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Bioconcentration tests using the freshwater amphipod Hyalella azteca as an alternative to conventional fish tests have recently received much attention. An appropriate computational model of H. azteca could help in understanding the mechanisms behind bioconcentration, in comparison to the fish as test organism. We here present the first mechanistic model for H. azteca that considers the single diffusive processes in the gills and gut. The model matches with the experimental data from the literature quite well when appropriate physiological information is used. The implementation of facilitated transport was essential for modeling. Application of the model for superhydrophobic compounds revealed binding to organic matter and the resulting decrease in bioavailable fraction as the main reason for the observed counterintuitive decrease in uptake rate constants with increasing octanol/water partition coefficient. Furthermore, estimations of the time needed to reach steady state indicated that durations of more than a month could be needed for compounds with a log Kow > 8, limiting the experimental applicability of the test. In those cases, model-based bioconcentration predictions could be a preferable approach, which could be combined with in vitro biotransformation measurements. However, our sensitivity analysis showed that the uncertainty in determining the octanol/water partition coefficients is a strong source of error for superhydrophobic compounds.

The persistence assessment of organic chemicals is based on neutral reference substances. Therefore, our study aimed at investigating the influence of a chemical charge on the degradation of organic compounds in a water-sediment system (OECD 308) and surface water (OECD 309). We used radiolabelled 4-n-dodecylbenzenesulfonic acid sodium salt (

Chemosphere : chemistry, biology and toxicology as related to environmental problems 303(Part 1), 134885 (2022). doi:10.1016/j.chemosphere.2022.134885, Published by Elsevier Science, Amsterdam [u.a.]

Chemosphere : chemistry, biology and toxicology as related to environmental problems 232, 164-170 (2019). doi:10.1016/j.chemosphere.2019.05.038, Published by Elsevier Science, Amsterdam [u.a.]

Polysensitizations to tree, grass, and weed pollen are found in ~ 20% of pollen-allergic individuals. They are often based on broad IgE cross-reactivities to pollen panallergens belonging to highly conserved protein families: 1. profilins, 2. polcalcins (calcium-binding proteins in pollen), 3. cyclophilins. They represent highly conserved cross-reactive minor allergens present in all pollen species, but also in plant foods and other organisms. Despite being rarely clinically relevant they can hamper allergy diagnostic tests with extracts. In this situation, molecular allergy diagnosis is able to distinguish broad cross-reactivity due to allergen-specific IgE to pollen panallergens (i.e. profilins Bet v 2 or Phl p 12; polcalcins Bet v 4 or Phl p 7; and, in the future, cyclophilins Bet v 7 or Ole e 15) from primary IgE sensitizations to so-called marker allergens represented by important pollen major allergens: Bet v 1 for the birch and beech family (Fagales), Ole e 1 for olive and ash (Oleaceae), Phl p 1 for temperate climate grasses (Poaceae), Art v 1 for mugwort (Artemisia), Amb a 1 for Ambrosia species (Ambrosia). Five typical cases (A - E) with positive skin prick test results to tree, grass, and weed pollen extracts demonstrate typical patterns of IgE sensitization with a variable impact of pollen panallergens: A - profilins, B - polcalcins, C - profilins and polcalcins, D - presumably cyclophilins, E - primary polysensitization to tree, grass, and weed pollen without interference from profilins or polcalcins. Differences between pollen extract-based skin prick test diagnosis and molecular allergen-specific IgE testing are explained using the presented concept. This approach allows to reduce the number of allergen extracts - presuming they are also clinically relevant - for allergen immunotherapy (i.e., only tree and/or grass pollen extracts), particularly in pollen-polysensitized patients.

The influence of an ionic functional group on the fate and behavior of chemicals in the environment has so far not been systematically investigated. This study, therefore, examines the following three substances with high structural similarity but differing charge: non-charged 4-n-dodecylphenol[phenylring

The influence of an ionic functional group on the fate of chemicals in the environment, especially the formation of non-extractable residues (NER), has not been systematically investigated. Using 4-n-dodecylphenol[phenylring

Persistent organic substances can have harmful effects on humans and on the environment. Nationwide studies of organic substances on forest sites are scarce. Therefore, the sampling area of the second National Forest Soil Inventory (NFSI) with the BIOSOIL grid was used to investigate the contents, stocks, and spatial distribution of persistent organic substances in forest soils. The investigated substances were polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), dichlorodiphenyltrichloroethane and its metabolites (DDx), hexachlorobenzene (HCB), polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), and dioxin-like polychlorinated biphenyls (dl-PCB). To our knowledge, this is the first study to show stocks of organic substances in forest soils on a nationwide basis. The results showed that the organic substance stocks were not dependent on forest type for the investigated substances, except for PCB. This indicated that other factors than forest type explained the differences in total stock amounts across Germany, e.g. deposition or vicinity to emission sources. The content of the investigated organic substances in German forest soils seemed to be generally low. This was underpinned by the values of PAH and PCB, which were lower than the precaution values prescribed in German soil protection legislation (BBodSchV). However, soils store organic substances over long periods. Additionally, deposition of organic substances stemming from industrial sources might accumulate in soils in the future and become a problem. It is therefore recommended to find appropriate measures to reduce these depositions. Furthermore, soil samplings to study the development of organic substances contents under forest should be conducted. In this study, a greater share of the variance was explained with nonlinear regression compared to linear methods. It seems therefore reasonable to consider nonlinear trends in the evaluation of data from future studies. The outcome will improve models that forecast the distribution of organic substances in forest soils. Eventually, the results can contribute to further develop background, precaution, trigger, and action values in the German soil protection legislation.

The influence of an ionic functional group on the fate and behavior of chemicals in the environment has so far not been systematically investigated. This study, therefore, examines the following three substances with high structural similarity but differing charge: non-charged 4-n-dodecylphenol[phenylring-14C(U)] (14C-DP), negatively charged 4-n-dodecylbenzenesulfonicacid[phenylring-14C(U)] sodium salt (14C-DS−) and positively charged 4-n-dodecylbenzyltrimethylammonium chloride[phenylring-14C(U)] (14C-DA+). They were investigated in a soil simulation study according to the OECD 307 test guideline by measuring the distribution of the applied radioactivity (AR) among volatile, mineralized, extractable and non-extractable residues (NER) in one soil after 0, 1, 7, 14, 49, 84 and 124 days of incubation. Extractable portions of 14C were examined by means of radio-TLC and -HPLC analyses. Microbial activity of the soil incubated with and without 14C-DP, 14C-DS− and 14C-DA+ was determined measuring the reduction of dimethylsulfoxide (DMSO) over time. After 124 days of incubation highest mineralization could be observed for 14C-DS− (64.5% AR). Except CO2, no volatile residues were formed over time. Besides the parent compounds, polar (14C-DP, 14C-DS− and 14C-DA+) and nonpolar (14C-DA+) transformation products were detected. Highest amounts of 14C were extracted using methanol and were thus potentially bioavailable for soil microorganisms. Microbial activity was markedly higher in soil incubated with 14C-DP and 14C-DS− compared to 14C-DA+ or soil without any treatment. Half-lives (DT50 k2) at 18 °C were as follows: DA+ (61.8 days) > DS− (18.2 days) > DP (10.0 days). In case of the cationic compound and its transformation products we conclude that a higher sorption affinity to soil particles leads to reduced bioavailability for microorganisms and thus reduced mineralization resulting in a higher persistence compared to anionic and non-charged organic compounds in soil. The impact of our findings on the persistence assessment of chemicals when performing OECD guideline tests in soil, water-sediment and surface water is discussed.

Arsenate (As v ) is the predominant form of arsenic in soils under aerobic conditions and competes with the major plant nutrient phosphorus (P) in the form of phosphare (P v ) not only for sorption sites on mineral surfaces in soil but also for root membrane transporters. Plants have evolved several mechanisms for the mobilization of P v in soils in response to P deficiency, such as the release of organic anions and protons. The aim of the present study was to test whether these mechanisms result in a simultaneous mobilization of arsenate and what would be the consequences for As transfer from soil to plant. The compartment system approach with Zea mays as model crop was chosen as an experimental setup. The system is equipped with micro suction cups and allowed us to investigate processes occurring in the vicinity of roots. As a case study, an artificial quartz substrate with well defined soil physical properties was fertilized, spiked with As v , and amended with increasing amounts of goethite (0, 1, and 4 g kg -1 in treatments G-0, G-1, and G-4, respectively). The addition of goethite alleviated the As v -induced growth reduction and reduced As v transfer from the substrate to the plant but induced P deficiency at the same time. When low amounts of goethite (1 g kg -1 ) were added, plants mobilized P v but not As v , which might be related to differences in surface complexation reported for P v and As v . No mobilization of P v or As v was observed with the addition of higher amounts of goethite, probably because of decreasing competition between organicanions, P v , and As v for binding sites.