Emission measurements at 4 Dutch hospital waste incinerators show dioxin concentrations in the flue-gas from 70 to 460 ng I-TEQ/m3 (101,3 kPa, 273 degrees K, dry 11 % O2). The emission of dioxins from hospital waste incinerators is high compared with the emission of dioxins from Dutch municipal waste incinerators. Hospital waste was incinerated in the Netherlands by about 25 hospitals in august 1991. The quantity of hospital waste incinerated in the Netherlands by hospitals, for the situation till august 1991, was about 4275 tons/year. The emission of dioxins caused by the incineration of this waste was about 5 g I-TEQ/year. With reference to the results of the measurements 3 of the 4 measured hospital waste incinerators are closed now, the 4th installation was already closed before the results of the measurements became known. The quantity of hospital waste incinerated by hospitals is decreased to about 675 tons/year in june 1992. By closing these installation the emission of dioxins by hospital waste incinerators is decreased to 2 g I-TEQ/year in june 1992.

Automated monitors for the determination of airborne radioactivity are widely in use as 'early warning' systems for nuclear emergencies, but seldom applied in quantitative studies to the appearance of natural radioactivity (especially radon and short-lived decay-products). This report describes how a specific type of airborne gross-alpha/beta monitor (FAG FHT59S), which is used by the Dutch National Radioactivity Monitoring Network (NRM) for the surveillance of the inhalation pathway, can be applied for this purpose. The main focus is on the performance of the applied algorithm which recalculates actual air activity concentrations from primary measurements, especially for circumstances contradicting assumptions made by the manufacturer. Furthermore, a complete uncertainty analysis has been carried out. As a result, a formula has been derived which converts, within a reasonable degree of uncertainty, the monitor recordings to the equilibrium-equivalent decay-product concentration (EEDC) of Rn-222. NRM-data of Rn-222 (progeny) obtained in this way agree with results of previous radon surveys carried out in the Netherlands.

This report describes the results of the analysis of brominated and mixed halogenated (Br/Cl) dibenzo-p-dioxins and furans (DD/Fs) in the stack gas of an industrial process in which significant amounts of flame retardants are being used. Stack gas samples have been collected prior and following the after burner gas cleaning facility. PCDD/F levels, expressed in 2,3,7,8 TCDD toxic equivalents (TEQ), as analysed by TNO were 0.20 ng TEQ/m3 ind (before) and 0.05 ng TEQ/m3 ind (after), respectively. Using both negative chemical ionization (NCI) and electron impact (EI)-mass spectrometry, several brominated compounds were found and tentatively identified as bromobiphenyls (BrBs) and bromochloropolyaromatic hydrocarbons (Br/Cl-PAHs). In addition, some 28 monobromo-polychlorinated (Br/Cln, n=3-7) DD/Fs could be demonstrated in low concentrations in both samples. Determination of their isomeric structure failed due to low sample sizes. Estimation of their TEQ value was performed on the basis of the response ratio for monobroom-heptachloor DD/Fs (Br-Cl7-DD/F) and quantified polychloro analogues (Cl8D/F). Assuming a random distribution of the Bratom, and an estimated relative occurrence of Br to Cl of 1:1000 per substituent, the additional BrCln-DD/F TEQ value was estimated to be not greater than approximately 1% of the corresponding PSDD/F-TEQ value.

This report describes a collaborative study carried out by the Regional Laboratory of Amsterdam and the National Institute of Public Health and Environmental Protection (RIVM), to improve the method for isolating Yersinia spp, from stools of patients with complaints of gastro-enteritis. During a period of one year, the Regional Laboratory of Amsterdam examined 1007 faecal samples for the presence of Yersinia spp, using 6 different methods. Best results were obtained with enrichment in physiological saline with phosphate buffer 0.01 M, pH 7.2 (PBS) during 7 days at 4 degrees C followed by inoculation on and incubation of cefsulodin irgasan novobiocine agar (CIN) during 24 and 48 hours at 37 degrees C. This met gave an isolation percentage of 1.4%. However drawback of this method is the long incubation period. This makes the method unpractical for primary diagnostical use. Therefore improvement of the enrichment was investigated. Tests were carried out at the RIVM, to examine the possibility of increasing the growth rate of Yersinia spp. and decreasing the incubation time by adding glucose and peptone to PBS. Increase of the glucose concentration in PBS+peptone seemed to have little effect on the groth rate of Yersinia. Buffered peptonwater (BPW) was used as an alternative medium. Comparison of BPW with glucose and PBS with glucose showed that BPW was superior. Evaluation took place by examining 1014 faecal samples from patients with complaints of gastroenteritis by the Regional Laboratory of Amsterdam using 4 isolation methods including enrichment in PBS and BPW. Of these methods, enrichment in Rappaport according to Wauters (RVW) and enrichment in PBS gave the best results. The difference with former results using RVW by the Regional Laboratory of Amsterdam is caused by quality improvement due to introduction of a quality assurance system for the media. Apparently the exact composition and preparation of Rappaport-broth according to Wauters is very critical. It is recommended that direct inoculation on CIN should take place and when clinical advantage is expected, enrichment in RVW could take place. When the low isolation frequency and long incubation periods are regarded, it doesn't seem sensible to perform "cold" enrichment methods for routine investigation of faeces for the presence of Yersinia spp.

The antimutagenic activity of chlorophyllin and hematin was investigated with the Salmonella typhimurium strains TA98 and TA100 by means of the Amestest. Benzo(a)pyrene, the food pyrolysate 2-amino-1-methyl-6- phenylimidazo [4,5]pyridine or PhIP and 2- aminoanthracene were used as mutagens in most experiments. These agents exert mutagenic activity only in the presence of mamalian metabolic activation. In all experiments the mutagenic activity of the three chemicals could be abolished by the presence of 2 mg of chlorophyllin or 0,5 mg of hematin per selection plate. Considering the results of experiments in which chlorophyllin and hematin were added at several different times after the addition of the metabolic activation system it was concluded that the formed mutagenic metabolites were trapped and inactivated by these porfyrines. The antimutagenic activities of these porfyrines decreased when the porfyrine ring was destroyed as appeared from experiments with biliverdin and bilirubin. Due to its low solubility the antimutagenic activity of chlorophyll is not or nearly not demonstrable. The antimutagenic activity of chlorophyllin or hematin on substances that are mutagenic in the absence of metabolic activation such as MNNG, furazolidone, dimetridazole, epichlorohydrin and 2-chloroethanol is lower or absent.

A definition study for the development of a model describing the complete chain ; source -> exhalation -> dispersion -> exposure -> effect/risk for radon is performed. The purpose of a source-risk model is to support policy making on radon mitigation by comparing effects of various policy options and to enable optimisation of counter measures applied to different parts of the source-risk chain. There are several advantages developing and using a source-risk model. - Risk calculations are standardized. The calculations are done with most appropriate models available at a moment. Parameter values are used consistently in the entire source-risk chain. - The effects of measures applied to different parts of the source-risk chain can be better compared because interactions are included. - Sensitivity analyses can be used to determine the most important parameters within the total source-risk chain. After making up an inventory of processes and sources to be included in the source-risk chain, we investigated the models presently available in the Netherlands by interviewing several owners of models. The models were screened for completeness, validation and operational status. The investigation made clear that, by choosing for each part of the source-risk chain the most convenient model, a source-risk chain model for radon may be realised. However, the calculation of dose out of the radon concentrations and the status of the validation of most models should be improved. Calculations with the proposed source-risk model will give estimations with a large uncertainty at the moment. Still, realisation of the proposed source-risk model is recommended because the investigations made clear that the use of a source-risk model will have a surplus value over the use of single models. For further development of the source-risk model an interaction between the source-risk model and experimental research is recommended.<br>

A new method is introduced for judgement of water (liquid) quality: the drop-picture method. With this method the movement-quality of water (liquid) can be studied as a totality-parameter (for instance of importance for the vital chemical biological processes in living nature). Beside the common analytical judgement technics (chemical, physical and/or biological), this method has in view to come to a kind of total-judgement of water (liquid) quality following a less analytical, more synthetical approach (partly) with supplemental aspects. It can be used in addition to the conventional judgement of water quality. This method is practised on water out of different stages of the water-purification process at the Gemeentewaterleidingen Amsterdam (GWA). The results roughly agree with the GWA-impressions regarding some weak and strong links in the purification process, but have no general correlation with commonly used analytical parameters (there is an additional information-contents). In its current stage of development, this method already appears to be reliable and manageable in practice. Necessary refinements are mentioned (they are for instance ment to answer future questions such as, on the one hand, designing additional criteria for the selection of drinking-water out of various kinds of water already released from the hygienic point of view, and, on the other hand, finding indicators for morpho-diversity of life in and around water).

In this report a conceptual method is proposed with which the status of ecosystems in the Netherlands can be described. This method can be used for state of the (ecological) environment reporting. The following issues are discussed: policy needs, current ecological yardsticks, indicator selection, resolution, aggregation of information, presentation of results, ecological models and ecological monitoring programmes. On the basis of this information the conceptual method is proposed at a regional level using target species, ecosystem species and abiotic conditions of target species and target ecosystems. Needs to work out this conceptual method are discussed in terms of research and compared with current reserach programmes of the RIVM and the IKC-NBLF. Ommisions and cornerstones have been identified.

A chain model for dioxins is discussed relating dioxin levels in cow's milk to emissions. It was used to explain the elevated dioxin concentrations found in cow's milk at various MSW incinerators. It also served as an aid in the selection of locations for milk analyses in still unexplored areas. And, most important, it enabled the evaluation of executed or proposed measures, such as closure of incinerators, soil clean up, or emission reduction. The model showed that, after implementation of the new emission requirements after November 1993, Dutch cow's milk from the areas around MSW incinerators will hardly exceed background levels, except for some locations at Zaandam where levels of 3-4 pg TEQ/g milk fat will continue to occur, due to high concentrations in soil caused by emissions in the past. Thus, it could be concluded that milk from these areas will not exceed the Dutch milk standard of 6 pg TEQ/g milk fat in the near future.<br>

In all stages of the development of societies, the objective of health policy has been to promote health, as measured by an increase in life expectancy. Not until the past two decades has an awareness grown that resources to be invested in health are limited and that the increase in survival may mean an increase in years spent in health but also in years spent with disease as the additional effect of socio-economic development and medical technology. This appreciation has created a need for an integrated approach to determine the positive and negative effects of socio-economic and technological advances on the level of health and disease in population as a whole. The purpose of this report is to explore the usefulness of the sustainable development concept, as used in environmental modelling research, in the search for a more comprehensive health policy approach. The application of sustainable development concepts for a comprehensive approach to health policy is a worthwhile enterprise as one can account for the role of health determinants, the beneficial and negative effects of preventive and curative care, as well as the limits to the necessary resources for health and the overall effects of economic development. Two important issues in the development of the model are the framing of an integrated methodology to allow for the inclusion of various sets of determinants and disease-specific subsidiary-models as well as the collection of global and regional data for model validation.