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Inorganic arsenic (iAs) and total arsenic (tAs) were determined in common food from the Swedish market. Special focus was on rice, fish and shellfish products. For the speciation of iAs the European standard EN:16802 based on anion exchange chromatography coupled to ICP-MS was used. The two market basket food groups cereals (including rice), and sweets and condiments (a mixed group of sugar, sweets, tomato ketchup and dressings), contained the highest iAs levels (means 9 and 7 μg iAs/kg), whereas other food groups, including fish, did not exceed 2 μg iAs/kg. Varying levels of iAs were found in separate samples of tomato ketchup, 2.4-26 μg/kg, and is suggested to be one reason of the rather high average level of iAs in the food group sweets and condiments. Some specific food products revealed iAs levels much higher, i.e. rice crackers 152 and Norway lobster 89 μg iAs/kg. The intake of iAs via food was estimated by data from two national consumption surveys, performed in 2010-11 (1797 adults) and 2003 (2259 children). The estimated median iAs intakes in adults and children were 0.047 and 0.095 μg/kg body weight and day, respectively. The iAs intake for rice eaters was about 1.4 times higher than for non-rice eaters. Validation of the consumption survey-based iAs intake, using food purchase and market basket data mainly from 2015, resulted in a per capita intake of a similar magnitude, i.e. 0.056 μg/kg body weight and day. The estimated cancer risk for adults using low-dose linear extrapolation is1 per 100,000 per year.

Surfactants may cause dysfunction of intestinal tight junctions (TJs), which is a common feature of intestinal autoimmune diseases. Effects of dietary surfactants on TJ integrity, measured as trans-epithelial resistance (TEER), were studied in Caco-2 cell monolayers. Cytotoxicity was assessed as apical LDH leakage. Monolayers were apically exposed for 60 min to the dietary surfactants solanine and chaconine (SC, potato glycoalkaloids, 0–0.25 mM), perfluorooctane sulfonic acid (PFOS, industrial contaminant, 0–0.8 mM), and sucrose monolaurate (SML, food emulsifier E 473, 0–2.0 mM) separately and as a mixture. Dose-response modelling of TEER EC50 showed that SC were 2.7- and 12-fold more potent than PFOS and SML, respectively. The mixture was composed of 1 molar unit SC, 2.7 units PFOS and 12 units SML (“SC TEER equivalent” proportions 1:1:1). Mixture exposure (0–0.05 mM SC equivalents) dose-response modelling suggested additive action on TJ integrity. Increasing SC and SML concentrations caused increased LDH leakage, but PFOS decreased LDH leakage at intermediate exposure concentrations. In the mixture PFOS appeared to protect from extensive SC- and SML-induced LDH leakage. Complex mixtures of surfactants in food may act additively on intestinal TJ integrity, which should be considered in risk assessment of emulsifier authorisation for use in food production.

A typical EFSA approach to assess dietary exposure is to combine data from national consumption surveys with chemical occurrence data that have been pooled across the EU Member States (pooled approach). This approach was compared to the case where occurrence data were stratified by country and used for food categories where national data were abundant (semi-pooled approach), using cadmium as a case study. Some differences in estimated dietary exposure were observed between the pooled and semi-pooled approach. They were explained by differences, between the national and the European occurrence data, with respect to (1) contamination values and (2) sample proportions of food items classified in the food categories the assessment was based on. The latter aspect highlighted the sensitivity of the approach of directly aggregating monitoring data into food categories. Both the pooled and semi-pooled approach tended to be conservative relative to approaches used at national level. This appears to be attributed to differences in the way the available occurrence data is aggregated. Refinement of the studied methodologies would include a better separation of the food items with high concentration from those with low concentration.

The use of sensitive test systems makes it possible to detect weakly genotoxic chemicals and to better define the shape of dose-response relationships, which make it easier to interpret the mechanism behind possible effects. In this study we have refined the flow cytometer-based micronucleus assay by use of a cytometer equipped with two lasers. Since micronucleated young polychromatic erythrocytes, MNPCE, are very few in number among the cells in peripheral blood, about one or two out of 100,000 erythrocytes, there is always a risk that other cells, doublets or crystals, by mistake will be classified as a MNPCE. With immunomagnetic separation of the very youngest erythrocytes - which are transferrin-positive (Trf+Ret) - prior to analysis, we have obtained an almost pure (>98%) Trf+Ret-population. To clarify whether this separation of cells prior to analysis increases the sensitivity of the already sensitive and further refined flow cytometer-based micronucleus assay, we studied the dose-response towards benzo(a)pyrene, B[a]P in the low-dose region, 0-30mg/kgbw. Thirty FVB mice were intraperitoneally injected with B[a]P. From the same blood samples collected from these mice, cells were prepared in the two different ways and analyzed in the flow-cytometer equipped with two lasers. The lowest dose of B[a]P that can be reliably determined without being overwhelmed by the estimated error was about the same for the two methods, about 7mg/kgbw, i.e. the immunomagnetic separation did not increase the sensitivity. A second study with BalbC mice strengthens the result obtained with the FVB mice. Prior to the low-dose study the optimal sampling time for the two methods was determined. In this case, the water-solouble chemical acrylamide was used. The time courses obtained show almost the same shape of the curves, with a maximum of fMNPCE and fMNTrf+Ret at about 40-50h after exposure.

In this study, the cumulative margin of exposure (MOE) was estimated for a group of polychlorinated biphenyls (PCBs) based on reduction of hepatic retinoids as a mode-of-action relevant toxicological endpoint. The MOE was defined as the ratio between a reference dose, derived using the benchmark dose (BMD) approach, and the estimated human dietary PCB exposure. A distribution for the cumulative MOE was established, taking into account inter- and intra-individual variability as well as uncertainty in data measurements. The cumulative MOE reflected mainly the MOE for PCB 126; other PCB congeners had little contribution to the cumulative exposure and MOE. The median of the 0.1st percentile for the cumulative MOE was about 20 for women; depending on the percentile, cumulative MOE was 2–4 times higher for men compared to women. Furthermore, a relative potency factor (RPF) based approach was compared to an RPF-free approach for estimating the cumulative MOE. The RPF-free approach more completely accounts for variability and uncertainty but is more data intensive than the RPF-based approach, which can be more easily implemented in practice and allows for a use of historical data on RPFs. Consideration of the discussed approaches may contribute to improving cumulative health risk assessments.

The median dietary cadmium exposure for adults in Sweden is around 1 μg/kg/week and the upper 95th and 99th percentiles are 1.6-1.8 and 1.9-2.2 μg/kg/week, respectively. Potatoes and wheat flour were the most important food categories, contributing with 40-50% to the exposure. Differences in dietary patterns between high and low exposed individuals were observed; for high exposed individuals, seafood and spinach contributed with an exposure similar to that low exposed individuals received from potatoes and wheat flour. Consequences of differences in methodology used for exposure assessment are discussed. The median exposure is a factor 2 lower compared to that estimated by the European Food Safety Authority (EFSA). It is also a factor 1.4 lower compared to that of the assessment used for development of the EFSA tolerable weekly intake (TWI). The potential importance of this latter fact was addressed by adjusting the present assessment to that used for TWI derivation. While the percentage of the population exceeding the TWI was1% for the present data, it was around 3% for adjusted data, which is more in line with observations at the level of urinary cadmium. Scenario analysis was also performed to addresses the consequence of increasing/decreasing cadmium occurrence levels.

The benchmark dose (BMD) method has been recommended to replace the no-observed-adverse-effect-level (NOAEL) approach in health risk assessment of chemical substances. In the present article, developments in BMD analysis from continuous experimental data are proposed. The suggested approach defines the BMD as the dose at which the slope of the S-shaped dose-response relationship changes the most in the low-dose region. This dose resides in a region where the sensitivity to chemical exposure may start to change noticeably. It is shown that the response (defined as a percent change relative to the magnitude, or size, of response) corresponding to the dose where the slope changes the most depends on the geometrical shape of the dose-response curve; the response becomes lower as the curve becomes more asymmetrical and threshold-like in the low-dose region. Given a symmetrical case, described by the Hill function, the response associated with the critical dose level becomes 21% (defined as a percent change relative to the magnitude, or size, of response). According to a limiting case of asymmetry and threshold-like characteristics, reflected by a Gompertz curve, the response corresponding to the dose of interest becomes as low as 7.3% (defined as a percent change relative to the magnitude, or size, of response). Use of a response in the range of 5-10% when estimating the BMD conservatively accounts for uncertainties associated with the proposed strategy, and may be appropriate in a risk assessment point of view. The present investigation also indicated that a BMD defined according to the suggested procedure may be estimated more precisely relative to BMDs defined under other approaches for continuous data.