Guided group discussion and attitude change: The roles of normative and informational influence

Kurt Lewin and others have showed that group discussion effectively changed attitudes and behaviors compared to individually targeted messages. This study examines the roles of normative and informational social influence in this effect. High school students heard a message about replacing toxic products with nontoxic alternatives; classes were randomly assigned to hear the message delivered as a lecture or via guided group discussion. For female students (N=250 in 26 classes), HLM mediation analyses suggested normative influence predominated: Discussion was more effective than lecture and this effect was fully mediated by students’ perceptions that other students endorsed nontoxics. Content analyses of students’ comments indicated that three kinds of remarks led female students to this perception: (1) sharing knowledge about nontoxics; (2) asking questions about nontoxics; and (3) little praise for toxic products. For male students in separate HLM analyses (N=107 in 19 of the same classes), informational influence was most apparent: Postmeeting attitudes were higher after discussion than lecture, and this effect was partially mediated by cognitive elaboration about the message (but not perceptions others endorsed the message). In addition, males’ quiz grades were higher after discussion, and students’ comments fully mediated the discussion to quiz grades relationship. Results support the importance of hearing others’ promessage comments for changing socially motivated behaviors, although the routes of influence appear to differ for these samples of male and female students.     

Distribution of detoxifying genes polymorphism in Maharastrian population of central India

The present study is aimed at evaluating the genotype frequency of detoxifying genes such as GSTM1, GSTT1 and NQO1 in Maharastrian population of central India. The study revealed about 64.6% of GSTM1-positive and 35.4% GSTM1-null population. GSTT1-positive genotype was found to be 87.5% and GSTT1-null showed 12.5%. The NQO1 genotype of Maharastrian population showed 52.3% of C/C, 42.48% C/T and 5.18% T/T. The NQO1 of this population does not deviate from the expected Hardy-Weinberg equilibrium. The genotype frequencies GSTM1 and GSTT1 of the population when compared with other ethnic groups of Asia and Caucasians show distinct nature of Maharastrian population from other Asian and Caucasian population.     

Variation in sensitivity to cadmium among genetically characterized laboratory strains of the midge Chironomus riparius

Estimating the extent of intraspecific variation in sensitivity to contaminant exposure is important in order to explain variation in the outcome of toxicity tests and to predict the effects of chemical stress on natural populations of plants and animals. However, only few studies provide evident data concerning intraspecific variation in life-history traits caused by a differential response to chemical stress. In this study, we compared the life-history response of six laboratory strains of the midge Chironomus riparius to cadmium exposure in a full life-cycle assay. In addition, the level of genetic variation in all strains was measured at five variable microsatellite loci. Several significant differences in life-history traits among the strains were observed in controls and cadmium treatments. The extent of variation among strains was largest at moderate cadmium concentration (0.42 mg Cd/kg dw). At increased Cd concentrations all strains showed similar levels of high mortality and reduced reproductive success. All strains exhibited considerable levels of genetic impoverishment compared to field populations. Strains with low genetic variation showed reduced fitness in the controls and were more susceptible to Cd exposure. For instance, no reproductive success in the lowest Cd treatment was observed for the strain with the lowest level of genetic diversity. In contrast, this Cd concentration had no negative effects on life-history traits of more variable strains. These results confirm recent findings, that inbreeding and reduced genetic variation influence the reaction of populations towards environmental stress. In addition, we show that the level of genetic variation and inbreeding directly influences the outcome of toxicity tests and contributes to the lack of reproducibility of test results among laboratories.     

"Ni-struvite" - a new biomineral formed by a nickel resistant Streptomyces acidiscabies

Biomineralization dependent on bacterial activity has been described for struvite which is formed in soils, guano, putrescent matter and sediments. A new biomineral containing nickel instead of magnesium, Ni(NH4)(PO4) . 6H2O, has been identified. It was formed by nickel resistant Streptomyces acidiscabies E13, and putatively named nickel struvite. The mineral formation is dependent on biological activity since non-viable bacterial cells are not capable to induce formation of Ni-struvite under identical conditions. Formation of Ni-struvite was observed on colony surfaces upon prolonged incubation of solid minimal or complex media containing elevated concentrations of 8-15mM NiCl2. The formation of magnesium containing crystals was not observed although Mg2+ is present in the medium. However, the process was not depending on desiccation since small crystals attached to the mycelial biomass of the bacteria were observed microscopically also in liquid cultures of nickel supplemented minimal and complex media after two weeks of incubation. The capacity to induce biomineralization of a nickel containing mineral is postulated to constitute a resistance factor, allowing the soil bacterium to withstand high nickel concentrations. The strain shows nickel resistance as an adaption to its habitat, since this bacterium was isolated from a former uranium mining site in Eastern Thuringia, Germany, where nickel concentrations of up to 2000ppm (translating to appr. 30mM) occur as a result of former mining activities.     

Estimating the contribution of precursor compounds in consumer exposure to PFOS and PFOA

The exposure of humans to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) was quantified with emphasis on assessing the relative importance of metabolic transformation of precursor compounds. A Scenario-Based Risk Assessment (SceBRA) approach was used to model the exposure to these compounds from a variety of different pathways, the uptake into the human body and resulting daily doses. To capture the physiological and behavioral differences of age and gender, the exposure and resulting doses for seven consumer groups were calculated. The estimated chronic doses of a general population of an industrialized country range from 3.9 to 520 ng/(kg day) and 0.3 to 140 ng/(kg day) for PFOS and PFOA, respectively. The relative importance of precursor-based doses of PFOS and PFOA was estimated to be 2-5% and 2-8% in an intermediate scenario and 60-80% and 28-55% in a high-exposure scenario. This indicates that sub groups of the population may receive a substantial part of the PFOS and PFOA doses from precursor compounds, even though they are of low importance for the general population. Similar to a preceding study, uptake of perfluorinated acids from contaminated food and drinking water was identified as the most important pathway of exposure for the general population. The biotransformation yields of telomer-based precursors and to a lesser extent perfluorooctanesulfonylfluoride-based precursors were identified as influential parameters in the uncertainty analysis. Fast food consumption and fraction of food packaging paper treated with PFCs were influential parameters for determining the doses of PFOA.     

Messung und Quantifizierung von Mineralölkohlenwasserstoffen

Investigations concerning the measurement and evaluation of mineral oil hydrocarbons using Fourier-transform-infrared (FT/IR-)-spectroscopy,¹H-Nuclear magnetic resonance (¹H-NMR)-spectroscopy and Capillary gas chromatography — Flame ionisation detection (GC-FID) are presented. By means of various mineral oils and three certified reference materials (CRM) all tested methods were within a ±7%-range to the mineral oil nominal value and the 95% confidence intervals of the CRM’s, respectively. The GC-FID evaluation could be done without calibration using an relative response ratio of mineral oil to an internal standard (n-tetracontane). A¹H-NMR-method was developed for the quantitative determination of mineral oil hydrocarbons, successfully applied down to 0.2 mg/ml. Due to the determination limit achieved, the¹H-NMR-spectroscopy gain in importance as a reference method for the analysis of mineral oils.     

Degrading permafrost river catchments and their impact on Arctic Ocean nearshore processes

Arctic warming is causing ancient perennially frozen ground (permafrost) to thaw, resulting in ground collapse, and reshaping of landscapes. This threatens Arctic peoples'' infrastructure, cultural sites, and land-based natural resources. Terrestrial permafrost thaw and ongoing intensification of hydrological cycles also enhance the amount and alter the type of organic carbon (OC) delivered from land to Arctic nearshore environments. These changes may affect coastal processes, food web dynamics and marine resources on which many traditional ways of life rely. Here, we examine how future projected increases in runoff and permafrost thaw from two permafrost-dominated Siberian watersheds—the Kolyma and Lena, may alter carbon turnover rates and OC distributions through river networks. We demonstrate that the unique composition of terrestrial permafrost-derived OC can cause significant increases to aquatic carbon degradation rates (20 to 60% faster rates with 1% permafrost OC). We compile results on aquatic OC degradation and examine how strengthening Arctic hydrological cycles may increase the connectivity between terrestrial landscapes and receiving nearshore ecosystems, with potential ramifications for coastal carbon budgets and ecosystem structure. To address the future challenges Arctic coastal communities will face, we argue that it will become essential to consider how nearshore ecosystems will respond to changing coastal inputs and identify how these may affect the resiliency and availability of essential food resources.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01666-z.     

Octanol/water partition coefficients for environmentally important organic compounds

Partition coefficients P_O,w ⁽ⁱ⁾ describing the distribution of a solute i onto coexisting phases of 1-octanol and water are needed in a large variety of applications. They can be measured directly by HPLC as long as log P_O,w ⁽ⁱ⁾≧ 3.5. For more hydrophobic substances, several experimental procedures have been proposed in the literature. The reliability of those methods is questionable. Therefore, in the present work, P_O,w ⁽ⁱ⁾ is determined experimentally by three HPLC methods using reversed-phase HPLC [1]. Results from different procedures are compared critically. The method of Braumann [2] proved to be superior over the OECD-guidelines [3]. It was therefore applied to determine octanol/water partition coefficients for 23 substances at 25 °C. For eight of those substances (4-methylindole; 9-(hydroxymethyl)anthracene; N-ethylcarbazol; ethylcyclohexane; trans-2-octene; l,l-dimethyl-(ethy])cyclohexane; heptylbenzene; 4-dodecyl-l,3-benzenediol) no experimentally determined number for P_O,w ⁽ⁱ⁾ has been published before.