TEF principle for risk assessment of dioxins related compunds in reference to the public health. The animals were exposed to the chemicals by a single injection in the air sac of the egg. After incubation, liver microsomes were isolated from the chicken-embryo, in which activity of ethoxyresorufine-o-dealkylase (EROD), and the amount of cytochrome P-450 and protein were determined. The objective of the first phase, reported here, was to optimize the amount of vehicle, the method of isolation, the time of injection and the duration of incubation and exposure. The best suitable vehicle appeared to be 25 mul dioxane, mixed with 25 mul of an isotonic salt solution per egg. Isolation of microsomes by ultracentrifugation turned out to be the mostly effective isolated method, compared to gelfiltration. Injection at the 17th day of incubation and an exposure time of 24 hours, prior to dissection, resulted in the highest EROD induction. The ED50 for EROD induction by 2, 3, 7, 8- tetrachlorodibenzodioxin determined was 10.8 ng/egg. In a second experiment the result was 9.2 ng/egg. For 2,3,4,7,8-pentachlorodibenzofuran the ED50 was assigned to 8.7 ng/egg.HIGB VVP VHI DGM/SVS RIV

Dioxinen en PCB's in voeding. Resultaten van aanvullend onderzoek

Betreft de resultaten van een onderzoek in het kader van project Dioxinen en PCB's in Voeding in de periode 1991-1995. De verschillende studies zijn uitgevoerd om onzekerheden met betrekking tot de meetgegevens die in 1991 zijn gebruikt voor berekening van de inname van dioxinen en planaire PCB's door de Nederlandse bevolking, nader te onderzoeken. De resultaten worden weergegeven van onderzoek naar de gehalten van de zeventien 2,3,7,8-chloorgesubstitueerde dibenzo-p-dioxinen (PCDD's) en dibenzofuranen (PCDF's) en drie non-ortho 3,3',4,4'-chloorgesubstitueerde (planaire) PCB's in voedingsprodukten die bij de berekening van de innamen in 1991 nog niet waren meegenomen (wild, graan, groenten en fruit) en aanvullend onderzoek naar de gehalten in consumptiemelk, visolien en schapevet. Het aanvullend onderzoek naar gehalten dioxine en verwante verbindingen is vervolgens gebruikt om een her-evaluatie uit te voeren van de resultaten van het onderzoek naar de blootstelling van de Nederlandse bevolking aan TEQ, zoals gerapporteerd in 1991. Door aanpassing van de concentraties op basis van het aanvullend onderzoek, in combinatie met de oorspronkelijke consumptiegegevens bleek, dat de mediane dagelijkse blootstelling via de voeding 14% lager is, dan volgens de berekening uit 1991. Dit wordt voornamelijk veroorzaakt door de aanpassing van het gehalte TEQ in industriele olien en vetten, wat voortvloeit uit de resultaten van het onderzoek aan visolie.<br