Risk assessment of chemicals and their mixtures are hindered by scarcity and inconsistencies between different environmental exposure limits.

In chemical risk assessment, measured or modelled environmental concentrations are compared to environmental exposure limits (EELs), such as Predicted No Effect Concentrations (PNECs) or hazardous concentrations for 5% of species (HC05s) derived from species sensitivity distributions (SSDs). However, for many chemicals the EELs include large uncertainties or, in the worst case, the necessary data for their estimation are completely missing. This makes the assessment of chemical risks and any subsequent implementation of management strategies challenging. In this study we analyzed the uncertainty of EELs and its impact on chemical risk assessment. First, we compared three individual EEL datasets, two primarily based on experimental data and one based on computational predictions. The comparison demonstrates large disagreements between EEL data sources, with experimentally derived EELs differing by more than seven orders of magnitude. In a case-study, based on the predicted emissions of 2005 chemicals, we showed that these uncertainties lead to significantly different risk assessment outcomes, including large differences in the magnitude of the total risk, risk driver identification, and the ranking of use categories as risk contributors. We also show that the large data-gaps in EEL datasets cannot be covered by commonly used computational approaches (QSARs). We conclude that an expanded framework for interpreting risk characterization outcomes is needed. We also argue that the large data-gaps present in ecotoxicological data need to be addressed in order to achieve the European zero pollution vision as the growing emphasis on ambient exposures will further increase the demand for accurate and well-established EELs.

Estimating the release of chemical substances from consumer products, textiles and pharmaceuticals to wastewater.

Chemical emissions from households originate from a wide range of sources and results in highly diverse mixtures. This makes traditional monitoring based on analytical chemistry challenging, especially for compounds that appear in low concentrations. We therefore developed a method for predicting emissions of chemicals from households into wastewater, relying on consumption patterns from multiple data sources. The method was then used to predict the emissions of chemical preparations, chemicals leaching from textiles and prescription pharmaceuticals in Sweden. In total we predicted emissions of 2007 chemicals with a combined emission of 62,659 tonnes per year - or 18 g/person and day. Of the emitted chemicals, 2.0% (w/w) were either classified as hazardous to the environment or were both persistent and mobile. We also show that chemical emissions come from a wide range of uses and that the total emission of any individual chemical is determined primarily by its use pattern, not by the total amount used. This emphasizes the need for continuous updates and additional knowledge generation both on emission factors and excretion rates as well as a need for improved reporting on the intended use of individual chemicals. Finally, we scrutinize the model and its uncertainty and suggest areas that need improvement to increase the accuracy of future emission modelling. We conclude that emission modelling can help guide environmental monitoring and provide input into management strategies aimed at reducing the environmental effect caused by hazardous chemicals.

Autoimmunity in Waldenström's macroglobulinaemia.

Fifty-seven consecutive patients with Waldenström's Macroglobuliemia were studied retrospectively for autoimmune manifestations. 28 patients or 51% (16 women and 13 men) had clinical and/or serological autoimmune manifestations, two or more of these being concomitant in 20 (12 women and 8 men). The predominant findings were Coombs' positive autoimmune hemolytic anemia (16%), seropositive rheumatoid arthritis (16%), inflammatory gastric ulcer with parietal cell autoantibodies (12%), and IgM-cardiolipin syndrome (11%). 40% of the autoimmune manifestations were present at the time of diagnosis of the Waldenström's Macroglobulinaemia and 60% were observed over a mean period of 4.7 years. All patients had an IgM M-component. There was no correlation between autoimmunity and the size of the M-component or the degree of hypo-IgG and hypo-IgA gammaglobulinemia. The only correlation between autoimmunity and infection was found in patients with gastric ulcer and parietal cell autoantibodies, in whom the infection was caused by Helicobacter pylori.

The effect of TBT on the structure of a marine sediment comunity--a Boxcosm study.

The effect of tri-n-butyl tin (TBT) on an intact marine sediment community after five months exposure was investigated. Changes in the structure of macro- and meiofauna communities were determined, as well as the functional diversity of the microbial community using BIOLOG microplates for Gram negative bacteria. Development of tolerance in the microbial community was investigated using Pollution Induced Community Tolerance (PICT) experiments with fluxes of nutrients as effect indicators. TBT affected the structure and recruitment of the macro- and meiofauna at nominal additions of 30-137 micromol TBT/m2 sediment. Number of species, diversity, biomass and community similarity was reduced at these concentrations compared to control. Species that molt seemed to be the most tolerant since they were predominant in boxes that had received the highest TBT addition and echinoderms were the most sensitive species. Renewed addition of TBT in PICT experiments with sediment from each boxcosm showed that TBT had an effect on individual nutrient fluxes from all sediments. Analyses of the flux patterns revealed a memory of previous TBT exposure, either due to induced tolerance or other community conditioning.

[Pseudolymphoma and ventricular maltoma in patients with chronic gastritis, ulcer and Helicobacter pylori infection]. / Pseudolymfom og ventrikelmaltom hos patienter med kronisk gastritis, ulcus og Helicobacter pylori-infektion.

Among 128 patients with malignant B-lymphoproliferative disorders, 19 patients had long lasting dyspepsia and gastroscopy showed chronic active gastritis or gastric ulcer. PCR analysis for TCR and IgH clonality in biopsies showed local involvement of the malignant lymphocyte clone in four patients out of eight indicating presence of these cells in the inflammatory infiltrate. Weak B-cell clonality was found in four patients. A close relationship was seen between lymphocytic clonality and immune response to H. pylori Cag A, and all patients had parietal cell antibodies. Thus, the malignant clone may participate in the local inflammatory reaction, and continued local stimulation by H. pylori as well as parietal cell antigens may lead both to autoimmunity as well as a clonal development of lymphocytes.