Het RIVM heeft risicogrenzen bepaald voor PFOS in bodem en grondwater. De risicogrenzen houden rekening met twee routes: directe effecten van PFOS op planten en dieren in de bodem, en effecten op vogels en zoogdieren die PFOS via hun voedsel binnenkrijgen. Het bevoegd gezag gebruikt de risicogrenzen om te beslissen of hergebruik van grond veilig is voor het milieu. PFOS en andere poly- en perfluoralkylstoffen (PFAS) zijn door de mens gemaakte stoffen die heel langzaam afbreken, ophopen in het lichaam en giftig zijn. Het gebruik van PFOS is wereldwijd zeer sterk aan banden gelegd. Maar doordat de stof bijna niet afbreekt, zitten er nog steeds resten in het milieu. PFOS hoopt zich op in planten en dieren. Daarom is het relevant om te kijken naar de risico's voor vogels en zoogdieren die PFOS binnenkrijgen via het eten van bodemdieren, zoals regenwormen. Dit heet doorvergiftiging. Per route zijn twee risiconiveaus bepaald: het Ernstig Risiconiveau (ER) en het Maximaal Toelaatbaar Risiconiveau (MTR). Het MTR is de concentratie waarbij geen nadelige effecten zijn te verwachten. Het MTR voor doorvergiftiging is 3 microgram per kilogram droge grond. Het ER (106 microgram per kilogram) is de concentratie waarbij PFOS ernstige effecten kan hebben op vogels en zoogdieren. Het RIVM heeft in 2011 ook ecotoxicologische risicogrenzen afgeleid voor PFOS in bodem en grondwater, toen op basis van beperkt beschikbare informatie. De risicogrenzen zijn nu beter onderbouwd. Het nieuwe MTR voor doorvergiftiging is hetzelfde als in 2011, het ER voor doorvergiftiging is nu voor het eerst bepaald. Dit onderzoek is onderdeel van een serie rapportages over risicogrenzen van PFAS. Hiermee draagt het RIVM bij aan een landelijk kader waarmee bevoegde gezagen kunnen bepalen hoe zij omgaan met PFAS-houdende grond en baggerspecie. Dit onderzoek is uitgevoerd in opdracht van het ministerie van Infrastructuur en Waterstaat (IenW).

This is a revised version of letter report 2020-0126 Every year, ProRail replaces 200,000 railway sleepers. In the last century, wooden sleepers were used treated with creosotes to preserve them. Creosotes contain substances of very high concern. More recently, sleepers have been made from concrete, but greater quantities of CO2 are released in the manufacture of these sleepers than from wooden sleepers. To minimize CO2 emissions and the use of substances of concern, ProRail is looking for alternative railway sleepers. To this end, RIVM has compared six different types of sleepers with cement concrete (100 percent Portland cement). The six sleeper types are made from copper-treated wood, untreated wood, recycled steel-reinforced plastic (PE), virgin steel-reinforced plastic (PE), glass-fiber-reinforced plastic (virgin PU) and Sulphur-based concrete (instead of cement-based concrete). The comparison of the various sleepers was based on the aspects that are important for sustainability and safety of substances for the environment. The sleepers made from recycled plastic and Sulphur-concrete are more sustainable than sleepers from concrete (Portland cement). The other types of sleepers are only favorable over concrete in certain aspects of sustainability. Based on the data available, the various types appear to be equally safe for the environment. Part of the sustainability assessment of the sleepers is done by looking at the extent to which they release greenhouse gases and how much land is needed to extract the materials to make them. The land used to produce wooden sleepers is greater than for the other sleeper types. This is important due to the effect on biodiversity, even though less greenhouse gases are released during production compared to concrete. The safety of the sleepers was analyzed by looking at the presence of pollutants and the degree to which these pollutants leach out. After all, any substance released during the use of the sleepers can end up in the soil and groundwater. There is legislation for all types of sleepers, the objective of which is to ensure that they are safe to use. For this study not all relevant data were available. Knowledge of the presence of any hazardous substances in sleepers is important if they are to be safely reused.

Pre-exposure prophylaxis (PrEP) users are routinely tested four times a year (3 monthly) for asymptomatic Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections on three anatomical locations. Given the high costs of this testing to the PrEP programme, we assessed the impact of 3 monthly screening(current practice), compared with 6 monthly on the disease burden. We quantified the difference in impact of these two testing frequencies on the prevalence of CT and NG among all men who have sex with men (MSM) who are at risk of an STI, and explored the cost-effectiveness of 3-monthly screening compared with a baseline scenario of 6-monthly screening.

Clear inter-individual differences exist in the response to C. trachomatis (CT) infections and reproductive tract complications in women. Host genetic variation like single nucleotide polymorphisms (SNPs) have been associated with differences in response to CT infection, and SNPs might be used as a genetic component in a tubal-pathology predicting algorithm. Our aim was to confirm the role of four genes by investigating proven associated SNPs in the susceptibility and severity of a CT infection. A total of 1201 women from five cohorts were genotyped and analyzed for TLR2 + 2477 G > A, NOD1 + 32656 T -> GG, CXCR5 + 10950 T > C, and IL10 - 1082 A > G. Results confirmed that NOD1 + 32656 T ->GG was associated with an increased risk of a symptomatic CT infection (OR: 1.9, 95%CI: 1.1-3.4, p = 0.02), but we did not observe an association with late complications. IL10 - 1082 A > G appeared to increase the risk of late complications (i.e., ectopic pregnancy/tubal factor infertility) following a CT infection (OR = 2.8, 95%CI: 1.1-7.1, p = 0.02). Other associations were not found. Confirmatory studies are important, and large cohorts are warranted to further investigate SNPs' role in the susceptibility and severity of a CT infection.

Recently, we reported an in vitro toxicogenomics comparison approach to categorize chemical substances according to similarities in their proposed toxicological modes of action. Use of such an approach for regulatory purposes requires, among others, insight into the extent of biological concordance between in vitro and in vivo findings. To that end, we applied the comparison approach to transcriptomics data from the Open TG-GATEs database for 137 substances with diverging modes of action and evaluated the outcomes obtained for rat primary hepatocytes and for rat liver. The results showed that a relatively small number of matches observed in vitro were also observed in vivo, whereas quite a large number of matches between substances were found to be relevant solely in vivo or in vitro. The latter could not be explained by physicochemical properties, leading to insufficient bioavailability or poor water solubility. Nevertheless, pathway analyses indicated that for relevant matches the mechanisms perturbed in vitro are consistent with those perturbed in vivo. These findings support the utility of the comparison approach as tool in mechanism-based risk assessment.

We used the validated 57-item QUOTEprenatal questionnaire, to measure clients' counseling preferences and experiences before and after counseling in 20 obstetric organizations throughout the Netherlands. Clients' preferences and experiences were compared between pregnant women and partners, nulliparous versus multiparous clients and between results of a Dutch survey in 2011 and the current one.