Hoogerbrugge R; Bakker MI; Hijman WC; Boer AC den; Hartog RS den; Baumann RA (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2004-10-19)
The exposure to dioxins (including polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls) occurs predominantly via the intake of food. The main contribution to the total intake originates from the consumption of animal fat. Nevertheless, vegetables were estimated to contribute 13 % to the total dietary intake, although the uncertainty in this figure was considered large (Freijer et al., 2001). In the present study, a detailed investigation into the concentrations of dioxins in vegetables and subsequently the intake via the consumption of vegetables is calculated. To that aim, eighteen different vegetables were bought in eight Dutch retail shops in two different seasons. The samples were pooled per season and analysed for dioxins. The summer vegetables could be measured very sensitively: the maximum levels (assuming that samples below the limit of detection -LOD- equal a concentration equal to the LOD) vary between 3 and 10 pg toxic equivalents (TEQ) per kg fresh weight (FW). The winter vegetables could be measured less sensitively; the LOD for each congener was approximately 10 pg TEQ/kg FW. The maximum levels (with the exception of curly kale) vary between 30 and 70 pg TEQ/kg FW. The average level in curly kale is estimated as 100-200 pg TEQ/ kg FW. Using the maximum levels, the average intake of dioxins, furans and dioxin-like PCBs by the consumption of vegetables is estimated as 0.12 pg TEQ/kg bodyweight/day. When a consistency of patterns between detected and non-detected levels is assumed, the most likely estimate is 0.014 pg TEQ/ kg bodyweight/day. The latter is less than 2 % of the mean daily intake from the total diet.
Mennen MG; Kwekkeboom JMI; Broekman MH; Brederode N van (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2004-09-10)
An investigation to assess health risks was commissioned by the Zaltbommel municipality and the Inspectorate of the Netherlands Ministry of Housing, Spatial Planning and the Environment in response to residents' concern about possible health effects due to emissions from the Van Voorden BV foundry in Zaltbommel. The emission of gaseous and particulate compounds from the foundry was measured, along with the concentrations and deposition of emitted compounds in the neighbourhood. The exposure of residents to compounds emitted from the foundry was quantified and compared to toxicological limits. Parallel to this, a survey was carried out among the residents, in which they were asked to keep a journal on annoyance and to complete a questionnaire on health, annoyance and well-being. Incidence rates were evaluated on the basis of cancer registration data. Measurement results showed that concentrations an deposition of foundry-related compounds were high relative to background levels; however, toxicological limits were not exceeded at all. Breast cancer incidence was significantly higher than expected, but no relation with environmental compounds could be established. No differences in self-reported health were reported, but results did show a high level of annoyance and anxiety combined with a low level of satisfaction concerning quality of life.
Raaij MTM van; Ossendorp BC (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2004-11-15)
In the project "Acute toxicity and risk assessment", one of the goals was to actively participate in activities that promote international harmonisation of the Acute Reference Dose (ARfD) concept. At the international level, the Joint Meeting of Pesticides Residues of the WHO and FAO develops international harmonised guidance for setting the ARfD in which RIVM/SIR contributes. A final EU guidance document is not yet released but the EU guidance will probably follow the WHO strategy in general. For acute food intake calculations, the introduction of probabilistic exposure tools is an important issue. International harmonisation as propmoted by VWS appears to be well developed now for pesticides but the following specific subjects will need further (policy) attention: 1) use of ARfD for both preventive risk assessment and inspection tasks, 2) use of ARfD in other chemical frameworks, 3) procedure for setting provisional national ARfD values for pesticides without an official European ARfD, 4) mixed sampling during inspection measurements (e.g. virtual cumulative exposure to various pesticides), and 5) (inter)national harmonisation of probabilistic exposure calculations.
Versantvoort CHM; Kamp E van de; Rompelberg CJM (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2004-04-13)
Food is considered a major source for exposure to many contaminants. Only the fraction of the contaminant that is released from the food (bioaccessible) and is bioavailable (concentration in blood, organ and tissues) can exert toxic effects. The oral bioavailability of compounds is dependent on the food product, food processing or food preparation. This hampers an accurate risk assessment of ingested toxic compounds in humans. This report documents the development of an in vitro digestion model allowing for measurement of the bioaccessibility of ingested contaminants from food as an indicator of oral bioavailability. The applicability of the in vitro digestion model was investigated in 4 food products containing the following contaminants: cadmium in lettuce and radish, aflatoxin B1 in peanuts and ochratoxin A in buckwheat. The bioaccessibility of contaminants from food and other ingested matrices could be determined reproducibly, was dependent on its matrix and could be affected by the experimental conditions applied in the in vitro digestion model, e.g. simulating fasted or fed conditions. Not all the contaminants were released from their matrices during digestion, indicating that internal exposure to the contaminant was lower than the external exposure. The results of the (pre)validation of the in vitro digestion model with adsorbents and bioaccessibility of aflatoxin B1 and ochratoxin A, show the in vitro digestion model as a possible powerful tool in predicting in vivo bioavailability of compounds.
Winter-Sorkina R de; Bakker MI; Baumann RA; Hoogerbrugge R; Zeilmaker MJ (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2004-01-09)
As part of a national survey on the occurrence of persistent organic contaminants in breast milk, a group of brominated flame retardants (polybrominated diphenyl ethers or PBDEs) was measured in breast milk which had been collected in 1998 from Dutch primiparous women on day 6 to 10 after labour. Together with data on milk intake, body weight and the duration of breast feeding these data were taken as a starting point for the calculation of the exposure to PBDEs via breast milk. The cumulative exposure was calculated for 10 PBDE congeners and for breast feeding periods of 8 days and 1, 2, 3, 4, 5, 6, 7.5 and 9 months. The mean, standard deviation, minimum, maximum, 5th and 95th percentile of these exposure doses were calculated. The mean cumulative exposure of the sum of the PBDEs was 2.9 mu g/kg bw (95th percentile 6.6 mu g/kg bw) for a breast feeding period of 6 months and 3.8 mu g/kg bw (95th percentile 8.6 mu g/kg bw) for a period of 9 months. BDE #47 contributed about 35 % to the total intake, while BDEs #153, #99, #183 en #100 contribute each. It appears that at 6 months the daily exposure of nursing infants to PBDEs via breast milk is about 6 times higher than the exposure of adults via food (the latter was calculated in an earlier study). In addition to the exposure to PBDEs, nursing infants are also expected to be exposed to the brominated flame retardant hexabromocyclododecane (HBCD). Consequently, measurements of HBCD in breast milk, followed by a risk assessment for nursing infants, is recommended.
Bakker MI (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2004-07-08)
The dietary intake of phytoestrogens supposedly influences a variety of diseases, both in terms of beneficial and adverse effects. This report describes current knowledge on dietary intakes of phytoestrogens in Western countries, and briefly summarizes the evidence for health effects. The predominant phytoestrogens in the Western diet are the isoflavones and the lignans. The consumer groups with the highest dietary intake of isoflavones are consumers taking dietary phytoestrogen containing supplements (+/- 40-100 mg/d), vegan consumers (+/- 75 mg/d), soy-based formula fed infants (+/- 40 mg/d) and consumers of a traditional South East Asian diet (+/- 25-100 mg/d). The dietary isoflavone intake of average Western (including Dutch) consumers and vegetarians is much lower (+/- <1-2 mg/d and +/- 3-12 mg/d, respectively). The intake of lignans is less well-studied and is estimated at 1.1 mg/d for the average Dutch consumer. However, this is likely an underestimation. Evaluation of the health implications of phytoestrogens is very complex, mainly because of insufficient data. There is concern about the use of soy-based infant formulae in view of the potential inhibition of the thyroid function. In addition, hypothyroid individuals and women with oestrogen-dependent breast disease are of potential concern. Although adverse health effects of isoflavones on the latter two subgroups have not been reported in the published literature, more research is needed that addresses the toxicological properties of soy or isoflavones for these groups specifically. To date, the effects of lignans on human health are still being investigated.
Oomen AG; Versantvoort CHM; Duits MR; Kamp E van de; Twillert K van (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2004-05-27)
Children can be orally exposed to compounds by chewing, sucking and ingestion of toy (parts). Only the fraction of contaminant that is released from the toy in the gastrointestinal tract can reach the blood stream (internal exposure) and can contribute to toxicity. Three physiologically based in vitro digestion models have been developed in the present project. These digestion models can be used to estimate the amount of contaminant that can be released from toy during sucking and/or ingestion. By using only this released fraction of the contaminant for exposure assessment, the risk assessment can be refined and risks will be less easily overestimated. The present report describes application of the in vitro digestion models to several cases. Firstly, the effect is studied of the amount of matrix on the release of lead from chalk and paint chips in the stomach and intestinal phase. Furthermore, the release of phthalate from PVC disks, and the release of azo dyes from textile into saliva simulant is investigated. In all cases, considerably less than 100% of the contaminant was released into digestive juice, indicating that children are probably exposed to only a fraction of the contaminant load during sucking and/or ingestion of the tested matrices. The results of phthalate were compared to results of a human volunteer study.
Oomen AG; Lijzen JPA (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2004-10-25)
The present report addresses the issues whether house dust is likely to contribute substantially to the exposure of humans, in particular for the contaminants lead and asbestos. House dust consists for 30-70% of soil material, indicating that contaminated soil can lead to contaminated house dust. It is concluded that exposure to lead via house dust should be included in risk assessment of soil contamination. The studies in which the amount of soil ingested by children are estimated use tracers in soil that are obviously both present in soil outdoors and in soil in house dust. Therefore, using this amount of soil ingested by children to cover both exposure of lead via soil outdoors and soil in house dust is reasonable. However, a correction factor of 2 is recommended to account for enrichment of lead in house dust in comparison with outdoor soil. This factor also accounts for other lead sources in house dust than contamination via soil. Significant contribution of asbestos to house dust from asbestos contaminated soil may occur at soil concentrations greater than 100 mg/kg. It is recommended to determine asbestos levels in house dust in houses adjacent to sites that are contaminated with asbestos above 1000 mg/kg for nonfriable asbestos, and above 100 mg/kg for friable asbestos. These recommendations are in agreement with a draft assessment protocol on site specific assessment of human risks to soil contamination with asbestos. A few comments on the protocol are made. For further recommendations for risk assessment of asbestos in house dust, we refer to this protocol.
Muller JJA; Bos PMJ (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2004-05-04)
The general public is protected from the effects of Carcinogenic, Mutagenic and Reprotoxic (CMR) substances partly by banning the sale of preparations containing classified CMR substances (Annex I of 67/548/EEC) at levels above the limit concentration for exposure of the general public. It is therefore important that consumer preparations are checked for the presence of these substances and that, in addition, potential CMR substances are assessed for inclusion in Annex I of 67/548/EEC. A search was made for potential CMR substances in electronically accessible databases, after which a list of 514 potential CMR substances not found in Annex 1 could be compiled. The occurrence of CMR category 1 and 2 substances, and of additional potential CMR substances, in consumer preparations was checked against the SPIN database, an initiative of the Nordic countries. A total of 146 Annex I substances for the CMR categories 1 and 2, and 24 potential CMR substances were found to be present in consumer preparations used in the Nordic countries. It cannot be ruled out that these substances will also be present in consumer preparations used in the Netherlands. A quantitative estimate of the potential exposure to CMR substances was not possible due to the lack of an adequate database of consumer preparations showing actual concentrations.
Waijers PMCM; Slob W; Ocke MC; Feskens EJM (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2004-07-08)
National food consumption surveys are conducted periodically in the Netherlands to gain insight into the food consumption of and nutrient supply to the Dutch population. Nutritional status has, to date, never been assessed systematically. This was the reason then for proposing a framework for assessing the actual micronutrient intake against the requirements. Folate was used as an example. The first step in the assessment procedure is to estimate the nutrient requirement and the requirement distribution. In the next step, the usual intake distribution of the nutrient needs to be estimated from the observed intakes by eliminating within-person variation. We compared two methods for this purpose: the Statistical Exposure Model (STEM) developed by Slob at the RIVM and the semi-parametric transformation approach (the Nusser method), developed by Nusser and co-workers. Each of these methods has its own underlying assumptions, and both have advantages and disadvantages. Finally, the distribution of intakes and requirements should be combined to estimate the prevalence of inadequate intakes. Two approaches used to achieve this are the EAR (Estimated Average Requirement) cut-point approach and the probability approach. We consider the probability approach the better method, because violation of assumptions underlying the EAR cut-point approach will result in unacceptably large deviations from the true prevalence estimate. For children, a more accurate estimate of nutrient adequacy may be obtained by expressing nutrient requirement as a function of age. This possibility needs to be explored further. The assessment of folate intake using data from the third Dutch National Food Consumption Survey (1997/98) revealed a highly inadequate folate intake for the whole population. The method proposed is also suitable for a quantitative assessment of the intake of other micronutrients by the population.
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